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Synthesis, characterization and structural aspects of diorganotellurium(IV) compounds containing (TeS) bonds
Polyhedron Vol. 9, No. 7, PP. Printed in Great Britain
943-948,
1990 0
0277-5387/90 $3.00+.00 1990 Pergamon Press
plc
SYNTHESIS, CHARACTERIZATION AND STRUCTURAL ASPECTS OF DIORGANOTELLURIUM(IV) COMPOUNDS CONTAINING (TM) BONDS T. N. SRIVASTAVA
and JAI DE0
SINGH
Department of Chemistry, University of Lucknow, Lucknow 226007, India and SANJAY
KUMAR
SRIVASTAVA*
School of Studies in Chemistry, Jiwaji University, Gwalior 474011, India (Received 25 April 1989 ; accepted 2 November
1989)
Abstract-Diorganotellurium(IV) compounds containing (Te-S) bonds of the general formulae [R2Te(S2POGQ)d [R = Ph or p-MeOC6H4 ; G = -CH(Me)CH(Me)-, -Me2C-CMe,--, -CH2C(Me2)CH2-, (Me)CHCH,C(Me2)--, CH,C(Et,)CH,-] have been prepared by the reaction of R2Te(OR’), (R’ = Me or.Et) and corresponding O,O’alkylene dithiophosphoric acids or by the reaction of R2TeC12 with [NH,S,POGG] in anhydrous toluene. The products have been characterized using analytical and spectroscopic (IR, ‘H, 13C, 3’P and “‘Te NMR) data. The products are monomeric in nature and their possible structures are discussed.
Although several dithiocarbamates containing the (T-S) bond are well known,le4 the analogous dithiophosphate complexes are scarce.596This may be due to the instability of the products due to their reduction from Ten’ to Te” and the formation of the corresponding disulphides. Recently from this laboratory7-’ and also by other workers, ‘O*’’ it has been reported that diorganotellurium(IV) bis(O,O’dialkyl dithiophosphates) [R2Te{S2P(OR’)2}2] decompose in low boiling solvents into R,Te” and the disulphides [(R’O),P(S)SS(S)P(OR’)~. In view of the increasing interest in (Te-S) bonded compounds, ’ I*12 we report the synthesis and characterization of [R,Te(S,POGQ),] compounds where the alcoholic (OR’) unit of [R2Te{S2P(OR’)2}d is replaced by the glycolic unit. The stability of [R,Te(S,POGQ)d in comparison to that of [R,Te{S,P(OR’),)J derivatives is examined. RESULTS
AND DISCUSSION
The diorganotellurium(IV) bis(O,O’-alkylene dithiophosphates) were synthesized by the reaction
of diorganotellurium(IV) alkoxides in anhydrous toluene by refluxing and removing the alcohol azeotropically or by stirring a mixture of diorganotellurium(IV) dihalide and the ammonium salt of the O,O’-dialkylene dithiophosphoric acids in 1: 2 molar ratio in toluene. Alternatively they may be prepared by the reaction of R2Te0 and corresponding O,O’-alkylene dithiophosphoric acid in -2 R ‘OH
[R = C6H, or p-MeOC,H,-; G = -(CH,)CHCH(CH,)-, --KH,),C-C(CH,),-_, -(CH,),CCH,CHCHs-, ~H2C(C2HWH,-_, CH2C(CH3)2CH2-].
2,2’-dimethoxypropane. The yield of the products in the latter case is less than that by the former [eq. (l)]. Similar reactions in benzene gave products
* Author to whom correspondence should be addressed. 943
T. N. SRIVASTAVA
944
which were different than those expected and are characterized as [R,Te(SaPOGQ)120 or [{R,Te (S,POGQ)),] - HzO. All the reactions [eq. (l)] are facile and are completed by stirring the reactant in toluene (30 min) or by refluxing the reactants in toluene (1 h). The products were obtained in greater than 80% yield in each case. The compounds are yellow, crystalline, sharp melting solids, soluble in all common organic solvents such as MeOH, EtOH, Pr’OH, C6H6, CCL,, CHC13, CH2C12, Me* SO, Me$O, MeCN, etc. They are stable towards atmospheric oxygen and moisture. However, they decompose slowly in low boiling organic solvents according to [eq. (2)] : [R,Te(S2Pm)2]
-
R,Te+[OGOP(S)S-S(S)POGQ]. I-
(2)
They are completely decomposed by keeping them in solution for 24 h or by refluxing them in low boiling solvents such as CH&12, CCL,, CHC13, etc. for l&12 h. The decomposition of the products [R,Te(S,POGQ),] is slower than [R,Te(S, P(OR’),} 23in low boiling solvents. This may be due to the presence of the cyclic ring in the former and an open chain alkoxy group in the latter. The cyclic ring makes the molecules stable.
et al.
