Zinc Complexes from Bromo Substituted Tris[(2‐pyridyl)methyl]amine Ligands. Influence of Sterically Demanding Substituents on Coordination Geometry

The reaction of zinc chloride with the tripodal tetradentate ligand [(6‐bromo‐2‐pyridyl)methyl]bis[(2‐pyridyl)methyl]amine (Brtpa), bis[(6‐bromo‐2‐pyridyl)methyl][(2‐pyridyl)methyl]amine (Br 2 tpa), or bis[(2‐pyridyl)methyl][(1‐methylimidazol‐2‐yl)methyl]amine (bpia) yields the new coordination compounds [Zn(Brtpa)Cl 2 ] (1) , [Zn(Br 2 tpa)Cl 2 ] (2) and the first zinc compound derived from bpia [Zn(bpia)Cl] 2 [ZnCl 4 ]·2CH 3 OH (3) , respectively. 1 and 2 are the first zinc complexes with halogen substituted tripodal ligands of the tpa type. The bromine substitutions of the ligands have a strong effect on coordination and binding. The new compounds were isolated and characterized by single crystal X‐ray crystallography as well as infrared spectroscopy and elemental analyses. Compound 1 crystallizes in the triclinic space group P1¯ (No. 2) with a = 7.503(2) , b = 8.815(2) , c = 15.924(3)Å, α = 94.19(3)°, β = 92.33(3)°, γ = 112.32(3)°, V = 969.1(3)Å 3 , Z = 2. Compound 2 crystallizes in the monoclinic space group P2 1 (No. 4) with a = 8.357(1), b = 10.882(1), c = 11.286(1)Å, β = 99.04(1)°, V = 1013.7(2)Å 3 , Z = 2. Compound 3 crystallizes in the orthorhombic space group P2 1 2 1 2 1 (No. 19) with a = 14.367(1), b = 17.269(1), c = 17.479(1)Å, V = 4336.5(2)Å 3 , Z = 4.