Bidentate formate ligand, vibrations

Time-resolved FTIR spectra of Rh4(CO)12 subjected to 266 nm. irradiation in heptane gave evidence for the formation of two isomeric forms of Rh4(CO)n(solv).144 Vibrational assignments were made to vCO modes for gas-phase rhodium cluster carbonyls using IR multiphoton depletion spectroscopy. For Rhn(CO), vCO was at 1950 2 cm-1 (n = 6), 1960-1965 cm-1 (n = 7-11 13-20).145 TRIR data (vCO) were used to follow the formation of intrinsically chiral clusters Rh6(CO)i4(p,K2-PX), where PX = bidentate bridging ligands diphenyl(benzothienyl)phosphine and related systems.146... 

The formation of chloroimino ligands has been proposed solely on weak v(C=N) vibrations in the 1600-1750 cm-1 IR region. A repeat of the vanadium reaction by other workers (109) found the product of their reaction to be VC13(CNBu )3, so some caution should be applied to the formulation of the proposed vanadium dimer at least. Substitution reactions on these compounds with a series of mono- and bidentate tertiary phosphorus ligands and metathetical replacements with lithium quinolin-8-olate and sodium diethyl dithiocarbamate have given a range of neutral and cationic products (204, 483). 

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