Bonding μ1, 3- (trans) vs μ1, 2- (cis) in squarato-bridging dinuclear copper(II) complexes derived from pyridyl amine ligands. (8th January 2015)

• Record Type: Journal Article
• Authors: Mautner, Franz A.; Mikuriya, Masahiro; Naka, Yuko; Louka, Febee R.; Massoud, Salah S.
• Is Part Of: Polyhedron. Volume 85(2015)
• Page Start: 110
• Page End: 116
• Publication Date: 2015-01-08
• Subjects: Copper -- Polynuclear complexes -- Squarato bridged -- Crystal structure -- Magnetic properties; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2014.08.040
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: A novel series of trans - and cis -dinuclear squarato-bridged copper(II) complexes: [Cu2 (dpya)4 (μ1, 3 -C4 O4 )](ClO4 )2 ·MeOH (1 ), [Cu2 (bdmpzpy)2 (μ1, 3 -C4 O4 )(H2 O)2 ](ClO4 )2· 5H2 O (2 ) and [Cu2 (pmea)2 (μ1, 2 -C4 O4 )](ClO4 )2 ·1.5H2 O (3 ) where dpya = di-2-pyridylamine, bdmpzpy = 2, 6-bis[(2, 5-dimethyl-1H-pyrazolyl)methyl]pyridine and pmea = bis(2-pyridylmethyl)-2-(2-pyridylethyl)amine were structurally and magnetically characterized. Complexes reveal weak antiferromagnetic interaction between the Cu 2+ centers. Abstract: A series of trans - and cis -dinuclear squarato-bridged copper(II) complexes [Cu2 (dpya)4 (μ1, 3 -C4 O4 )](ClO4 )2 ·MeOH (1 ), [Cu2 (bdmpzpy)2 (μ1, 3 -C4 O4 )(H2 O)2 ](ClO4 )2 ·5H2 O (2 ) and [Cu2 (pmea)2 (μ1, 2 -C4 O4 )](ClO4 )2 ·1.5H2 O (3 ) derived from di-, tri- and tetra-dentate pyridyl amine ligands (C4 O4 2− is the 3, 4-dihydroxycyclobut-3-en-1, 2-dione dianion = squarate dianion, dpya = di-2-pyridylamine, bdmpzpy = 2, 6-bis[(2, 5-dimethyl-1H-pyrazolyl)methyl]pyridine, pmea = bis(2-pyridylmethyl)-2-(2-pyridylethyl)amine) were synthesized and structurally characterized by single crystal X-ray crystallography. In this series, structures consist of the ClO4 − groups as counter ions and the C4 O4 2− is bridging two Cu(II) ions in a μ-1, 3-bis(monodentate) (1 and2 ) and a μ-1, 2-bis(monodentate) (3 ) bonding modes. The coordination environment around the Cu(II) centers in these complexes is a five-coordinate with a distorted square geometry where the intra-dinuclear Cu⋯Cu distances across the bridged squarato ligand are in the range 7.26–7.82 Å in the trans μ1, 3 - complexes1 and2, and 6.76 Å in the corresponding cis μ1, 2 - complex3 . The magnetic measurements in the 4.5–300 K temperature range reveal weak antiferromagnetic coupling in the three complexes (| J | = 2.4–12.4 cm −1 ).