Chemistry Department, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Feb;102:175-85. doi: 10.1016/j.saa.2012.10.047. Epub 2012 Nov 2.
Copper guanine and barbital complexes were prepared and characterized by elemental analyses and spectral measurements. The data typified the formation of stoichiometries 1:1 (M:L) with possible Cu-Cu interaction "association". The complexes are with different geometries: square planar, square pyramidal and tetrahedral. The mode of bonding was identified by IR spectra. EPR spectra of the powdered complexes were recorded at X band at the room temperature. Different ESR parameters were calculated and discussed: g(//), g(⊥), A(//), [g], G, F, K, α(2). Molecular modeling techniques and quantum chemical methods have been performed for copper complexes to correlate the chemical structures of the complexes with their physical molecular properties. Bond lengths, bond orders, bond angles, dihedral angles, close contact, dipole moment (μ), sum of the total negative charge (STNC), electronegativity (χ), chemical potential (Pi), global hardness (η), softness (σ), the highest occupied molecular orbital energy (E(HOMO)), the lowest unoccupied molecular orbital energy (E(LUMO)) and the energy gap (ΔE) were calculated using PM3 semi-empirical and Molecular Mechanics (MM+) methods. The study displays a good correlation between the theoretical and experimental data which confirms the reliability of the quantum chemical methods.
铜鸟嘌呤和巴比妥酸配合物通过元素分析和光谱测量进行了制备和表征。数据典型地形成了化学计量比 1:1（M:L），可能存在 Cu-Cu 相互作用“缔合”。这些配合物具有不同的几何形状：平面正方形、四方锥和四面体。通过红外光谱确定了键合模式。在室温下，在 X 波段记录了粉末状配合物的 EPR 光谱。计算并讨论了不同的 ESR 参数：g(//)、g(⊥)、A(//)、[g]、G、F、K、α(2)。采用分子建模技术和量子化学方法对铜配合物进行了研究，以将配合物的化学结构与其物理分子性质相关联。使用 PM3 半经验和分子力学（MM+）方法计算了键长、键级、键角、二面角、紧密接触、偶极矩（μ）、总负电荷之和（STNC）、电负性（χ）、化学势（Pi）、全局硬度（η）、软度（σ）、最高占据分子轨道能量（E（HOMO））、最低未占据分子轨道能量（E（LUMO））和能隙（ΔE）。研究显示了理论和实验数据之间的良好相关性，这证实了量子化学方法的可靠性。
