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Unusual reactions of ruthenium–polycyanocarbon complexes: formation of an η2-CNR ligand and cleavage of C(sp2)–CN bonds
Inorganic Chemistry Communications 4 (2001) 617±620
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Unusual reactions of ruthenium±polycyanocarbon complexes: formation of an g2-CNR ligand and cleavage of C(sp2)±CN bonds Michael I. Bruce b
a,*
, Brian W. Skelton b, Allan H. White b, Natasha N. Zaitseva
a
a Department of Chemistry, Adelaide University, Adelaide 5005, Australia Department of Chemistry, University of Western Australia, Crawley 6009, Australia
Received 10 May 2001; accepted 27 June 2001
Abstract Unusual formation of an g2 -bonded polycyanocarbon ligand from tetracyanoethene, C2 (CN)4 (tcne) and the allylic ligand in Ru{g3 -CHPhCHC@CPh(CBCPh)}(PPh3 )Cp (1), and migration of CN from the polycyanocarbon in Ru{C[@C(CN)2 ]CPh@ C(CN)2 }(dppm)Cp (3), have been established by crystal structure determinations on Ru{C(CH@CHPh)@CPhC[CPh@ C(CN)2 ]C(CN)(g2 -CN)}(PPh3 )Cp (2) and Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4), which are the respective products. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Ruthenium; Cyanocarbon; Crystal structure; CN group migration
1. Introduction The electrophilic cyclo-addition of tetracyanoethene, C2 (CN)4 (tcne), to transition metal r-alkynyl complexes was ®rst reported in 1979 [1] and has been extensively studied since [2]. These reactions appear to proceed via a charge-transfer complex (not observed in all cases) to give ®rstly a r-cyclobutenyl complex (A; Scheme 1) which undergoes a more or less rapid ring-opening to form the buta-1,3-dien-2-yl derivative B. The latter may evolve to form an g3 -allylic complex C if a readily dissociable ligand is present in B. To our knowledge, no further reactions of the cyanocarbon ligands have been reported, except for the addition of a second MLn group to one of the CN groups [3]. Our earlier work has used r-alkynyl and r-diynyl complexes also containing tertiary phosphines and Cp ligands in reactions with electron-de®cient cyano- and ¯uoro-alkenes [2,4]. In developing our studies of related systems which contain g-C5 Me5 (Cp ) ligands, we have uncovered a series of reactions during which the cyanocarbon ligand is further transformed. This Communication describes two of these reactions, in which (a) * Corresponding author. Tel.: +61-88-303-5939; fax: +61-88-3034358. E-mail address: [email protected] (M.I. Bruce).
one of the CN groups becomes side-bonded (g2 ) and (b) the metal centre formally inserts into a C(sp2 )±CN bond to give a cyanoruthenium complex. These results are of contemporary interest since they relate to the recent report of the reaction between {Ni(l-H)(dippe)}2 (dippe PPri2 CH2 CH2 PPri2 ) and benzonitrile, which after initially aording the g2 -nitrile complex Ni(g2 -NCPh)(dippe), then undergoes a reversible intramolecular oxidative addition reaction to give NiPh(CN)(dippe) upon standing [5]. 2. Results and discussion The reaction of Ru{g3 -CHPhCHC@CPh(CBCPh)} (PPh3 )Cp (1; Scheme 2) [6] with tcne was carried out in benzene at room temperature for 30 min and aorded Ru{C(CH@CHPh)@CPhC[CPh@C(CN) 2 ]C(CN)(g2 CN)}(PPh3 )Cp (2) as green crystals in 51% yield. 1 A plot of the molecular structure of 2, determined from a 1 Ru{C(CH@CHPh)@CPhC[CPh@C(CN)2 ]C(CN)(g2 -CN)}(PPh3 ) Cp (2): Anal. found: C, 74.03; H, 5.18; N, 5.98. Calc. for C58 H47 N4 PRu: C, 74.74; H, 5.08; N, 6.01%; M, 932. IR (Nujol): m(CN)2230w, 2208s cm 1 . 1 H NMR (CDCl3 ): d 1.44 [d,J(PH) 1.4,15H,Me], 3.34 [d,J(HH) 16,1H,@CH], 4.41 [d,J(HH) 16,1H,@CH], 5.92±7.33 (m, 30H, Ph). ES mass spectrum (MeOH): 934, [M+2H] ; 672, [M+2H± PPh3 ] .
