title: Two isomorphous transition metal complexes containing a protonated diaminopurine ligand: diaquabis(2,6-diamino-7H-purin-1-ium-κN9)bis(homophthalato-κO)nickel(II) tetrahydrate and the cobalt(II) analogue.
abstract: The two isomorphous title compounds, [M(C(5)H(7)N(6))(2)(C(9)H(6)O(4))(2)(H(2)O)(2)]·4H(2)O or M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2)·4H(2)O {where dap is 2,6-diaminopurine, H(2)hpt is homophthalic acid [2-(2-carboxyphenyl)acetic acid] and M is Ni(II) or Co(II)}, consist of neutral M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2) monomers, where the M(II) cation lies on an inversion centre and its MN(2)O(4) octahedral environment is defined by one N atom (from Hdap(+)), two O atoms (from one hpt(2-) dianion and one water molecule) and their inversion images. The structures are unusual in that the Hdap(+) cation occurs in an uncommon protonated state (as 2,6-diamino-7H-purin-1-ium) and both ligands bind in an unprecedented monodentate fashion. The existence of a large number of donors and acceptors for hydrogen bonding, together with π-π interactions, leads to a rather complex three-dimensional structure.
authors.affiliation: Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Atria
authors.forename: Gino
authors.initials: G
authors.lastname: Corsini
authors.forename: Natalia
authors.initials: N
authors.lastname: Herrera
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Garland
authors.forename: Ricardo
authors.initials: R
authors.lastname: Baggio
mesh_terms: D015075:2-Aminopurine / Q000031:analogs & derivatives* / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008024:Ligands; D008968:Molecular Conformation; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D009942:Organometallic Compounds; D028561:Transition Elements; C559604:diaquabis(2,6-diamino-7H-purin-1-ium-kappaN9)bis(homophthalato-kappaO)nickel(II) tetrahydrate; D003035:Cobalt; D015075:2-Aminopurine; C007300:2,6-diaminopurine; D009532:Nickel