Chromium species matrix studies

Focusing on reactions using the Fluid Matrix Technique, we have studied the interaction of chromium vapor with 2 at 200 K (13). The resulting film was found to contain metal complexes encapsulated within the polymer in which the isocyanide group adopts a well-defined octahedral arrangement around the chromium center, i.e. a species of type Cr(CN-[P])g. Since characterization of this metal complex within the polymer is not trivial we shall develop the analysis in a little detail. 

The bond distance is taken from Brewer et al. (3 ). The bond distances for all of the transition metal difluorides from chromium through copper were estimated to be the same with the assessment that an error of 0.5 A would lead to an error of less than 1 cal K" mol" in the entropy. The bond angle and vibrational frequencies are those derived by Hastie et al. ( ) from infrared studies of matrix-isolated isotopic species. The electronic states and levels are assumed the same as those assigned to... 

I.r. laser techniques have been used to study [Fe(CO)4] in a nitrogen matrix at 20 K. Surprisingly, the quantum yield for intramolecular isomerization is greato-than the quantum yield for formation of [Fe(CO)4(N2)]. Photolysis of matrix isolated [Mo(CO)s] in the presence of Na at 20 K affords [Mo(CO)5Na)]. Under similar conditions, the analogous chromium and tungsten complexes have been detected by i.r. and Raman techniques. The photochemistry of [O(C0)5] and related species in matrices has been studied via polarized light spectroscopy. A mechanism has been proposed which accounts for almost all the experimental data on matrix-isolated [M(CO)s] (M=Cr, Mo, or W), [M(CO)5(Na)], and [M(CO)4(CS)]. Reactions occur via the following steps ... 

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