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M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
Scheme 1.
single-crystal X-ray study 2, is shown in Fig. 1, while signi®cant bond parameters are given in the caption. The ruthenium is attached by a r bond to C(4) and by the g2 interaction with C(11)±N(11). The latter, with a lengthened C±N distance [1.215(3), compared with and the bending of the N(11)± C(12)±N(12) 1.141(4) A] C(11)±C(1) moiety [145.5(3)°] are both consistent with p donation from the C B N triple bond to the Ru centre. N±C± Similar features [C±N between 1.209 and 1.267 A,
2 Full spheres of diraction data to 2h 58° (Ntot re¯ections) were measured at ca. 153 K using a Bruker AXS CCD area-detector merginstrument (monochromatic Mo-Ka radiation, k 0.71073 A), ing to N unique re¯ections (Rint quoted) after ``empirical''/multiscan absorption correction (proprietary software), N0 with F>4r(F) being used in the full matrix least squares re®nement. Anisotropic thermal parameter forms were re®ned for the non-hydrogen atoms, (x,y,z,Uiso )H being re®ned for 2 (unsolvated) or constrained at estimated values (others). Conventional residuals R, Rw on |F| are given [weights: (r2 (F)+0.0004F2 ) 1 ]. Neutral atom complex scattering factors were used; computation used the XT A L 3.7 program system [9]. Pertinent results are given in the ®gures (which show non-hydrogen atoms with 50% probability amplitude displacement ellipsoids and and captions. hydrogen atoms with arbitrary radii of 0.1 A) Crystal data. 2 Ru{C(CH@CHPh)@CPhCCPh@C(CN)2 ]C(CN) (g2 -CN)}(PPh3 )Cp B C58 H47 N4 PRu, M 932.1. Monoclinic, space b 115.526 group P21 /c, a 22.057(3), b 11.492(2), c 21.588(3) A, 3 ; qc 1.254 g cm 3 for Z 4. Crystal: 0.30 ´ 0.30 ´ (2)°, V 4938 A 0.06 mm3 , l 3.9 cm 1 , `TÕmin ;max 0.66, 0.84. Ntot 48112, N 12508 (Rint 0.049), N0 8293, R 0.037, Rw 0.041. |Dqmax | 3. 0.76(4) eA An initial, inferior, study was carried out on 2.S, S modelled as (disordered) CH2 Cl2 , isomorphous with the unsolvated form: C58 H47 N4 PRu.CH2 Cl2 , M 1017.0, a 21.729(3), b 11.930(2), b 117.860(2)°, V 5007 A 3 ; qc 1.349 g cm 3 for c 21.847(3) A, 3 Z 4. Crystal: 0.22´0.14´0.07 mm , l 5.0 cm 1 , `TÕmin ;max 0.72, 0.84. Ntot 50046, N 8606 (Rint 0.096), N0 5993, R 0.084, 3. Rw 0.098. |Dqmax | 4.1(2) eA (4) Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp á2(0.5C6 H6 )á 0.5C6 H14 (4) B C49 H42 N4 P2 Ruá2(0.5C6 H6 )á0.5C6 H14 , M 971.1. Tri clinic, space group P 1, a 10.800(2), b 12.080(2), c 18.992(3) A, 3 ; qc a 74.910(3), b 87.554(3), c 87.884(3)°, V 2389 A
1.354 g cm 3 for Z 2. Crystal: 0.30´0.20´0.08 mm3 , l 4.4 cm 1 , `TÕmin ;max 0.52, 0.78. Ntot 36544, N 12035(Rint 0.056), 3. N0 9849, R 0.070, Rw 0.083.|Dqmax | 3.4(1) eA Occupancy of a considerable tunnel, parallel to a, through the centre of the cell as set, was modelled as above, all solvent molecules disposed about crystallographic inversion centres; diraction characteristics of the crystal were inferior (vide residuals, Fig. 2) and derivative parameters should be treated circumspectly.
Scheme 2.
