Bidentate organophosphorus ligands formed via P–N bond formation: synthesis and coordination chemistry

Coordination Chemistry Reviews 176 Ž1998. 451]481

Bidentate organophosphorus ligands formed via P]N bond formation: synthesis and coordination chemistry Tuan Q. Ly U , J.D. Woollins Department of Chemistry, Loughborough Uni¨ ersity, Leicestershire, Loughborough LE11 3TU, UK Received 3 March 1998; accepted 11 May 1998 Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. General introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. BisŽdiphenylphosphino.amine, Ph 2 PNHPPh 2 ŽDPPA. . . . . . . . . 3. Coordination chemistry of Ph 2 NHPŽE.Ph 2 ŽE s O, S, or Se. . . . . 4. Coordination chemistry of HNPŽE.R 2 42 ŽE s O, S, or Se. . . . . . 4.1. Group 5: V, Nb and Ta . . . . . . . . . . . . . . . . . . . . . . . 4.2. Group 6: Cr, Mo and W . . . . . . . . . . . . . . . . . . . . . . 4.3. Group 7: Mn, Tc and Re . . . . . . . . . . . . . . . . . . . . . . 4.4. Group 8: Fe, Ru and Os . . . . . . . . . . . . . . . . . . . . . . 4.5. Group 9: Co, Rh and Ir . . . . . . . . . . . . . . . . . . . . . . 4.6. Group 10: Ni, Pd and Pt . . . . . . . . . . . . . . . . . . . . . . 4.7. Group 11: Cu, Ag and Au . . . . . . . . . . . . . . . . . . . . . 4.8. Group 12: Zn, Cd and Hg . . . . . . . . . . . . . . . . . . . . . 4.9. Group 13: B, Al, Ga, In and Tl . . . . . . . . . . . . . . . . . . 4.10. Group 14: C, Si, Ge, SN and Pb . . . . . . . . . . . . . . . . . 4.11. Group 15: N, P, As, Sb and Bi . . . . . . . . . . . . . . . . . . 4.12. Group 15: O, S, Se, Te and Po . . . . . . . . . . . . . . . . . . 5. Diphenylphosphinyl ureas and thioureas . . . . . . . . . . . . . . . . X 6. Structure of RCŽE.NHPŽE .Ph 2 ŽE and E9 s O or S. . . . . . . . . 7. Coordination chemistry of diphenylphosphinyl ureas and thioureas 8. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. 451 . 452 . 452 . 453 . 456 . 458 . 459 . 459 . 460 . 460 . 461 . 461 . 461 . 461 . 462 . 464 . 464 . 466 . 467 . 472 . 478 . 478

Abstract This article outlines two related bidentate organophosphorus ligand systems prepared by phosphorus]nitrogen ŽP]N. bond formation } R 2 ŽE.PNHPR 2 , RCŽE.NHPR 2 ŽE s O, S, or Se. and their derivatives. The focus is on the extensive coordination chemistry exhibited U

Corresponding author.

0010-8545r98r$ - see front matter Q 1998 Elsevier Science S.A. All rights reserved. PII S0010-8545Ž98.00147-7

452

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

by these systems to transition metals. A brief description of the syntheses of the ligands and metal complexes is given. Q 1998 Elsevier Science S.A. All rights reserved. Keywords: Coordination; Organophosphorus; Phosphorus]nitrogen; Tranisition metal

1. General introduction Coordination chemistry contains numerous examples of bidentate ligands, which form ring closure through the donor atoms binding to the same metal. The most used ligands are those derived from that containing carbon, nitrogen, oxygen, phosphorus and sulphur atoms. Such chelates are widely used in catalysis, metal extraction, bioinorganic chemistry, tribology and many other fields. Heteroatom ligands containing a phosphorus]nitrogen bond have been known for over three decades. Phosphorus groups have been shown to form bonds with nitrogen groups with relative ease, and compounds containing phosphorous]nitrogen ŽP]N. bonds are chemically very stable. These facts make any investigation of ligands containing P]N bonds an interesting project.

2. Bis(diphenylphosphino)amine, Ph 2 PNHPPh 2 (DPPA) BisŽdiphenylphosphino.amine has generated much interest since its discovery. Numerous examples of derivatives and metal complexes have been prepared w1,2x. The condensation of hexamethyldisilazane with chlorodiphenylphosphine gives DPPA in good yield ŽEq. Ž1.. w3x. The P]N bonds are fused together, with the loss of trimethylsilyl chloride providing the thermodynamic driving force for the reaction.

Both phosphorusŽIII. atoms can be sequentially oxidised by selected chalcogen elements Ži.e. oxygen, sulphur or selenium. to make a range of possible ligands ŽScheme 1.. Double oxidation of DPPA gives another set of ligands, wPh 2 ŽE.NHPŽE.Ph 2 x ŽE s O, S or Se., that have shown an extensive coordination chemistry with numerous metals Žsee Section 4.. Imidodiphosphinates, wHN PŽS.Ph 2 4 2 x, were first synthesised by Schmidpeter et al. w4x. Later, the seleno wHN PŽSe.Ph 2 4 2 x analogue was prepared by oxidation of Ph 2 PNHPPh 2 ŽDPPA. with potassium selenocyanate followed by acidic work upw5x, or by direct reaction with grey selenium at reflux in toluene w6x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

453

Scheme 1. Heteroatom ligands derived from DPPA.

3. Coordination chemistry of Ph 2 NHP(E)Ph 2 (E s O, S or Se) Recently, the monosubstituted compounds of DPPA with oxygen, sulphur and selenium have been prepared by direct oxidation of one of the two phosphorusŽIII. groups with hydrogen peroxide, elemental sulphur and grey selenium, respectively. Monochalcogenides of DPPA, Ph 2 NHPŽE.Ph 2 ŽE s O, S or Se., have been shown to coordinate with a number of metals affording five-membered ring metallacycles of the generic structure MPNPE ŽFig. 1.. The coordination of these compounds can be described by two possible resonance structures, a neutral chelating ligand Ža. or a chelating anion with the loss of

Fig. 1. Coordination pattern of monochalcogenides of DPPA.

Scheme 2. Unidentate complexes of wPh 2 ŽO.PNHPPh 2 x with Rh, Ir, Pd, Pt and Au w9]11x.

454

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 2. The structures of cis-wMPh 2 PŽO.NPPh 2 42 x and wPdŽh 3-C 3 H 5 .Ph 2 PNPŽO.Ph 2 4x2 w12x.

Fig. 3. The structures of wMŽCOD.Ph 2 PŽO.NPPh 2 4xq and wMŽh 3 ]C 3 H 5 .Ph 2 PŽO.NPPh 2 4x ŽM s Pd or Pt. w12x.

the imido proton in the neutral chelate ring Žb.. Rossi et al. w7x have reported rhenium complexes with the neutral Ph 2 PŽO.NHPPh 2 and the deprotonated Ph 2 PŽO.NPPh 2 vy ligands from wAsPh 4 xwReOCl 4 x and Ph 2 PNHPPh 2 . A cobaltŽII. complex with both a chelating DPPA and a unidentate P-bound Ph 2 PŽO.NPPh 2 vy ligand has been prepared w8x. The neutral Ph 2 PŽO.NHPPh 2 ligand containing a hard and a soft donor, mostly acts as a unidentate compound with coordination through the phosphorusŽIII. atom } several examples involving RhI , Ir I , Pd II , Pt II and AuI are illustrated in Scheme 2. The ligands, when attached to a metal in a unidentate fashion, can subsequently be deprotonated by potassium tertbutoxide. Upon deprotonation the free oxygen atom may be coordinated to the same metal centre ŽM s Pd or Pt. or to a second metal, to form either P,O-chelate complexes or P,O-bridging complexes ŽFigs. 2 and 3.. Mono-oxidation of bisŽdiphenylphosphino.phenylamine with sulphur or selenium gives Ph 2 PŽE.NphPPh 2 ŽE s S or Se.. These compounds act as bidentate chelate ligands towards metal forming complexes of the type ŽCO.4 MŽL. ŽM s Mo or W., COŽCl.RhŽL. and Cl 2 MŽL. ŽM s Pt or Pd., where wL s Ph 2 PŽE.NPhPPh 2 ŽE s S or Se.x ŽScheme 3.. In wPt Ph 2 PŽSe.NHPPh 2 . 2 xCl 2 , the platinum centre has been shown to have a square-planar geometry from the coordination of two neutral Ph 2 PŽSe.NBPPh 2

Fig. 4. The structures of wPtPh 2 PŽSe.NHPPh 2 42 xCl 2 and wPtPh 2 PŽSe.NPPh 2 42 x w14x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

455

Scheme 3. Complexation of Ph 2 ŽE.PNPhPPh 2 with Mo, W, Rh, Pd and Pt w13x.

