Metallathiirenes. 3. 1 Thiocarbamoyl and Alkoxythiocarbonyl Complexes of Molybdenum(II) and Tungsten(II)

Synthetic routes to thiocarbamoyl (thiocarboxamide) complexes of divalent molybdenum and tungsten are reported:  The reaction of fac-[Mo(CO)3(NCMe)3] with N,N-dimethyl thiocarbamoyl chloride (Me2NC(S)Cl) at low temperature provides a thermally labile intermediate (1) presumed on the basis of subsequent transformations to be [Mo(η2-SCNMe2)Cl(CO)3(NCMe)]. Reactions of 1 with K[HB(pz)3] (pz = pyrazol-1-yl), NaC5H5, bipy, or tmeda provide the complexes [Mo(η2-SCNMe2)(CO)2{HB(pz)3}] (2), [Mo(η2-SCNMe2)(CO)2(η-C5H5)] (3), [Mo(η2-SCNMe2)Cl(CO)2(bipy)] (4), and [Mo(η2-SCNMe2)Cl(CO)2(tmeda)] (5), respectively. The complex cis,cis,trans-[Mo(η2-SCNMe2)Cl(CO)2(PPh3)2] (6) results from the oxidative addition of Me2NC(S)Cl to [Mo(NCMe)2(CO)2(PPh3)2] and is one of two isomers obtained from the reaction of 1 with PPh3. The complex 2 may also be obtained from reaction of (i) K[Mo(CO)3{HB(pz)3}] with Me2NC(S)Cl; (ii) [Mo(CO)3(η6-C7H8)] with Me2NC(S)Cl and K[HB(pz)3]; and (iii) K[HB(pz)3] with either 5 or 6. Sequential trea...