C between 129.7° and 141°] have been reported in other structurally characterised g2 -nitrile complexes [7]. Formally, at least, the cyanocarbon ligand in 2 appears to be derived by the addition of tcne to the noncoordinated C B C triple bond of 1. We surmise that the presence of the bulky Cp ligand facilitates opening of the allylic ligand to allow either tcne or the free C B C triple bond to become coordinated to the ruthenium centre. Rearrangement by cycloaddition of the tcne to the C B C triple bond then generates a butadienyl ligand by the same type of ring-opening reaction that occurs in the reactions with conventional alkynyl complexes (Scheme 2). Although previous observations indicate that cycloaddition of tcne to C B C triple bonds remote from the metal centre is dicult, this route cannot be excluded in the present circumstance. Complex 2 does not undergo an oxidative addition analogous to that of the nickel complex mentioned above. However, a spontaneous rearrangement of Ru{C[@C(CN)2 ]CPh@C(CN)2 }(dppm)Cp (3), obtained from a conventional reaction between tcne and Ru(CBCPh)(dppm)Cp , in CH2 Cl2 solution at room temperature, or adsorbed in silica gel, resulted in the formation of the dark red zwitterionic complex
M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
051
011
01 02
03 Ru
62
5
122 121 132
61
4 N(11) 11 P(1)
131
041
04
32 3 31
1 2
111
71 7
CN(12)
72
112 8
CN(81)
CN(82)
Fig. 1. Plot of a molecule of Ru{C(CH@CHPh)@CPhCCPh@ C(CN)2 ]C(CN)(g2 -CN)}(PPh3 )Cp (2) showing atom numbering scheme. Selected bond data: Ru±C(Cp ) 2.254±2.304(3) [av 2.27(3)], Ru±P(1) 2.3520(7), Ru±C(4) 2.097(3), Ru±C(11) 2.061(3), Ru±N(11) 2.208(2), C(1)±C(11) 1.423(3), C(1)±C(2) 1.382(4), C(2)±C(3) 1.445(4), C(3)±C(4) 1.378(3), C(4)±C(5) 1.471(4), C(5)±C(6) 1.343(5), C(11)± P(1)±Ru±C(4) 90.13(7), P(1)± N(11) 1.215(3), C(12)±N(12) 1.141(4) A. Ru±C(11) 97.40(8), P(1)±Ru±N(11) 87.09(7), N(11)±C(11)±C(1) 145.5(3), C(11)±C(1)±C(2) 120.1(3), C(1)±C(2)±C(3) 124.7(3), C(2)± C(3)±C(4) 124.4(3), C(3)±C(4)±C(5) 117.4(3), C(4)±C(5)±C(6) 124.2(3)°.
031 021
02
011
041
04
05
01
051
619
Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4) in 71% isolated yield. 3 A single-crystal X-ray structure determination gave the structure shown in Fig. 2, the caption to which contains important bond parameters. 2 The NMR spectra are consistent with the solid-state structure, with the Cp resonances at dH 1.60 and dC 9.42 and 99.90. Multiplets at dH 3.34 and 5.40 are assigned to the dppm CH2 group, but there is no obvious reason why their separation should be so large. Atoms C(1±4) are found at d 153.22, under the aromatic multiplet between 128 and 136, 125.33 and 126.43; the Ru±CN carbon doublet is at d 179.96. Two 31 P resonances are found at d 13.87 and 58.61 and are assigned to P(2) and P(1), respectively. As can be seen, formal exchange of one CN group and the Ru atom has occurred, in addition to attack of the uncoordinated PPh2 group of the dppm ligand in 3 on the a-carbon of the cyanocarbon ligand to give a new P±C bond. A possible course for this reaction is shown in Scheme 3. In this case, the reaction is not so much an oxidative addition as one resulting from electron redistribution to give charge separation. In both cases, unusual complexes have resulted from the increased electron density at the ruthenium centre resulting from the presence of the bulky and strongly electron donating Cp ligand. While several other examples of g2 -nitriles are known [7], we believe that this is the ®rst example of a polycyanocarbon ligand to exhibit this type of bonding. For tcne complexes, both g2 -ole®nic and N-bonded examples have been described [8]. Further details of these reactions will be reported elsewhere.
Ru 122 P(1)
CN(11) CN(10)
121
1
3. Supplementary material
CN(42)
111 2
112
4 CN(41)
0
3 P(2) 311 221
211 222 212
312
Fig. 2. Plot of a molecule of Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4). Selected bond data: Ru±C(Cp ) 2.251±2.304(5) [av. 2.28(2)], Ru±P(1) 2.237(1), Ru±C(1) 2.010(5), Ru±C(10) 1.996(5), P(1,2)±C(0) 1.839, 1.810(5), P(2)±C(2) 1.792(4), C(1)±C(2) 1.420(6), P(1)± C(2)±C(3) 1.461(6), C(3)±C(4) 1.377(6), C(10)±N(10) 1.159(7) A. Ru±C(1) 87.6(1), P(1)±Ru±C(10) 86.8(1), Ru±C(10)±N(10) 177.2(4), Ru±C(1)±C(2) 140.1(3), P(2)±C(2)±C(1) 121.7(3), C(1)±C(2)±C(3) 123.6(4), C(2)±C(3)±C(4) 121.9(4)°. s(Ru±C(5)±C(6)±C(61)) is 129.0(2)°. The dihedral angle between the C(1,11,12)N(11,12) and C(7,8,81,82)N(81,82) planes (v2 666, 69) is 109.7(1); s (C(1)±C(2)±C(7)± C(8)) is 63.9(4)°.
