Vibrational and theoretical studies of urea and magnesium-urea complexes

Raptis, SG; Anastassopoulou, J; Theophanides, T

dc.contributor.author	Raptis, SG	en
dc.contributor.author	Anastassopoulou, J	en
dc.contributor.author	Theophanides, T	en
dc.date.accessioned	2014-03-01T01:15:58Z
dc.date.available	2014-03-01T01:15:58Z
dc.date.issued	2000	en
dc.identifier.issn	1432-881X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13852
dc.subject	Environmental Change	en
dc.subject	Experimental Data	en
dc.subject	Ir Spectra	en
dc.subject	Low Energy	en
dc.subject	Magnesium	en
dc.subject	Molecular Structure	en
dc.subject	Symmetry Group	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.other	MOLECULAR-ORBITAL METHODS	en
dc.subject.other	QUARTIC FORCE-FIELD	en
dc.subject.other	BASIS-SETS	en
dc.subject.other	SPECTROSCOPIC PROPERTIES	en
dc.subject.other	AB-INITIO	en
dc.subject.other	SPECTRUM	en
dc.subject.other	FREQUENCIES	en
dc.subject.other	ABINITIO	en
dc.subject.other	METAL	en
dc.title	Vibrational and theoretical studies of urea and magnesium-urea complexes	en
heal.type	journalArticle	en
heal.identifier.primary	10.1007/s002140000200	en
heal.identifier.secondary	http://dx.doi.org/10.1007/s002140000200	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	The molecular structure and IR spectra of urea, H2NCONH2, in gas phase and in acetonitrile solution, as well as of the two complexes [MgU4Cl2] and [MgU6]Cl-2 have been observed. The influence of environmental changes to geometry and spectra are shown. Various basis sets have been employed to safeguard the validity of the reported findings, using polarization functions for all calculations to get the correct pyramidal amide configuration. The erroneous low energy of the C-2v symmetry group, after the addition of the ZPVE correction, is discussed. For the solvated urea molecule a reduction of the energy barrier, compared to the gas phase urea, between the two minimum configurations, C-2 and C-S, and the planar geometry, is observed. The lowest energy minimum in acetonitrile is found to be the C-2 symmetry group, while for the two complexes, the local symmetry of urea is C-S or C-2 depending on the complex, or even on the coordination position of urea in the complex. The wagging motion of the amide group is also discussed in all the studied urea species. The computed geometries and most of the spectroscopic results are in good agreement with the available experimental data.	en
heal.publisher	SPRINGER-VERLAG	en
heal.journalName	THEORETICAL CHEMISTRY ACCOUNTS	en
dc.identifier.doi	10.1007/s002140000200	en
dc.identifier.isi	ISI:000166245700006	en
dc.identifier.volume	105	en
dc.identifier.issue	2	en
dc.identifier.spage	156	en
dc.identifier.epage	164	en