Structure of Hydrated Copper(II) Colchiceine

Abstract

Hydrated crystals of copper(II) colchiceine belong to the tetragonal space group P 4₃2_I2 with a 13·415(1), c 50·169(8) Å and Z 8. The structure has been refined to a conventional R factor of 0·077 for 4560 observed data. The tropolonic oxygens from two colchiceine molecules are coordinated to the copper atom in this bis-chelated complex to form a square planar arrangement. The sites of three of the waters are clearly defined, but the others are disordered over seven partially occupied sites. An intricate hydrogen-bonding system links the complex and water molecules into a three-dimensional network in the crystal.