Organometallics 1995, 14, 2047-2056
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Organometallic Chemistry of Diphosphazanes. 112 Reactions of fuc- [Mo(CO)s(MeCN){ q2-Ph2PN(Pri)PPh(DMP)} I (DMP = 3,5-Dimethyl-l-pyrazolyl) with Diphosphazanes and Diphosphinoalkanes and Oxidative Addition with Iodine Ruppa P. K. Babu, Setharampattu S. Krishnamurthy," and Munirathinam Nethaji Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India Received June 21, 1994@ The use of fuc-[Mo(C0)3(MeCN)(y2-L1)](la) {L' = Ph2PN(Pri)PPh(DMP)}2a s a precursor to metalloligands and bimetallic, heterotrimetallic, and heptacoordinated complexes is reported. The reaction of l a with diphosphazane, dppa, or a diphoophinoalkane such as dppm or dppe yields t h e fuc-7'-diphosphine substituted metalloligands, f ~ c - [ M o ( C O ) ~ ( y ~ Ll)(y'-PXP)l {PXP = dppa (2), dppm (3), and dppe (4)). These undergo isomerization to yield t h e corresponding mer-diphosphine complexes (5-7). Oxidation of the uncoordinated phosphorus atom of the mer-y l-dppm-substituted complex eventually provides mer-[Mo(CO)s(y2-L1){y1-Ph2PCH2P(0)Ph2}1(8). The structure of the latter complex has been confirmed by single crystal X-ray diffraction {triclinic system, Pi;a = 11.994(3), b = 14.807(2), c = 15.855(3) a = 114.24(1),/? = 91.35(2), and y = 98.95(1)"; 2 = 2, 4014 data (F, > 5a(F0)), R = 0.066, R, = 0.069). Treatment of the dppe metalloligand 7 with [PtC12(COD)] yields the heterotrimetallic complex cis-[PtCl~{mer-[Mo(C0)~(y2-L1)(y1-dppe)l}~l (9). Attempts to prepare a related trimetallic complex with t h e dppm-containing metalloligand were unsuccessful; only t h e tetracarbonyl complex cis-[Mo(C0)4(y2-L1)1(lb) and cis-[PtC12(y2dppm)] were obtained. Reaction of l a with dppe in the ratio 2:l yields the mer-mer dinuclear (10)bridged by dppe. Oxidation of l a with iodine complex [{mer-[Mo(C0)3(y2-L1)1}2(~-dppe)] yields the Mo(I1) heptacoordinated complex [Mo12(C0)2(y3-L1)l(11) with tridentate PPN coordination. The same Mo(I1) complex 11 is also obtained by the direct oxidation of the tetracarbonyl complex ~ i s - [ M o ( C O ) ~ ( y ~ -(lb) L ~ ) with l iodine. The structure of 11 has been confirmed by X-ray diffraction studies {monoclinic system, Cc; u = 10.471(2), b = 19.305(3), c = 17.325(3) /? = 95.47(2)";2 = 4, 3153 data (F, > 50(F0)),R = 0.049, R, = 0.051). This complex exhibits a n unusual capped-trigonal prismatic geometry around the metal. A similar heptacoordinated complex 12 with a chiral diphosphazane ligand { L3 = (S,R)-PhzPN(*CHMePh)*PPh(DMP)} has also been synthesized.
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Introduction Heterofunctional ligands containing soft and hard donor sites is of considerable current interest in connection with the development of novel homogeneous catalyst^.^ Organotransition metal chemistry of symmetrically substituted diphosphazanes have been investigated extensively over the past three decades4 whereas studies on unsymmetrically substituted diphosphazanes are ~ p a r s e . Unsymmetrically ~ substituted diphosphazanes offer an advantage in that the 2 J p p coupling constant can be obtained directly from their 31PNMR spectra. The facile synthetic route for diphosphazanes can be gainfully employed to prepare various ~~
e Abstract published in Advance ACS Abstracts, February 15,1995.
(1)For Part 10, see: Reddy, V. S.; Krishnamurthy, S. S.; Nethaji, M. J. Chem. Soc., Dalton Trans. 1994, 2661. (2) Abbreviations used: DMP = 3,B-dimethyl-l-pyrazolyl; dppa = bis(dipheny1phosphino)amine;dppm = bis(dipheny1phosphino)methane; dppmo = bis(dipheny1phosphino)methane monoxide; dppe = bis(dipheny1phosphino)ethane;COD = cycloocta-1,5-diene. (3)Bader, A,; Lindner, E. Coord. Chem. Rev. 1991, 108, 27. (4) (a)Balakrishna, M. S.; Reddy, V. S.; Krishnamurthy, S. S.; Nixon, J. F.; Burckett St. Laurent, J. C. T. R. Coord. Chem. Rev. 1994, 129, 1. (b) King, R. B. Acc. Chem. Res. 1980, 13, 243.
unsymmetrical ligand^.^ We have synthesized a series of unsymmetrically substituted diphosphazanes possessing heterofunctional donor sites and also a few chiral dipho~phazanes.~,~ We have recently reported the synthesis of a molybdenum tricarbonyl complex of a heterofunctional diphosphazane Ph2PN(Pri)PPh(DMP) (L1) uiz., fac-[Mo(CO)3(MeCN)(r2-L1)l (la)that contains a labile acetonitrile ligand and its substitution reactions with monophosphines.* In this paper, we report the syntheses of metalloligands and polymetallic complexes starting from l a and also a Mo(I1) heptacoordinated complex in which the heterofunctional diphosphazane (5) ( a ) Cross, R. J.; Green, T. H.; Keat, R. J . Chem. Soc., Dalton Trans. 1976, 1424. (b) Colquhoun, I. J.;McFarlane, W. J. Chem. Soc.. Dalton Trans. 1977, 1674. (c) Prout, T. R.; Imiolczyk, T. W.; Haltiwanger, R. C.; Hill, T. G.; Norman, A. D. Inorg. Chem. 1992,31. 215. (6) (a) Babu, R. P. K.; Krishnamurthy, S. S.; Nethaji, M. H(~tc~,riot~irii Chem. 1991, 2, 477. (b) Babu, R. P. K.; Krishnamurthy. S . S.I'r.rw. Indian Acad. Sci. (Chem. Sci.) 1994, 106, 37. (7) ( a ) Babu, R. P. K.; Aparna, K.; Krishnamurthy. S. S.: Nt,(h;i,ji. M. Phosphorus, Sulfur, Silicon, in press. ( b ) Rtihu. It. 1'. I
