Premium
A coordinatively flexible hexadentate ligand gives structurally isomeric complexes M 2 ( L ) X 3 ( M = Cu, Zn; X = Br, Cl)
Author(s) -
Wegeberg Christina,
McKee Vickie,
McKenzie Christine J.
Publication year - 2016
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229615023773
Subject(s) - ethylenediamine , chemistry , ligand (biochemistry) , denticity , carboxylate , trigonal bipyramidal molecular geometry , zinc , bromide , tris , isostructural , medicinal chemistry , stereochemistry , crystallography , crystal structure , inorganic chemistry , organic chemistry , biochemistry , receptor
Polypyridyl multidentate ligands based on ethylenediamine backbones are important metal‐binding agents with applications in biomimetics and homogeneous catalysis. The seemingly hexadentate tpena ligand [systematic name: N , N , N ′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐ N ′‐acetate] reacts with zinc chloride and zinc bromide to form trichlorido[μ‐ N , N , N ′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐ N ′‐acetato]dizinc(II), [Zn 2 (C 22 H 24 N 5 O 2 )Cl 3 ], and tribromido[μ‐ N , N , N ′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐ N ′‐acetato]dizinc(II), [Zn 2 Br 3 (C 22 H 24 N 5 O 2 )]. One Zn II ion shows the anticipated N 5 O coordination in an irregular six‐coordinate site and is linked by an anti carboxylate bridge to a tetrahedral Zn X 3 ( X = Cl or Br) unit. In contrast, the Cu II ions in aquatribromido[μ‐ N , N , N ′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐ N ′‐acetato]dicopper(II)–tribromido[μ‐ N , N , N ′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐ N ′‐acetato]dicopper(II)–water (1/1/6.5) [Cu 2 Br 3 (C 22 H 24 N 5 O 2 )][Cu 2 Br 3 (C 22 H 24 N 5 O 2 )(H 2 O)]·6.5H 2 O, occupy two tpena‐chelated sites, one a trigonal bipyramidal N 3 Cl 2 site and the other a square‐planar N 2 OCl site. In all three cases, electrospray ionization mass spectra were dominated by a misleading ion assignable to [ M (tpena)] + ( M = Zn 2+ and Cu 2+ ).