Infrared, pmr, and X-ray photoelectron spectral data are presented to substantiate the existence of conformational isomers of the nitrosyl complexes CoCl2(NO)L2. The first isomer A has trigonal-bipyramidal geometry with a linear nitrosyl (NO+) while the second isomer B is believed to have square-pyramidal geometry with a bent nitrosyl (NO+) at the apex. A low-temperature crystalline form of CoCl2(NO)(P(CH3)(C6H5)2)2 containing almost solely isomer A was found to transform partially to B by grinding in preparation for a Nujol mull. Nitrogen Is electron binding energies suggest an unexpectedly high preference for isomer B at the surface of most solid samples. The crystal and molecular structures of the room-temperature form of CoCl2(NO)(P(CH3)(C6H5)2)2 have been determined from three-dimensional X-ray data collected at room temperature by counter methods. The material crystallizes with 8 molecules in space group C2h6-C2/c of the monoclinic system in a cell of dimensions a= 16.970 (14), b = 17.035 (9), c= 18.735 (8) Å, and ²= 108.00 (2)°. The calculated and observed densities are 1.445 and 1.44(2) g cm-3, respectively. The structure has been solved and refined by conventional mean. The final R factor (on F) for the 2428 unique reflections having Fo2> 3σ(Fo2) is 0.046. The resultant structure is of isomer A, a somewhat distorted trigonal bipyramid, and there is no evidence for the coexistence of isomer B in the crystal used in the X-ray analysis.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry