Complexes of the crown thioether ligand 2,5,8-trithia[9]-o-benzenophane, (TT[9]OB). Synthesis and molecular structure of [Cu(NCS)(TT[9]OB)]
The macrocyclic thioether ligand 2,5,8-trithia[9]-o-benzenophane (TT[9]OB) reacts with [Cu(CH3CN)4][ClO4] to yield the Cu(I) complex [Cu(CH3CN)(TT[9]OB)][ClO4]. The coordinated acetonitrile molecule is displaced by the ambidentate, thiocyanate (NCS)− ion to form the neutral complex [Cu(NCS)(TT[9]OB)] which was characterized by infrared spectroscopy, 1H NMR spectroscopy, and X-ray crystallography. The title complex crystallized in the orthorhombic space group Pbca with a = 14.447(3) Å, b = 15.034(4) Å, c = 14.851(4) Å, V = 3232.2(14) Å3, and Z = 8. The structure refined to R = 5.15% and Rw = 5.92% for 1149 reflections with Fo2 > 3σ(Fo2). The Cu(I) ion has a distorted tetrahedral coordination sphere with TT[9]OB occupying three sites while the fourth site is occupied by the thiocyanate ligand which is N-bound to the metal centre. A comparison is made of the molecular conformations of free TT[9]OB and that found for complexed TT[9]OB in [Cu(NCS)(TT[9]OB)] and [Cu(Ph2PMe)(TT[9]OB)][ClO4]. Key words: thioether, macrocyclic metal complex.