Reaction of [TcBr2N(PPh3)2] with (pyCH2)2NCH2CMe2SCH2Ph (L1) in acetonitrile gives [TcBr2N(L1)] in good yield. Crystal data: triclinic, space group P1 (No 2), a=7.458(1), b=10.852(3), c=16.598(6) Å; α=84.07(2), β=86.24(2), γ=72.44(2)°; U=1273.1 Å3, λ=1.5406 Å, Z=2; Dcalc=1.694 g cm-3; F(000)=644. A total of 4204 unique reflections was collected; 3173 were used for structure solution and refinement to give R=0.070. The geometry about the Tc atom is pseudo-octahedral with L1 functioning as a tridentate ligand, the S atom being uncoordinated. However, NMR spectroscopy shows that in solution there is an equilibrium between this form and one in which a bromide ion is expelled and the thioether sulphur is ligated. The related unmethylated ligand, (pyCH2)2NCH2CH2SCH2Ph (L2) behaves similarly. © 1992.
