COMPLEXES OF TRIS(3,5-DIMETHYLPYRAZOLYL)BORATES ALKYLATED ON THE 4-POSITION OF THE PYRAZOLYL RINGS - X-RAY CRYSTAL-STRUCTURE OF MOLYBDENUM DICARBONYL NITROSYL TRIS(3,5-DIMETHYL-4-N-BUTYLPYRAZOLYL)BORATE

The 4-substituted tris(3,5-dimethylpyrazolyl)borato compounds [Mo(CO)( 2)(NO){HB(4-R-dmpz)(3)}] (R: = Me, Et, Bu(n) and C5HII) and [MoCl2(NO) {HB(4-R-dmpz)(3)}] (R = Me or Bu(n)) have been prepared and characteri zed spectroscopically and electrochemically. X-ray crystal structural determination of [Mo(CO)(2)(NO){HB(4-R-dmpz)(3)}] (R = Bu(n)) revealed that the n-butyl chains attached to the 4-position of the pyrazolyl r ings were orientated, overall, in a random fashion, although the fist and second C atoms of each chain extended in a star-shaped configurati on, similar to that observed in [Mo(CO)(2)(NO){HB(4-bzdmpz)(3)}](4-bzd mpz = 4-benzyl-3,5-dimethylpyrazolyl)