IR spectra
IR spectra of these new compounds have been examined in KBr as discs and in CS2 solution in the region 4000-400 cm-‘, and tentative assignments have been made on the basis of earlier reports. I’714 The bands present in the regions 1090-970 and 890-760 cm-’ are assigned to v(P)-O-C and vP-O---(C). A strong to medium band in the region 950-910 cm- ’ is due to rings. A strong band present in the region 685620 cm- ’ in O,O-alkylene dithiophosphoric acids assigned to v(P=S) does not undergo shifts in the compounds reported in the present study. The bands of medium intensity in the region 51&470 cm-’ may be attributed to v(P-S) vibrations. The IR spectra of the products in KBr discs and in CS2 solution are almost similar and do not yield any significant information about the nature of coordination of the diothiophosphate ligand. ‘H NMR spectra The ‘H NMR spectra of the compounds have been recorded in CDC13 and the data are given in Table 2. The ‘H NMR spectra show the characteristic proton resonances of the corresponding
Table 1. Analytical data for [R,Te(S,POGO)J derivatives
Compound
Melting point (“C)
1
[Ph,Te(S,pO(Me)CHCH(Me)Q},]
2
[PhzTe{s,po(Me,)CC(M~~~l
139
3
[Ph,Te{S2PO(Me2)CCH2CH(Me)Q)21
126
4
ph,Te{S,IfOCH,C(EtJCH,Q},]
15.5
5
[Ph,Te{S$OCH,C(Me,)CH,Q},]
108
6
[(p-MeOC,H,),Te{SJfO(Me)CHCH(Me)Q}J
7
[(p-MeOCgH4),Te{S,qO(Me,)CC(Me*)8}d
149
8
[(p-MeOCgH4),Te{S,PO(Me,)CCH,CH(Me)Q},]
153
9
[(p-MeOCgH4),Te{S,f’OCH,C(Et,)CH,Q},]
160d
[(p-MeOCgH4),Te{S,~OCH,C(Me,)CHzQ}2]
137
10
Viscous
Te 19.4 (19.7) 18.0 (18.1) 18.0 (18.1) 17.4 (17.4) 18.7 (18.9) 17.8 (18.0) 16.6 (16.7) 16.4 (16.7) 16.0 (16.1) 17.1 (17.3)
Elemental analysis ; Found( %) (Calc.) C H 36.9 (37.0) 40.5 (40.9) 40.7 (40.9) 42.3 (42.6) 38.9 (39.1) 37.1 (37.3) 40.4 (40.8) 40.7 (40.8) 42.3 (42.4) 39.1 (39.1)
S
3.8 (4.0) 4.6 (4.8) 4.6 (4.8) 5.1 (5.2) 4.5 (4.4)
19.5 (19.7) 18.0 (18.2) 18.0 (18.2) 17.3 (17.5) 18.6 (18.9)
(Z) 4.6 (5.0)
(Z) 16.6 (16.8)
(Z) 5.1 (5.3)
(Z) 16.1 (16.2)
(Z)
(K)
Diorganotellurium(IV) compounds alkylene as well as aryl groups. A sharp singlet at 6 3.15-3.7 due to the S-H protons of free acids is absent in the spectra of the compounds indicating elimination of “H” of the acid derivatives on compound formation. 13CNMR spectra 13C NMR spectra of the representative complexes were recorded and the data are summarized in Table 3. The 13C resonances of the compounds show that the two 0,0-alkylene dithiophosphate ligands are equivalent.
3‘P NMR spectra The 3’P chemical shift values depend on the size
of the glycol ring. In the case of five-membered rings [G = -C(Me,)C(Me,)-, -CH [S,POGQ](Me)CH(Me)-] the 31P signals are not very different from those in the free ligands, indicating monodentate coordination of the O,O-alkylene dithiophosphate ligand. In the case of the six-membered glycol rings, G = -CH(Me)CH,C(Me2)-, -CH,C(Me,)CH,-, -CH2C(Et2)CHr--, a shift of N IO-15 ppm in the 31P signals is observed in comparison to that in the free acids. The downfield chemical shift indicates a chelated structure with bidentate alkylene dithiophosphate groups. I5 125TeNMR spectra ‘25Te NMR spectra of a few representative compounds have been recorded in C6H6 and CHCl, and are listed in Table 3. Only a single peak was observed. However, at high scans instead of the product signal (“‘Te chemical shift) another peak was observed at 724.8 ppm in the case of [(pMeOC,H,)2Te(S2POGQ)2] and at 689 ppm in the case of [Ph2Te(S2POGQ)2], corresponding to R,Te (R = p-MeOC6H4and Ph) indicating a slow decomposition of the products’ 6in solution [Tel”-+ Te”]. Structure and bonding
The 3’P NMR spectra of the products show that there are two modes of bonding in [R,Te (S2POGQ)d derivatives. Where the glycol unit is five-membered, monodentate bonding of alkylene dithiophosphate ligand is observed, while in the case of six-membered glycol units a bidentate nature of the ligand is indicated. The change in the bonding may be explained as due to the electron-releasing effect of the alkyl groups in the six-membered ring is more than that
945
in the five-membered ring. Further, the soft nature of the Te4+ species and also that of the ligand enables a soft-soft interaction of the metal and ligand atom, the bidentate nature of the ligand more plausible. The unusual behaviour of the two types of ligand (five- and six-membered glycol unit) also seems to be due to stereochemical activity I7 of the lone pair present in the tellurium(IV) species (as observed in many Te-S compounds where the tellurium(IV) lone pair is stereochemically active) or it may be due secondary interactions”*19 between tellurium and the non-bonded sulphur atom of the ligand. Thus for [R,Te(S,POGQ),] two possible structures may be suggested for five- and six-membered glycol units of the alkylene dithiophosphate ligands and these are consistent with the reported X-ray crystal structure of R2TeX2 derivatives.‘2*‘9
k
(R = Ph or p-MeOC,H,) G = -CH2C(Me,)CH,-, -CH(Me)CH,C(Me,)-, -CH,C(Et2)CH, G = ---CH(Me)CH(Me)---, -C(MeNMedScheme1.
