Specific structural features of copper(II) complexonates with nitrilotriacetate anions: A review

The specific structural features of copper(II) complexes with nitrilotriacetate anions (H n Nta , n = 0−2) are considered with due regard for the original results and data available in the literature. The structural features and the degree of distortion of copper coordination polyhedra (such as a (4 + 1) elongated square pyramid, a trigonal bipyramid, a (4 + 2) symmetric elongated tetragonal bipyramid, and a (4 + 1 + 1) asymmetric elongated tetragonal bipyramid) are discussed. Criteria for identification of five-vertex copper(II) polyhedra of the general formula Cu(H n Nta ) X ( n = 0−2; X = Cl, Br, N, O) are proposed for the cases of a distorted square pyramid, a distorted trigonal bipyramid, and a polyhedron intermediate between them. The modes of coordination of H n Nta 3 − n ligands with a mctal arc described in terms of crystal chemical formulas.