Synthesis and Reactions of Group 6 Metal Half-Sandwich Complexes of 2,2-Dicyanoethylene-1,1-dichalcogenolates [(Cp*)M{E₂CC(CN)₂}₂]^- (M = Mo, W; E = S, Se)

Abstract

A series of group 6 transition metal half-sandwich complexes with 1,1-dichalcogenide ligands have been prepared by the reactions of Cp*MCl(4)(Cp* = eta(5)-C(5)Me(5); M = Mo, W) with the potassium salt of 2,2-dicyanoethylene-1,1-dithiolate, (KS)(2)C=C(CN)(2) (K(2)-i-mnt), or the analogous seleno compound, (KSe)(2)C=C(CN)(2) (K(2)-i-mns). The reaction of Cp*MCl(4) with (KS)(2)C=C(CN)(2) in a 1:3 molar ratio in CH(3)CN gave rise to K[Cp*M(S(2)C=C(CN)(2))(2)] (M = Mo, 1a, 74%; M = W, 2a, 46%). Under the same conditions, the reaction of Cp*MoCl(4) with 3 equiv of (KSe)(2)C=C(CN)(2) afforded K[Cp*Mo(Se(2)C=C(CN)(2))(2)] (3a) and K[Cp*Mo(Se(2)C=C(CN)(2))(Se(Se(2))C=C(CN)(2))] (4) in respective yields of 45% and 25%. Cation exchange reactions of 1a, 2a, and 3a with Et(4)NBr resulted in isolation of (Et(4)N)[Cp*Mo(S(2)C=C(CN)(2))(2)] (1b), (Et(4)N)[Cp*W(S(2)C=C(CN)(2))(2)] (2b), and (Et(4)N)[Cp*Mo(Se(2)C=C(CN)(2))(2)] (3b), respectively. Complex 4 crystallized with one THF and one CH(3)CN molecule as a three-dimensional network structure. Inspection of the reaction of Cp*WCl(4) with (KSe)(2)C=C(CN)(2) by ESI-MS revealed the existence of three species in CH(3)CN, [Cp*W(Se(2)C=C(CN)(2))(2)]-, [Cp*W(Se(2)C=C(CN)(2))(Se(Se(2))C=C(CN)(2))]-, and [Cp*W(Se(Se(2))C=C(CN)(2))(2)]-, of which [Cp*W(Se(2)C=C(CN)(2))(Se(Se(2))C=C(CN)(2))]-(5) was isolated as the main product. Treatment of 2a with 1/4 equiv of S(8) in refluxing THF resulted in sulfur insertion and gave rise to K[Cp*W(S(2)C=C(CN)(2))(S(S(2))C=C(CN)(2))](6), which crystallized with two THF molecules forming a three-dimensional network structure. 6 can also be prepared by refluxing 2a with 1/4 equiv of S(8) in THF. 3a readily added one Se atom upon treatment with 1 mol of Se powder in THF to give 4 in high yield, while the treatment of 3a or 4 with 2 equiv of Na(2)Se in THF led to formation of a dinuclear complex [(Cp*Mo)(2)(mu-Se)(mu-Se(Se(3))C=C(CN)(2))] (7). The structure of 7 consists of two Cp*Mo units bridged by a Se(2-) and a [Se(Se(3))C=C(CN)(2)](2-) ligand in which the triselenido group is arranged in a nearly linear way (163 degrees). The reaction of 2a with 2 equiv of CuBr in CH(3)CN yielded a trinuclear complex [Cp*WCu(2)(mu-Br)(mu(3)-S(2)C=C(CN)(2))(2)] (8), which crystallized with one CH(3)CN and generated a one-dimensional chain polymer through bonding of Cu to the N of the cyano groups.

Synthesis and spectral characterization of chloro-organotin(IV) complexes of S-donor ligand: Crystal structure of chloro-t-dibutyltin[4-methyl-1-piperidine]thiocarboxylate

“…The car bon atoms at 2,2' positions have also been shifted down field in the compounds (1)- (3). The other car bon atoms appear with slight change in their chemical shift values.…”

“…692448 for complex 2 2 ' S CNR (3). Copies of these information may be obtained free of charge from the Director, CCDC, 12 Union Road, Cambridge, CBZ 1EZ, UK (Fax: +44 1223 336033; email: deposit@ccdc.cam.ac.uk, www.ccdc.cam.…”

“…Indeed, the increasing renewed attention paid nowadays to these species arises from their high stabil ity, solvatochromic behaviour, room temperature luminescence in solution [3] and their status as excel lent candidates for applications such as photocatalysis [4]. In addition the variable coordination modes of 1,1 dithiolate ligands to metals make the structural studies more interesting [5].…”

Synthesis of stannic(IV) complexes: Their structural elucidation in solid and solution state and antimicrobial activity

“…Synthesized piperidine-1-thiocarboxylic acid (1 mmol) was suspended in dry toluene (100 cm 3 ) and was treated with triethylamine in a round bottom two-necked flask equipped with water condenser. The mixture was refluxed for 2-3 h. To a solution of triethyl ammonium salt of the ligand in dry toluene, diorganotin dichloride (2 mmol)/triorganotin chloride (1 mmol) was added as solid to a reaction flask with constant stirring and reaction mixture was refluxed for 4 h. After cooling the reaction mixture to room temperature, Et 3 NHCl was filtered off and the solvent was evaporated by rotary apparatus under reduced pressure.…”

“…1,1-Dithiolate ligands have recently attracted much attention mainly because of their interesting photophysical properties derived from their extensive electron delocalization onto all of the ligand atoms [2]. Indeed, the increasing renewed interest nowadays to these species is due to their high stability, solvatochromic behavior, room temperature luminescence in solution [3], and their status as excellent candidates for applications such as photocatalysis [4]. In addition, the variable coordination modes of 1,1-dithiolate ligands to metals make the structural studies more interesting [5].…”