EXPERIMENTAL
All manipulations were carried out under a dry nitrogen atmosphere. TeCl, (BDH) was used as such, and Ph,TeCl, (ref. 20) and (p-MeOC,H,), TeC12 (ref. 21) were prepared according to the established procedures. Solvents were purified and dried by standard procedures. Alkylene dithiophosphoric acids, HS,POGQ, and their ammonium salts were prepared by reported methods22,23 by passing dry ammonia through a benzene solution of the acids. R,Te(OR’), (R = Me or Et) were prepared in situ by reaction of R,TeCl, with the corresponding sodium or potassium alkoxides in benzene. ‘H, 13C, 31P and ‘25Te NMR spectra were recorded on a Jeol Fx 90 Q FT NMR spectrometer and other physicochemical studies were made as
m, 10H(C,HrTe)
m, 10H(C,HrTe) m, 10H(C,HrTe)
7.83-7.30, 7.867.30, 7.83-7.17, 8.05-7.34,
Ph,Te{S$o(MeJCC(Mez>Q>21
~h,Te{S,~O(Me,)CCH$H(Me)o),l
[PhzTe{S,qOCH,C(Et2)CH@}J
m, 2H(OCH),
5.144.44,
8.05-7.6, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.084.8, d, 4H(metu protons) (JH_-H = 9.0 Hz) 3.78, s, 6H(OCH3)
m, 2H(OCH),
1.05, s, 12H(CH3)
2.1-1.14, m, 22H(CH,,
0.99, s, 12H(CH,)
1.62-1.23, d, 12H(CH3)
4.25-3.74, d, 8H(OCH,), 1.67-1.1, q, 8H(CH2, CH,), 1.1-0.51, t, 12H(CHJ
CH,)
0.96, s, 24H(CHJ
8.00-7.6, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.08-6.8, d, 4H(meta protons) (JH_-H = 9.0 Hz) ; 3.80, s, 6H(OCH,)
d, IH(OCH,),
4.Oc3.9,
d, 8H(OCH3, d, 4H(OCH),
8.Os7.43, d, 4H(orrho protons) (JH_-H = 9.0 Hz) ; 7.08-6.55, d, 4H(meta protons) (.&_, = 9.0 Hz), 3.82, s, 6H(OCH,)
4.22-3.87, 4.84-4.00,
8.03-7.68, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.14.67, d, 4H(meta protons) (JH_-H = 9.0 Hz) ; 3.82, s, 6H(OCH,)
1.89-0.83, m, 22H(CH2,
1.67-1.18, d, 12H, d(-CH,)
Alkyl protons
4.26-3.74, d, 8H(OCHJ, 1.67-1.05, q, 8H(CH,, CH& 1.01-0.57, t, 12H(CH,)
CH,)
5.104.66,
1.45, s, 24H(CH,)
4.22, m, 4H(OCH),
7.967.39, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.046.51, d, 4H(meta protons) (JH_-H = 9 Hz) ; 3.78, s, 6H(OCH,)
m, 10H(C,HrTe)
m, 10H(C,HrTe)
7.87-7.35,
Aryl protons
ph,Te{S$O(Me)CHCH(Me)Q)J
Compound
Table 2. ‘H NMR spectral data for [R2Te(S2~)J
’ “P NMR signals for the free ligands.
881.55(&H,) 889.66(&H,) 883.19(CHC13)
92.16(C6H6) 94.48(C,H,) 89.16(CHCl3)
134.91(C), 132.09(C,), 130.79(C.J, 126.78(C3), aryl carbons, 86.50, 84.76(C-Me,); 71.60, 71.10(CH2), 76.80, 75.60(CH); 21.16, 20.98, 31.17, 30.88,43.55, 43.17, [C(CH,), and CH,CH]
867.70(C,H,) 97.63(C,H6)
-
900.70(CHC13)
-
97.13(&H,) [(77.73)C,H,]
95.53(CHCl,) [(95.41)CHCl,]
886.7(C,H,) 877.86(CH3CN)
884.68(CsH6)
93.06(CHC13) 122.05(DMSO)
121.67(Cl), 139.44(C2), 115.60(C3), 161.49(C,), 55.3(C,), aryl carbons; 82.67, 81.26, (OCH); 17.55, 17.17(OCHCH3)
[(p-MeOC,H&Te{S,POCHMeCHMeQ),I
](78.98)(C,H,)l
88.53(CHC13) 87.48(&H,)
92.21(C,H,) 91.51(CH,Cl,) 112.51(DMSO) [(78.77)CHC13]
‘*‘Te NMR
134.91(C2), 132.04(Cl), 130.74(C4), 127.38(C3); aryl carbons, 24.46, 24.24 (CMe,), 90.06, 89.17C(Me,)
125.4(Cl), 139.5(C2), 115.2(C3), 161.47(&), 54.9(C,), aryl carbons; 86.67, 81.19(C-Me,); 71.29, 70.96(CH,), 76.95, 75.11(CH), 21.37, 20.99, 31.07, 30.75, 43.38, 43.05 [C(CH,), and CH,CH]
129.48(Cl), 138.15(C2), 116.81(C3), 163.02(C,), 54.34(C5), aryl carbons; 77.80, 77.42(QCH2); 2244(CH,), 33.65, 33.33 [C(CH,),]
3 ‘P NMR 93.17(CHC13) [92.98(CHC13)]
shift (6) ppm
91.10,
Chemical
122.7(C,), 138.98(&), 115.60(C3), 160.80(&); 55.4(CJ, aryl carbons; 24.90, 24.26 C(CH,),; 90.70, CMe,
13C NMR
[(p-MeOC,HJ,Te{S,POCMe,CH,CHMeQ},]
Compounds
Table 3. 13C, 3’P and ‘*‘Te NMR spectral data for [R,Te(S,PB)J
948
T. N. SRIVASTAVA et al.
described earlier. 7 Some are described for the
representative preparation
reactions of [R,Te
(C6H,--Te); 4.2fL3.85, d, 16H (OCH*); 1.02, s, 24H (CH,) ; HzO, 6 3.35 (br).
and pH4S2
Acknowledgements-Financial support from the CSIR and UGC, New Delhi, for the present work is gratefully acknowledged.
