Coordination chemistry of novel scorpionate ligands based on 3-cyclohexylpyrazole and 3-cyclohexyl-4-bromopyrazole

The ligands hydrotris(3-cyclohexylpyrazol-1-yl)borate, Tp(Cy)](-), tetrakis(3-cyclohexylpyrazol-1-yl)borate, pz(o)Tp(Cy)](-), and hydrotris(3-cyclohexyl-4-bromopyrazol-1-yl)borate, Tp(Cy,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(Tp(Cy))](2)(CO(3)), 4, and the compound NiTp(Cy,4Br)]pz(Cy,4Br)](3)(H)(2), 5. The structures of CoTp(Cy)]Cl, 1, CoTp(Cy,4Br)]Cl, 2, CoTp(Cy,4Br)]NCS, 3, Ni(Tp(Cy))](2)(CO(3)), 4, NiTp(Cy,4Br)]pz(Cy,4Br)](3)(H)(2), 5, and MoTp(Cy)](CO)(2)(eta(3)-methallyl), 6, were determined by X-ray crystallography. The structures of paramagnetic heteroleptic complexes CoTp(Cy)]Tp], CoTp(Cy)]Tp], CoTp(Cy,4Br)]Tp], and CoTp(Cy,4Br)]Tp] were established by NMR. The homoleptic compounds CoTp(Cy)](2) and CoTp(Cy,4Br)](2) rearrange thermally to CoTp(Cy)](2) and to CoTp((Cy,4Br))](2), respectively, containing one 5-cyclohexyl group/ligand.