Fig. 5. The structure of NawŽPhO. 2 ŽO.PNPŽO.ŽOPh. 2 x with two bridging chelates at the front, and the back omitted for clarity w15x.

456

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 6. The structure of NawPh 2 ŽO.PNPŽS.Ph 2 x ? 2THF with carbon atoms of THF omitted for clarity w16x.

ligands arranged in the trans]bis configuration. However, the ligand has been shown to coordinate to a platinum in the cis configuration in its deprotonated form ŽFig. 4.. The bond lengths of the anionic chelates are shorter, with the exception of P]E which is longer than that in wPt Ph 2 PŽSe.NHPPh 2 4 2 xCl 2 . These differences support the notion of partial delocalisation within the chelate ring, as illustrated in Fig. 4. 4. Coordination chemistry of HN{P(E)R 2 }2 (E s O, S or Se) Salts of the imidophosphinate, wR 2 PŽE.NPŽE9.R 2 4 2 xy, often display cross-coordination, resulting in interesting three-dimensional Ž3D. structures. In the 3D cluster core wNa 6 O 12 xq, the complexation is accomplished by long Na ??? O5P interactions ˚ . in a hexameric form ŽFig. 5.. The salt of the ligand with mixed donor Ž2.23]2.50 A atoms, NawPh 2 ŽO.PNPŽS.Ph 2 x, displays a dimeric structure with two tetrahydro-

Fig. 7. The structures of KwNPŽS.Ph 2 42 x w17x and wKŽ18-crown-6.xq wNPŽS.Ph 2 42 xy w18x.

Fig. 8. The structures of wNŽPPh 3 . 2 x wNPŽS.Ph 2 42 x w19x and wTePh 3 xq wNPŽS.Ph 2 42 xy w20x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

457

furan molecules completing the coordination sphere ŽFig. 6.. The P]O distance is similar to that in wPh 2 ŽO.PNHPŽS.Ph 2 x, but the P]S bond is lengthened ˚ x, whilst the P]N bonds have contracted w1.577Ž9. and 1.606Ž9. w1.925Ž14. ]1.979Ž4. A ˚ x. from 1.694Ž4., and 1.668Ž5. A Salts of the imidothiophosphinate, wN PŽS.Ph 2 4 2 xy, with four cations, Kq, wKŽ18crown-6.xq, wNŽPPh 3 . 2 xq and wTePh 3 xq, have revealed interesting structural configurations. In the potassium salt, the structural feature of the anion is much like a chelating ligand, with long-range interactions linking the potassium atoms in a zigzag fashion ŽFig. 7.. The wKŽ18-crown-6.xq Ž1,4,7,10,13,16-hexaoxacyclooctadecane. cation shows no interaction with the anion, and it has adopted a syn orientation ŽFig. 7.. The organic salt, wNŽPPh 3 . 2 xq, revealed an unusual linear P]N]P w180.0Ž1.8x in the anion, that is rationalised in terms of double bond character in the P]N bonds ŽFig. 8.. No cation]anion interactions were found. The molecular structure of wTePh 3 xwN PŽS.Ph 2 4 2 x displays weak cation]anion Te ??? S ˚ x. The P]S bonds are in the syn conforsecondary interactions w3.264 and 3.451 A mation with close similarity to that seen in the wKŽ18-crown-6.xq salt ŽFig. 8.. The KwN PŽSe.Ph 2 4 2 x salt has an angular P]N]P bond and forms a ladder structure similar to that in KwN PŽS.Ph 2 4 2 x. The coordination chemistry of wR 2 ŽE.PNPŽE9.R 2 xy has been widely investigated and reviewed w21,22x. Selected metal complexes with these ligands are discussed. The first substantial investigation into the coordination chemistry of wHN PŽS.Ph 2 4 2 x

Fig. 9. The structure of wVŽO.ŽPh 2 ŽO.P. 2 N42 x w24x.

Fig. 10. The structure of wMoXŽO.ŽPh 2 ŽO.P. 2 N42 x ŽX s Cl or O. w25x.

458

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 11. Molecular structure of wMoŽN3 S 2 .R 2 ŽO.PNPŽS.R 2 42 x ŽR s Ph or i Pr. w26x.

was reported in 1978 w23x. The typical preparation of metal complexes required the reactions at reflux, of a ligand or its salt, with a metal dihalide ŽEq. Ž2... No complexes of the imidodiphosphinates with the metals from group 2, 3 or 4 have been reported. 4.1. Group 5: V, Nb and Ta In wVŽO. Ph 2 ŽO.P. 2 N4 2 x, the metal is in the centre of a square-based pyramid with the rings nearly planar ŽFig. 9.. No complexes with niobium or tantalum have been structurally characterised.

Fig. 12. The structures of wMnŽCO.4ŽPh 2 ŽS.P. 2 N4x w27x and wMnŽPh 2 ŽS.P. 2 N42 x w28x.

Fig. 13. The structures of wReŽO.Cl 2 ŽPh 2 ŽO.P. 2 N4ŽPPh 3 .x, wReŽO.Cl 2 ŽPh 2 ŽS.P. 2 N4 ŽPPh 3 .x, wReOŽOEt.ŽPh 2 ŽS.P. 2 N42 x w29x and wReŽN.ClŽPh 2 ŽS.P. 2 N4ŽPPh 3 .x w30x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

459

4.2. Group 6: Cr, Mo and W The coordination geometry of the dioxygen complexes of molybdenum, wMoCIŽO.ŽPh 2 ŽO.P. 2 N4 2 x and wMoO 2ŽPh 2 ŽO.P. 2 N4 2 x, are both octahedral and have cis conformation ŽFig. 10.. In wMOŽN3 S 2 . R 2 ŽO.PNPŽS.R 2 4 2 x, molybdenumŽV. is at the centre of an octahedral coordination complex ŽFig. 11.. The oxygen donors lie trans to nitrogen in both compounds. 4.3. Group 7: Mn, Tc and Re The manganeseŽI. complex with one chelate ligand is arranged octahedrally, whilst the manganeseŽII. compound contains two chelate ligands in a tetrahedron geometry ŽFig. 12.. Rhenium has been subjected to coordination of the ligands with oxygen, sulphur and selenium donor groups. The molecular structures of four metal complexes are shown in Fig. 13. The upper two compounds are octahedrally coordinated with the oxo in the cis or trans Žwith respect to oxygen and sulphur.

Fig. 14. The structures of wFeŽMe 2 ŽS.P. 2 N42 x w31x and wFeŽPh 2 ŽO.P. 2 N43 x w32x.

Fig. 15. The structures of wCoŽMe 2 ŽS.P. 2 N42 x and wCoŽPh 2 ŽSe.P. 2 N42 x w33x.

Fig. 16. The structures of w Ni Ž Ph 2 Ž S . P . 2 N 4 2 x w 6,34,35 x , wNi i Pr 2 ŽS.P. 2 N42 x w38x and wNiPh 2 ŽS.PNPŽS.Me 2 42 x w39x.

w Ni Ž M e 2 Ž S . P . 2 N 4 2 x

w 36,37 x ,

460

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

conformation, depending on the donor groups on the chelate ligands. In wReOŽOEt.ŽPh 2 ŽS.P. 2 N4 2 x, the rhenium atom is octahedrally coordinated with the two chelate ligands lying trans to each other. The rhenium complex, wReŽN.ClŽPh 2 ŽS.P. 2 N4ŽPPh 3 .x, displays a square pyramid with the Re]N bond ˚ x. The structure of the compound with considered to be a triple bond w1.630Ž1. A selenium donor groups has yet to be determined. 4.4. Group 8: Fe, Ru and Os The ironŽII. complex with sulphur donor groups consists of two chelate ligands in a tetrahedral configuration. However, ironŽIII. complexes with oxygen donor groups displays an octahedral Tris-chelate geometry ŽFig. 14.. 4.5. Group 9: Co, Rh and Ir The cobaltŽII. complexes shown in Fig. 15 are both tetrahedral with sulphur and selenium donor groups.

