Synthesis and characterisation of rhenium dithiocarbamate complexes.Crystal structures of[ReO{O(OH)C6H4}(S2CNEt2)2],[Re{PPh2(C6H4S-2)}2(S2CNEt2)]·Me2CO and[ReO{PPh(C6H4S-2)2}(S2CNEt2)]

The reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with catechol in acetone yielded the dark orange complex [ReO{O(OH)C 6 H 4 }(S 2 CNEt 2 ) 2 ] 1. The crystal structure shows a distorted-octahedral geometry with the oxo group trans to the monodentate catecholate ligand. The Re–O (catechol) bond length is typical of a Re–O single bond and implies little trans influence of the oxo ligand. Reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with 1,4-dihydroxybenzene yielded the red-brown dimer [{ReO(S 2 CNEt 2 ) 2 } 2 (C 6 H 4 O 2 -1,4)] 2, in which the dianionic ligand bridges two rhenium centres. With 2-amino-4-methylphenol [ReO(OC 6 H 3 NH 2 -2-Me-4)(S 2 CNEt 2 ) 2 ] 3 was obtained containing the ligand co-ordinated in a monodentate mode. Reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with dithiolate proligands such as ethane-1,2-dithiol yielded [NEt 2 H 2 ][ReOL 2 ], L = C 2 H 4 S 2 -1,2 4, C 6 H 4 S 2 -1,2 5 or MeC 6 H 3 S 2 -3,4 6, where degradation of the dithiocarbamate ligands to form the diethylammonium counter ion occurs. Reaction of 1 with bidentate phosphines yielded green complexes of the general formula [Re(S 2 CNEt 2 ) 2 L][BPh 4 ], where L = Me 2 PCH 2 CH 2 PMe 2 7 or Ph 2 PCH 2 CH 2 PPh 2 8. These reactions can be contrasted to the inactivity of these phosphine ligands towards [Re 2 O 3 (S 2 CNEt 2 ) 4 ]. The reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with the bidentate phosphinothiolate proligand PPh 2 (C 6 H 4 SH-2) in acetone at room temperature yielded the red-orange rhenium(III) complex [Re{PPh 2 (C 6 H 4 S-2)} 2 (S 2 CNEt 2 )]·Me 2 CO 9. The crystal structure revealed a distorted-octahedral geometry. The sulfur donors of the phosphinothiolate ligands adopt a cis configuration. Reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with the tridentate phosphinothiolate proligand PPh(C 6 H 4 SH-2) 2 proceeded at room temperature to yield the red rhenium(V) complex [ReO{PPh(C 6 H 4 S-2) 2 }(S 2 CNEt 2 )] 10. Its crystal structure shows a distorted-octahedral geometry. Reaction of [Re 2 O 3 (S 2 CNEt 2 ) 4 ] with SiMe 3 Cl yielded the new rhenium(V) precursor [ReCl 2 (S 2 CNEt 2 ) 2 ][BPh 4 ] 11 which permits investigation into rhenium dithiocarbamate chemistry without an oxo core.