title: Achieving Reversible Sensing of Nitroxyl by Tuning the Ligand Environment of Azamacrocyclic Copper(II) Complexes.
abstract: To elucidate the factors that impart selectivity for nitroxyl (HNO) over nitric oxide (NO), thiols, and H2S in metal-based fluorescent probes, we investigated five Cu(II)-cyclam (14-N4) derivatives. Upon exposure to NO gas at pH 7, no changes occur in the UV-vis spectra of any of the complexes. Addition of Angeli's salt to generate HNO promotes reduction of Cu(II) only in the case of [Cu(II)(14-N4-Ts)(OTf)2], which has the most positive reduction potential of the series. To gain insight into the observed reactivity, we prepared the Cu(II) complex of the mixed thia/aza 14-N2S2 ligand. [Cu(II)(14-N2S2)(OTf)2] reacts reversibly with HNO at pH 7, although nonselectively over thiols and H2S. The recurrent sensing of HNO uncovered with the study of Cu(II) azamacrocyclic complexes is a remarkable feature that opens the door for the design of a new generation of metal-based probes.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Sunghee
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Mikael A
authors.initials: MA
authors.lastname: Minier
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Andrei
authors.initials: A
authors.lastname: Loas
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Sabine
authors.initials: S
authors.lastname: Becker
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Lippard