A series of carbonylchromium and tungsten complexes containing pyrazole ligands [M(CO)5L] has been synthesized by the photochemical reactions of pyrazole ligands with M(CO)6(M=Cr or W). Their electrochemical behaviors have also been investigated by cyclic voltammetry, indicating that the chromium complexes exhibit one reversible or quasi - reversible couple corresponding to a one - electron oxidation, but the tungsten complexes have one irreversible oxidation process. The crystal structure of Cr (CO)5L(L represents 3, 4,5-trimethylpyrazole) was determined by X-ray diffraction method, which is monoclinic, space group P2(1)/m with unit cell parameters a=0.9106(3) nm, b=07627(2) nm, c=0.9637(3) nm, β＝91.855(5)°, V=0. 6689(3) nm^3, Z=2, R=0.042. The central metal of Cr is six- coordinated with a quasi - octahedral coordination geometry.

Key words: PYRAZOLE P, CHROMIUM CARBONYL, CHROMIUM COMPLEX, TUNGSTEN COMPLEX, PHOTOCHEMISTRY, CARBONYL COMPLEX, ELECTROCHEMISTRY, CRYSTAL STRUCTURE, CYCLOVOLTAMGRAPH