Fig. 17. The structures of wPdŽPhO. 2 ŽS.PNPŽS.ŽOPh. 2 42 x w41x, wMŽ i Pr 2 ŽS.P. 2 N42 x ŽM s Pd or Pt4 ŽD. Cupertino, R. Keyte, A.M.Z. Slawin, D.J. Williams, J.D. Woollins, unpublished work. and wPdPh 2 ŽO.PNPŽSe.Ph 2 42 x ŽR s Ph or i Pr. w40x.

Fig. 18. The structures of wPtNPŽS.Ph 2 42 4ŽPEt 3 . 2 xq and wPtŽPhO. 2 ŽS.PNPŽS.ŽOPh. 2 4ŽPMe 3 . 2 xq w43x.

Fig. 19. The structures of wCuŽPPh 3 .ŽPh 2 ŽS.P. 2 N4x w44x and wCu 4ŽPh 2 ŽS.P. 2 N43 xq wCuCl 2 xy Žwith phenyls omitted for clarity. w45x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

461

4.6. Group 10: Ni, Pd and Pt The nickelŽII. complexes adopt tetrahedral geometry with symmetrical ligands. In wNiŽPh 2 ŽS.P. 2 N4 2 x, wNiŽMe 2 ŽS.P. 2 N4 2 x and wNiŽ i Pr 2 ŽS.P. 2 N4 2 x, the compounds display the tetrahedral configuration whilst the mixed R system wNi Ph 2 ŽS.PNPŽS.Me 2 4 2 x is square planar ŽFig. 16.. The palladium and platinum complexes wMŽPh 2 ŽE.P. 2 N4 2 x ŽE s S or Se. are all square planar, with the chelate rings in the pseudo-boat conformation ŽFig. 17.. The pseudo-boat conformation is also found in the chelate ring with mixed donor atoms coordinated to platinum wPtŽC 8 H 12 OMe. Ph 2 ŽO.PNPŽS.Ph 2 4 2 x w40x. The boat conformation of the chelate ring in wPt Ph 2 ŽS.PNPŽS.Ph 2 4ŽPEt 3 . 2 xq is rearranged to a chair conformation by putting an oxygen atom between the phenyl and the phosphorus groups, wPtŽPhO. 2 ŽS.PNPŽS.ŽOPh. 2 4 2 ŽPMe 3 . 2 xq ŽFig. 18.. 4.7. Group 11: Cu, Ag and Au The copperŽI. complex, wCuŽPPh 3 .ŽPh 2 ŽS.P. 2 N4x, displays a monocyclic structure with three atoms bound to the copper atom ŽFig. 19.. In wCu 4ŽPh 2 ŽS.P. 2 N4 3 xq wCuCl 2 xy, the third coordination of the copper atom is completed by bonding to another sulphur donor atom, in such a way that a small cluster of four copper atoms with three chelate ligands is formed ŽFig. 19.. The reaction of wHNŽPŽS.Ph 2 4 2 x with wAuCl 2 ŽTHT.x gives wAuCl 2ŽPh 2 ŽS.P. 2 N4x, with the loss of a proton. The gold atom is tetracoordinated in a square-planar configuration ŽFig. 20.. The Reaction of wHN PŽS.Ph 2 4 2 x with wAuR 2 Clx gives wAuR 2 ŽPh 2 ŽS.P. 2 N4x w47x. 4.8. Group 12: Zn, Cd and Hg ZincŽII. and cadmiumŽII. complexes with wHN PŽS. i Pr 2 4 2 x are isostructural in the tetrahedral configuration ŽFig. 21.. The geometry of the chelate rings is puckered with a pseudo-boat conformation. 4.9. Group 13: B, Al, Ga, In and Tl The thalliumŽIII. complex, wTlPh 2 ŽPh 2 ŽS.P. 2 N4x, is prepared by reacting

Fig. 20. The structure of wAuCl 2 ŽPh 2 ŽS.P. 2 N4x w46x.

462

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 21. The structure of wMŽ i Pr 2 ŽS.P. 2 N42 x ŽM s Zn or Cd. w38x.

Fig. 22. The structure of wTlPh 2 ŽPh 2 ŽS.P. 2 N4x w48x.

diphenylthalliumŽIII. bromide with KwN PŽS.Ph 2 4 2 x. The metal has a tetrahedral coordination ŽFig. 22.. 4.10. Group 14: C, Si, Ge, Sn and Pb This group is well represented, and is dominated by tin compounds that display coordination with oxygen, sulphur and selenium donor groups. The tin complexes with oxo ligands are illustrated in Fig. 23. When the ligand wHN PŽO.Ph 2 4 2 x is reacted with tinŽII. acetate, the resulting structure is a distorted trigonal bipyramid. The geometry at the tin atom suggests the presence of a lone pair of electrons at the vacant equatorial site ŽFig. 23.. In wSnI 2 ŽPh 2 ŽO.P. 2 N.4 2 x, the coordination at

Fig. 23. The structures of wSnŽPh 2 ŽO.P. 2 N42 x, wSnI 2 ŽPh 2 ŽO.P. 2 N42 x w49x and wSnŽ n Bu. 2 ŽPh 2 ŽO.P. 2 N42 x w50x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

463

Fig. 24. The structure of wSnR 2 Ph 2 PŽS.NPŽO.Ph 2 42 x ŽR s Me or Ph. w51x.

Fig. 25. The structure of wSnMe 2 ŽPh 2 ŽS.P. 2 N42 x w52x.

the tin atom is octahedral with the iodine atoms in the cis position. However, it is interesting to note with the substitution of the iodine atoms for n butyl groups, wSnŽ n Bu. 2 ŽPh 2 ŽO.P. 2 N4 2 x, the two chelate ligands formed in the trans position to each other. When one oxygen is replaced by a sulphur the planarity of the ME 2 P2 N ring ŽE s O or S. is lost and a boat conformation is observed ŽFig. 24.. It is interesting to note the isomer in which the sulphur and oxygen are trans to one another is preferred. This may be explained by the fact that the Sn]S and P]S bonds are ˚ longer than Sn]O and P]O bonds, and the Sn]O]P angle is generally 0.5 A almost 308 greater than the Sn]S]P angle. The trans geometry probably reduces steric hindrance and any ring strain. The dimethyltin complex with the thio chelate ligand, wSnMe 2 ŽPh 2 ŽS.P. 2 N4 2 x, has the tin atom in an octahedral configuration ŽFig. 25.. The chelate ligands approximate to a square planar geometry in a boat conformation. The selenium analogue exists in two forms: a distorted square Žtetragonal. pyramid with the MSe 2 P2 N ring adopting the boat conformation Žred crystals .; and a square planar complex with the MSe 2 P2 N ring adopting the chair conformation Žyellow crystals, Fig. 26.. The two isomers were recrystallised from the same yellow chloroformrhexane solution of SnwN PŽSe.Ph 2 4 2 x 2 , suggesting that the difference in energy between the two conformers is very little, The leadŽII. complex, wPbŽPh 2 ŽS.P. 2 N4 2 x, has two chelate ligands bound to the

Fig. 26. The structures of boat-wSnŽPh 2 ŽSe.P. 2 N42 x Žred crystals . and chair-wSnŽPh 2 ŽSe.P. 2 N42 x Žyellow crystals . w53x.

464

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 27. The structure of wPbŽPh 2 ŽS.P. 2 N42 x w54x.