~S2poc9)21. (a) Reaction of (p-MeOCsH,),TeC1, POC(Me3C(MeJQ]
REFERENCES
To a stirring suspension of [NH,S,POC(Me,) C(Me,)G] (4.58 g, 20 mmol) in toluene (25 cm3) was added a solution of (P-MeOC6H&TeC12 (4.12 g, 10 mmol) in toluene (50 cm’). The reaction mixture was stirred for 1 h. Filtration followed by the distillation of the solvent gave the yellow product which was recrystallized from toluenen-pentane (1 : 5 ratio). (b) Reaction of R,Te(OR’),
and [HSJ’OGQ]
In a representative reaction, a mixture of Ph*Te (OC$H& was prepared by the reaction of sodium (0.46 g, 20 mmol) and Ph,TeCl, (3.52 g, 10 mmol) in ethanol. The solution was filtered to remove NaCl, and to the concentrated viscous mass in toluene (20 cm’) was added [HS$OCH,C(Me,)CH@] (3.96 g, 20 mmol) in toluene (10 cm3). The reaction mixture was refluxed for 1 h and ethanol was removed azeotropically. The solvent was removed under reduced pressure and dried in vacua giving a yellow viscous mass which was recrystallized a toluene-pentane (1 : 9 ratio) mixture.
from
(c) Reaction of Ph,TeO and [H&Pm]
Ph,TeO (2.97 g, 10 mmol) and [HS2POCH2 C(Me,)CH,G] (3.96 g, 20 mmol) were refluxed together in anhydrous benzene (60 cm3). The water was removed azeotropically. The yellow product thus obtained was identified as Ph2Te(S,POCH2 C(Me2)CH2Q)20 after several washings with CH-pet-ether mixture :
+H,0+2[HS2PG_CH,C(Me,)CH2Q]. 31P NMR signals at 6 91.98 (C,H,). Found (%) (Calc.): C, 48.1 (48.2); H, 4.6(4.7); S, 14.9 (15.1); Te, 14.9 (15.1%). The products are slightly soluble in common organic solvents. When a similar reaction was carried out in methanol and the solution was filtered and allowed to evaporate slowly, yellow crystals of [{Ph,Te(S,POCH2CMe2CH2Q)}20]2 HZ0 were produced. 3‘P NMR signals at 6 91.87 (C,H&. Found (%) (Calc.): C, 41.4 (41.5); H, 4.0 (4.2); S, 13.0 (13.0); Te, 25.6 (26.0%); ‘H NMR spectra (CDCl,): 6 7.96-7.22, m, 40H
1. W. R. McWhinnie and J. E. Stuckey, The Use of Selenium and Tellurium in Rubber Technology. Selenium & Tellurium Development Corp. Inc. (1983). 2. M. A. K. Ahmed, W. R. McWhinnie and P. Granger, Polyhedron 1986,5, 859. 3. S. Husebye, in Proceedings of the Fourth International Conference on the Organic Chemistry of Selenium and Tellurium (Edited by F. J. Berry and W. R. McWhinnie), pp. 298-369. University of Aston in Birmingham (1983). N. Zumbulyadis and H. J. Glysling, Znorg. Chem. 1982,21, 564. S. Husebye, Acta Chem. Stand. 196519, 1045. L. S. Refaat, M. K. Maartmann and S. Husebye, Acta Chem. Stand. 1984,38A, 147. T. N. Srivastava, Jai Deo Singh and Sanjay Kumar Srivastava, Phosphorus Sulfur 1989, submitted for publication. 8. T. N. Srivastava, J. D. Singh and S. K. Srivastava, Synth. React. Inorg. Met. Org. Chem. 1989, in press. 9. Jai Deo Singh, PhD thesis, Lucknow University, India (1985). 10. D. Dakternieks, R. D. Giacomo, R. W. Gable and B. F. Hoskins, .J. Organomet. Chem. 1988,349, 305. 11. D. Dakternieks, R. D. Giacomo, R. W. Gable and B. F. Hoskins, J. Am. Chem. Sot. 1988, 110, 6541, 6753 and 6762. 12. R. K. Chadha, J. E. Drakes, N. T. McManus, B. A. Quinlan and A. B. Sarkar, Organometallics 1987,6, 813. 13. R. J. Rao, G. Srivastava, R. C. Mehrotra, B. S. Saraswat and J. Mason, Polyhedron 1984, 3,485. 14. C. P. Bhasin, G. Srivastava and R. C. Mehrotra, Inorg. Chim. Acta 1983, 77, L131. 15. C. Glidewell, Znorg. Chim. Acta 1977, 25, 159. 16. C. Rodger, N. Sheppard, C. Mcfarlane and W. Mcfarlane, in NMR and Periodic Table (Edited by R. V. Harris and B. F. Mann), p. 383. Academic Press, London (1978). 17. S. Esperas, J. W. George, S. Husebye and 0. Mikalsen, Acta Chim. Stand. 1975, 29A, 141. 18. N. W. Alcock, Adv. Inorg. Chem. Radiochem. 1972, 15, 1. 19. N. W. Alcock and W. D. Harrison, J. Chem. Sot., Dalton Trans. 1984, 869. 20. R. C. Paul, K. K. Bhasin and R. K. Chadha, J. Znorg. Nucl. Chem. 1975,37,2337. 21. J. Bergman, Tetrahedron 1972,37, 3323. 22. G. M. Kosolapoff and L. Maier, Organic Phosphorus Compounds, Vol. 7, p. 519. John Wiley, New York (1976). 23. H. P. S. Chauhan, C. P. Bhasin, G. Srivastava and R. C. Mehrotra, Phosphorus Sulfur 1983,15,99.
