Targeting divalent metal cations with Re(i) tetrazolato complexes. Issue 47 (11th November 2015)

• Record Type: Journal Article
• Authors: Fiorini, Valentina; Ranieri, Anna Maria; Muzzioli, Sara; Magee, Karen D. M.; Zacchini, Stefano; Akabar, Nurshadrina; Stefan, Alessandra; Ogden, Mark I.; Massi, Massimiliano; Stagni, Stefano
• Is Part Of: Dalton transactions. Volume 44:Issue 47(2015)
• Page Start: 20597
• Page End: 20608
• Publication Date: 2015-11-11
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt03690a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The design, preparation and characterization of four new Re(i ) tetrazolato complexes together with the study of their luminescent sensing abilities toward Zn(ii ), Cd(ii ) and Cu(ii ) are described herein. Abstract : In order to exploit their potential as versatile luminescent sensors, four new Re(i )-tetrazolato complexes with the general formula fac -[Re(CO)3 (diim )(L )], wherediim is 2, 2′-bipyridine (bipy ) or 1, 10-phenanthroline (phen ) andL − is either the anion 5-(2′-pyridyl)tetrazolato (2-PTZ − ) or 5-(2′-quinolyl)tetrazolato (2-QTZ − ), were prepared and fully characterized. In all cases, the regioselective coordination of the Re(i ) center through the N2 atom of the tetrazolato ring was observed. This particular feature ensures the availability of the diiminic (N^N ) site that was systematically incorporated into the structure of the2-PTZ − and2-QTZ − ligands for further coordination with metal cations. Such a diimine-type coordination mode was preliminarily tested by using the mononuclear Re(i ) complexes asN^N ligands for the preparation of two [(N^N )Cu(POP )] cationic species, where POP is the chelating diphosphine bis[2-(diphenylphosphino)phenyl]ether. The X-ray structures of the resulting Re(i )–Cu(i ) dyads revealed that the Re(i ) mononuclear complexes effectively behaved as chelatingN^N ligands with respect to the [Cu(POP )] + fragment, the coordination of which also resulted in significant modification of the Re(i )-centered luminescence. With these data in hand, the luminescent sensing abilities of the four new Re(i ) tetrazolato complexes were screened with respect to divalent metal ions of toxicological and biological importance such as Zn(ii ), Cd(ii ) and Cu(ii ). The interaction of the Re(i ) complexes with Zn(ii ) and Cd(ii ) was witnessed by the evident blue shift (Δ λ max = 22–36 nm) of the emission maxima, which was also accompanied by a significant elongation of the emission lifetimes. On the contrary, the addition of the cupric ion caused substantial quenching of the radiative processes originating from the Re(i ) luminophores.