An unusual axial co-ordination of phenolate oxygen to copper(II): crystal structure of chloro{2-[bis(2-pyridylmethyl)aminomethyl]-4-nitrophenolato}copper(II)

Abstract

A tripod ligand possessing two pyridine moieties and a phenolato group as pendants forms a mononuclear complex with an axial copper(ii)-phenolate co-ordination in a square-pyramidal environment.* For the polycrystalline sample at room temperature, gll = 2.269, go = 2.073, A, = 13 x 1 V cm-'. In dmf at 77 K, g l l = 2.244, A I , = 179 x 10-4cm-1,g, = 2.070, A, = 33 x l p c m -' .

Bis[2-(2-pyridylmethylaminomethyl)phenol]copper(II) Diacetate Trihydrate [Cu(HBPA)2](CH3COO)2.3H2O

“…The Cu--N(amine) [average 2.003 (5).4,1 and the Cu--N(pyridine) [average 2.051 (6)A] bond lengths in the equatorial plane agree very well with those generally found in square-planar (Tamburini, Vigato & Casellato, 1989), square-pyramidal (Rajendran, Viswanathan, Palaniandavar & Lakshminarayanan, 1992) and distorted octahedral (Ranford, Sadler & Tocher, 1993) complexes. In addition, the Cun ion makes two axial Cu---O contacts to the O atoms of the two phenolic groups of the HBPA ligands.…”

“…In addition, the Cun ion makes two axial Cu---O contacts to the O atoms of the two phenolic groups of the HBPA ligands. These contacts [Cu---O1 = 2.494 (6) and Cu---O2 = 2.449 (6) k,] are significantly longer than that detected in the neutral° complex [Cu(BPNP)C1] [Cu--O(phenolate) = 2.268A] {HBPNP = 2-[bis(2-pyridylmethyl)aminomethyl]-4-nitrophenol}, in which the pnitrophenolate group is coordinated in the axial position in the square-pyramidal species (Rajendran et al, 1992). From this information and from the fact that (1) is a 2+ charged species we can assign a structure involving two axial copper(II)-phenol-OH bonds.…”

Síntese e caracterização de novos compostos de coordenação de cobre (II) com ligantes não-simétricos N,O-doadores: contribuições para o sítio ativo da galactose oxidase

“…Medidas de condutividade foram efetuadas em soluções 1 x 10 -3 mol.L -1 dos compostos (1), (2), (3) 10 , enquanto que os outros três compostos exibem duas bandas também observadas em outros complexos de Cu(II) descritos na literatura 2,9,10,13 e consistentes com uma geometria piramidal quadrada.…”

“…Alguns complexos, envolvendo o íon de cobre(II) com esfera de coordenação do mesmo tipo que a da galactose oxidase, têm sido descritos como modelos estruturais para o sítio ativo desta enzima 5,[8][9][10][11][12][13][14] . Outros complexos, envolvendo uma esfera de coordenação diferente para o cobre, têm sido descritos como modelos funcionais 5,[15][16][17][18] .…”

Pincer Complexes of Lithium, Sodium, Magnesium and Related Metals: A Discussion of Solution and Solid-State Aggregated Structure and Reactivity

“…25) likewise forms an unusual cluster species with CuBr (32) ( [136]; for other examples, NCN Pincer: [137], ONN Pincer: [138]). …”