CRYSTAL-STRUCTURE AND SPECTROSCOPIC STUDIES OF TRIS(2-AMINOETHYL)AMINE COPPER(II) COMPLEXES WITH 4-AMINOPYRIDINE

A tris (2-aminoethyl)amine (tren) copper(II) complex with a coordinate d 4-aminopyridine (4-APy) ligand was synthesized and characterized. Si ngle crystal X-ray diffraction study reveals that there are two slight ly different cations and four perchlorate anions present in an asymmet ric unit. The coordination geometry of both Cu(II) centers are nearly identical and close to trigonal bipyramidal with three terminal amine nitrogen atoms forming the equatorial plane, while the tertiary nitrog en atom and the pyridine nitrogen atom from 4-APy occupy the apical po sitions. Of the two different cations, one shows an outer-sphere, brid ged copper dimer with the nitrogen atom N(6) from 4-APy and the termin al amino nitrogen atom N(3) linked together by hydrogen bonds N(6)-H.. .N(3a) and N(3)..H-N(6a) (1 - x - y, 1 - z). Magnetic and spectroscopi c data support the outer-sphere, bridged dimeric structure. The title complex, Cu(tren)(4-Apy)](ClO4)(2), crystallizes in the monoclinic spa ce group P2(1)/n with cell parameters a = 8.150(1), b = 33.854(2), c = 14.810(1) Angstrom, beta = 90.00(1)degrees, V = 3967(2) Angstrom(3) a nd Z = 8. The structure was refined by full-matrix least-squares to R = 0.065 and Rw = 0.088 with 3880 reflections having F > 6 sigma(F).