Fig. 28. The structures of wSbPh 2 Cl 2 ŽPh 2 ŽO.P. 2 N4x, wSbPh 2 Cl 2 ŽPh 2 ŽS.PNPŽO.Ph 2 4x w55xŽE s 0 or S. and wBiŽPh 2 ŽS.P. 2 N43 x w56x.

lead atom. Close inspection of the structure revealed a pseudo octahedral coordination geometry with the interaction of two phenyl groups, from the ligands, completing the coordination sphere ŽFig. 27.. 4.11. Group 15: N, P, As, Sb and Bi In diphenylantimonyŽV. compound, wSbPh 2 Cl 2 ŽPh 2 ŽO.P. 2 N4x, the antimony atom is octahedrally coordinated with a monocyclic chelate ring. The oxo-thio analogue, wSbPh 2 Cl 2 Ph 2 ŽS.PNPŽO.Ph 2 4x, displays similar features with normal bond lengths ŽFig. 28.. The bismuthŽIII. complex, wBiŽPh 2 ŽS.P. 2 N4 3x, has three chelate ligands organised octahedrally around the bismuth atom ŽFig. 28.. 4.12. Group 15: O, S, Se, Te and Po The square planar complexes of wHN PŽS.Ph 2 4 2 x with selenium and tellurium

Fig. 29. The structures of wSeŽPh 2 ŽS.P. 2 N42 x w57x and wTeŽPh 2 ŽS.P. 2 N42 x w58x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

465

Scheme 4. Heteroatom ligands from selective oxidation of DPPA.

have been reported ŽFig. 29.. The SeS 2 P2 N ring is a slightly distorted chair as opposed to the TeS 2 P2 N ring, which is a near perfect chair conformation. The range of ligands derived from DPPA is numerous, and in some cases there are as many as four different atom types in the chelate skeletal Že.g. wPh 2 ŽSe.PNHPŽO.Ph 2 x, wPh 2 ŽSe.PNHPŽS.Ph 2 x and wPh 2 ŽS.PNHPŽO.Ph 2 x shown in Scheme 4.. Compared with the extensive research on DPPA and its derivatives, less research has been carried out on phosphorusŽIII. systems such as diphenylphos-

466

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Scheme 5. Synthesis of Ph 2 PŽS.NHCŽE.R9.

phino thioureas, Ph 2 PNHCŽS.R ŽDPPTs.. The DPPTs systems can be oxidised to form diphenylthiophosphinyl thioureas Ph 2 PŽS.NHCŽS.R ŽDPTPTs. and related compounds. 5. Diphenylphosphinyl ureas and thioureas Diphenylphosphinyl thioureas, Ph 2 PŽO.NHCŽS.R, have been prepared from the reaction of phosphoroisothiocyanatidates with amines ŽEq. Ž3.. w59]61x. The reac-

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

467

tion proceeds by nucleophilic amine-attack upon the carbon atom of the isothiocyanate, followed by the loss of a proton to the nitrogen of the isothiocyanate at room temperature. The choice of oxygen and sulphur donor atoms in the ligands can be changed by manipulating the starting material } see Eq. Ž4.. The synthesis of the ligands with sulphur donors, such as diphenylthiophosphinyl thioureas ŽDPTPT., in quantitative yields, was reported by the addition of amines to the isothiocyanate group ŽEq. Ž3..w62]67x. The compounds can also be prepared by clipping the metallated acid amides together with acid chlorides or chlorophosphine w68x ŽScheme 5.. The reactions proceed via P]N bond formation the two reagents } the driving force in these reactions is the formation of sodium chloride. Another route for synthesising these compounds was investigated by SchmutzIer et al. w69x, who used the condensation of silylated ureas and thioureas with chlorophosphines, followed by direct oxidation with sulphur or selenium ŽEqs. Ž5. ] Ž7... One advantage of this synthetic method is that the phosphorus group can be selectively oxidised by oxygen, sulphur or selenium, in a similar fashion to the chemistry of DPPA Že.g. Scheme 4.. Woollins et al. w70x later prepared this ligand system at a faster rate, with the introduction of a catalyst, 4-dimethylaminopyridine. The resulting phosphorusŽIII. intermediate can then be oxidised selectively with the desired chalcogenides Žoxygen, sulphur or selenium; Eq. Ž8... 6. Structure of RC(E)NHP(E9)Ph 2 (E and E9 s O or S) DPTPT, closely related to Ph 2 ŽE.PNHPŽS.Ph 2 ŽE s O or S., can exist in three possible tautomeric forms ŽScheme 6.. Infrared and NMR spectroscopy suggest the compound is in the imido form. X-ray studies of R 2 ŽE.PNHCŽE.R9 ŽE s O or S. established that this system is predominantly in the imido form and is well represented by many examples. Selected bond lengths and angles of the compounds to follow are listed in Table 1. Single crystal X-ray diffraction studies of wPhCŽO.NHPŽO.PhŽOMe.x, indicate the oxygen atoms are arranged in the anti orientation ŽFig. 30.. The phosphoryl and imido groups are syn coplanar, whilst the carbonyl and imido are anti coplanar. The phosphoryl oxygen and the imido hydrogen are involved in an inter-

468

˚ . and angles Ž8. of RCŽE.NHPŽE9.R9 Selected bond lengths ŽA Compound

POŽS.

PN

NC

COŽS.

PNC

Ref.

wPhCŽO.NHPŽO.PhŽOMe.x wPhŽMe.NCŽO.NHPŽO.ŽOPh.2 x wMeCŽO.NHPŽO.ŽOMe.ŽSMe.x wPhCŽS.NHPŽO.ŽOi Pr.2 x wPh2 PCŽS.NHPŽO.ŽOPh.2 x wPhHNCŽS.NHPŽO.ŽNHi Pr.ŽNŽC2 H4 Cl.2 4x wPhCŽO.NHPŽS.Ph2 x wPhŽMc.NCŽS.NHPŽS.ŽOPh.2 x wPhCŽS.NHPŽS.ŽOi Pr.2 x wŽPhO.2 PŽO.NHCŽO.NHCŽO.NŽn Pr.2 x wPh2 ŽS.PNHCŽO.NBPŽS.Ph2 x

1.469Ž5. 1.462Ž4. 1.463Ž3. 1.457Ž1. 1.460Ž1. 1.493Ž4. 1.941Ž6. 1.895Ž2. 1.912Ž1. 1.445Ž2. 1.931Ž1. 1.942Ž1.

1.673Ž6. 1.646Ž5. 1.641Ž4. 1.672Ž1. 1.658Ž2. 1.694Ž4. 1.720Ž1. 1.671Ž3. 1.686Ž3. 1.646Ž3. 1.702Ž2. 1.686Ž2.

1.393Ž8. 1.406Ž8. 1.365Ž5. 1.360Ž2. 1.372Ž2. 1.376Ž6. 1.360Ž2. 1.378Ž6. 1.354Ž5. 1.370Ž4. 1.367Ž3. 1.379Ž3.

1.216Ž8. 1.213Ž7. 1.219Ž4. 1.646Ž1. 1.637Ž2. 1.670Ž6. 1.220Ž2. 1.664Ž3. 1.635Ž4. 1.211Ž4. 1.219Ž3. }

122.0Ž4. 125.6Ž4. 123.9Ž3. 127.9Ž9. 130.5Ž1. 129.5Ž4. 120Ž1. 127.5Ž2. } 128.1Ž2. 121.8Ž2. 134.6Ž2.

w71x w72x w73x w74x w75x w76x w70x w72x w85x w86x w87x

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Table 1

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

469

Scheme 6. Tautomeric structures of diphenylthiophosphinyl urea and thiourea ŽE s O or S..

molecular hydrogen bond to an adjacent molecule in a dimer formation. In wPhŽMe.NCŽO.NIHPŽO.ŽOPh. 2 x, the molecules display isostructural arrangement to the above compound with a similar hydrogen-bonding interaction ŽFig. 30.. Interestingly, a similar compound, wMeCŽO.NHPŽO.ŽSMe.OMex, was found to have the two oxygen atoms arranged in the syn orientation ŽFig. 30.. There are intermolecular P5O ??? H]N hydrogen bonds in the crystal structure of this compound, but instead of seeing a dimer, a chain like arrangement was found. This system containing mixed donor atoms e.g. wPhCŽS.NHPŽO.ŽO i Pr. 2 x, has the phosphoryl oxygen atom in the anti orientation relative to the thiocarbonyl group. The molecules are arranged as dimers Žback-to-back. formed by intermolecular P5O ??? H]N hydrogen bonds between two adjacent molecules ŽFig. 31.. However, the structure of wPhHNCŽS.NHPŽO.ŽNH i Pr. ŽNŽC 2 H 4 Cl. 2 4x demonstrates a very different configuration } the molecules are arranged in the anti orientation with the phosphoryl and imido groups are anti coplanar, whilst the thiocarbonyl and imido are syn coplanar. The intramolecular hydrogen bond between the phosphoryl oxygen and the amino hydrogen forms a ring closure to give a pseudo six-membered ring ŽFig. 31..

Fig. 30. The structures of wPhCŽO.NHPŽO.PhŽOMe.x Žchiral. w71x, wPhŽMe.NCŽO.NHPŽO.ŽOPh. 2 x w72x and wMeCŽO.NHPŽO.ŽSMe.OMex Žchiral. w73x.

Fig. 31. The structures of wPhCŽS.NHPŽO.ŽO i Pr. 2 x w74x, wPh 2 PCŽS.NHPŽO.ŽOPh. 2 x w75x and wPhHNCŽS.NHPŽO.ŽNH i Pr. ŽNŽC 2 H 4 Cl. 2 4x ŽR5NH i Pr,R95NŽC 2 H 4 Cl. 2 . w76x.