Crystallographic data (excluding structure factors) in CIF format for 2 (two forms) and 4 have been deposited with the Cambridge Crystallographic Data Centre as CCDC 162 953, 162 954 and 162 955, respectively. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, England (fax: +44-1223-336033; e-mail: [email protected]). 3 Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4): Anal. found: C, 68.06; H, 5.15; N, 6.03. Calc. for C49 H42 N4 P2 Ru: C, 69.25; H, 4.98; N, 6.59%; M, 850. IR (Nujol): m(CN)2218m, 2157w, 2070m cm 1 . 1 H NMR (CDCl3 ): d1.60 [d,J(HP) 1.6,15H,Me], 3.24 (m, 1H, CH2 ), 5.40 (m, 1H, CH2 ), 6.64±7.76 (m, 25H, Ph). 13 C NMR: d 9.42 (s, Me), 30.09 [dd, J(CP) 48, 37, CH2 ], 99.90 (s, Cp ), 114.87, 116.14, 122.58 (3´s, CN), 125.33 [s, C(3)], 126.43 [s, C(4)], 127.92± 135.85 [m, Ph + C(2)], 153.22 [d, J(CP) 18.9, C(1)], 179.96 [d, J(CP) 19.2, CN]. 31 P NMR: d 13.87 (s, P±C), 58.61 (s, P±Ru). ES mass spectrum (MeOH): 851, [M+H] ; 824, [M CN] ; 621, [Ru(dppm)Cp*] .
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M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
Scheme 3.
Acknowledgements This work was supported by the Australian Research Council. We thank Johnson Matthey plc, Reading, England for a generous loan of RuCl3 áxH2 O. References [1] A. Davison, J.P. Solar, J. Organomet. Chem. 166 (1979) C13. [2] [a] M.I. Bruce, J.R. Rodgers, M.R. Snow, A.G. Swincer, J. Chem. Soc., Chem. Commun. (1981) 271; [b] M.I. Bruce, T.W. Hambley, M.R. Snow, A.G. Swincer, Organometallics 4 (1985) 494,500.
[3] [a] M.I. Bruce, T.W. Hambley, M.J. Liddell, A.G. Swincer, E.R.T. Tiekink, Organometallics 9 (1990) 2886; [b] M.I. Bruce, P.J. Low, B.W. Skelton, A.H. White, New J. Chem. 22 (1998) 419. [4] [a] M.I. Bruce, T.W. Hambley, M.J. Liddell, M.R. Snow, A.G. Swincer, E.R.T. Tiekink, Organometallics 9 (1990) 96; [b] M.I. Bruce, M. Ke, P.J. Low, B.W. Skelton, A.H. White, Organometallics 17 (1998) 3539; [c] M.I. Bruce, B.C. Hall, B.D. Kelly, P.J. Low, B.W. Skelton, A.H. White, J. Chem. Soc., Dalton Trans. (1999) 3719. [5] J.J. Garcia, W.D. Jones, Organometallics 19 (2000) 5544. [6] M.I. Bruce, B.C. Hall, B.W. Skelton, A.H. White, N.N. Zaitseva, J. Chem. Soc., Dalton Trans. (2000) 2279. [7] [a] K. Krogmann, R. Mattes, Angew. Chem. Int. Ed. Engl. 5 (1966) 1046; [b] T.C. Wright, G. Wilkinson, M. Motevalli, M.B. Hursthouse, J. Chem. Soc., Dalton Trans. (1986) 2017; [c] P.A. Chetcuti, C.B. Knobler, M.F. Hawthorne, Organometallics 7 (1988) 650; [d] S.J. Anderson, F.J. Willis, G. Wilkinson, B. Hussain, M.B. Hursthouse, Polyhedron 7 (1988) 2615; [e] J. Barrera, M. Sabat, W.D. Harman, J. Am. Chem. Soc. 113 (1991) 8178. [8] [a] W.H. Baddley, Inorg. Chim. Acta Rev. 2 (1968) 7; [b] H. K ohler, Z. Chem. 13 (1973) 401; [c] M. Leirer, G. Kn or, A. Vogler, Inorg. Chem. Commun. 2 (1999) 110. [9] S.R. Hall, D.J. du Boulay, R. Olthof-Hazekamp (Eds.), The XT A L 3.7 System, University of Western Australia, Australia, 2000.
