Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja s/n, 18071 Granada, Spain.
Dalton Trans. 2013 May 7;42(17):6119-30. doi: 10.1039/c2dt32191b.
For a better understanding of the versatile behaviour of adenine as a ligand, a series of 10 ternary copper(II) complexes with deaza-adenine ligands [7-azaindole (1,6,7-trideaza-adenine, H7azain), 4-azabenzimidazole (1,6-dideaza-adenine, H4abim), 5-azabenzimidazole (3,6-dideaza-adenine, H5abim), and 7-deaza-adenine (H7deaA)] have been synthesised and characterised by X-ray diffraction. Likewise, all the compounds studied have been analysed by spectral and thermal methods. The proton tautomers and donor capabilities of the above-mentioned deaza-adenine ligands have been calculated by DFT. We conclude that the increasing presence of N-donors in deaza-adenine ligands favours the proton tautomerism and their versatility as co-ligands. Notably, H7azain consistently uses the same tautomer, H4abim uses two different tautomers but is not protonated by the pentadentate H(2)EDTA(2-) ligand, and H(N1)5abim displays the μ(2)-N7,N9 mode, whereas H(N9)7deaA binds Cu(II) by N3 in cooperation with an intra-molecular N9-H···O interaction or using the unprecedented bidentate μ(2)-N1,N3 bridging mode.
为了更好地理解腺嘌呤作为配体的多功能性，我们合成了一系列 10 种与去氮腺嘌呤配体的三元铜（II）配合物[7-氮杂吲哚（1,6,7-三氮杂腺嘌呤，H7azain）、4-氮杂苯并咪唑（1,6-二氮杂腺嘌呤，H4abim）、5-氮杂苯并咪唑（3,6-二氮杂腺嘌呤，H5abim）和 7-脱氮腺嘌呤（H7deaA）]，并用 X 射线衍射进行了表征。同样，我们还通过光谱和热方法分析了所有研究的化合物。通过 DFT 计算了上述去氮腺嘌呤配体的质子互变异构体和供体能力。我们得出的结论是，去氮腺嘌呤配体中 N-供体的增加有利于质子互变异构体及其作为共配体的多功能性。值得注意的是，H7azain 始终使用相同的互变异构体，H4abim 使用两种不同的互变异构体，但不会被五齿 H(2)EDTA(2-)配体质子化，而 H(N1)5abim 显示 μ(2)-N7,N9 模式，而 H(N9)7deaA 则通过 N3 与 Cu(II)配位，同时通过分子内 N9-H···O 相互作用或使用前所未有的双齿 μ(2)-N1,N3 桥接模式。
