STRUCTURAL CHARACTERIZATIONS OF CIS-MO(CO)4(PPHME2)(NHC5H10) AND CIS-MO(CO)4(PPHME2)(PPH3) AND THEIR SOLUTION REACTIVITIES TOWARD CARBON-MONOXIDE

The crystal and molecular structures of cis-Mo(CO)4(PPhMe2)(HNCsH10) (1) and cis-Mo(CO)4(PPhMe2)(PPh3) (2) have been determined and are discussed in terms of the influence of structural and steric factors on the reactivities of cis-Mo(CO)4L2 molecules. Compound 1 forms monoclinic crystals in space group P21/c with a = 13.764 (3) , b = 10.693 (2) , c = 13.585 (2) , = 98.99 (2), V = 1974 (1) 3, and Z = 4. The structure was refined to R1, = 0.038. Compound 2 forms monoclinic crystals in space group P21 with a = 9.487 (1) , b = 17.757 (2) , c = 16.920 (1) , = 98.72 (1), V = 2817.5 (5) 3, and Z = 4. The structure was refined to R1 = 0.030. The 13C NMR spectra have also been recorded, and they show that 31P13C couplings are in the ranges 7.89.8 Hz for the cis arrangement and 24.231.3 Hz for the trans arrangement and that chemical shifts are increasingly downfield as the MoC bond lengths become shorter. Relative rates of reaction of the cis-Mo(CO)4LL' compounds with CO to give Mo(CO)5PMe2Ph are found to correlate well with steric factors. 1982, American Chemical Society. All rights reserved.

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