943-948,
1990 0
0277-5387/90 $3.00+.00 1990 Pergamon Press
plc
SYNTHESIS, CHARACTERIZATION AND STRUCTURAL ASPECTS OF DIORGANOTELLURIUM(IV) COMPOUNDS CONTAINING (TM) BONDS T. N. SRIVASTAVA
and JAI DE0
SINGH
Department of Chemistry, University of Lucknow, Lucknow 226007, India and SANJAY
KUMAR
SRIVASTAVA*
School of Studies in Chemistry, Jiwaji University, Gwalior 474011, India (Received 25 April 1989 ; accepted 2 November
1989)
Abstract-Diorganotellurium(IV) compounds containing (Te-S) bonds of the general formulae [R2Te(S2POGQ)d [R = Ph or p-MeOC6H4 ; G = -CH(Me)CH(Me)-, -Me2C-CMe,--, -CH2C(Me2)CH2-, (Me)CHCH,C(Me2)--, CH,C(Et,)CH,-] have been prepared by the reaction of R2Te(OR’), (R’ = Me or.Et) and corresponding O,O’alkylene dithiophosphoric acids or by the reaction of R2TeC12 with [NH,S,POGG] in anhydrous toluene. The products have been characterized using analytical and spectroscopic (IR, ‘H, 13C, 3’P and “‘Te NMR) data. The products are monomeric in nature and their possible structures are discussed.
Although several dithiocarbamates containing the (T-S) bond are well known,le4 the analogous dithiophosphate complexes are scarce.596This may be due to the instability of the products due to their reduction from Ten’ to Te” and the formation of the corresponding disulphides. Recently from this laboratory7-’ and also by other workers, ‘O*’’ it has been reported that diorganotellurium(IV) bis(O,O’dialkyl dithiophosphates) [R2Te{S2P(OR’)2}2] decompose in low boiling solvents into R,Te” and the disulphides [(R’O),P(S)SS(S)P(OR’)~. In view of the increasing interest in (Te-S) bonded compounds, ’ I*12 we report the synthesis and characterization of [R,Te(S,POGQ),] compounds where the alcoholic (OR’) unit of [R2Te{S2P(OR’)2}d is replaced by the glycolic unit. The stability of [R,Te(S,POGQ)d in comparison to that of [R,Te{S,P(OR’),)J derivatives is examined. RESULTS
AND DISCUSSION
The diorganotellurium(IV) bis(O,O’-alkylene dithiophosphates) were synthesized by the reaction
of diorganotellurium(IV) alkoxides in anhydrous toluene by refluxing and removing the alcohol azeotropically or by stirring a mixture of diorganotellurium(IV) dihalide and the ammonium salt of the O,O’-dialkylene dithiophosphoric acids in 1: 2 molar ratio in toluene. Alternatively they may be prepared by the reaction of R2Te0 and corresponding O,O’-alkylene dithiophosphoric acid in -2 R ‘OH
[R = C6H, or p-MeOC,H,-; G = -(CH,)CHCH(CH,)-, --KH,),C-C(CH,),-_, -(CH,),CCH,CHCHs-, ~H2C(C2HWH,-_, CH2C(CH3)2CH2-].
2,2’-dimethoxypropane. The yield of the products in the latter case is less than that by the former [eq. (l)]. Similar reactions in benzene gave products
* Author to whom correspondence should be addressed. 943
T. N. SRIVASTAVA
944
which were different than those expected and are characterized as [R,Te(SaPOGQ)120 or [{R,Te (S,POGQ)),] - HzO. All the reactions [eq. (l)] are facile and are completed by stirring the reactant in toluene (30 min) or by refluxing the reactants in toluene (1 h). The products were obtained in greater than 80% yield in each case. The compounds are yellow, crystalline, sharp melting solids, soluble in all common organic solvents such as MeOH, EtOH, Pr’OH, C6H6, CCL,, CHC13, CH2C12, Me* SO, Me$O, MeCN, etc. They are stable towards atmospheric oxygen and moisture. However, they decompose slowly in low boiling organic solvents according to [eq. (2)] : [R,Te(S2Pm)2]
-
R,Te+[OGOP(S)S-S(S)POGQ]. I-
(2)
They are completely decomposed by keeping them in solution for 24 h or by refluxing them in low boiling solvents such as CH&12, CCL,, CHC13, etc. for l&12 h. The decomposition of the products [R,Te(S,POGQ),] is slower than [R,Te(S, P(OR’),} 23in low boiling solvents. This may be due to the presence of the cyclic ring in the former and an open chain alkoxy group in the latter. The cyclic ring makes the molecules stable.
et al.
