Norharmane rhenium(I) polypyridyl complexes: synthesis, structural and spectroscopic characterization

I. MAISULS; E. WOLCAN; O.E. PIRO, ; G.A. ECHEVERR¨ªA, ; G. PETROSELLI, ; F.M. CABRERIZO, ; G.T. RUIZ.; , ROSA ERRA-BALSELLS; ERRA BALSELLS, ROSA

DALTON TRANSACTIONS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 44 p. 17064 - 17074

1477-9226

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)¨CnHo complexes were characterized by structural X-ray diffraction, 1H and 13C 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 metalatom by the pyridine nitrogen of the molecule. X-ray structural analysis revealed that the crystal latticesfor both complexes are further stabilized by a strong >N¨CH⋯O bond between the pyrrole NH group ofthe pyridoindole ligand and one oxygen atom of the trifluoromethanesulfonate counter-ion. Groundstate geometry optimization by DFT calculations showed that in fluid solution the nHo ligand may rotatefreely. 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¦Ð ¡ú ¦Ð* electronic transitions centered on bpy and nHo moieties, LLCTnHo¡úCOs, MLLCTRe(CO)3¡úbpy andLLCTnHo¡úbpy transitions. Additionally, TD-DFT calculations predict the existence of another two intenseMLLCTRe(CO)3¡únHo electronic transitions. Calculated UV-vis absorption spectra are in good agreementwith the corresponding experimental data for the bpy-containing complex.