Coordination Chemistry of Novel Scorpionate Ligands Based on 3-Cyclohexylpyrazole and 3-Cyclohexyl-4-bromopyrazole

The ligands [hydrotris(3-cyclohexylpyrazol-1-yl)borate, [TpCy]-, tetrakis(3-cyclohexylpyrazol-1-yl)borate, [pzoTpCy]-, and hydrotris(3-cyclohexyl-4-bromopyrazol-1-yl)borate, [TpCy,4Br]- were synthesized and characterized as their Tl(I) derivatives. They were converted to a variety of tetrahedral LMX and octahedral LML‘ complexes, as well as to the dinuclear nickel carbonate complex [Ni(TpCy)]2(CO3), 4, and the compound Ni[TpCy,4Br][pzCy,4Br]3(H)2, 5. The structures of Co[TpCy]Cl, 1, Co[TpCy,4Br]Cl, 2, Co[TpCy,4Br]NCS, 3, [Ni(TpCy)]2(CO3), 4 , Ni[TpCy,4Br][pzCy,4Br]3(H)2, 5, and Mo[TpCy](CO)2(η3-methallyl), 6, were determined by X-ray crystallography. The structures of paramagnetic heteroleptic complexes Co[TpCy][Tp], Co[TpCy][Tp*], Co[TpCy,4Br][Tp], and Co[TpCy,4Br][Tp*] were established by NMR. The homoleptic compounds Co[TpCy]2 and Co[TpCy,4Br]2 rearrange thermally to Co[TpCy*]2 and to Co[Tp(Cy,4Br)*]2, respectively, containing one 5-cyclohexyl group/ligand.