IR spectra
IR spectra of these new compounds have been examined in KBr as discs and in CS2 solution in the region 4000-400 cm-‘, and tentative assignments have been made on the basis of earlier reports. I’714 The bands present in the regions 1090-970 and 890-760 cm-’ are assigned to v(P)-O-C and vP-O---(C). A strong to medium band in the region 950-910 cm- ’ is due to rings. A strong band present in the region 685620 cm- ’ in O,O-alkylene dithiophosphoric acids assigned to v(P=S) does not undergo shifts in the compounds reported in the present study. The bands of medium intensity in the region 51&470 cm-’ may be attributed to v(P-S) vibrations. The IR spectra of the products in KBr discs and in CS2 solution are almost similar and do not yield any significant information about the nature of coordination of the diothiophosphate ligand. ‘H NMR spectra The ‘H NMR spectra of the compounds have been recorded in CDC13 and the data are given in Table 2. The ‘H NMR spectra show the characteristic proton resonances of the corresponding
Table 1. Analytical data for [R,Te(S,POGO)J derivatives
Compound
Melting point (“C)
1
[Ph,Te(S,pO(Me)CHCH(Me)Q},]
2
[PhzTe{s,po(Me,)CC(M~~~l
139
3
[Ph,Te{S2PO(Me2)CCH2CH(Me)Q)21
126
4
ph,Te{S,IfOCH,C(EtJCH,Q},]
15.5
5
[Ph,Te{S$OCH,C(Me,)CH,Q},]
108
6
[(p-MeOC,H,),Te{SJfO(Me)CHCH(Me)Q}J
7
[(p-MeOCgH4),Te{S,qO(Me,)CC(Me*)8}d
149
8
[(p-MeOCgH4),Te{S,PO(Me,)CCH,CH(Me)Q},]
153
9
[(p-MeOCgH4),Te{S,f’OCH,C(Et,)CH,Q},]
160d
[(p-MeOCgH4),Te{S,~OCH,C(Me,)CHzQ}2]
137
10
Viscous
Te 19.4 (19.7) 18.0 (18.1) 18.0 (18.1) 17.4 (17.4) 18.7 (18.9) 17.8 (18.0) 16.6 (16.7) 16.4 (16.7) 16.0 (16.1) 17.1 (17.3)
Elemental analysis ; Found( %) (Calc.) C H 36.9 (37.0) 40.5 (40.9) 40.7 (40.9) 42.3 (42.6) 38.9 (39.1) 37.1 (37.3) 40.4 (40.8) 40.7 (40.8) 42.3 (42.4) 39.1 (39.1)
S
3.8 (4.0) 4.6 (4.8) 4.6 (4.8) 5.1 (5.2) 4.5 (4.4)
19.5 (19.7) 18.0 (18.2) 18.0 (18.2) 17.3 (17.5) 18.6 (18.9)
(Z) 4.6 (5.0)
(Z) 16.6 (16.8)
(Z) 5.1 (5.3)
(Z) 16.1 (16.2)
(Z)
(K)
Diorganotellurium(IV) compounds alkylene as well as aryl groups. A sharp singlet at 6 3.15-3.7 due to the S-H protons of free acids is absent in the spectra of the compounds indicating elimination of “H” of the acid derivatives on compound formation. 13CNMR spectra 13C NMR spectra of the representative complexes were recorded and the data are summarized in Table 3. The 13C resonances of the compounds show that the two 0,0-alkylene dithiophosphate ligands are equivalent.
3‘P NMR spectra The 3’P chemical shift values depend on the size
of the glycol ring. In the case of five-membered rings [G = -C(Me,)C(Me,)-, -CH [S,POGQ](Me)CH(Me)-] the 31P signals are not very different from those in the free ligands, indicating monodentate coordination of the O,O-alkylene dithiophosphate ligand. In the case of the six-membered glycol rings, G = -CH(Me)CH,C(Me2)-, -CH,C(Me,)CH,-, -CH2C(Et2)CHr--, a shift of N IO-15 ppm in the 31P signals is observed in comparison to that in the free acids. The downfield chemical shift indicates a chelated structure with bidentate alkylene dithiophosphate groups. I5 125TeNMR spectra ‘25Te NMR spectra of a few representative compounds have been recorded in C6H6 and CHCl, and are listed in Table 3. Only a single peak was observed. However, at high scans instead of the product signal (“‘Te chemical shift) another peak was observed at 724.8 ppm in the case of [(pMeOC,H,)2Te(S2POGQ)2] and at 689 ppm in the case of [Ph2Te(S2POGQ)2], corresponding to R,Te (R = p-MeOC6H4and Ph) indicating a slow decomposition of the products’ 6in solution [Tel”-+ Te”]. Structure and bonding
The 3’P NMR spectra of the products show that there are two modes of bonding in [R,Te (S2POGQ)d derivatives. Where the glycol unit is five-membered, monodentate bonding of alkylene dithiophosphate ligand is observed, while in the case of six-membered glycol units a bidentate nature of the ligand is indicated. The change in the bonding may be explained as due to the electron-releasing effect of the alkyl groups in the six-membered ring is more than that
945
in the five-membered ring. Further, the soft nature of the Te4+ species and also that of the ligand enables a soft-soft interaction of the metal and ligand atom, the bidentate nature of the ligand more plausible. The unusual behaviour of the two types of ligand (five- and six-membered glycol unit) also seems to be due to stereochemical activity I7 of the lone pair present in the tellurium(IV) species (as observed in many Te-S compounds where the tellurium(IV) lone pair is stereochemically active) or it may be due secondary interactions”*19 between tellurium and the non-bonded sulphur atom of the ligand. Thus for [R,Te(S,POGQ),] two possible structures may be suggested for five- and six-membered glycol units of the alkylene dithiophosphate ligands and these are consistent with the reported X-ray crystal structure of R2TeX2 derivatives.‘2*‘9
k
(R = Ph or p-MeOC,H,) G = -CH2C(Me,)CH,-, -CH(Me)CH,C(Me,)-, -CH,C(Et2)CH, G = ---CH(Me)CH(Me)---, -C(MeNMedScheme1.
