INVESTIGADORES
SCHERLIS PEREL Damian Ariel
artículos
Título:
Electronic Perturbation in a Molecular Wire.
Autor/es:
F. DI SALVO, N. ESCOLA, D. A. SCHERLIS, D. A. ESTRIN, C. BONDÍA, D. MURGIDA, J. M. RAMALLO LÓPEZ, F. G. REQUEJO, L. SHIMON, F. DOCTOROVICH
Revista:
CHEMISTRY-A EUROPEAN JOURNAL
Editorial:
WILEY-V C H VERLAG GMBH
Referencias:
Año: 2007 vol. 13 p. 8428 - 8436
ISSN:
0947-6539
Resumen:
The nitrosyl in [IrCl5(NO)]is probably the most electrophilicknown to date. This fact is reflected byits extremely high IR frequency in thesolid state, electrochemical behavior,and remarkable reactivity in solution.PPh4ACHTUNGTRENUNG[IrCl5(NO)] forms a crystal inwhich the [IrCl5(NO)] anions are in acurious wire-like linear arrangement, inwhich the distance between the NOmoiety of one anion and the trans chlorideof the upper one nearby is only2.8 3. For the same complex[IrCl5(NO)] but with a different counterion,NaACHTUNGTRENUNG[IrCl5(NO)], the anions arestacked one over the other in a sideby-side arrangement. In this case theelectronic distribution can be depictedas the closed-shell electronic structureIrIIINO+, as expected for any d6 thirdrowtransition metal complex. However,in PPh4ACHTUNGTRENUNG[IrCl5(NO)] an unprecedentedelectronic perturbation takes place,probably due to NOCCl acceptordonor interactions among a largenumber of [IrCl5(NO)] units, favoringa different electronic distribution,namely the open-shell electronic structureIrIVNOC. This conclusion is basedon XANES experimental evidence,which demonstrates that the formal oxidationstate for iridium in PPh4-ACHTUNGTRENUNG[IrCl5(NO)] is +4, as compared with+3 in KACHTUNGTRENUNG[IrCl5(NO)]. In agreement,solid-state DFT calculations show thatthe ground state for [IrCl5(NO)] inthe PPh4+ salt comprises an open-shell singlet with an electronic structurewhich encompasses half of the spindensity mainly localized on a metalcenteredorbital, and the other half onan NO-based orbital. The electronicperturbation could be seen as an electronpromotion from a metalchlorideto a metalNO orbital, due to thesmall HOMOLUMO gap in PPh4-ACHTUNGTRENUNG[IrCl5(NO)]. This is probably inducedby electrostatic interactions acting as aresult of the closeness and wire-likespatial arrangement of the Ir metalcenters, imposed by lattice forces dueto pp stacking interactions among thephenyl rings in PPh4+. Experimentaland theoretical data indicate that inPPh4ACHTUNGTRENUNG[IrCl5(NO)] the IrNO moiety ispartially bent and tilted.