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Unusual reactions of ruthenium±polycyanocarbon complexes: formation of an g2-CNR ligand and cleavage of C(sp2)±CN bonds Michael I. Bruce b
a,*
, Brian W. Skelton b, Allan H. White b, Natasha N. Zaitseva
a
a Department of Chemistry, Adelaide University, Adelaide 5005, Australia Department of Chemistry, University of Western Australia, Crawley 6009, Australia
Received 10 May 2001; accepted 27 June 2001
Abstract Unusual formation of an g2 -bonded polycyanocarbon ligand from tetracyanoethene, C2 (CN)4 (tcne) and the allylic ligand in Ru{g3 -CHPhCHC@CPh(CBCPh)}(PPh3 )Cp (1), and migration of CN from the polycyanocarbon in Ru{C[@C(CN)2 ]CPh@ C(CN)2 }(dppm)Cp (3), have been established by crystal structure determinations on Ru{C(CH@CHPh)@CPhC[CPh@ C(CN)2 ]C(CN)(g2 -CN)}(PPh3 )Cp (2) and Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4), which are the respective products. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Ruthenium; Cyanocarbon; Crystal structure; CN group migration
1. Introduction The electrophilic cyclo-addition of tetracyanoethene, C2 (CN)4 (tcne), to transition metal r-alkynyl complexes was ®rst reported in 1979 [1] and has been extensively studied since [2]. These reactions appear to proceed via a charge-transfer complex (not observed in all cases) to give ®rstly a r-cyclobutenyl complex (A; Scheme 1) which undergoes a more or less rapid ring-opening to form the buta-1,3-dien-2-yl derivative B. The latter may evolve to form an g3 -allylic complex C if a readily dissociable ligand is present in B. To our knowledge, no further reactions of the cyanocarbon ligands have been reported, except for the addition of a second MLn group to one of the CN groups [3]. Our earlier work has used r-alkynyl and r-diynyl complexes also containing tertiary phosphines and Cp ligands in reactions with electron-de®cient cyano- and ¯uoro-alkenes [2,4]. In developing our studies of related systems which contain g-C5 Me5 (Cp ) ligands, we have uncovered a series of reactions during which the cyanocarbon ligand is further transformed. This Communication describes two of these reactions, in which (a) * Corresponding author. Tel.: +61-88-303-5939; fax: +61-88-3034358. E-mail address: [email protected] (M.I. Bruce).
one of the CN groups becomes side-bonded (g2 ) and (b) the metal centre formally inserts into a C(sp2 )±CN bond to give a cyanoruthenium complex. These results are of contemporary interest since they relate to the recent report of the reaction between {Ni(l-H)(dippe)}2 (dippe PPri2 CH2 CH2 PPri2 ) and benzonitrile, which after initially aording the g2 -nitrile complex Ni(g2 -NCPh)(dippe), then undergoes a reversible intramolecular oxidative addition reaction to give NiPh(CN)(dippe) upon standing [5]. 2. Results and discussion The reaction of Ru{g3 -CHPhCHC@CPh(CBCPh)} (PPh3 )Cp (1; Scheme 2) [6] with tcne was carried out in benzene at room temperature for 30 min and aorded Ru{C(CH@CHPh)@CPhC[CPh@C(CN) 2 ]C(CN)(g2 CN)}(PPh3 )Cp (2) as green crystals in 51% yield. 1 A plot of the molecular structure of 2, determined from a 1 Ru{C(CH@CHPh)@CPhC[CPh@C(CN)2 ]C(CN)(g2 -CN)}(PPh3 ) Cp (2): Anal. found: C, 74.03; H, 5.18; N, 5.98. Calc. for C58 H47 N4 PRu: C, 74.74; H, 5.08; N, 6.01%; M, 932. IR (Nujol): m(CN)2230w, 2208s cm 1 . 1 H NMR (CDCl3 ): d 1.44 [d,J(PH) 1.4,15H,Me], 3.34 [d,J(HH) 16,1H,@CH], 4.41 [d,J(HH) 16,1H,@CH], 5.92±7.33 (m, 30H, Ph). ES mass spectrum (MeOH): 934, [M+2H] ; 672, [M+2H± PPh3 ] .
