4,4-Bis(isopropylthio)-1,1-diphenyl-2-azabuta-1,3-diene Adducts with Cadmium(II), Mercury(II) and Copper(I) Iodides: Crystal, Molecular and Electronic Structures of d10 Transition Metal Chelate Complexes

The thioether-functionalized 2-azabutadiene (iPrS)2C=C(H)-N=CPh2 L ligates to CdI2 and HgI2 to form the chelate compounds [CdI2{(iPrS)2C=C(H)-N=CPh2] (1) and [HgI2(iPrS)2C=C(H)-N=CPh2] (2). Their crystal structures were solved via X-ray diffraction. Both crystallize in the non-centrosymmetric space groups: monoclinic P21 (1) and orthorhombic P212121 (2), respectively. The closed-shell d10 metal centers are four-coordinated (two iodides and S and N coordinating atoms from the ligand L) in both complexes. The geometrical indexes τ indicate that a highly distorted trigonal pyramidal is adopted for 1 and a seesaw geometry for 2. The comparative nature of metal–ligand bonds is discussed on the basis of metric parameters and of QT-AIM (quantum theory of atoms in molecules) calculations. L was also treated with CuI to obtain the dinuclear species [LCu(μ2-I2)CuL] (3), in which the two Cu(I) centers are linked by a short metal–metal bond. The geometric and electronic properties of 3 are compared with those of 1 and 2.