470

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 32. Molecular structure of wPhCŽO.NHPŽS.Ph 2 x w70x.

In wPhCŽO.NHPŽS.Ph 2 x, the X-ray structure shows the compound is in the keto form ŽFig. 32.. However, the chalcogen groups lie in the syn orientation whilst the compounds above have them in the anti orientation. The structure of the disulphide analogue, wPhŽMe.NCŽS.NHPŽS.ŽOPh. 2 x, shows the compound is in the keto form, with the proton bonded to the nitrogen and not to either sulphur atoms ŽFig. 33.. It is best described as Z, Z9 with absolute values of torsion angles w v 1ŽS1]C1]N1]P1.x s 5.18 and w v 2 ŽC1]N1]P1]S2.x s 55.08. In wPhCŽS.NHPŽS.ŽO i Pr. 2 x, a similar syn orientation was found ŽFig. 33.. The P]S ˚ . is amongst the shortest bond length in wPhŽMe.NCŽS.NHPŽS.ŽOPh. 2 x Ž1.895Ž2. A ˚ . w77x, for a P5S bond } comparable lengths are found in w b-P4 S 7 x Ž1.890 A i i ˚ wŽ PrO. 2 PŽS.SSŽS.PŽO Pr. 2 x Ž1.890 A.w78x, wŽMeO. 2 PŽS.SSŽS.PŽOMe. 2 x Ž1.898 and ˚ . w79x, wŽPhO. 2 PŽS.SSŽS.PŽOPh. 2 x Ž1.898 and 1.900 A ˚ . w80,81x, ŽPhS. 3 P5Sx 1.903 A ˚ . w82x, w1,3,5- t Bu 3 C 6 H 2 PŽ5S. 2 x Ž1.890, 1.891 A ˚ . w83x and w1-Me,3,5Ž1.899 A t ˚ . w84x. The C]S bond length in thiourea comBu 2 C 6 H 2 PŽ5S. 2 x Ž1.894, 1.900 A pounds is generally longer than that in benzamide compounds ŽTable 1.. This is probably due to some distribution of the p-bond in the C5S bond to the adjacent nitrogen atoms, which would account for the contraction of the C]N bonds } in particular the C]NŽR,R9. bond as oppose to the C]NH bond. In wŽPhO. 2 PŽO.NHCŽO.NHCŽO.NŽ n Pr. 2 x, the phosphinyl group, attached to a biuret backbone, exists in the anti orientation relative to the central carbonyl group ŽFig. 34.. Strong inter and intramolecular hydrogen bonding between the amine protons and the carbonyl groups are responsible for the anti, anti orientation. The end carbonyl group is positioned syn coplanar to the second imido group, and a ring closure influenced by an intramolecular hydrogen bond is formed.

Fig. 33. The structures of wPhŽMe.NCŽS.NHPŽS.ŽOPh. 2 x w72x and wPhCŽS.NHPŽS.ŽO i Pr. 2 x w85x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

471

Fig. 34. The structure of wŽPhO. 2 PŽO.NHCŽO.NHCŽO.NŽ n Pr. 2 x w86x.

Fig. 35. The structure of wPh 2 ŽS.PNHCŽO.NHPŽS.Ph 2 x w87x.

The solid state structure of wPh 2 ŽS.PNHCŽO.NHPŽS.Ph 2 x has one P5S group lying in a syn orientation relative to the central C5O, whilst the other P5S group is in the anti orientation ŽFig. 35.. The syn coplanarity between one P5S group and an imido group is influenced by an intramolecular hydrogen bond formed by those two groups. Further, the molecules are inverted, which can be described as dimer pairs resulting from intermolecular hydrogen bond interactions between the central carbonyl group and the syn coplanar imido to the adjacent molecule. Interestingly, the X-ray structure of the phosphorusŽIII. analogue, wPh 2 PNHCŽS.

Fig. 36. Molecular structure of wPh 2 PNHCŽS.NHPPh 2 x ? Me 2 SO w87x.

472

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 37. Coordination patterns of diphenylthiophosphinyl thioureas.

NHP-Ph 2 x, has the PNCŽS.NP section planar. Intermolecular hydrogen bonding to dimethyl sulphoxide may be a contributing factor for the syn, syn orientation ŽFig. 36.. 7. Coordination chemistry of diphenylthiophosphinyl ureas and thioureas These ligands can form cyclic structures with a metal, either as the neutral ligand or in the deprotonated form ŽFig. 37.. The coordination of the deprotonated ligands can take two possible patterns } delocalised or localised bonding wpattern Žd. and Že. in Fig. 37, respectivelyx. When the interatomic distances are between single and double bonds then the delocalised pattern is used. Selected bond lengths and angles of the compounds to follow are listed in Table 2. The potassium salt of this system with mixed chalcogen donor atoms, KwPhCŽO.NPŽS.Ph 2 x, displays a dimeric structure ŽFig. 38.. Close analysis of the coordination of potassium revealed that both atoms are octahedrally bound; three oxygen, two sulphur and a p interaction from a phenyl group. The manner of dimerisation is accomplished by an anti arrangement, with cross coordination from oxygen and sulphur atoms. Each potassium atom is bound in a distorted octahedral sphere by three oxygen, two sulphur and a p-bond from a nearby phenyl group.

Fig. 38. Molecular structure of KwPhCŽO.NPŽS.Ph 2 x2 ? 2CH 3 OH w70x.

˚ . and angles Ž8. of MRCŽE.NPŽE9.R92 4x ŽM s K, Ni, Pt, Cu, Hg, Pb, or Sm; E and E9 s O or S. Selected bond lengths ŽA Compound

MOŽS.

MOŽS.

POŽS.

PN

NC

COŽS.

PNC

Ref.

KwPhCŽO.NPŽS.Ph2 x2 ? 2CH3 OH wNiŽn Pr.2 NCŽS.NPŽS.ŽOph.2 42 x wNiMeHNCŽS.NPŽS.Ph2 42 x wPtH2 NCŽS.NPŽS.Ph2 4 H2 NCŽS.NHPŽS.Ph2 4xq Cly wPtH2 NCŽS.NPŽS.Ph2 42 x wCuŽPhO.2 PŽS.NCŽS.NŽEt.2 x3

2.667Ž3. 2.226Ž1. 2.216Ž3. 2.33Ž1. 2.31Ž1. 2.321Ž4. 2.249Ž2. 2.263Ž2. 2.275Ž2. 2.553Ž3. 2.548Ž3. 2.703Ž2. 2.703Ž2. 2.394Ž4. 2.398Ž5. 2.398Ž5.

3.244Ž2. 2.205Ž1. 2.214Ž4. 2.312Ž9. 2.315Ž9. 2.313Ž4. 2.220Ž2. 2.230Ž2. 2.224Ž2. 2.470Ž3. 2.474Ž4. 2.488Ž5. 2.417Ž5. 2.532Ž4. 2.543Ž4. 2.528Ž4.

1.951Ž2. 1.978Ž1. 2.016Ž5. 1.97Ž1. 1.98Ž1. 1.986Ž7. 1.965Ž2. 1.958Ž2. 1.957Ž2. 1.980Ž4. 1.981Ž4. 1.492Ž50 1.470Ž6. 1.455Ž4. 1.465Ž4. 1.459Ž5.

1.617Ž4. 1.574Ž3. 1.610Ž9. 1.68Ž3. 1.59Ž3. 1.62Ž1. 1.581Ž5. 1.571Ž5. 1.596Ž5. 1.610Ž9. 1.618Ž9. 1.634Ž6. 1.630Ž7. 1.663Ž5. 1.655Ž6. 1.655Ž6.

1.333Ž6. 1.321Ž4. 1.294Ž14. 1.37Ž4. 1.34Ž4. 1.34Ž2. 1.309Ž6. 1.313Ž7. 1.312Ž7. 1.286Ž13. 1.290Ž13. 1.268Ž1. 1.294Ž1. 1.366Ž8. 1.365Ž10. 1.343Ž10.

1.243Ž5. 1.745Ž4. 1.760Ž9. 1.78Ž3. 1.73Ž4. 1.71Ž2. 1.785Ž5. 1.776Ž6. 1.768Ž5. 1.733Ž11. 1.726Ž2. 1.740Ž8. 1.741Ž8. 1.211Ž6. 1.205Ž7. 1.223Ž8.