EXPERIMENTAL
All manipulations were carried out under a dry nitrogen atmosphere. TeCl, (BDH) was used as such, and Ph,TeCl, (ref. 20) and (p-MeOC,H,), TeC12 (ref. 21) were prepared according to the established procedures. Solvents were purified and dried by standard procedures. Alkylene dithiophosphoric acids, HS,POGQ, and their ammonium salts were prepared by reported methods22,23 by passing dry ammonia through a benzene solution of the acids. R,Te(OR’), (R = Me or Et) were prepared in situ by reaction of R,TeCl, with the corresponding sodium or potassium alkoxides in benzene. ‘H, 13C, 31P and ‘25Te NMR spectra were recorded on a Jeol Fx 90 Q FT NMR spectrometer and other physicochemical studies were made as
m, 10H(C,HrTe)
m, 10H(C,HrTe) m, 10H(C,HrTe)
7.83-7.30, 7.867.30, 7.83-7.17, 8.05-7.34,
Ph,Te{S$o(MeJCC(Mez>Q>21
~h,Te{S,~O(Me,)CCH$H(Me)o),l
[PhzTe{S,qOCH,C(Et2)CH@}J
m, 2H(OCH),
5.144.44,
8.05-7.6, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.084.8, d, 4H(metu protons) (JH_-H = 9.0 Hz) 3.78, s, 6H(OCH3)
m, 2H(OCH),
1.05, s, 12H(CH3)
2.1-1.14, m, 22H(CH,,
0.99, s, 12H(CH,)
1.62-1.23, d, 12H(CH3)
4.25-3.74, d, 8H(OCH,), 1.67-1.1, q, 8H(CH2, CH,), 1.1-0.51, t, 12H(CHJ
CH,)
0.96, s, 24H(CHJ
8.00-7.6, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.08-6.8, d, 4H(meta protons) (JH_-H = 9.0 Hz) ; 3.80, s, 6H(OCH,)
d, IH(OCH,),
4.Oc3.9,
d, 8H(OCH3, d, 4H(OCH),
8.Os7.43, d, 4H(orrho protons) (JH_-H = 9.0 Hz) ; 7.08-6.55, d, 4H(meta protons) (.&_, = 9.0 Hz), 3.82, s, 6H(OCH,)
4.22-3.87, 4.84-4.00,
8.03-7.68, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.14.67, d, 4H(meta protons) (JH_-H = 9.0 Hz) ; 3.82, s, 6H(OCH,)
1.89-0.83, m, 22H(CH2,
1.67-1.18, d, 12H, d(-CH,)
Alkyl protons
4.26-3.74, d, 8H(OCHJ, 1.67-1.05, q, 8H(CH,, CH& 1.01-0.57, t, 12H(CH,)
CH,)
5.104.66,
1.45, s, 24H(CH,)
4.22, m, 4H(OCH),
7.967.39, d, 4H(ortho protons) (JH_-H = 9.0 Hz); 7.046.51, d, 4H(meta protons) (JH_-H = 9 Hz) ; 3.78, s, 6H(OCH,)
m, 10H(C,HrTe)
m, 10H(C,HrTe)
7.87-7.35,
Aryl protons
ph,Te{S$O(Me)CHCH(Me)Q)J
Compound
Table 2. ‘H NMR spectral data for [R2Te(S2~)J
’ “P NMR signals for the free ligands.
881.55(&H,) 889.66(&H,) 883.19(CHC13)
92.16(C6H6) 94.48(C,H,) 89.16(CHCl3)
134.91(C), 132.09(C,), 130.79(C.J, 126.78(C3), aryl carbons, 86.50, 84.76(C-Me,); 71.60, 71.10(CH2), 76.80, 75.60(CH); 21.16, 20.98, 31.17, 30.88,43.55, 43.17, [C(CH,), and CH,CH]
867.70(C,H,) 97.63(C,H6)
-
900.70(CHC13)
-
97.13(&H,) [(77.73)C,H,]
95.53(CHCl,) [(95.41)CHCl,]
886.7(C,H,) 877.86(CH3CN)
884.68(CsH6)
93.06(CHC13) 122.05(DMSO)
121.67(Cl), 139.44(C2), 115.60(C3), 161.49(C,), 55.3(C,), aryl carbons; 82.67, 81.26, (OCH); 17.55, 17.17(OCHCH3)
[(p-MeOC,H&Te{S,POCHMeCHMeQ),I
](78.98)(C,H,)l
88.53(CHC13) 87.48(&H,)
92.21(C,H,) 91.51(CH,Cl,) 112.51(DMSO) [(78.77)CHC13]
‘*‘Te NMR
134.91(C2), 132.04(Cl), 130.74(C4), 127.38(C3); aryl carbons, 24.46, 24.24 (CMe,), 90.06, 89.17C(Me,)
125.4(Cl), 139.5(C2), 115.2(C3), 161.47(&), 54.9(C,), aryl carbons; 86.67, 81.19(C-Me,); 71.29, 70.96(CH,), 76.95, 75.11(CH), 21.37, 20.99, 31.07, 30.75, 43.38, 43.05 [C(CH,), and CH,CH]
129.48(Cl), 138.15(C2), 116.81(C3), 163.02(C,), 54.34(C5), aryl carbons; 77.80, 77.42(QCH2); 2244(CH,), 33.65, 33.33 [C(CH,),]
3 ‘P NMR 93.17(CHC13) [92.98(CHC13)]
shift (6) ppm
91.10,
Chemical
122.7(C,), 138.98(&), 115.60(C3), 160.80(&); 55.4(CJ, aryl carbons; 24.90, 24.26 C(CH,),; 90.70, CMe,
13C NMR
[(p-MeOC,HJ,Te{S,POCMe,CH,CHMeQ},]
Compounds
Table 3. 13C, 3’P and ‘*‘Te NMR spectral data for [R,Te(S,PB)J
948
T. N. SRIVASTAVA et al.
described earlier. 7 Some are described for the
representative preparation
reactions of [R,Te
(C6H,--Te); 4.2fL3.85, d, 16H (OCH*); 1.02, s, 24H (CH,) ; HzO, 6 3.35 (br).
and pH4S2
Acknowledgements-Financial support from the CSIR and UGC, New Delhi, for the present work is gratefully acknowledged.
