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Immobilized metal ion affinity chromatography(IMAC) is an importantchromatographic technique for biomolecules. In order to get a detailedunderstanding of the hydration of immobilized Fe(III), complexes ofFe(III) with methyl substituted iminodiacetate ([Fe(MSIDA)(H2O)3]+) as well as with methyl substituted nitrilotriacetate([Fe(MSNTA)(H2O)2]) were simulated in aqueoussolutions with the quantum mechanical charge field molecular dynamics(QMCF MD) approach. The simulations were carried out at the Hartree–Fock(HF) level of theory, since cluster calculations at the HF, MP2, andB3LYP levels of theory showed that this method results in a good compromisebetween computational effort and accuracy. None of the coordinatingwater molecules were exchanged during the simulation period of 15ps. The Fe–OH2Obond distances as wellas the Fe–OH2Ostretching motions differedamong the coordinating water molecules, indicating different bondstrengths. For the water molecules in the second hydration layer,mean residence times of 2.7 and 1.9 ps were obtained for [Fe(MSIDA)(H2O)3]+and [Fe(MSNTA)(H2O)2], respectively. Furthermore, infrared measurements were carriedout to characterize the most prominent bond features of aqueous Fe(III)–NTAand to discuss these results in conjunction with the computationallyderived frequencies. [ABSTRACT FROM AUTHOR]

The cis- and trans-bis(glycinato)copper(II) complexes in aqueous solution have been investigated by means of a combined theoretical and experimental approach. The conducted quantum mechanical charge field molecular dynamics (QMCF-MD) studies, being the first quantum mechanical simulations of organometallic complexes by this method, yielded accurate structural details of the investigated isomers as well as novel dynamic data, which has successfully been confirmed and extended by subsequent mid-infrared measurements. The spectroscopic results, critically assessed by adjacent multivariate data analysis, indicate an isomeric stability at ambient conditions, vanishing at elevated temperatures.