Comparison of the Properties of SnCl3- and SnBr3- Complexes of Platinum(II)
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- 作者：John H. Nelson ; William L. Wilson ; Lewis W. Cary ; Nathaniel W. Alcock ; Howard J. Clase ; Gouri S. Jas ; Lori Ramsey-Tassin ; and John W. Kenney ; III
- 刊名：Inorganic Chemistry
- 出版年：1996
- 出版时间：February 14, 1996
- 年：1996
- 卷：35
- 期：4
- 页码：883 - 892
- 全文大小：507K
- 年卷期：v.35,no.4(February 14, 1996)
- ISSN：1520-510X
文摘
The complexes M3[Pt(SnX3)5](M = Bu4N+,PhCH2PPh3+; X = Cl, Br),cis-M2[PtX2(SnX3)2](M = Bu4N+,PhCH2PPh3+,CH3PPh3+,Pr4N+; X = Cl, Br), and[PhCH2PPh3]2[PtBr3(SnBr3)]have been prepared andcharacterized by 119Sn and 195Pt NMR,far-infrared, and electronic absorption and emission spectroscopies.Inacetone solutions the[Pt(SnX3)5]3-ions retain their trigonal bipyramidal structures but arestereochemically nonrigidas evidenced by 119Sn and 195Pt NMRspectroscopy. For[Pt(SnCl3)5]3-spin correlation is preserved between183 and 363 K establishing that the nonrigidity is due tointramolecular tin site exchange, probably via Berrypseudorotation. Whereas,[Pt(SnCl3)5]3-does not undergo loss of SnCl3- orSnCl2 to form either[Pt(SnCl3)4]2-or[PtCl2(SnCl3)2]2-,[Pt(SnBr3)5]3-is not stable in acetone solution in the absence of excessSnBr2 and forms[PtBr2(SnBr3)2]2-and[PtBr3(SnBr3)]2-by loss of SnBr2. Similarly,[PtCl2(SnCl3)2]2-is stable in acetone atambient temperatures but disproportionates at elevated temperatures and[PtBr2(SnBr3)2]2-loses SnBr2 in acetoneto form[PtBr3(SnBr3)]2-.The crystal structures of methyltriphenylphosphoniumcis-dibromobis(tribromostannyl)platinate(II) and benzyltriphenylphosphoniumtribromo(tribromostannyl)platinate(II) have beendetermined. Bothcompounds crystallize in the triclinic space group P
in unit cells with a = 12.293(16) Å, b= 12.868(6) Å, c =25.047(8) Å, 
= 96.11(3)
, 
= 91.06(3),
= 116.53(3), 
calc = 2.30 gcm-3, Z = 3 and witha = 11.046(7)Å, b = 14.164(9) Å, c =22.549(10) Å, = 89.44(4), = 83.32(5), = 68.31(5), calc = 1.893 gcm-3, Z= 2, respectively. Least-squares refinements converged atR = 0.057 and 0.099 for 4048 and 4666independentobserved reflections with I/
(I) > 3.0and I/(I) > 2.0, respectively. Forthe former, the asymmetric unit contains1.5cis-[PtBr2(SnBr3)2]2-ions, 0.5 of which is disordered in such a way as to bepseudocentrosymmetric. Thisdisordering involves a half-occupied PtBr2 unit appearingon either side of the center. Simultaneously, onebrominefrom each SnBr3 ligand changes sides while the other twobromines appear in average positions with very smalldisplacements between their positions. The Pt-Sn distance in[PtBr3(SnBr3)]2-(2.486(3) Å) is slightly shorterthan that incis-[PtBr2(SnBr3)2]2-(2.4955(3) Å, average), and both are significantly longer thanthat previouslyfound incis-[PtCl2(SnCl3)2]2-(2.3556 Å, average), which is not consistent with the relativemagnitudes of the1J(195Pt-119Sn)coupling constants (28 487, 25 720, and 27 627 Hz, respectively).From our electronic absorptionand emission studies of the Pt-SnX3-complexes, we conclude that (a) the low-energy transitions ared-dtransitions analogous to those found in[PtX4]2- systems, (b) theSnCl3- ligand is a stronger donor thanSnBr3-,(c) the triplet state from which the emission occurs is split byspin-orbit coupling into different spin-orbitstates, (d) a forbidden spin-orbit state must lie at or near thebottom of the spin-orbit manifold, (e) the solidstate crystal environment perturbs the platinum-tin halide electronicstates, and (f) dispersion of the samples insolvents changes this perturbation, which can be rationalized in termsof an in-plane distortion of the squareplanar platinum coordination sphere.
in unit cells with a = 12.293(16) Å, b= 12.868(6) Å, c =25.047(8) Å, = 96.11(3), = 91.06(3), = 116.53(3), calc = 2.30 gcm-3, Z = 3 and witha = 11.046(7)Å, b = 14.164(9) Å, c =22.549(10) Å, = 89.44(4), = 83.32(5), = 68.31(5), calc = 1.893 gcm-3, Z= 2, respectively. Least-squares refinements converged atR = 0.057 and 0.099 for 4048 and 4666independentobserved reflections with I/(I) > 3.0and I/(I) > 2.0, respectively. Forthe former, the asymmetric unit contains1.5cis-[PtBr2(SnBr3)2]2-ions, 0.5 of which is disordered in such a way as to bepseudocentrosymmetric. Thisdisordering involves a half-occupied PtBr2 unit appearingon either side of the center. Simultaneously, onebrominefrom each SnBr3 ligand changes sides while the other twobromines appear in average positions with very smalldisplacements between their positions. The Pt-Sn distance in[PtBr3(SnBr3)]2-(2.486(3) Å) is slightly shorterthan that incis-[PtBr2(SnBr3)2]2-(2.4955(3) Å, average), and both are significantly longer thanthat previouslyfound incis-[PtCl2(SnCl3)2]2-(2.3556 Å, average), which is not consistent with the relativemagnitudes of the1J(195Pt-119Sn)coupling constants (28 487, 25 720, and 27 627 Hz, respectively).From our electronic absorptionand emission studies of the Pt-SnX3-complexes, we conclude that (a) the low-energy transitions ared-dtransitions analogous to those found in[PtX4]2- systems, (b) theSnCl3- ligand is a stronger donor thanSnBr3-,(c) the triplet state from which the emission occurs is split byspin-orbit coupling into different spin-orbitstates, (d) a forbidden spin-orbit state must lie at or near thebottom of the spin-orbit manifold, (e) the solidstate crystal environment perturbs the platinum-tin halide electronicstates, and (f) dispersion of the samples insolvents changes this perturbation, which can be rationalized in termsof an in-plane distortion of the squareplanar platinum coordination sphere.