www.elsevier.nl/locate/ica Inorganica Chimica Acta 300–302 (2000) 698–708 Electronic spectra of trans -[Ru(NH 3 ) 4 (L)NO] 3 +/2 + complexes Sergey I. Gorelsky a , Sebastia ˜o C. da Silva b , A.B.P. Lever a, *, Douglas W. Franco b a Department of Chemistry, York Uniersity, Toronto, Ont., Canada M3J 1P3 b Uniersidade de Sa ˜o Paulo -USP, Instituto de Quı ´mica de Sa ˜o Carlos, Caixa Postal 780, 13560 -970 Sa ˜o Carlos -SP, Brazil Received 7 October 1999; accepted 29 November 1999 Abstract Density functional theory (DFT) with local, non-local and hybrid functionals has been used to obtain the geometry of a series of nitrosyl – metal complexes [Ru(NH 3 ) 4 (L)NO] n + , where L =NH 3 ,H 2 O, pyrazine and pyridine (n =3), Cl - and OH - (n =2). Based on the molecular orbital analysis and the time dependent DFT (TD-DFT) calculations, we discuss the electronic structure and the assignment of the bands in the electronic spectra of these complexes. © 2000 Elsevier Science S.A. All rights reserved. Keywords: Electronic spectra; Ruthenium complexes; Nitrosyl – metal complexes; DFT; TD-DFT 1. Introduction Studies of electronic structure and electronic spec- troscopy of nitrosyl complexes of transition metals are dominated by investigations of the nitroprusside ion [Fe(CN) 5 NO] 2 - , initiated by the pioneering work of Manoharan and Gray [1]. Hollauer and Olabe, and Westcott and Enemark have reviewed the progress in this field [2]. Ruthenium nitrosyl complexes, however, have not been the subject of as many studies as penta- cyanonitrosometallates in spite of the fact that they are better suited for quantum chemical calculations. These nitrosyl complexes are amenable to simpler and more accurate calculations than the pentacyanonitrosometal- lates because they are positively charged. We reconsider the assignments of the electronic spec- tra of these [Ru(NH 3 ) 4 (L)NO] n + species and discuss their electronic structure with respect to variation of ligand L. We are especially interested in how such variation of L influences the RuNO bonding interaction. 2. Computational details It was not clear, a priori, what is the best procedure to study the geometry and electronic structure of these complexes and therefore we tried several methods. We used the semi-empirical ZINDO method and the linear combination of Gaussian type orbitals-density func- tional (LCGTO-DF) method [3] with the following exchange-correlation functionals SVWN5 (functional 5 in [4]) and PVS1 [3], the GGA exchange and correlation functional of Perdew and Wang (PD86) [5], the GGA exchange functional of Becke [6], and nonlocal general- ization of the correlation functional (LAP3). This is a gradient corrected functional that combines Becke’s exchange [6] to the kinetic energy density and Laplacian dependent correlation functional ‘LAP3’ of the LAP family developed by Proynov [3b,f,g,h] and employing the deMon-KS3p2 package [3c]. The split valence dou- ble-zeta orbital basis set DZVP [7] 1 was used for all 1 Basis sets were obtained from the Extensible Computational Chemistry Environment Basis Set Database, Version 1.0, as devel- oped and distributed by the Molecular Science Computing Facility, Environmental and Molecular Sciences Laboratory, which is part of the Pacific Northwest Laboratory, P.O. Box 999, Richland, Washing- ton 99352, USA, and funded by the US Department of Energy. The Pacific Northwest Laboratory is a multi-program laboratory operated by Battelle Memorial Institute for the US Department of Energy under contract DE-AC06-76RLO 1830. Contact David Feller or Karen Schuchardt for further information. * Corresponding author. Tel.: +1-416-736 5246; fax: +1-416-736 5936. E-mail address: blever@yorku.ca (A.B.P. Lever) 0020-1693/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved. PII:S0020-1693(99)00611-8