Synthesis of (3-(2-thiazolin-2-yl)thiazolidine-2-thione) (triphenylphosphine)-copper(I) bromide with a new coordination core of Cu(I)

<div><p>The thio-ligand, 3-(2-thiazolin-2-yl)thiazolidine-2-thione (<i>L</i><sup><i>2</i></sup>, C<sub>3</sub>H<sub>4</sub>S<sub>2</sub>N-C<sub>3</sub>H<sub>4</sub>SN), generated <i>in situ</i> from the reaction of thiazolidine-2-thione (L<sup>1</sup>, NC<sub>3</sub>H<sub>5</sub>S<sub>2</sub>) with copper(I) bromide in CH<sub>3</sub>CN under aerobic conditions involved C–S bond cleavage and yielded a three coordinate complex, (3-(2-thiazolin-2-yl)thiazolidine-2-thione)copper(I) bromide <b>1</b>. Treatment of <b>1</b> with PPh<sub>3</sub> in MeOH/CH<sub>2</sub>Cl<sub>2</sub> mixture formed a copper(I) complex, (3-(2-thiazolin-2-yl)thiazolidine-2-thione)(triphenylphosphine)copper(I) bromide <b>2</b>. This complex has four different types of donor atoms bonded to Cu(I) forming a central core,{Cu(N,P,S,Br)}, which is very unusual as normally the cores of known tetrahedral complexes are of type, {Cu(P<sub>2</sub>,S,X)}(X = halogen).</p><p>Complex (3-(2-thiazolin-2-yl)thiazolidine-2-thione)(triphenylphosphine)copper(I) bromide <b>2</b> has unusual coordination core, Cu(N,P, S, Br).</p></div>