CRYSTAL AND MOLECULAR-STRUCTURE OF [SNLCL3] - THE SINGLE-CRYSTAL ELECTRON-PARAMAGNETIC-RESONANCE SPECTRA OF [MOE(L)CL2] AND [MOO(L)(NCS)2] DILUTED IN [SNLCL3] [E=O OR S, L=TRIS(3,5-DIMETHYLPYRAZOLYL)HYDROBORATE

The crystal structure of [SnLCl3] has been determined and shown to con sist ol discrete distorted fac-octahedral molecules [L = tris(3,5-dime thylpyrazolyl)hydroborate]. The single-crystal EPR spectra, at room te mperature and Q-band frequencies, of [MoE(L)Cl2] and [MoO(L)(NCS)2], E = O or S, diluted in the structurally similar [SnLCl3] have been reco rded. The data from the different possible diluent sites in [SnLCl3] a re consistent with exact, or nearly exact, monoclinic EPR symmetry for each of the molybdenum compounds which involves a rotation of the g a nd A tensors about an axis perpendicular to the mirror plane in each m olecule. The angles of rotation are in the range 30-38-degrees and are in good agreement with those obtained via simulation of the frozen-so lution X-band EPR spectra of the compounds. The relationships between the g and A tensors, the molecular geometries, and the electronic stru ctures are discussed.