Clegg W, Harrington RW, Barati K, Habibi MH, Montazerozohori M, Lalegani A. Synthesis, characterization and crystal structures of the bidentate Schiff base N,N'-bis(2-nitrocinnamaldehyde)ethylenediamine and its complex with CuNCS and triphenylphosphane.
Acta Crystallogr C Struct Chem 2015;
71:578-83. [PMID:
26146396 DOI:
10.1107/s2053229615010815]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/04/2015] [Indexed: 11/11/2022] Open
Abstract
Reaction of copper(I) thiocyanate and triphenylphosphane with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, (1); systematic name (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]}, C20H18N4O4, in a 1:1:1 molar ratio in acetonitrile resulted in the formation of the complex {(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}(thiocyanato-κN)(triphenylphosphane-κP)copper(I)], [Cu(NCS)(C20H18N4O4)(C18H15P)] or [Cu(NCS)(Nca2en)(PPh3)], (2). The Schiff base and copper(I) complex have been characterized by elemental analyses, IR, electronic and (1)H NMR spectroscopy, and X-ray crystallography [from synchrotron data for (1)]. The molecule of (1) lies on a crystallographic inversion centre, with a trans conformation for the ethylenediamine unit, and displays significant twists from coplanarity of its nitro group, aromatic ring, conjugated chain and especially ethylenediamine segments. It acts as a bidentate ligand coordinating via the imine N atoms to the Cu(I) atom in complex (2), in which the ethylenediamine unit necessarily adopts a somewhat flattened gauche conformation, resulting in a rather bowed shape overall for the ligand. The NCS(-) ligand is coordinated through its N atom. The geometry around the Cu(I) atom is distorted tetrahedral, with a small N-Cu-N bite angle of 81.56 (12)° and an enlarged opposite angle of 117.29 (9)° for SCN-Cu-P. Comparisons are made with the analogous Schiff base having no nitro substituents and with metal complexes of both ligands.
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