Crystal structures and electronic properties of three fluxional [Cu(di-2-pyridylamine)2(OXO)]Y complexes

• Published in: Journal of coordination chemistry 2007-01, Vol.60 (2), p.131-142
• Main Authors: Youngme, Sujittra, Phuengphai, Pongthipun, Chaichit, Narongsak, Mutikainen, Ilpo, Turpeinen, Urho, Murphy, Brian M.
• Format: Article
• Language: English
• Subjects: Cis-distortion; Copper(II); Di-2-pyridylamine; Fluxional behaviour; Plasticity effect
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958970600736629

The crystal structures of three bis(dpyam)copper(II) complexes, [Cu(dpyam) 2 (ONO)](SO 4 ) 0.5 (H 2 O) (I), [Cu(dpyam) 2 (O 2 CCH 3 )](ClO 4 ) (II) and [Cu(dpyam) 2 (O 2 CCH 2 CH 3 )](ClO 4 ) (III) (dpyam = di-2-pyridylamine) have been determined at room temperature by single-crystal X-ray methods. The complexes involve a CuN 4 O 2 chromophore with a symmetric cis-distorted octahedral stereochemistry for I, and an asymmetric cis-distorted octahedral stereochemistry for II and III. In I the copper atom and the oxygen donor atoms of the symmetrically bonded nitrito group lie on a crystallographic C 2 axis. This is the first reported example in the literature of such a complex with this type of stereochemistry, involving the [Cu(dpyam) 2 (OXO)][Y] series as a whole, where (OXO) − involves an oxoanion. In contrast, complexes II and III involve a distortion of the CuN 4 O 2 chromophore towards a square pyramidal (4 + 1 + 1) stereochemistry. Here, the stereochemistries of I, II and III are compared with other closely related complexes. The highly asymmetric geometry of the CuN 4 O 2 chromophores of II and III suggests that both complexes appear to be static in nature. Electronic spectra of the three complexes involve two bands of similar intensity corresponding to cis-distorted octahedral copper(II) stereochemistry.