No abstract

No abstract

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 (Me 2 NC(dS)Cl) at low temperature provides a thermally labile intermediate (1) presumed on the basis of subsequent transformations to be [Mo(η 2 -SCNMe 2 )-Cl(CO) 3 (NCMe)]. Reactions of 1 with K[HB(pz) 3 ] (pz ) pyrazol-1-yl), NaC 5 H 5 , bipy, or tmeda provide the complexes [Mo(η 2 -SCNMe 2 )(CO) 2 {HB(pz 4), and [Mo(η 2 -SCNMe 2 )Cl(CO) 2 (tmeda)] (5), respectively. The complex cis,cis,trans-[Mo(η 2 -SCNMe 2 )Cl(CO) 2 (PPh 3 ) 2 ] (6) results from the oxidative addition of Me 2 NC(dS)Cl to [Mo(NCMe) 2 (CO) 2 (PPh 3 ) 2 ] and is one of two isomers obtained from the reaction of 1 with PPh 3 . The complex 2 may also be obtained from reaction of (i) K[Mo(CO) 3 {HB(pz) 3 }] with Me 2 NC(dS)Cl; (ii) [Mo(CO) 3 (η 6 -C 7 H 8 )] with Me 2 NC(dS)Cl and K[HB(pz) 3 ]; and (iii) K[HB(pz) 3 ] with either 5 or 6. Sequential treatment of either [Mo(CO) 3 -Attempts to prepare a mononuclear thiocarbamoyl complex by addition of elemental sulfur or propene episulfide to the aminomethylidyne complex [Mo(tCN i Pr 2 )(CO) 2 {HB(pz) 3 }] (8) were unsuccessful; however addition of [Fe 2 (CO) 9 ] to 8 provided the thermally unstable complex [MoFe(µ-CN i Pr 2 )(CO) 5 {HB(pz) 3 }] (9), which reacts with sulfur to provide the heterobimetallic bridging thiocarbamoyl complex [MoFe(µ-SCN i Pr 2 )(CO) 5 {HB(pz) 3 }] (10). Treating fac-[W(CO) 3 (NCMe) 3 ] sequentially with Me 2 NC(dS)Cl and K[HB(pz) 3 ] provided [W(η 2 -SCNMe 2 )(CO) 2 {HB(pz) 3 }] (11); however replacing Me 2 NC(dS)Cl with ClC(dS)OC 6 H 4 -Me-4 led to [WCl(CO) 3 {HB(pz) 3 }] (12).

Sequential treatment of [M(CO)6] (M = W, Mo, but not Cr) with 1 equiv of LiNiPr2, iodine, and PPh3 provides [M(η2-OCNiPr2)I(CO) 3 (PPh3)], which serve as precursors for a wide range of bidentate carbamoyl complexes; however, if for M = W, an excess of LiN i Pr2 is employed, the aminomethylidyne complex [W(⋮CNiPr2)I(CO)3(PPh3)] is also obtained.

No abstract