Investigation of isomerism rates and mechanism of some 17- and 18-electron substituted carbonyl complexes of chromium, molybdenum, and tungsten using double potential step chronoamperometry

Infrared Spectroelectrochemistry

“…The more stable forms are the cis M 0 and trans M I species. 17,18 The n(CO) bands are a particularly useful probe of the chemistry since a shift in wave number is indicative of a change in the electron richness of the metal and the stereochemistry is flagged by the presence of one (trans) or two (cis) IR-active bands. The reduction of trans-[Cr(dppm) 2 (CO) 2 ] 1 (dppm ¼ Ph 2 PCH 2 PPh 2 ) in an external reflectance SEC experiment is shown in Figure 1.5.…”

“…The absorbance changes associated with the decay of the trans-neutral and appearance of the cis-neutral species fit to a single exponential with a rate constant of 0.14 (2) s -1 (Figure 1 22 1C obtained by double-potential-step chronoamperometry in acetone. 17 It is clear that the rate of electrosynthesis is of vital importance when examining reactions of this sort. Clearly, the half-life of the reaction should be at least comparable to the time required for electrosynthesis and the data shown in Figure 1.5 is close to that limit.…”

Electrochemical study of thermodynamics and kinetics of the cis-trans isomerization of dicarbonylbis[1,2-bis(diphenylphosphino)ethane]molybdenum and -tungsten complexes and their cations

“…Ordering information is given on any current masthead page. (5,7,7,12,14,4,8,,ll-diene)copper(II) Cations with Mononegative Ligands Jy-Wann Chen, Chi-Chang Chang, and Chung-Sun Chung*…”

“…Methanol was dried by fractional distillation, followed by treatment with Drierite for a period of several days. 4,5 Analysis of water in solvents was carried out by using an automatic Karl Fischer titrator. The water content of all purified solvents was found to be less than 100 ppm.…”

Preparation of cis-Mo(CO)2(Ph2P(CH2)nPPh2)2 (n = 1, 2, 3) from cis-dicarbonylbis(norbornadiene)molybdenum and crystal structure of [cis-Mo(CO)2(Ph2P(CH2)3PPh2)2]

“…cis-dicarbonylbis[bis(diphe-nylphosphino)methane]molybdenum (cis-Mo(CO),(DPM),, II) [9,10], cis-dicarbonylbis[l,2-bis(diphenylphosphino)ethane]molybdenum (cis-Mo(CO),(DPE),, III) [ll-131, and cis-dicarbonylbis[l,3-bis(diphenylphosph (cis-Mo(CO),(DPP),, IV). The preparation of IV has been described previously [14], but lacks the details of structural information. Aided by the present method we were able to produce single crystals of good quality for X-ray diffraction structural analysis.…”