Synthesis and structural characteristics of metal-acyclovir (ACV) complexes: [Ni(or Co)(ACV)(2)(H2O)(4)]Cl-2 center dot 2ACV, [Zn(ACV)Cl-2(H2O)], [Cd(ACV)Cl-2]center dot H2O and [{Hg(ACV)Cl-2}(x)]. Recognition of acyclovir by Ni-ACV

The monomeric [M(AVC)(2)(H2O)(4)]Cl-2. 2ACV (M = Ni-II 1 or Co-II 2), [Zn(A CV)Cl2H2O)] 3 and the polymeric [Cd(ACV)Cl-2]. H2O 4 [ACV = acyclovir = 9-( 2- hydroxymethoxymethyl)guanine] complex have been prepared and characteris ed by x-ray diffraction and IR data; H-1 and C-13 NMR have been used to int erpret the structural characteristics of the complexes in solution. compoun ds 1 and 2 exist as octahedral complexes with four H2O ligands in the basal plane [Ni-OW 2.053(2) and 2.057(7) Angstrom] and two axial ACV molecules l inked to Ni through N(7) [Ni-N(7) 2.160(2) Angstrom]. Two additional ACV mo lecules are included in the outer sphere of the complex, interacting by mea ns of hydrogen bonds with the co-ordinated ACVs. This reveals the unprecede nted recognition of free acyclovir molecules by Ni(or Co)-ACV (1 and 2). Th e monomeric zinc(II) complex 3 exhibits a distorted-tetrahedral geometry, i nvolving two chlorides, the N(7) of the ACV ligand [Zn-N(7) 2.009(2) Angstr om] and a water molecule. The hydrogen bonding of two guanine bases via NH2 and N(3) (unit 1) and N(3) and NH2 (unit 2) represents a novel type of int eraction between nucleobases. In the case of the cadmium(II) complex 4 the structure is built by polymeric (CdCl2)(n) chains which are held together b y ACV ligands. The cadmium cation is octahedrically coordinated by four chl orides, the N(7) from an ACV molecule and the hydroxylic oxygen from anothe r ACV molecule, the latter two atoms being placed in cis disposition. On th e other hand, the complex [{Hg(ACV)Cl-2}(x)] 5 can be tentatively assigned as a polymer by comparison with analogous guanosine systems and spectroscop ic and conductomet ric data.