Synthesis, structure, reactivity and electrochemistry of a new molybdenum(0) dithiocarbamato complex, [Et 4N][Mo(CO) 4(S 2CNEt 2)

Abstract

A new molybdenum(0) dithiocarbamato complex [Et 4N] [Mo(CO) 4(S 2CNEt 2)] ( 1) has been synthesized by the reaction of Mo(CO) 6, NaS 2CNEt 2 and Et 4NCl in MeCN and characterized by routine elemental analysis, spectroscopy methods. The crystal and molecular structure of 1 was determined from X-ray three dimension data. 1 crystallizes in the orthorhombic, space group Pbc2 1 with a= 8.148(2), b=19.618(2), c=14.354(2) Å; V=2294 Å 3; Z=4; R 1=0.052, R 2=0.058 for 1308 independent reflections with I ⩾ 3σ( I). The geometry around Mo(0) atom in the anion [Mo(CO) 4(S 2CNEt 2)] - of 1 is distorted octahedral with a small SMoS of 67.70° and a small angle of 3.6° between plane MoSS and MoC(1)C(2). Two groups of MoCO bond distances and the longer MoS bond distance observed in 1 are similar to that in the dinuclear Mo(0) complexes containing SR bridges but very different from those observed in the dithiocarbamato complexes of Mo in higher oxidation states. Different oxidizing products containing Mo in II-V oxidation states Mo(CO) 2(S 2CNEt 2) 2, MoO(S 2CNEt 2) 2, Mo 2O 3(S 2CNEt 2) 4 and Mo 2O 4(S 2CNEt 2) 2 were isolated from the oxidation of 1 with I 2 (or in the presence of traces of air). The electrochemical behavior of 1 in MeCN was investigated by cyclic voltammetry at Pt and C electrodes. The anodic peaks observed at 0.04, 0.14, 0.26 and 0.44 V versus SCE implied that 1 probably underwent oxidation in company with dissociation of dithiocarbamate and substitution of carbonyls resulting in several complexes of Mo in different oxidation states. The relationship between reactivity and structure is also discussed.