The vibrational behaviour of complexes of general formula [(ML5CN)2ML4] with either a cis or trans geometry has been studied. The ν(CN) modes have been assigned on the basis of both infrared and Raman intensities. The CN vibrators are but weakly coupled, particularly so in the cis arrangement. The spectroscopic analysis offers insights into the interpretation of the spectra of Prussian Blue species as cis and trans M–CN–M–NC–M complexes may be regarded as building blocks of Prussian Blue. The structure of the complex [(CO)5- MoCNNi(Bipy)2NCMo(CO)5] confirms the expected cis geometry of the metal core. The complex [Cp(dppe)FeNCRu(4-EtPy)4CNFeCp(dppe)]3+[PF6 –]3 was prepared by oxidising the reduced form (2+ cation) and its crystal structure was determined and compared with that of the starting complex. Analysis of the structural and spectroscopic data led to the conclusion that the two iron atoms in the oxidised form have different charges and that the vibrations of the two CN groups are essentially independent. DFT calculations indicate that although π-bonding and antibonding occur, electrostatic effects (as described by the IVSE model) are probably more important.
The Vibrational Spectra of the Cyanide Ligand Revisited: Double BridgingCyanides
DIANA, Eliano;
2010-01-01
Abstract
The vibrational behaviour of complexes of general formula [(ML5CN)2ML4] with either a cis or trans geometry has been studied. The ν(CN) modes have been assigned on the basis of both infrared and Raman intensities. The CN vibrators are but weakly coupled, particularly so in the cis arrangement. The spectroscopic analysis offers insights into the interpretation of the spectra of Prussian Blue species as cis and trans M–CN–M–NC–M complexes may be regarded as building blocks of Prussian Blue. The structure of the complex [(CO)5- MoCNNi(Bipy)2NCMo(CO)5] confirms the expected cis geometry of the metal core. The complex [Cp(dppe)FeNCRu(4-EtPy)4CNFeCp(dppe)]3+[PF6 –]3 was prepared by oxidising the reduced form (2+ cation) and its crystal structure was determined and compared with that of the starting complex. Analysis of the structural and spectroscopic data led to the conclusion that the two iron atoms in the oxidised form have different charges and that the vibrations of the two CN groups are essentially independent. DFT calculations indicate that although π-bonding and antibonding occur, electrostatic effects (as described by the IVSE model) are probably more important.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
