Misra S N, Anjaiah K, Joseph G, Abdi S H
Chemistry Department, Bhavnagar University.
Indian J Biochem Biophys. 1992 Feb;29(1):70-6.
The interactions of praseodymium(III) and neodymium(III) with nucleosides and nucleotides have been studied in different stoichiometry in water and water-DMF mixtures by employing absorption difference and comparative absorption spectrophotometry. The 4f-4f bands were analysed by linear curve analysis followed by gaussian curve analysis, and various spectral parameters were computed, using partial and multiple regression method. The magnitude of changes in both energy interaction and intensity were used to explore the degree of outer and inner sphere coordination, incidence of covalency and the extent of metal 4f-orbital involvement in chemical bonding. Crystalline complexes of the type [Ln(nucleotide)2(H2O)2]- (where nucleotide--GMP or IMP) were characterized by IR, 1H NMR, 31P NMR data. These studies indicated that the binding of the nucleotide is through phosphate oxygen in a bidentate manner and the complexes undergo substantial ionisation in aqueous medium, thereby supporting the observed weak 4f-4f bands and lower values for nephelauxetic effect (1-beta), bonding (b) and covalency (delta) parameters derived from coulombic and spin orbit interaction parameters.
通过吸收差示光谱法和比较吸收分光光度法，研究了镨（III）和钕（III）在水以及水 - 二甲基甲酰胺混合体系中与不同化学计量比的核苷和核苷酸之间的相互作用。通过线性曲线分析，随后进行高斯曲线分析，对4f - 4f能带进行分析，并使用偏回归和多元回归方法计算各种光谱参数。利用能量相互作用和强度变化的幅度来探究外层和内层球配位程度、共价性发生率以及金属4f轨道参与化学键合的程度。通过红外光谱（IR）、核磁共振氢谱（1H NMR）、核磁共振磷谱（31P NMR）数据对[Ln（核苷酸）2（H2O）2]-类型的晶体配合物（其中核苷酸为GMP或IMP）进行了表征。这些研究表明，核苷酸以双齿方式通过磷酸氧结合，并且配合物在水性介质中发生大量电离，从而支持所观察到的较弱的4f - 4f能带以及从库仑和自旋轨道相互作用参数得出的弱场效应（1 - β）、键合（b）和共价性（δ）参数的较低值。
