Synthesis and crystal structure of chlorobis(η 5-cyclopentadienyl)purinato titanium(IV), a model compound for the Interaction of the antitumor titanocene dichloride molecule with DNA bases

• Published in: Inorganica Chimica Acta Vol. 92; no. 3; pp. 191 - 197
• Main Authors: Beauchamp, André L., Cozak, Daniel, Mardhy, Abdelhakim
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.1984; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic compounds; Metal complexes; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Antineoplastic agent; Unsaturated cyclic compound; Hydrocarbon; Molecular structure; Titanium IV Complexes; Transition metal Compounds; Nickel Organic compounds; Organic ligand; Purine base; Experimental study; X ray diffraction; Inorganic compound; Complexes Mixed; Chloro complex; Hapto complex; Monocyclic compound; Crystalline structure
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(00)87758-0

(η 5-C 5H 5) 2TiCl 2 shows significant antitumor activity and the title compound was investigated as a possible model for a species initially formed between titanocene dichloride and a purine base of DNA. The (η 5-C 5H 5) 2TiCl(C 5H 3N 4) complex was prepared by refluxing the dichloride with purine in the presence of triethylamine in THF. The crystals are monoclinic, space group P2 1/c, a = 7.484(2) Å, b = 25.85(1) Å, c = 9.134(3) Å, β = 127.53(3)° and Z = 4 molecules per cell. The structure was refined on 1378 independent nonzero reflections to an R factor of 0.045. The unit cell contains individual molecules in which the basic features of titanocene dichloride are not profoundly affected. The rings show the usual ‘open clamshell’ arrangement. One of the Cl atoms has been replaced by the N9 atom of deprotonated purine. The purine moiety makes an angle of only 7.2° with the Cl—Ti—N9 plane, thus avoiding steric interference from the cyclopentadienyl rings. The structure is discussed in connection with the possibility of inter-and intra-strand crosslinking of DNA by a (η 5-C 5H 5) 2Ti unit binding to the bases.