1387-7003/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 1 3 8 7 - 7 0 0 3 ( 0 1 ) 0 0 2 8 0 - 5
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M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
Scheme 1.
single-crystal X-ray study 2, is shown in Fig. 1, while signi®cant bond parameters are given in the caption. The ruthenium is attached by a r bond to C(4) and by the g2 interaction with C(11)±N(11). The latter, with a lengthened C±N distance [1.215(3), compared with and the bending of the N(11)± C(12)±N(12) 1.141(4) A] C(11)±C(1) moiety [145.5(3)°] are both consistent with p donation from the C B N triple bond to the Ru centre. N±C± Similar features [C±N between 1.209 and 1.267 A,
2 Full spheres of diraction data to 2h 58° (Ntot re¯ections) were measured at ca. 153 K using a Bruker AXS CCD area-detector merginstrument (monochromatic Mo-Ka radiation, k 0.71073 A), ing to N unique re¯ections (Rint quoted) after ``empirical''/multiscan absorption correction (proprietary software), N0 with F>4r(F) being used in the full matrix least squares re®nement. Anisotropic thermal parameter forms were re®ned for the non-hydrogen atoms, (x,y,z,Uiso )H being re®ned for 2 (unsolvated) or constrained at estimated values (others). Conventional residuals R, Rw on |F| are given [weights: (r2 (F)+0.0004F2 ) 1 ]. Neutral atom complex scattering factors were used; computation used the XT A L 3.7 program system [9]. Pertinent results are given in the ®gures (which show non-hydrogen atoms with 50% probability amplitude displacement ellipsoids and and captions. hydrogen atoms with arbitrary radii of 0.1 A) Crystal data. 2 Ru{C(CH@CHPh)@CPhCCPh@C(CN)2 ]C(CN) (g2 -CN)}(PPh3 )Cp B C58 H47 N4 PRu, M 932.1. Monoclinic, space b 115.526 group P21 /c, a 22.057(3), b 11.492(2), c 21.588(3) A, 3 ; qc 1.254 g cm 3 for Z 4. Crystal: 0.30 ´ 0.30 ´ (2)°, V 4938 A 0.06 mm3 , l 3.9 cm 1 , `TÕmin ;max 0.66, 0.84. Ntot 48112, N 12508 (Rint 0.049), N0 8293, R 0.037, Rw 0.041. |Dqmax | 3. 0.76(4) eA An initial, inferior, study was carried out on 2.S, S modelled as (disordered) CH2 Cl2 , isomorphous with the unsolvated form: C58 H47 N4 PRu.CH2 Cl2 , M 1017.0, a 21.729(3), b 11.930(2), b 117.860(2)°, V 5007 A 3 ; qc 1.349 g cm 3 for c 21.847(3) A, 3 Z 4. Crystal: 0.22´0.14´0.07 mm , l 5.0 cm 1 , `TÕmin ;max 0.72, 0.84. Ntot 50046, N 8606 (Rint 0.096), N0 5993, R 0.084, 3. Rw 0.098. |Dqmax | 4.1(2) eA (4) Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp á2(0.5C6 H6 )á 0.5C6 H14 (4) B C49 H42 N4 P2 Ruá2(0.5C6 H6 )á0.5C6 H14 , M 971.1. Tri clinic, space group P 1, a 10.800(2), b 12.080(2), c 18.992(3) A, 3 ; qc a 74.910(3), b 87.554(3), c 87.884(3)°, V 2389 A
1.354 g cm 3 for Z 2. Crystal: 0.30´0.20´0.08 mm3 , l 4.4 cm 1 , `TÕmin ;max 0.52, 0.78. Ntot 36544, N 12035(Rint 0.056), 3. N0 9849, R 0.070, Rw 0.083.|Dqmax | 3.4(1) eA Occupancy of a considerable tunnel, parallel to a, through the centre of the cell as set, was modelled as above, all solvent molecules disposed about crystallographic inversion centres; diraction characteristics of the crystal were inferior (vide residuals, Fig. 2) and derivative parameters should be treated circumspectly.
Scheme 2.
