A tetra-nuclear copper(II) complex stabilizes an extended structure of a water nonamer: Synthesis and characterization of [Cu < inf > 4 < /inf > (C < inf > 54 < /inf > H < inf > 46 < /inf > N < inf > 4 < /inf > O < inf > 14 < /inf > )(OH) < inf > 2 < /inf > ] · 10H < inf > 2 < /inf > O

Abstract

A tetra-nuclear copper(II) complex [Cu4(C54H46N4O14)(OH)2] · 10H2O (1) has been synthesized starting from l-tyrosine, NaOH, 2,6-diformyl-4-methylphenol (dfp) and CuSO4 · 5H2O. Compound 1 crystallizes from an ethanol-water mixture in triclinic P over(1, ̄) space group. In the crystal of 1, two binuclear copper units, related by a center of symmetry, are bridged by two hydroxo bridges and results in the formation of a tetra-nuclear {Cu4} structure. Five lattice water molecules, located in the asymmetric unit, interact among themselves and form an unusual form of a water nonamer. In the crystal, the water nonamer is again hydrogen bonded to the next nonamer forming a chainlike polymer. Each {Cu4} complex unit attaches four such water nonamer chains. Variable temperature magnetic data fit to the Bleaney-Bower's equation with a Curie type of impurity of S = 0.5. The best fit of the magnetic data to this equation yielded 2J = -217, g = 2.019 and a TIP value of 60 × 10-6 cm3 mol-1. © 2006 Elsevier Ltd. All rights reserved.