Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, E-18071 Granada, Spain.
Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, E-18071 Granada, Spain.
J Inorg Biochem. 2020 Feb;203:110920. doi: 10.1016/j.jinorgbio.2019.110920. Epub 2019 Nov 13.
Four ternary metal-complexes with Cu(II) or Zn(II), 2,6-pyridine-dicarboxylate (pdc) or glycyl-glycinate (GG) and the synthetic nucleoside 9-(2-hydroxyethyl)adenine (9heade) have been synthesized and studied by single-crystal X-ray diffraction and other physical methods. Relevant supramolecular assemblies found in the solid state structures have been further studied using density functional theory (DFT) calculations. In addition, the energetic features of the non-covalent interactions as well as the cooperativity effects have been calculated and characterized using the non-covalent interaction plot computational tool. Compounds trans-[Cu(pdc)(9heade)(HO)]·3HO (1a) and [Cu(pdc)(9heade)(HO)]·HO (1b), trans-[Zn(pdc)(9heade)(HO)] (2), share the same molecular recognition pattern consisting in the cooperation of the metal-N7(9heade) bond and an interligand (9heade)N6-H···O(pdc) interaction, regardless of the nature of the metal, the coordination environment and the water content. At a supramolecular level, these compounds exhibit pairs of complex molecules linked by H-bonds and interesting anion-π/π-π/π-anion assemblies (in 1a and 1b) or the unprecedented π-π interactions (in 2), involving the purine moieties or the exocyclic -NH purine groups, respectively. Compound 3, {[Cu(GG)(9heade)(HO)·Cu(GG)(μ-9heade)]·8HO}, consists in asymmetric dinuclear complex units (Cu···Cu 7.83 Å) that connect with adjacent ones by pairs of very weak Cu-O(carboxylate) bonds (Cu···Cu 3.81 Å) building a polymeric chain. The supramolecular transition from a single molecule to dinuclear units and finally a polymeric chain is also observed in the electron paramagnetic resonance spectra and discussed from a structural point of view as well as by DFT calculations. The unprecedented N7 and μ-N7,O(ol) metal binding patterns of 9heade differs from that recently reported (μ-N1,N7) in a Cd(II) polymer.
已经合成了四个包含 Cu(II) 或 Zn(II)、2,6-吡啶二甲酸（pdc）或甘氨酰甘氨酸（GG）和合成核苷 9-(2-羟乙基)腺嘌呤（9heade）的三元金属配合物，并通过单晶 X 射线衍射和其他物理方法进行了研究。在固态结构中发现的相关超分子组装体已使用密度泛函理论（DFT）计算进一步研究。此外，使用非共价相互作用图计算工具计算和表征了非共价相互作用的能量特征以及协同效应。化合物反式-[Cu(pdc)(9heade)(HO)]·3HO (1a) 和 [Cu(pdc)(9heade)(HO)]·HO (1b)、反式-[Zn(pdc)(9heade)(HO)] (2) 具有相同的分子识别模式，包括金属-N7(9heade)键和配体间 (9heade)N6-H···O(pdc) 相互作用的协同作用，无论金属的性质、配位环境和含水量如何。在超分子水平上，这些化合物表现出由氢键连接的复杂分子对，以及有趣的阴离子-π/π-π/π-阴离子组装体（在 1a 和 1b 中）或前所未有的 π-π 相互作用（在 2 中），分别涉及嘌呤部分或外环-NH 嘌呤基团。化合物 3，{[Cu(GG)(9heade)(HO)·Cu(GG)(μ-9heade)]·8HO}，由不对称双核配合物单元（Cu···Cu 7.83 Å）组成，通过两对非常弱的 Cu-O（羧酸盐）键（Cu···Cu 3.81 Å）与相邻单元连接，形成聚合物链。从电子顺磁共振光谱也观察到从单个分子到双核单元再到聚合物链的超分子转变，并从结构角度以及通过 DFT 计算进行了讨论。9heade 的前所未有的 N7 和 μ-N7,O(ol) 金属结合模式与最近报道的 Cd(II) 聚合物中的（μ-N1,N7）不同。