119.5Ž3. 127.5Ž3. 125.6Ž6. 130Ž2. 129Ž3. 128Ž1. 135.9Ž4. 131.1Ž4. 129.5Ž4. 133.1Ž8. 131.8Ž8. 125.0Ž6. 127.7Ž6. 127.5Ž4. 125.9Ž5. 127.3Ž5.

w70x w87x w88x w70x } w70x w89x } } w90x } w74x } w91x } }

wHgPhCŽS.NPŽS.ŽOi Pr.2 42 x wPbPhCŽS.NPŽO.ŽOi Pr.2 42 x wSmŽEtO.2 PŽO.NHCŽO.NHCŽO.Phx3

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Table 2

473

474

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

DPTPT demonstrates a similar coordinative versatility to its carbon free analogue. The first substantial investigation into the coordination chemistry of diphenylthiophosphinyl thioureas was reported by Ojima et al. w62,63x. The compounds behave as bidentate ligands and have been shown to form a number of metals complexes. Typical coordination chemistry of these ligands is with direct reaction to MX 2 ŽM s Co, Ni, Cu or Pd; X s Cl. at room temperature ŽEq. Ž9... Interestingly, these reactions proceed at room temperature, compared with wPh 2 ŽS.PNHPŽS.Ph 2 x which requires heating at reflux.

The nickelŽII. and palladiumŽII. complexes containing this ligand system are square planar, while the complex containing cobalt is tetrahedral. Ojima et al. proposed that some diphenylphosphinothioylthioureato metalŽII. complexes have a chelate structure containing five different atoms } C, N, P, 2S and MŽII. } in their six-membered ring metallacycles. The structure of the nickelŽII. complex was later established by Iwamoto et al. from X-ray studies ŽFig. 39.. The nickel atom is bound to sulphur donors of the ligands in a square planar trans configuration. The ˚ x. expansion of the P]S and the C]S bonds are observed w2.016Ž9. and 1.760Ž9. A ˚ x. w Ž . Ž . The P]N and the N]C bonds are contracted 1.610 9 and 1.294 14 A These changes in the chelating ligands are similar to those observed with the imidophosphinate ligands. The structure of a similar nickel complex, wNiŽPhO. 2 PŽS.NCŽS.NŽ n Pr. 2 4 2 w87x, also displays a square planar geometry. The ˚ x; the P]N and the N]C P]S and the C]S are shorter w1.978Ž1. and 1.745Ž4. A ˚ Ž . Ž . bonds are observed at 1.574 3 and 1.321 4 A.

Fig. 39. Molecular structure of wNiMeHNCŽS.NPŽS.Ph 2 42 x w88x.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

475

Fig. 40. Molecular structure of wPtH 2 NCŽS.NPŽS.Ph 2 4ŽH 2 NCŽS.NHPŽS.Ph 2 4xq Cly w70x.

The platinum complex, wPt H 2 NCŽS.NPŽS.Ph 2 4 ŽH 2 NCŽS.NHPŽS.Ph 2 4xq Cly, was prepared by the reacting wPtCl 2 ŽCOD.x with 2wH 2 NCŽS.NHPŽS.Ph 2 x. Its X-ray structure revealed the chelates are arranged in the trans orientation around platinum ŽFig. 40.. One chelate is deprotonated and displays a contraction of the chelate backbone wSPNCSx with respect to its protonated counterpart. The neutral platinum complex containing this ligand system is achieved reacting wPtCl 2 ŽCOD.x with two equivalents of KwH 2 NCŽS.NPŽS.Ph 2 x to give

Fig. 41. Molecular structure of wPtH 2 NCŽS.NPŽS.Ph 2 42 x ? ŽEt 2 O. w70x.

Fig. 42. Molecular structure of wCuŽPhO. 2 PŽS.NCŽS.NŽEt. 2 x 3 ŽEt and Ph omitted for clarity. w89x.

476

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

wPt H 2 NCŽS.NPŽS.Ph 2 4 2 x. However, the X-ray structure of this complex shows the chelates are arranged in the cis orientation ŽFig. 41.. The metal complex, wCuŽPhO. 2 PŽS.NCŽS.NŽEt. 2 x 3 , was formed by a reduction of copperŽII. to copperŽI. with wŽEt. 2 NCŽS.NHPŽS.ŽOPh. 2 x in the presence of ethanol ŽEq. Ž10... It contains a ligand coordinated to a copper atom, with further coordination to an adjacent copper atom from the thiocarbonyl sulphur ŽFig. 42.. There are three metal complexes localised by second-order coordination, where the central part of the collective complexes displays Cu 3 S 3 in a chair conformation. The Cu]S Žphosphoryl. bond is longer than the Cu]S Žthiocarbonyl. bond, but it is comparable with Cu]S from the adjacent thiocarbonyl group wŽaverage. 2.626, ˚ respectivelyx. 2.225 and 2.260 A, q Cuq 2 q 2HL | CuL 2 q 2H

6CuL 2 q 3CH 3 OH | 2 Ž CuL . 3 q 3CH 3 CHO q 6HL

Ž 10 .

The mercury complexes, wHgŽRCŽX.NPŽY.ŽOR9. 2 4 2 x, are prepared from direct reaction of the ligand RCŽX.NPŽY.ŽOR9. 2 with mercuryŽII. oxide in an organic solvent at reflux ŽEq. Ž11... No reaction was observed when the ligand does not contain at least a sulphur donor atom. In the unit cell of the complex with N-Ždiisopropoxyphosphinothioyl.thiobenzamide, the mercury atom is in a tetrahedral coordination as a result of 4S atoms from two symmetrically independent

Fig. 43. Molecular structure of wHgPhCŽS.NPŽS.ŽO i Pr. 2 42 x w90x.

ligands ŽFig. 43.. All four Hg]S bonds in the complex have a covalent character, in which the Hg]S bonds from the thiocarbonyl group are shorter than the Hg]S

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

477

˚ x. The C]S and the P]S bonds from the phosphoryl group wlengths 2.470]2.553 A ˚ ˚ x in the w Ž . x bonds are longer than the C5S bond 1.635 4 A and the P5S w1.912Ž1. A free ligand. All the bond lengths in one chelate ring are closely matched in the other. R5Ph, R5 i Pr, X5Y5S; R5Me, R95 i Pr, X5Y5S; R5Ph, R95Et, X5S, Y5O; R5Ph, R95 i Pr, X5S, Y5O; R5Ph, R95 i Pr, X5O, Y5S. The leadŽII. complexes of N-diisopropoxyphosphorylthiobenzamide and N-diisopropoxythiophosphorylthiobenzamide, w Pb  PhC Ž S . NP Ž O .Ž O i Pr . 2 4 2 x and wPbŽPhCŽS.NPŽS.ŽO i Pr. 2 4 2 x, are prepared by direct reaction of the ligands with lead oxides in CCl 4 , or by reacting lead nitrate with the sodium salt of the ligands in methanol. The coordination pattern in wPb PhCŽS.NPŽO.ŽO i Pr. 2 4 2 x has a distorted tetrahedral structure with bonding from oxygen and sulphur of the two chelating ligands ŽFig. 44.. This metalla-heterocycle is a rare example of a compound containing six different atoms in a six-membered ring. The Samarium Complex, wSmŽEtO. 2 PŽO.NHCŽO.NHCŽO.Phx 3 ŽClO4 . 3 ? 3H 2 O, was found to be a nine-coordinate compound with oxygen donors ŽFig. 45.. The samarium atom is bonded to three phosphoryl oxygen atoms, three carbonyl oxygen atoms, and three oxygen atoms from water molecules. The wŽEtO. 2 PŽO.NHCŽO.NH]CŽO.Phx ligand behaves as a bidentate compound in this complex, where the phosphoryl group is induced to coordination as oppose to the possibility of coordination by both carbonyl groups. The chelate rings are close to planarity in this complex. All the Sm]OŽP. bonds are shorter than that in Sm]OŽC., indicating that the phosphoryl oxygen atom has a stronger coordinative function than that of the carbonyl oxygen.

Fig. 44. Molecular structure of wPbPhCŽS.NPŽO.ŽO i Pr.242x w72x.

478

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

Fig. 45. Molecular structure of the cation in wSmŽEtO. 2 PŽO.NHCŽO.NHCŽO.Phx 3 ŽClO4 . 3 ? 3H 2 O w91x.

