title: Norharmane rhenium(I) polypyridyl complexes: synthesis, structural and spectroscopic characterization.
abstract: Two novel Re(i) complexes with the general formula fac-[Re(CO)3(L)(nHo)]CF3SO3, where L = 2,2'-bipyridine (bpy) or 1,10 phenanthroline (phen) and nHo (9H-pyrido[3,4-b]indole; norharmane) have been synthesized. The Re(i)-nHo complexes were characterized by structural X-ray diffraction, (1)H and (13)C NMR, UV-vis absorption and FT-IR spectroscopy, and by a combination of two mass spectrometry techniques, namely ESI-MS and UV-MALDI-MS. All characterizations showed that nHo is coordinated to the metal atom by the pyridine nitrogen of the molecule. X-ray structural analysis revealed that the crystal lattices for both complexes are further stabilized by a strong >N-HO bond between the pyrrole NH group of the pyridoindole ligand and one oxygen atom of the trifluoromethanesulfonate counter-ion. Ground state geometry optimization by DFT calculations showed that in fluid solution the nHo ligand may rotate freely. The nature of the electronic transitions of Re(CO)3(bpy)(nHo)(+) were established by TD-DFT calculations. The set of the most important electronic transitions present in this complex are comprised of π→π* electronic transitions centered on bpy and nHo moieties, LLCTnHo→COs, MLLCTRe(CO)3→bpy and LLCTnHo→bpy transitions. Additionally, TD-DFT calculations predict the existence of another two intense MLLCTRe(CO)3→nHo electronic transitions. Calculated UV-vis absorption spectra are in good agreement with the corresponding experimental data for the bpy-containing complex.
authors.affiliation: INIFTA, UNLP (CCT La Plata-CONICET), Diag. 113 y 64, C.C. 16, Suc. 4, B1906ZAA, La Plata, Argentina. gruiz@inifta.unlp.edu.ar.
authors.forename: Iván
authors.initials: I
authors.lastname: Maisuls
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Wolcan
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Piro
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Etcheverría
authors.forename: Gabriela
authors.initials: G
authors.lastname: Petroselli
authors.forename: Rosa
authors.initials: R
authors.lastname: Erra-Ballsels
authors.forename: Franco M
authors.initials: FM
authors.lastname: Cabrerizo
authors.forename: Gustavo T
authors.initials: GT
authors.lastname: Ruiz
mesh_terms: D002243:Carbolines / Q000032:analysis / Q000737:chemistry*; D015394:Molecular Structure; D012211:Rhenium / Q000032:analysis / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D002243:Carbolines; D012211:Rhenium; C010262:norharman