Theoretical Investigation on the Effect of Different Nitrogen Donors on Intramolecular Se center dot center dot center dot N Interactions

Sarma, Bani Kanta and Mugesh, Govindasamy (2009) Theoretical Investigation on the Effect of Different Nitrogen Donors on Intramolecular Se center dot center dot center dot N Interactions. In: ChemPhysChem, 10 (17). pp. 3013-3020.

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Abstract

The effect of different donor nitrogen atoms on the strength and nature of intramolecular Se center dot center dot center dot N interactions is evaluated for organoselenium compounds having N,N-dimethylaminomethyl (dime), oxazoline (oxa) and pyridyl (py) substituents. Quantum chemical calculations on three series of compounds [2-(dime)C6H4SeX (1a-g), 2-(oxa)C6H4SeX (2a-g), 2- (py)C6H4SeX (3-ag); X=Cl, Br, OH, CN, SPh, SePh, CH3] at the B3LYP/6-31G(d) level show that the stability of different conformers depends on the strength of intramolecular nonbonded Se center dot center dot center dot N interactions. Natural bond orbital (NBO), NBO deletion and atoms in molecules (AIM) analyses suggest that the nature of the Se center dot center dot center dot N interaction is predominantly covalent and involves nN ->sigma*(Se-X) orbital interaction. In the three series of compounds, the strength of the Se center dot center dot center dot N interaction decreases in the order 3>2>1 for a particular X, and it decreases in the order Cl > Br > OH>SPh approximate to CN approximate to SePh>CH3 for all the three series 1-3. However, further analyses suggest that the differences in strength of Se center dot center dot center dot N interaction in 1-3 is predominantly determined by the distance between the Se and N atoms, which in turn is an outcome of specific structures of 1, 2 and 3, and the nature of the donor nitrogen atoms involved has very little effect on the strength of Se center dot center dot center dot N interaction. It is also observed that Se center dot center dot center dot N interaction becomes stronger in polar solvents such as CHCl3, as indicated by the shorter r(Se center dot center dot center dot N) and higher E-Se center dot center dot center dot N values in CHCl3 compared to those observed in the gas phase.

Item Type:	Journal Article
Publication:	ChemPhysChem
Publisher:	Wiley
Additional Information:	Copyright for this article belongs to Wiley.
Keywords:	bonding analysis; density functional calculations; nitrogen; nonbonded interactions; selenium
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	05 Jan 2010 11:05
Last Modified:	19 Sep 2010 05:54
URI:	http://eprints.iisc.ac.in/id/eprint/25339

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