~S2poc9)21. (a) Reaction of (p-MeOCsH,),TeC1, POC(Me3C(MeJQ]
REFERENCES
To a stirring suspension of [NH,S,POC(Me,) C(Me,)G] (4.58 g, 20 mmol) in toluene (25 cm3) was added a solution of (P-MeOC6H&TeC12 (4.12 g, 10 mmol) in toluene (50 cm’). The reaction mixture was stirred for 1 h. Filtration followed by the distillation of the solvent gave the yellow product which was recrystallized from toluenen-pentane (1 : 5 ratio). (b) Reaction of R,Te(OR’),
and [HSJ’OGQ]
In a representative reaction, a mixture of Ph*Te (OC$H& was prepared by the reaction of sodium (0.46 g, 20 mmol) and Ph,TeCl, (3.52 g, 10 mmol) in ethanol. The solution was filtered to remove NaCl, and to the concentrated viscous mass in toluene (20 cm’) was added [HS$OCH,C(Me,)CH@] (3.96 g, 20 mmol) in toluene (10 cm3). The reaction mixture was refluxed for 1 h and ethanol was removed azeotropically. The solvent was removed under reduced pressure and dried in vacua giving a yellow viscous mass which was recrystallized a toluene-pentane (1 : 9 ratio) mixture.
from
(c) Reaction of Ph,TeO and [H&Pm]
Ph,TeO (2.97 g, 10 mmol) and [HS2POCH2 C(Me,)CH,G] (3.96 g, 20 mmol) were refluxed together in anhydrous benzene (60 cm3). The water was removed azeotropically. The yellow product thus obtained was identified as Ph2Te(S,POCH2 C(Me2)CH2Q)20 after several washings with CH-pet-ether mixture :
+H,0+2[HS2PG_CH,C(Me,)CH2Q]. 31P NMR signals at 6 91.98 (C,H,). Found (%) (Calc.): C, 48.1 (48.2); H, 4.6(4.7); S, 14.9 (15.1); Te, 14.9 (15.1%). The products are slightly soluble in common organic solvents. When a similar reaction was carried out in methanol and the solution was filtered and allowed to evaporate slowly, yellow crystals of [{Ph,Te(S,POCH2CMe2CH2Q)}20]2 HZ0 were produced. 3‘P NMR signals at 6 91.87 (C,H&. Found (%) (Calc.): C, 41.4 (41.5); H, 4.0 (4.2); S, 13.0 (13.0); Te, 25.6 (26.0%); ‘H NMR spectra (CDCl,): 6 7.96-7.22, m, 40H
1. W. R. McWhinnie and J. E. Stuckey, The Use of Selenium and Tellurium in Rubber Technology. Selenium & Tellurium Development Corp. Inc. (1983). 2. M. A. K. Ahmed, W. R. McWhinnie and P. Granger, Polyhedron 1986,5, 859. 3. S. Husebye, in Proceedings of the Fourth International Conference on the Organic Chemistry of Selenium and Tellurium (Edited by F. J. Berry and W. R. McWhinnie), pp. 298-369. University of Aston in Birmingham (1983). N. Zumbulyadis and H. J. Glysling, Znorg. Chem. 1982,21, 564. S. Husebye, Acta Chem. Stand. 196519, 1045. L. S. Refaat, M. K. Maartmann and S. Husebye, Acta Chem. Stand. 1984,38A, 147. T. N. Srivastava, Jai Deo Singh and Sanjay Kumar Srivastava, Phosphorus Sulfur 1989, submitted for publication. 8. T. N. Srivastava, J. D. Singh and S. K. Srivastava, Synth. React. Inorg. Met. Org. Chem. 1989, in press. 9. Jai Deo Singh, PhD thesis, Lucknow University, India (1985). 10. D. Dakternieks, R. D. Giacomo, R. W. Gable and B. F. Hoskins, .J. Organomet. Chem. 1988,349, 305. 11. D. Dakternieks, R. D. Giacomo, R. W. Gable and B. F. Hoskins, J. Am. Chem. Sot. 1988, 110, 6541, 6753 and 6762. 12. R. K. Chadha, J. E. Drakes, N. T. McManus, B. A. Quinlan and A. B. Sarkar, Organometallics 1987,6, 813. 13. R. J. Rao, G. Srivastava, R. C. Mehrotra, B. S. Saraswat and J. Mason, Polyhedron 1984, 3,485. 14. C. P. Bhasin, G. Srivastava and R. C. Mehrotra, Inorg. Chim. Acta 1983, 77, L131. 15. C. Glidewell, Znorg. Chim. Acta 1977, 25, 159. 16. C. Rodger, N. Sheppard, C. Mcfarlane and W. Mcfarlane, in NMR and Periodic Table (Edited by R. V. Harris and B. F. Mann), p. 383. Academic Press, London (1978). 17. S. Esperas, J. W. George, S. Husebye and 0. Mikalsen, Acta Chim. Stand. 1975, 29A, 141. 18. N. W. Alcock, Adv. Inorg. Chem. Radiochem. 1972, 15, 1. 19. N. W. Alcock and W. D. Harrison, J. Chem. Sot., Dalton Trans. 1984, 869. 20. R. C. Paul, K. K. Bhasin and R. K. Chadha, J. Znorg. Nucl. Chem. 1975,37,2337. 21. J. Bergman, Tetrahedron 1972,37, 3323. 22. G. M. Kosolapoff and L. Maier, Organic Phosphorus Compounds, Vol. 7, p. 519. John Wiley, New York (1976). 23. H. P. S. Chauhan, C. P. Bhasin, G. Srivastava and R. C. Mehrotra, Phosphorus Sulfur 1983,15,99.