| Abstract: | Mixed-ligand Complexes of Technetium. XV. The Reaction of [TcNCl2(Me2PhP)3] with Dialkyldithiocarbamates and N,N-Dialkylthio-carbamoylbenzamidines [TcN(Cl)(Me2PhP)2(Et2dtc)], [TcN(Me2PhP)(Et2dtc)2], and [TcN(Et2dtc)2] can be prepared by stepwise ligand exchange reactions starting from dichlorotris(dimethylphenylphosphine)nitridotechnetium(V), [TcNCl2(Me2PhP)3], and diethyldithiocarbamate. In contrast to this, only one intermediate, [TcN(Cl)(Me2PhP)2(HEt2tcb)], could be isolated during the reaction with N,N-Diethlthiocarbamoylbenzamidine, which yields the bis chelate [TcN(HEt2tcb)2]. [TcN(Me2PhP)(Et2dtc)2] crystallizes in the monoclinic space group P21/c; a = 17.369(5) Å, b = 15.024(1) Å, c = 9.906(3) Å, β = 76.47(1)º, Z = 4. The phosphine is coordinated equatorially. The multiply bonded nitrogen ligand (Tc? N(1) 1.624(3) Å) strongly labilizes the trans positioned donor atom (distance Tc? S(4) 2.826(1) Å). [TcN(HEt2tcb)2] crystallizes in the triclinic space group P1 with a = 9.749(4) Å, b = 11.264(4) Å, c = 12.359(4) Å, α = 75.34(2)º, β = 79.69(2)º, γ = 87.55(2)º, Z = 2. The metal is five-coordinate with the nitrido donor atom occupying the apex of a square pyramid. It's basal plane is formed by the cis-coordinated chelate ligands. The technetium is situated over the basal plane by about 0.6 Å. The Tc?N distane was found to be 1.610(5) Å. |