C between 129.7° and 141°] have been reported in other structurally characterised g2 -nitrile complexes [7]. Formally, at least, the cyanocarbon ligand in 2 appears to be derived by the addition of tcne to the noncoordinated C B C triple bond of 1. We surmise that the presence of the bulky Cp ligand facilitates opening of the allylic ligand to allow either tcne or the free C B C triple bond to become coordinated to the ruthenium centre. Rearrangement by cycloaddition of the tcne to the C B C triple bond then generates a butadienyl ligand by the same type of ring-opening reaction that occurs in the reactions with conventional alkynyl complexes (Scheme 2). Although previous observations indicate that cycloaddition of tcne to C B C triple bonds remote from the metal centre is dicult, this route cannot be excluded in the present circumstance. Complex 2 does not undergo an oxidative addition analogous to that of the nickel complex mentioned above. However, a spontaneous rearrangement of Ru{C[@C(CN)2 ]CPh@C(CN)2 }(dppm)Cp (3), obtained from a conventional reaction between tcne and Ru(CBCPh)(dppm)Cp , in CH2 Cl2 solution at room temperature, or adsorbed in silica gel, resulted in the formation of the dark red zwitterionic complex
M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
051
011
01 02
03 Ru
62
5
122 121 132
61
4 N(11) 11 P(1)
131
041
04
32 3 31
1 2
111
71 7
CN(12)
72
112 8
CN(81)
CN(82)
Fig. 1. Plot of a molecule of Ru{C(CH@CHPh)@CPhCCPh@ C(CN)2 ]C(CN)(g2 -CN)}(PPh3 )Cp (2) showing atom numbering scheme. Selected bond data: Ru±C(Cp ) 2.254±2.304(3) [av 2.27(3)], Ru±P(1) 2.3520(7), Ru±C(4) 2.097(3), Ru±C(11) 2.061(3), Ru±N(11) 2.208(2), C(1)±C(11) 1.423(3), C(1)±C(2) 1.382(4), C(2)±C(3) 1.445(4), C(3)±C(4) 1.378(3), C(4)±C(5) 1.471(4), C(5)±C(6) 1.343(5), C(11)± P(1)±Ru±C(4) 90.13(7), P(1)± N(11) 1.215(3), C(12)±N(12) 1.141(4) A. Ru±C(11) 97.40(8), P(1)±Ru±N(11) 87.09(7), N(11)±C(11)±C(1) 145.5(3), C(11)±C(1)±C(2) 120.1(3), C(1)±C(2)±C(3) 124.7(3), C(2)± C(3)±C(4) 124.4(3), C(3)±C(4)±C(5) 117.4(3), C(4)±C(5)±C(6) 124.2(3)°.
031 021
02
011
041
04
05
01
051
619
Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4) in 71% isolated yield. 3 A single-crystal X-ray structure determination gave the structure shown in Fig. 2, the caption to which contains important bond parameters. 2 The NMR spectra are consistent with the solid-state structure, with the Cp resonances at dH 1.60 and dC 9.42 and 99.90. Multiplets at dH 3.34 and 5.40 are assigned to the dppm CH2 group, but there is no obvious reason why their separation should be so large. Atoms C(1±4) are found at d 153.22, under the aromatic multiplet between 128 and 136, 125.33 and 126.43; the Ru±CN carbon doublet is at d 179.96. Two 31 P resonances are found at d 13.87 and 58.61 and are assigned to P(2) and P(1), respectively. As can be seen, formal exchange of one CN group and the Ru atom has occurred, in addition to attack of the uncoordinated PPh2 group of the dppm ligand in 3 on the a-carbon of the cyanocarbon ligand to give a new P±C bond. A possible course for this reaction is shown in Scheme 3. In this case, the reaction is not so much an oxidative addition as one resulting from electron redistribution to give charge separation. In both cases, unusual complexes have resulted from the increased electron density at the ruthenium centre resulting from the presence of the bulky and strongly electron donating Cp ligand. While several other examples of g2 -nitriles are known [7], we believe that this is the ®rst example of a polycyanocarbon ligand to exhibit this type of bonding. For tcne complexes, both g2 -ole®nic and N-bonded examples have been described [8]. Further details of these reactions will be reported elsewhere.
Ru 122 P(1)
CN(11) CN(10)
121
1
3. Supplementary material
CN(42)
111 2
112
4 CN(41)
0
3 P(2) 311 221
211 222 212
312
Fig. 2. Plot of a molecule of Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4). Selected bond data: Ru±C(Cp ) 2.251±2.304(5) [av. 2.28(2)], Ru±P(1) 2.237(1), Ru±C(1) 2.010(5), Ru±C(10) 1.996(5), P(1,2)±C(0) 1.839, 1.810(5), P(2)±C(2) 1.792(4), C(1)±C(2) 1.420(6), P(1)± C(2)±C(3) 1.461(6), C(3)±C(4) 1.377(6), C(10)±N(10) 1.159(7) A. Ru±C(1) 87.6(1), P(1)±Ru±C(10) 86.8(1), Ru±C(10)±N(10) 177.2(4), Ru±C(1)±C(2) 140.1(3), P(2)±C(2)±C(1) 121.7(3), C(1)±C(2)±C(3) 123.6(4), C(2)±C(3)±C(4) 121.9(4)°. s(Ru±C(5)±C(6)±C(61)) is 129.0(2)°. The dihedral angle between the C(1,11,12)N(11,12) and C(7,8,81,82)N(81,82) planes (v2 666, 69) is 109.7(1); s (C(1)±C(2)±C(7)± C(8)) is 63.9(4)°.
