A New Class of Biomimetically Relevant “Scorpionate” Ligands. 1. The (2-Hydroxyphenyl)bis(pyrazolyl)methanes: Synthesis and Structural Characterization of Some Cobalt(II) Complexes

The syntheses of a new class of potentially biomimetic, tripodal, mixed functionality ligands, (2-hydroxyphenyl)bis(pyrazolyl)methane (L1), (2-hydroxyphenyl)bis(3,5-dimethylpyrazolyl)methane (L2), and (2-hydroxyphenyl)bis(3-isopropylpyrazolyl)methane (L3), are described. These ligands have been used to prepare the cobalt(II) complexes [Co(L1) 2 ]·2.5MeOH·1.5H 2 O, 1 ·2.5MeOH·1.5H 2 O; [Co(L2) 2 ]·0.5H 2 O, 2 ·0.5H 2 O; [Co(L3)Cl 2 ], 3; and [Co 3 (μ 3 -OH) 2 (μ-L3) 2 (L3)(H 2 O)]BF 4, 4 . X-ray structural analysis of 1 − 4 gave the following structural parameters: 1, C 30 H 34 N 8 CoO 6, triclinic, a = 8.286(2) Å, b = 10.053(3) Å, c = 10.562(2) Å, α = 109.66(2)°, β = 96.57(1)°, γ = 91.11(3)°, space group P 1̄, Z = 1; 2, C 38 H 38 N 8 CoO 6, triclinic, a = 8.746(5) Å, b = 10.900(5) Å, c = 11.399(8) Å, α = 70.82(4)°, β = 75.13(5)°, γ = 81.46(4)°, space group P 1̄, Z = 1; 3, C 20 H 26 N 4 Cl 4 CoO, monoclinic, a = 10.934(2) Å, b = 12.404(2) Å, c = 19.267(3) Å, β = 98.33(1)°, space group P 2 1 / n, Z = 4; 4, C 58 H 70 N 12 BCo 3 F 4 O 9, monoclinic, a = 14.798(5) Å, b = 23.657(8) Å, c = 20.614(7) Å, β = 97.75(2)°, space group P 2 1 / n, Z = 4.