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NEW FAMILY OF PH3RP+ CATIONS AND THEIR [IrCl5(NO)]- SALTS: STRUCTURAL DIVERSITY TUNED BY ARYL EMBRACES.
MARÍA ANA FOI; DAMIAN E. BIKIEL; FABIO DOCTOROVICH; FLORENCIA DI SALVO
Encuentro; Reunión Anual de la Asociación Argentina de Cristalografía; 2012
In our laboratory we demonstrated that by changing the counterion of the [IrCl5(NO)]- salts from K+ to PPh4+, it was possible to stabilize an exited state of the metal complex anion. The electronic distribution of the IrNO moiety in K[IrCl5(NO)] can be depicted as the closed-shell electronic structure IrIII-NO+, as expected for any d6 third row transition metal complex. However, in PPh4[IrCl5(NO)] an unprecedented electronic perturbation takes place favoring the open-shell electronic structure IrIV-NO(*) . These results together with the interesting systematic studies on MPE, encouraged us to explore the synthesis of new phosphonium salts. In this work we report the synthesis and the structural studies of three new phosphonium ions (1c,d,f) and five phosphonium [IrCl5(NO)]- salts (2a,c-f). Structural analyses of the new compounds were done in the context of the multiple embraces motifs. In Figure 1b the compound 1c is showed as an example: the naphtyl breaks the symmetry of the system in comparison with 1b, but maintains the overall feature of the supramolecular motifs. Along the crystallographic bc plane an irregular hexagonal net is described by a zig-zag chain of offset 6PE motifs interacting as well, with adjacent cations through other 6PE and parallel 4PE motifs. For the new [IrCl5(NO)]- salts 2a and 2c-f, the supramolecular arrangements are different from the one observed for the PhP4+ one 2b. In the last one, the 4PE infinite chains run parallel to the columns described by the anions  and for the others, the presence of bulkier subtitutents give place to symmetries that favors other kinds of aryl embraces resulting in a side by side location for the anions. DFT calculations were performed to evaluate the theoretical concerns regarding the structural behavior as well as the electronic distribution along the compounds family. Finally, structural parameters and IR studies were used to analyze the electronic structure effects on the IrNO moiety.  I. Dance, M. Scudder. CrystEngComm, 11 (2009), 2233 and references therein.  E. D´Oria, D. Braga, J Novoa. CrystEngComm, 14 (2012), 792.  F. Di Salvo, N. Escola, D. Scherlis, D. Estrin, C. Bondía, D. Murgida, J. Ramallo-López, F. Requejo, J. Doctorovich F. Chem. Eur. J. 13 (2007), 8428.