Crystallographic data (excluding structure factors) in CIF format for 2 (two forms) and 4 have been deposited with the Cambridge Crystallographic Data Centre as CCDC 162 953, 162 954 and 162 955, respectively. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, England (fax: +44-1223-336033; e-mail: [email protected]). 3 Ru(CN){C(CN)C[CPh@C(CN)2 ]PPh2 CH2 PPh2 }Cp (4): Anal. found: C, 68.06; H, 5.15; N, 6.03. Calc. for C49 H42 N4 P2 Ru: C, 69.25; H, 4.98; N, 6.59%; M, 850. IR (Nujol): m(CN)2218m, 2157w, 2070m cm 1 . 1 H NMR (CDCl3 ): d1.60 [d,J(HP) 1.6,15H,Me], 3.24 (m, 1H, CH2 ), 5.40 (m, 1H, CH2 ), 6.64±7.76 (m, 25H, Ph). 13 C NMR: d 9.42 (s, Me), 30.09 [dd, J(CP) 48, 37, CH2 ], 99.90 (s, Cp ), 114.87, 116.14, 122.58 (3´s, CN), 125.33 [s, C(3)], 126.43 [s, C(4)], 127.92± 135.85 [m, Ph + C(2)], 153.22 [d, J(CP) 18.9, C(1)], 179.96 [d, J(CP) 19.2, CN]. 31 P NMR: d 13.87 (s, P±C), 58.61 (s, P±Ru). ES mass spectrum (MeOH): 851, [M+H] ; 824, [M CN] ; 621, [Ru(dppm)Cp*] .
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M.I. Bruce et al. / Inorganic Chemistry Communications 4 (2001) 617±620
Scheme 3.
Acknowledgements This work was supported by the Australian Research Council. We thank Johnson Matthey plc, Reading, England for a generous loan of RuCl3 áxH2 O. References [1] A. Davison, J.P. Solar, J. Organomet. Chem. 166 (1979) C13. [2] [a] M.I. Bruce, J.R. Rodgers, M.R. Snow, A.G. Swincer, J. Chem. Soc., Chem. Commun. (1981) 271; [b] M.I. Bruce, T.W. Hambley, M.R. Snow, A.G. Swincer, Organometallics 4 (1985) 494,500.
[3] [a] M.I. Bruce, T.W. Hambley, M.J. Liddell, A.G. Swincer, E.R.T. Tiekink, Organometallics 9 (1990) 2886; [b] M.I. Bruce, P.J. Low, B.W. Skelton, A.H. White, New J. Chem. 22 (1998) 419. [4] [a] M.I. Bruce, T.W. Hambley, M.J. Liddell, M.R. Snow, A.G. Swincer, E.R.T. Tiekink, Organometallics 9 (1990) 96; [b] M.I. Bruce, M. Ke, P.J. Low, B.W. Skelton, A.H. White, Organometallics 17 (1998) 3539; [c] M.I. Bruce, B.C. Hall, B.D. Kelly, P.J. Low, B.W. Skelton, A.H. White, J. Chem. Soc., Dalton Trans. (1999) 3719. [5] J.J. Garcia, W.D. Jones, Organometallics 19 (2000) 5544. [6] M.I. Bruce, B.C. Hall, B.W. Skelton, A.H. White, N.N. Zaitseva, J. Chem. Soc., Dalton Trans. (2000) 2279. [7] [a] K. Krogmann, R. Mattes, Angew. Chem. Int. Ed. Engl. 5 (1966) 1046; [b] T.C. Wright, G. Wilkinson, M. Motevalli, M.B. Hursthouse, J. Chem. Soc., Dalton Trans. (1986) 2017; [c] P.A. Chetcuti, C.B. Knobler, M.F. Hawthorne, Organometallics 7 (1988) 650; [d] S.J. Anderson, F.J. Willis, G. Wilkinson, B. Hussain, M.B. Hursthouse, Polyhedron 7 (1988) 2615; [e] J. Barrera, M. Sabat, W.D. Harman, J. Am. Chem. Soc. 113 (1991) 8178. [8] [a] W.H. Baddley, Inorg. Chim. Acta Rev. 2 (1968) 7; [b] H. K ohler, Z. Chem. 13 (1973) 401; [c] M. Leirer, G. Kn or, A. Vogler, Inorg. Chem. Commun. 2 (1999) 110. [9] S.R. Hall, D.J. du Boulay, R. Olthof-Hazekamp (Eds.), The XT A L 3.7 System, University of Western Australia, Australia, 2000.