104033-91-2Relevant academic research and scientific papers
Syntheses and dynamic stereochemistry of hydrido-carbonyl heterobinuclear metal-metal bonded complexes. Crystal structures of MoPt(H)(η-C5H5)(CO)3(PPh3) 2(Mo-Pt) and MnPt(μ-H)(μ-CO)(CO)4(PEt3)2(Mn-Pt)
Bars, Odile,Braunstein, Pierre,Geoffroy, Gregory L.,Metz, Bernard
, p. 2021 - 2030 (2008/10/08)
The hydrido-carbonyl heterobinuclear complexes MPt(H)(η-C5H5)(CO)3(PPh3) 2(M-Pt) (M = Mo, 1; M = W, 2) and MnPt(μ-H)(μ-CO)(CO)4(PR3)2(Mn-Pt) (R = Ph, 3; R = Et, 4) were prepared by the reaction of the corresponding carbonylmetalates with trans-PtH(Cl)(PR3)2. X-ray diffraction studies have been performed on complexes 1 and 4. Data for 1: monoclinic, P21/n, a = 15.42 (1) A?, b = 16.44 (1) A?, c = 16.50 (2) A?, β = 103.13 (5)°, V = 4076 A?3, Z = 4, R = 0.053, Rw = 0.080 for 4159 reflections with I ≥ 3σ(I). The molecule consists of a CpMo(CO)3 fragment bonded to a Pt atom (Mo-Pt = 2.839 (1) A?) which is further ligated by two mutually cis PPh3 ligands and a hydride ligand in a terminal position. Data for 4: monoclinic, P21/n, a = 11.142 (2) A?, b = 18.999 (4) A?, c = 11.661 (2) A?, β = 104.81 (1)°, V = 2387 A?3, Z = 4, R = 0.059, Rw = 0.075 for 2899 reflections with I ≥ 3σ(I). The environment about the Pt atom is planar and consists of the two mutually cis PEt3 ligands, the bridging carbonyl, and the bridging hydride (the latter not located by X-ray diffraction). The Mn atom, which is in the octahedral environment defined by the bridging ligands and the four terminal carbonyls, is at distance of 2.730 (2) A from the Pt atom. Spectroscopic, IR, and 1H, 31P{1H}, and 31P NMR data are discussed and are consistent with the structure of the complexes. These heterobinuclear complexes undergo a unique fluxional process, which is detailed for 1 and 4. The observed changes in the temperature-dependent 1H NMR spectra imply a mutual exchange process, equivalencing the phosphorus atoms, that maintains spin correlation and is thus strictly intramolecular and nondissociative, within the limits of the NMR experiment. The mechanism is discussed, and connections made with the chemical behavior of the complexes.
