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H(N3)dap (Hdap = 2,6-diaminopurine) Recognition by Cu2(EGTA): Structure, Physical Properties and DFT-Calculations of [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O
Mousavi, H.; García-Rubiño, M.E.; Choquesillo-Lazarte, D.; Castiñeiras, A.; Lezama, L.; Frontera, A.; Niclós-Gutiérrez, J. H(N3)dap (Hdap = 2,6-Diaminopurine) Recognition by Cu2(EGTA): Structure, Physical Properties, and Density Functional Theory Calculations of [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O. Molecules2023, 28, 6263.
Mousavi, H.; García-Rubiño, M.E.; Choquesillo-Lazarte, D.; Castiñeiras, A.; Lezama, L.; Frontera, A.; Niclós-Gutiérrez, J. H(N3)dap (Hdap = 2,6-Diaminopurine) Recognition by Cu2(EGTA): Structure, Physical Properties, and Density Functional Theory Calculations of [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O. Molecules 2023, 28, 6263.
Mousavi, H.; García-Rubiño, M.E.; Choquesillo-Lazarte, D.; Castiñeiras, A.; Lezama, L.; Frontera, A.; Niclós-Gutiérrez, J. H(N3)dap (Hdap = 2,6-Diaminopurine) Recognition by Cu2(EGTA): Structure, Physical Properties, and Density Functional Theory Calculations of [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O. Molecules2023, 28, 6263.
Mousavi, H.; García-Rubiño, M.E.; Choquesillo-Lazarte, D.; Castiñeiras, A.; Lezama, L.; Frontera, A.; Niclós-Gutiérrez, J. H(N3)dap (Hdap = 2,6-Diaminopurine) Recognition by Cu2(EGTA): Structure, Physical Properties, and Density Functional Theory Calculations of [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O. Molecules 2023, 28, 6263.
Abstract
Reactions in water between the Cu2(µ-EGTA) chelate (EGTA = ethylene-bis(oxyethyleneimino)tetraacetate(4-) ion) and 2,6-diaminopurine (Hdap) in molar ratios 1:1 and 1:2 yield only blue crystals of the ternary compound [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O (1) that has been studied by single crystal X-ray diffractometry, various physical methods (thermal stability, spectral and magnetic properties), as well as DFT theoretical calculations. In the crystal, uncoordinated water is disordered. The tetranuclear complex molecule also has some irrelevant disorder in an EGTA-ethylene moiety. In the complex molecule, both bridging organic molecules act as binucleating ligands. There are two distorted five- (type 4+1) and two six- (type 4+1+1) Cu(II) centres. Each half EGTA acts as a tripodal tetradentate Cu(II) chelator, with mer-NO2+O(ether, distal) conformation. Hdap exhibits the tautomer H(N3)dap, with the dissociable H-atom on its less basic N-heterocyclic atom. These features favour the efficient cooperation between Cu-N7 or Cu-N9 bonds with appropriate O-EGTA atoms, as N6-H···O or N3-H···O interligand interactions respectively. Bridging role of both organics determines the tetranuclear dimensionality of the complex in 1. In this crystal, such molecules associate in zig-zag chains, built by alternating ,-interactions between the five- or six-atom rings of Hdap ligands of adjacent molecules. DFT theoretical calculations (using two different theoretical models and characterized by the quantum theory of “atoms in molecules”) reveal the importance of these ,-interactions between Hdap ligands, as well as that corresponding to the referred hydrogen bonds in the contributed tetranuclear molecule.
Chemistry and Materials Science, Inorganic and Nuclear Chemistry
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