8. Summary In comparision, with the well-established coordination chemistry of imidodiphosphinates, the chemistry of phosphinated ureas and thioureas is largely unexplored to date. The ligands can readily be prepared by: v v

v

direct addition of amines to phosphorus isocyanaterisothiocyanate; clipping the metallated acid amides together with acid chlorides or chlorophosphines; and base-catalysed condensation, or use of silylated derivatives.

The above synthetic methods might well find a more general application in the synthesis of organophosphorus bidentate ligands. Further studies with this synthetic method to prepare other ligand systems should prove productive. Both systems are excellent chelating agents and are extensively studied for their extraction potential toward metals w92]106x.

References w1x w2x w3x w4x w5x

M. Witt, H.W. Roesky, Chem. Rev. 94 Ž1994. 1163. P. Bhattacharyya, J.D. Woollins, Polyhedron 14 Ž1995. 3367. H. Noeth, L. Meinel, Z. Anorg. Allg. Chem. 349 Ž1967. 225. A. Schmidpeter, H. Groeger, Z. Anorg. Allg. Chem. 345 Ž1966. 106. F.T. Wang, J. Najdzionek, K.L. Leneker, H. Wasserman, D.M. Braitsch, Synth. React. Inorg. Met. Org. Chem. 8 Ž1978. 119. w6x P. Bhattacharyya, J. Novosad, J. Phillips, A.M.Z. Slawin, D.J. Williams, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1995. 1607. w7x R. Rossi, L. Marvelli, A. Marchi, L. Magon, V. Bertolasi, V. Ferretti, J. Chem. Soc., Dalton Trans. Ž1994. 339. w8x D. Pohl, E. Ellermann, F.A. Knoch, M.J. Moll, J. Organomet. Chem. 495 Ž1995. C6.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481 w9x w10x w11x w12x w13x w14x w15x w16x w17x w18x w19x w20x w21x w22x w23x w24x w25x w26x w27x w28x w29x w30x w31x w32x w33x w34x w35x w36x w37x w38x w39x w40x w41x w43x w44x w45x w46x w47x w48x w49x w50x w51x

479

A.M.Z. Slawin, M.B. Smith, J.D. Woollins, J. Chem. Soc., Dalton. Trans. Ž1996. 1283. P. Bhattacharyya, A.M.Z. Slawin, M.B. Smith, J.D. Woollins, Inorg. Chem. 35 Ž1996. 3675. A.M.Z. Slawin, M.B. Smith, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1996. 4567. A.M.Z. Slawin, M.B. Smith, J.D. Woollins, Polyhedron 15 Ž1996. 1579. M.S. Balakrishna, R. Klein, S. Uhlenbrock, A.A. Pinkerton, R.G. Cavell, Inorg. Chem. 32 Ž1993. 5676. P. Bhattacharyya, A.M.Z. Slawin, D.J. Williams, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1995. 3189. H. Bock, H. Schodel, Z. HavIas, E. Herrmann, Angew. Chem. Int. Ed. Engl. 34 Ž1995. 1355. ¨ J. Yang, J.E. Drake, S. Hernandez-Ortega, R. Rosler, C. Silvestru, Polyhedron 16 Ž1997. 4061. ´ ¨ A.M.Z. Slawin, J. Ward, D.J. Williams, J.D. Woollins, J. Chem. Soc., Chem. Commun. Ž1994. 421. R. Cea-Olivares, H. Noth, ¨ Z. Naturforsch. 42Žb. Ž1987. 1507. I. Haiduc, R. Cea-Olivares, S. Hernandez-Ortega, C. Silvestru, Polyhedron 14 Ž1995. 2041. ´ A. Silvestru, I. Haiduc, R.A. Toscano, H.J. Breunig, Polyhedron 14 Ž1995. 2047. J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1996. 2893. I. Haiduc, Coord. Chem. Rev. 158 Ž1997. 325. G.P. McQuillan, I.A. Oxton, Inorg. Chim. Acta 29 Ž1978. 69. M. Rietzel, H.W. Roesky, Y.V. Katti, M. Noltemeyer, M.C.R. Symons, A. Abu-Raqabah, J. Chem. Soc., Dalton Trans. Ž1991. 1285. M. Rietzel, H.W. Roesky, K.V. Katti, H.-G. Schmidt, R. Herbst-Irmer, M. Noltemeyer, M.C.R. Symons, A. Abu-Raqabah, J. Chem. Soc., Dalton Trans. Ž1990. 2387. T.Q. Ly, A.M.Z. Slawin, J.D. Woollins Žin press.. N. Zuniga-Villarreal, C. Silvestru, M.R. Lezama, S. Hernandez-Ortega, C.A. Toledano, J. ´˜ ´ Organomet. Chem. 496 Ž1995. 169. O. Simnan, H.B. Gray, Inorg. Chem. 13 Ž1974. 1185. R. Rossi, A. Marchi, L. Magon, U. Casellato, S. Tamburini, R. Graziani, J. Chem. Soc., Dalton Trans. Ž1991. 263. R. Rossi, A. Marchi, L. Marvelli, L. Magon, M. Peruzzini, U. Casellato, R. Graziani, J. Chem. Soc., Dalton Trans. Ž1993. 723. M.R. Churchill, J. Wormald, Inorg. Chem. 10 Ž1971. 1778. C.S. Browning, D.H. Farrar, D.C. Frankel, Inorg. Chim. Acta 241 Ž1996. 111. C. Silvestru, R. Rosler, I. Haiduc, R. Cea-Olivares, G. Espinosa-Perez, Inorg. Chem. 34 Ž1995. ¨ ´ 3352. S. Husebye, K. Maartmann-Moe, Acta Chem. Scand. A37 Ž1983. 439. R. Rosler, C. Silvestru, G. Espinosa-Perez, I. Haiduc, R. Cea-Olivares, Inorg. Chim. Acta 241 ¨ ´ Ž1996. 47. M.R. Churchill, J. Cooke, J. Wormald, K. Davison, E.S. Switkes, J. Am. Chem. Soc. 91 Ž1969. 6518. M.K. Churchill, J. Cooke, J.P. Fennessey, J. Wormald, Inorg. Chem. 10 Ž1971. 1031. D. Cupertino, R. Keyte, A.M.Z. Slawin, D.J. Williams, J.D. Woollins, Inorg. Chem. 35 Ž1996. 2695. P.B. Hitchcock, J.F. Nixon, I. Silaghi-Dumitrescu, I. Haiduc, Inorg. Chim. Acta 96 Ž1985. 77. A.M.Z. Slawin, M.B. Smith, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1996. 3659. M. Novomann, Z. Zak, ´ E. Herrmann, O. Navratil, ´ Z. Anorg. Allg. Chem. 619 Ž1993. 11474. J. Phillips, A.M.Z. Slawin, A.J.P. White, D.J. Williams, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1995. 2467. I. Haiduc, R. Cea-Olivares, R.A. Toscano, C. Silvestru, Polyhedron 14 Ž1995. 1067. C.P. Huber, M.L. Post, O. Siiman, Acta Crystallogr. B34 Ž1978. 2629. A. Laguna, M. Laguna, M.N. Fraile, P. Jones, Inorg. Chim. Acta 150 Ž1988. 233. A. Laguna, M. Laguna, A. Rojo, M.N. Fraile, J. Organomet. Chem. 315 Ž1986. 269. J.S. Casas, A. Castineiras, I. Haiduc, A. Sanchez, J. Sordo, E.M. Vazquez-Lopez, Polyhedron 14 ˜ ´ ´ ´ Ž1995. 805. R.O. Day, R.R. Holmes, A. Schmidpeter, K. Stoll, L. Howe, Chem. Ber. 124 Ž1991. 2443. C. Silvestru, I. Haiduc, R. Cea-Olivares, A. Zimbron, Polyhedron 13 Ž1994. 3159. R. Rosler, J.E. Drake, C. Silvestru, J. Yang, I. Haiduc, J. Chem. Soc., Dalton Trans. Ž1996. 391. ¨

