Structure of hydrated copper(II) colchiceine

Hydrated crystals of copper(II) colchiceine belong to the tetragonal space group P 4(3)2(1)2 with a 13.415(1), c 50.169(8) Angstrom and Z 8. The struc ture has been refined to a conventional R factor of 0.077 for 4560 observed data. The tropolonic oxygens from two colchiceine molecules are coordinate d to the copper atom in this bis-chelated complex to form a square planar a rrangement. The sites of three of the waters are clearly defined, but the o thers are disordered over seven partially occupied sites. An intricate hydr ogen-bonding system links the complex and water molecules into a three-dime nsional network in the crystal.