Facile conversion of a cationic Mo IV phosphinimato complex into an anionic nitrido-bridged dimer with a bis(trimethylphosphine)iminium counterion
作者:Vernon C. Gibson、David N. Williams、William Clegg
DOI:10.1039/c39890001863
日期:——
[Mo(NPMe3)Cl2(PMe3)3]Cl is formed in 82% yield upon treatment of [Mo(N)Cl3] with four equivalents of trimethylphosphine in CH2Cl2 and rearranges to the nitrido-bridged dimer [(Me3P)2Cl3MoNMoCl3(PMe3)2][Me3PNPMe3] upon standing at room temperature in CH2Cl2; X-ray structural analyses of these compounds are reported.
The reaction of MoCl5 with Cl3VNCl at 140degreesC in a sealed glass ampoule yields air sensitive black crystals of the mixed valent molybdenum(V,VI) nitride chloride, Mo2NCl8. It crystallizes in the monoclinic space group P2/c with a=996.1(1), b=629.4(1), c=1780.8(3) pm, beta=101.82(2)degrees, and Z=4. The crystal structure consists of dinuclear C-2-symmetrical units [Cl-2(Nequivalent to)Mo(mu(2)-Cl)(3)-Mo(equivalent toN)Cl-2](-) and [Cl4Mo(mu(2)-Cl)MoCl4](+), connected in an alternating sequence by asymmetric nitrido bridges Moequivalent toN-Mo to form chains. The reaction of Cl3VNCl with MoCl3 at 140degreesC affords Mo3N2Cl11, but for the prolonged reaction period, MoNCl3 is observed in addition. Mo3N2Cl11 can also be obtained from MoNCl3 and MoCl5 (2:1) at 140degreesC. It forms orthorhombic, black crystals with the space group Pca2(1) and a=1256.1(1), b=1001.9(1), c=1330.10(5) pm, and Z=4. The structure contains the same dinuclear units [Cl-2(Nequivalent to)Mo(mu(2)-Cl)(3)Mo(equivalent toN)Cl-2](-) as in Mo2NCl8, which in this case are connected with MoCl4+ moieties by asymmetric nitrido bridges Moequivalent toN-Mo forming chains. In Mo2NCl8 the Mo-N distances in the nearly linear nitrido bridges are 167.6(2), and 214.8(2) pm, whereas in case of Mo3N2Cl11 two sets of Mo-N distances of 166,8(4) and 214,0(4) pm as well as 166,9(4) and 211,9(4) pm are observed.