480

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

w52x I. Haiduc, C. Silvestru, H.W. Roesky, H.-G. Schmidt, M. Noltemeyer, Polyhedron 12 Ž1993. 69. w53x R. Cea-Olivares, J. Novosad, J.D. Woollins, A.M.Z. Slawin, V. Garcıa-Montalvo, G. Espinosa´ Perez, P. Garcıa ´ ´ y Garcıa, ´ J. Chem. Soc., Chem. Commun. Ž1996. 519. w54x J.S. Casas, A. Castineiras, I. Haiduc, A. Sanchez, J. Sordo, E.M. Vazquez-Lopez, Polyhedron 13 ˜ ´ ´ ´ Ž1994. 2873. w55x C. Silvestru, R. Rosler, I. Haiduc, R.A. Toscano, D.B. Sowerby, J. Organomet. Chem. 515 Ž1996. ¨ 131. w56x D.J. Williams, C.O. Quicksall, K.M. Barkigia, Inorg. Chem. 21 Ž1982. 2097. w57x S. Husebye, K. Maartmann-Moe, Acta Chem. Scand. A37 Ž1983. 219. w58x S. Bjørnevig, S. Husebye, K. Maartmann-Moe, Acta Chem. Scand. A36 Ž1982. 195. w59x J. Michalski, J. Wieczorkowski, Roczniki Chem. 29 Ž1955. 137. w60x J. Michalski, J. Wieczorkowski, Roczniki Chem. 31 Ž1957. 585. w61x D.T. Elmore, J.R. Ogle, J. Chem. Soc. Ž1959. 2286. w62x A. Schmidpeter, H. Groeger, Chem. Ber. 100 Ž1967. 3052. w63x I. Ojima, T. Iwamoto, T. Onishi, N. Inamoto, K. Tamaru, Chem. Commun. Ž1969. 1501. w64x I. Ojima, T. Iwamoto, T. Onishi, N. Inarnoto, K. Tamaru, Bull. Chem. Soc. Jpn 44 Ž1971. 1150. w65x I. Ojima, K.-Y. Akiba, N. Inamoto, Bull. Chem. Soc. Jpn 46 Ž1973. 2559. w66x A. Spencer, J.M. Swan, H.B. Wright, Aust. J. Chem. 22 Ž1969. 2359. w67x A. Ziegler, V.P. Botha, I. Haiduc, Inorg. Chim. Acta 15 Ž1975. 123. w68x J. Bodeker, H. Zartner, J. Prakt. Chem. 318 Ž1976. 149. ¨ ¨ w69x R. Vogt, P.G. Jones, A. Kolbe, R. Schmutzler, Chem. Ber. 124 Ž1991. 2705. w70x T.Q. Ly, A.M.Z. Slawin, J.D. Woollins Žin press.. w71x E. Breuer, A. Schlossman, M. Safadi, D. Gibson, M. Chorev, H. Leader, J. Chem. Soc., Perkin Trans. 1 Ž1990. 3263. w72x R. Richter, J. Sieler, H. Borrmann, A. Simon, N.T.T. Chau, E. Herrmann, Phosphorus, Sulfur Silicon 60 Ž1991. 107. w73x V.N. Solovyov, I.V. Martynov, Phosphorus, Sulfur Silicon 57 Ž1991. 135. w74x N.G. Zabirov, V.N. Solov’ev, F.M. Shamsevaleev, R.A. Cherkasov, A.N. Chekhlov, A.G. Tsifarkin, I.V. Martynov, J. Gen. Chem. USSR 61 Ž1991. 597. w75x H. Wilhelm, E. Herrmann, Phosphorus, Sulfur Silicon 73 Ž1992. 81. w76x R.-Y. Chen, H.-L. Wang, J. Zhou, R.-J. Wang, H.-G. Wang, Chinese J. Struct. Chem. ŽRegou Humue. 13 Ž1994. 307. w77x D.T. Dixon, F.W.B. Einstein, B.R. Penfold, Acta Crystallogr. 18 Ž1965. 221. w78x V.V. Tkachev, L.O. Atovmyan, S.A. Shchepinov, Zh. Strukt. Khim. 17 Ž1976. 945. w79x M.J. Potrzebowski, J.H. Reibenspies, Z. Zhong, Heteroatom Chem. 2 Ž1991. 455. w80x A.C. Gallacher, A.A. Pinkerton, Acta Crystallogr. C49 Ž1993. 701. w81x P. Knopik, L. Luczak, M.J. Potrzebowski, J. Michalski, J. Blaswzyk, M.W. Wieczorek, J. Chem. Soc., Dalton Trans. Ž1993. 2749. w82x R.K. Shibao, N.L. Keder, H. Eckert, Acta Crystallogr. C48 Ž1992. 1525. w83x R. Appel, F. Knock, H. Kunze, Angew. Chem. Int. Ed. Engl. 22 Ž1983. 1004. w84x H. Beckmann, G. Grossmann, G. Ohms, J. Sieler, Heteroatom Chem. 5 Ž1994. 73. w85x V.N. Solov’ev, A.N. Cheklov, N.G. Zabirov, R.A. Cherkasov, I.V. Martynov, Zh. Strukt. Khim. 31 Ž1990. 103. w86x E. Herrmann, N.T.T. Chau, G. Ohms, P.G. Jones, Z. Anorg. Allg. Chem. 594 Ž1991. 146. w87x P. Bhattacharyya, A.M.Z. Slawin, M.B. Smith, D.J. Williams, J.D. Woollins, J. Chem. Soc., Dalton Trans. Ž1996. 3647. w88x Z. Zak, ´ T. Glowiak, N.T.T. Chau, E. Herrmann, Z. Anorg. Allg. Chem. 586 Ž1990. 136. w89x T. Iwamoto, F. Ebina, H. Nakazawa, C. Nakatsuka, Bull. Chem. Soc. Jpn 52 Ž1979. 1857. w90x E. Herrmann, R. Richter, J. Sieler, N.T.T. Chau, Z. Anorg. Allg. Chem. 623 Ž1997. 403. w91x N.G. Zabirov, V.N. Solov’ev, F.M. Shamsevaleev, R.A. Cherkasov, I.V. Martynov, J. Gen. Chem. USSR 61 Ž1991. 1608. w92x W. Zhang, M. Tan, W. Liu, K. Yu, Polyhedron 11 Ž1992. 1581. w93x O. Navratil, ´ E. Herrmann, N.T.T. Chau, C. Tea, J. Smola, Collect. Czech. Chem. Commun. 58 Ž1993. 798.

T.Q. Ly, J.D. Woollins r Coordination Chemistry Re¨ iews 176 (1998) 451]481

481

w94x E. Uhlemann, R. Schulz, A. Friedrich, Z. Chem. 27 Ž1987. 225. w95x E. Herrmann, N.T.T. Chau, O. Navratil, ´ G. Ohms, L. Beyer, Phosphorus, Sulfur Silicon 51 Ž1990. 366. w96x E. Herrmann, O. Navratil, Phosphorus, Sulfur Silicon 109 Ž1996. 201. ´ P. Sladek, ´ w97x Z.P. Vetrova, N.G. Zabirov, T.N. Shuvalova, L.S. Smerkovich, L.A. Ivanova, A.K. Gol’berg, N.T. Karabanov, J. Gen. Chem. USSR 63 Ž1993. 883. w98x O. Navratil, ´ M. Fofana, J. Smola, Z. Chem. 24 Ž1984. 30. w99x O. Navratil, ´ E. Herrmann, G. Grossmann, J. Teply, Collect. Czech. Chem. Commun. 55 Ž1990. 364. w100x O. Navratil, A. Tokarova, E. Herrmann, M. Nouaman, Collect. Czech. Chem. Commun. ´ P. Sladek, ´ 62 Ž1997. 620. w101x O. Navratil, A. Tokarova, E. Herrmann, M. Nouaman, Collect. Czech. Chem. Commun. ´ P. Sladek, ´ 62 Ž1997. 375. w102x O. Navratil, ´ E. Herrmann, Collect. Czech. Chem. Commun. 57 Ž1992. 1655. w103x E. Herrmann, M. Nouaman, Z. Zak, ´ G. Grossmann, G. Ohms, Z. Anorg. Allg. Chem. 1994 Ž1879. 620. w104x O. Navratil, ´ E. Herrmann, P. Slezak, ´ Collect. Czech. Chem. Commun. 52 Ž1987. 1708. w105x E. Herrmann, O. Navratil, ´ H. Nang, J. Smola, J. Friedrich, J. Prihoda, R. Dreyer, V.A. Chalkin, S. Kulpe, Collect. Czech. Chem. Commun. 49 Ž1984. 201. w106x E. Herrmann, O. Navratil, ´ H. Nang, J. Smola, J. Friedrich, J. Prihoda, R. Dreyer, V.A. Chalkin, Z. Chem. 22 Ž1982. 346.