The Fe(III), Co(III), and V(III) Complexes of the “Heteroscorpionate” Ligand (2-Thiophenyl)bis(pyrazolyl)methane

The synthesis and characterization of the tridentate “heteroscorpionate” mixed functionality ligand, (2-thiophenyl)bis(pyrazolyl)methane, L1, is reported. This ligand was used to synthesize the complexes, [Fe(L1) 2 ][ClO 4 ], [Co(L1) 2 ][BPh 4 ], and [V(L1) 2 ][BPh 4 ]. X-ray crystallographic analysis of the latter two complexes gave the following structural parameters: [V(L1) 2 ][BPh 4 ] · MeCN · i Pr 2 O, C 58 H 57 N 9 B 1 O 1 S 2 V 1, monoclinic, a = 16.197(2) Å, b = 19.281(2) Å, c = 17.985(2) Å, β = 102.343(9)°, space group P 2 1 / c; [Co(L1) 2 ][BPh 4 ] · CH 2 Cl 2, C 51 H 42 N 8 B 1 Cl 2 Co 1 S 2, triclinic, a = 12.751(1) Å, b = 12.830(1) Å, c = 14.740(1) Å, α = 98.351(7)°, β = 98.122(6)°, γ = 97.023(8)°, space group P 1̄. An example of the use of this new class of “heteroscorpionate” ligands for systematic comparisons of electronic properties of metal complexes with identical topology that vary only in the nature of one of the donor atoms is given.