Synthesis and characterization of binuclear and polymeric five-coordinate copper(II) complexes derived from 3,3′,3″-triaminotripropylamine (trpn): Crystal structure of [Cu(trpn)(N 3)]ClO 4 ( I) and [Cu 2(trpn)(tren)(NO 2)(H 2O)](ClO 4) 3 ( II)

Abstract

The synthesis and characterization of five-coordinate copper(II) complexes derived from 3,3′,3″-triaminotripropylamine (trpn) are described. The X-ray diffraction studies have established the structures [Cu(trpn)(N 3)]ClO 4 ( I) and [Cu 2(trpn)(tren)(NO 2)(H 2O)](ClO 4) 3 ( II). Compound ( I) consists of a polymeric cation chain and ClO 4 − counter ions. The coordination geometry of the Cu(II) centers may be described as distorted square pyramidal (SP) with the azido group at the apical site and three nitrogen donors of the trpn molecule occupy the basal sites. The CuN5 chromophore is completed by a bridging aminopropyl group of neighboring trpn ligand. Compound ( II) is a dinuclear complex cation with two different cation geometries in the unit cell. The geometry of the Cu(II) binding tren ligand is close to trigonal bipyramidal (TBP), with the basal and apical sites are occupied by the four nitrogen atoms of the tren ligand. The fifth coordination site is bridged to one of the aminopropyl arms of the trpn ligand. The geometry of the second Cu(II) center may be described as close to distorted SP, where the trpn ligand is binding the Cu(II) ion via the two primary aminopropyl groups and the tertiary nitrogen. The remaining two sites are occupied by oxygen atoms of a water molecule and nitrite ion. The intramolecular Cu…Cu distance in I and II ranges from 7.55 Å to 7.94 Å. The visible spectra of the complexes in DMSO are consistent with the X-ray results found for I and II and show a greater tendency toward SP geometry.