C. M. Mikulski, L. Mattucci, Y. Smith
1983
Citations
0
Influential Citations
45
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract Complexes of guanine (LH) with 3 d metal perchlorates were prepared by refluxing a mixture of ligand and metal salt (4:1 molar ratio) in ethanol2triethyl orthoformate. This synthetic procedure led to the formation of some adducts of the neutral ligand (LH), some complexes with anionic L − , and one complex involving both LH and L − (M = Co 2+ ). Ir evidence indicates that neither of the exocyclic potential ligand sites (N(2) nitrogen and O(6) oxygen) of guanine is involved in coordination. Among the new complexes, the hexacoordinated [M(LH) 2 (EtOH) 2 (OClO 3 ) 2 ](ClO 4 ) (M = Cr 3+ , Fe 3+ ) are apparently monomeric, with terminal unidentate LH, coordinating through the N(9) imidazole ring nitrogen. For the M 2+ complexes isolated, namely [MnL 2 (EtOH) 3 ] n , [FeL(OH 2 ) 4 ] n (ClO 4 ) n , [CoL(LH)(EtOH)(OH 2 ) 2 ] n (ClO 4 ) n , [Ni(LH) 2 (EtOH) 3 ] n (ClO 4 ) 2n and [Zn(LH) 2 (EtOH) 3 ] n (ClO 4 ) 2n ·2nEtOH, linear chain-like hexacoordinated polymeric structures, involving single bridges of bidentate guanine ligands (-M-guanine-M-guanine- sequences), binding through N(9) and, most probably, N(7) to adjacent M 2+ ions, are proposed; in most cases (M = Mn 2+ , Co 2+ , Ni 2+ , Zn 2+ ), a second guanine ligand acts as terminal, unidentate, N(9) nitrogen-bonded.