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.

Two isomorphous lanthanide crotonate complexes: di-μ-but-2-enoato-bis[diaquabis(but-2-enoato)dysprosium(III)] adenine monosolvate heptahydrate and the samarium(II) analogue

“…A point of interest in these systems is the possibility of introducing extra ligands as bridges and thus obtaining grid structures and/or clusters, which are appealing not only structurally but also for their potential application in ion-exchange, catalysis, molecular absorption, optical, electronic and magnetic areas (Ma et al, 2000;Wang et al, 2002;Xu et al, 2002;Benelli & Gatteschi, 2002;Pan et al, 2004). In parallel, our investigation of carboxylate complexes has showed that the incorporation of some purine derivatives, like 2,6-diaminopurine (dap), might facilitate crystallization, either through their inclusion as neutral cocrystallization agents (Atria et al, 2009) or as counter-ions (Atria, Morel et al, 2011), or even as coordinating ligands (Atria, Corsini et al, 2011;. In parallel, our investigation of carboxylate complexes has showed that the incorporation of some purine derivatives, like 2,6-diaminopurine (dap), might facilitate crystallization, either through their inclusion as neutral cocrystallization agents (Atria et al, 2009) or as counter-ions (Atria, Morel et al, 2011), or even as coordinating ligands (Atria, Corsini et al, 2011;.…”

Anion–Cation Recognition Pattern, Thermal Stability and DFT-Calculations in the Crystal Structure of H2dap[Cd(HEDTA)(H2O)] Salt (H2dap = H2(N3,N7)-2,6-Diaminopurinium Cation)

“…The tautomers H 2 (N1,N3)dap + , H 2 (N3,N9)dap + and H 2 (N7,N9)dap + do not have received crystallographic support. The H 2 (N1,N7)dap + tautomer acts as N9-donor ligand in two isomorphous compounds having all-trans octahedral complex molecules [M II (H 2 dap) 2 (hpt) 2 (H 2 O) 2 ]·4H 2 O (M = Co or Ni, htp = homophthalato(2-) ligand) [56] (see Scheme 1). The κN9-H 2 (N1,N7)dap+ coordinating role was consistent not only with the highest proton affinity of the donor atom but also to its less steric hindrance.…”

A polymeric cobalt(II) complex derived from citric acid (H4cit) and 2,6-diaminopurine (dap): {[Co4(cit)2(dap)4(H2O)4]·6.35H2O}n

“…[References: OQUMOD and OQUMUJ (Atria, Corsini et al, 2011); AWICUF ; QUDKAC, QUDKEG, QUDKIK, QUDKOQ, QUDKUW and QUDLAD (Yang et al, 2009); WULXEG (Badura & Vahrenkamp, 2002). ]…”