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8334433 
Journal Article 
Syntheses and Crystal Structures of Syn and Gauche Isomers of the Chloride-Bridged Face-Sharing Bioctahedral Molybdenum (III) Dimers [PHMe3][Mo2Cl7(PMe3)2] 
Cotton, FA; Luck, RL 
1989 
Yes 
Inorganic Chemistry
ISSN: 0020-1669
EISSN: 1520-510X 
AMER CHEMICAL SOC 
WASHINGTON 
28 
2 
182-187 
English 
WOS:A1989R945100006 
The reaction of Mo2Cl4(PMe3)4and 2PhICl2yields the compound [PHMe3][Mo2Cl7(PMe3)2], in which the anion is the syn conformer with respect to the arrangement of the two terminal tertiary phosphine ligands. Two crystalline forms containing this syn conformer, 1 and 2, are reported. The equilibration of the syn and gauche conformers has been monitored by 1H NMR spectroscopy and is found to involve phosphine dissociation. Solutions of these two forms eventually attained the statistically expected 1:2 (syn:gauche) ratio (k1= 1.09 X 10–4s-1, k-1= 5.43 X 10-5s-1in CD2Cl2at 293 K), and from such solutions single crystals of the gauche isomer were obtained. Crystal data: compound 1 (syn conformer, from CH2C12), triclinic, space group PĪ, a = 13.271 (2) Å, b = 17.855 (3) Å, c = 11.418 (2) Å, α = 107.18 (1)°,β = 101.13 (2)°, γ = 93.82 (1)°, V = 2513.8 (8) Å3, Z = 4, R = 0.041 (Rw= 0.066) for 379 parameters and 4621 unique data having F02> 3σ(F02); compound 2 (syn conformer, from CH2Cl2/hexane), orthorhombic, space group Pnma, a = 28.098 (6) Å, b = 10.140 (1) Å, c = 9.839 (2) Å, V = 2803.4 (9) Å3, Z = 4, R = 0.079 (Rw= 0.103) for 115 parameters and 1091 unique data having F02> 3σ(F02); compound 3 (gauche conformer, from acetone-d6), monoclinic, space group P21/n, a = 10.888 (2) Å, b = 20.633 (2) Å, c = 11.375 (1) Å, β = 106.86 (1)°, V = 2445.4 (7) Å3, Z = 4, R = 0.022 (Rw= 0.031) for 302 parameters and 3764 unique data having F02> 3σ(F02). © 1989, American Chemical Society. All rights reserved.