15844-52-7Relevant articles and documents
Copper(II) and nickel(II) chelates of the dihydrogen nitrilotriacetate(1-) ion: Crystal and molecular structure of bis(N,N-bis(carboxymethyl)glycinato)copper(II) dihydrate
Dung, Nguyen-Huy,Viossat,Busnot,González Pérez,González García,Niclós Gutiérrez
, p. 1227 - 1231 (2008/10/08)
Bis(dihydrogen nitrilotriacetato) chelates of copper(II) and nickel(II) have been obtained as dihydrates, [M(H2NTA)2]· 2H2O (M = Cu, Ni; H3NTA = nitrilotriacetic acid or N,N-bis(carboxymethyl)glycine). The potentiometric and conductometric titration curves, TG-DTA analysis, spectral properties (IR, reflectance, ESR), and magnetic susceptibility data of these sparingly soluble in water compounds are discussed, taking in view the crystal structure of the copper complex [Cu(H2NTA)2]·2H2O, which crystallizes in the monoclinic system, space group P21/c (a = 6.845 (1) A?, b = 14.095 (4) A?, c = 9.427 (3) A?, β = 91.95 (2)°, Z = 2, V = 909.1 A?3, dmeasd = 1.73 (2) g·cm-3, dexptl = 1.75 g·cm-3, μ = 1.631 mm-1 (Mo Kα)). Final R = 0.032 and Rw = 0.033 for 1416 independent observed reflections. The copper atom lies in the center of symmetry. Two dihydrogen nitrilotriacetate(1-) or N,N-bis(carboxymethy)glycinate(1-) ions, H2NTA-, act as tridentate chelating agents, making up an all-trans elongated octahedral coordination around the same copper atom (Cu-N = 2.062 (3) A?, Cu-O(3) = 1.954 (2) A?, Cu-O(13) = 2.321 (2) A?) where each ligand remains with a free carboxylic group of one of the two acetic or N-carboxymethyl arms. Two interesting structural features of this solid are (1) the very short trans-apical Cu-O(13) and Cu-O(13i) bonds (symmetry code i: 1 - x, 1 - y, 1 - z), as compared with the un-ionized carboxyl-to-copper(II) coordination bonds in related compounds (2.467-2.518 A?), and (2) the formation of hydrogen bonds O(14)-H?OW (2.598 (4) A?; 164°) involving one water oxygen atom and the carboxylic group of each ligand bonded to copper.
