97133-85-2Relevant academic research and scientific papers
Molybdenum and tungsten germylyne complexes of the general formula trans-[X(dppe)2M≡Ge-(η1-Cp*)] (X = Cl, Br, I; dppe = Ph2PCH2CH2PPh2; Cp* = C5Me5): Syntheses, molecular structures, and bonding features of the germylyne ligand
Filippou, Alexander C.,Portius, Peter,Philippopoulos, Athanassios I.
, p. 653 - 661 (2002)
The halogermylenes (Cp*GeX)n (1a, X = Cl, n = 1; 1b, X = Br, n = 2; Cp* = pentamethylcyclopentadienyl) were prepared in high yield by a redistribution reaction of GeCp*2 with GeX2(1,4-dioxane). The ionic compounds [Cp*Ge] [GeX3] (2a, X = Cl; 2b, X = Br) were also formed to a small extent in this reaction. Treatment of trans-[Mo(dppe)2(N2)2] (3) (dppe = Ph2PCH2CH2PPh2) with 1 equiv of 1a,b affords in refluxing toluene the germylyne complexes trans-[X(dppe)2Mo≡Ge-(η1-Cp*)] (4a, X = Cl; 4b, X = Br). Concomitant formation of GeCp*2 and the dihalo complexes trans-[Mo(dppe)2(X)2] (5a, X = Cl; 5b, X = Br) is observed in this reaction. In comparison, the reactions of trans-[W(dppe)2(N2)2] (6) with 1a,b and (Cp*GeI)∞ (1c) afford selectively the germylyne complexes trans-[X(dppe)2W≡Ge-(η1-Cp*)] (7a-c). The molecular structures of 4a·0.5pentane and 4b·0.5pentane reveal very short Mo-Ge bonds, almost linear Mo-Ge-C(Cp*) sequences, and an η1-bonded Cp* substituent indicating the presence of a molybdenum-germanium triple bond. The structural features of the germylyne ligand in 4a and 4b are compared with those in the corresponding tungsten complexes trans-[X(dppe)2W≡Ge-(η1-Cp*)] (7a-c), and the bonding parameters of the Cp* substituent are shown to be similar to those in the germanes (η1-Cp*)GeI3 (8) and (η1-Cp*)2GeCl2 (9).
Reaction products of 1,2-bis(diphenylphosphino)ethane with the octabromodimolybdate(II) ion
Agaskar, Pradyot A.,Cotton, F. Albert,Derringer, Daniel R.,Powell, Gregory L.,Root, Dawn R.,Smith, Thomas J.
, p. 2786 - 2791 (2008/10/08)
Reactions of (NH4)4[Mo2Br8] with dppe (Ph2PCH2CH2PPh2) in alcohols yield three products, with the proportions depending on conditions: 1, green α-Mo2Br4(dppe)2; 2, red-brown β-Mo2Br4(dppe)2; 3, light-brown trans-MoBr2(dppe)2. All three solids are stable in air and soluble in dichloromethane. By the reactions just mentioned, 1 and 2 are both obtained as microcrystalline products. By reaction of Mo2(O2CCF3)4 with (CH3)3SiBr and dppe, 2 was obtained in the form of larger crystals, but these were not of good quality and only a coarse crystallographic structure determination was made: space group P21/n, with unit cell dimensions of a = 23.35 A?, b = 13.29 A?, c = 16.91 A?, and β = 106.82°, which indicate isomorphicity with β-Mo2Cl4(dppe)2. Compound 3 afforded good crystals directly from the reaction mixture. These are triclinic, space group P1, with unit cell dimensions of a= 10.493 (2) A?, b = 12.773 (3) A?, c = 10.331 (2) A?, α = 94.78 (2)°, β = 117.39 (2)°, γ = 104.64 (2)°, V = 1157 (1)A?3 and Z = 1. The trans-MoBr2(dppe)2 molecule, which has a magnetic moment indicating two unpaired electrons, has inversion symmetry with Mo-Br = 2.569 (1) A? Mo-P = 2.516 (1) and 2.523 (1) A?, and endocyclic P-M-P angles of 78.81 (4)°. Infrared and UV-visible spectra are reported for all compounds. The process of isomerization of α-Mo2Br4(dppe)2 to β-Mo2Br4(dppe)2 has been studied, and a unimolecular mechanism involving internal rotation of the Mo2 unit within the ligand cage is suggested.
