Copper complexes of the functionalised tripodal ligand tris(2-pyridyl)methylamine and its derivatives

The coordination chemistry of the new tripodal ligand tris(2-pyridyl)methylamine (tpm) with copper(I), copper(II) and zinc(II) has been investigated. The synthesis of tpm can readily be modified to access a variety of related tripodal ligands such as 2-(methylsulfanyl)-1,1-di(2-pyridyl)ethylamine (mde); in addition, the primary amine function can be derivatised to extend further the range of complexes obtained. tpm itself is a versatile ligand, showing three distinct coordination modes: bidentate (py, NH2), tridentate (2py, NH2) and tridentate (3py). Complexes of stoichiometries Cu(tpm)(n) (n=1-3) have been obtained. The (2py, NH2) coordination mode is illustrated by the crystal structure of [Cu(tpm)(2)][BF4](2). Me2CO, whilst (3py) coordination is found in the crystal structures of [Cu(SO4)(tpm)(H2O)]. 3H(2)O, [{Cu(tpm)}(2)Br-3]Br . 3MeOH and also the zinc complex [Zn(tpm)(H2O)(3)](2)[Zn(H2O)(6)][SO4](3). 3H(2)O. Amide derivatives of tpm give complexes of stoichiometry CuL2, and the crystal structures of [Cu(tpma)(2)][BF4](2) [tpma=tris(2-pyridyl)methylacetamide] and [Cu(tpms)(2)]. 8H(2)O {tpmsH=4-oxo-4-[tris(2-pyridyl)methylamino]butanoic acid} have been determined. The crystal structure of the sulfate-bridged dimeric complex [{Cu(SO4)(mde)}(2)]. 3H(2)O shows the mde ligand to be tridentate, with (2py, NH2) coordination.