Mixed-ligand complexes of cadmium(II) containing bulky polydentate nitrogen-based ligands

The reaction of equimolar amounts of CdCl2, Tl[H2B(3-Butpz)2] (pz=pyrazolyl ring) and Na[Et2NCS2] yields [H2B(3-Butpz)2]Cd(S2CNEt2) (1) and a similar reaction using Tl[HB(3-Butpz)3] yields [HB(3-Butpz)3]Cd(S2CNEt2) (2). The solid state structure of [HB(3-Butpz)3]Cd(S2CNEt2) shows the arrangement of the donor atoms is a distorted trigonal bipyramid, an unusual geometry for a molecule containing a tridentate [HB(3-Butpz)3]− ligand. Mixing CdCl2 with 2 equiv. of MeLi yields the Me2Cd intermediate that reacts with Tl[HB(3-Phpz)3] to yield [HB(3-Phpz)3]CdCH3 (3). Compound 3 reacts with thiotoluene to yield [HB(3-Phpz)3]CdS(p-C6H4CH3) (4) and mercaptopyridine to yield [HB(3-Phpz)3]Cd(SNC6H4) (5). The neutral 2,6-bis(2,6-dimethylphenylimino)pyridine ligand (pydim) reacts with CdCl2 in equimolar amounts to yield the adduct (pydim)CdCl2 (6). The cadmium(II) is in a five-coordinate arrangement that is best described as a distorted trigonal bipyramid. The three nitrogen atoms of the planar pyridine ligand occupy an equatorial and both axial sites, but the intrinsic bite angle of the ligand forces a significant distortion in the axial bond angle. Compound 6 reacts with an equimolar amount of Na[Et2NCS2] to yield [(pydim)Cd(S2CNEt2)][Cl] (7). The reaction of equimolar amounts of pydimMe2 and Cd(NO3)2 yields (pydimMe2)Cd(NO3)2 (8). In the structure of this complex, one nitrate ligand is bidentate and the other monodentate. If the bidentate ligand is considered as occupying one site of a polyhedron, the structure of 8 can be considered as a trigonal bipyramid, very similar to that of 6.