title: Spontaneous and Selective Formation of HSNO, a Crucial Intermediate Linking H2S and Nitroso Chemistries.
abstract: Thionitrous acid (HSNO), a potential key intermediate in biological signaling pathways, has been proposed to link NO and H2S biochemistries, but its existence and stability in vivo remain controversial. We establish that HSNO is spontaneously formed in high concentration when NO and H2S gases are mixed at room temperature in the presence of metallic surfaces. Our measurements reveal that HSNO is formed by the reaction H2S + N2O3 → HSNO + HNO2, where N2O3 is a product of NO disproportionation. These studies also suggest that further reaction of HSNO with H2S may form HNO and HSSH. The length of the S-N bond has been derived to high precision and is found to be unusually long: 1.84 Å, the longest S-N bond reported to date for an R-SNO compound. The present structural and, particularly, reactivity investigations of this elusive molecule provide a firm foundation to better understand its potential physiological chemistry and propensity to undergo S-N bond cleavage in vivo.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: Nava
authors.affiliation: Harvard-Smithsonian Center for Astrophysics and School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Marie-Aline
authors.initials: MA
authors.lastname: Martin-Drumel
authors.affiliation: Institute for Theoretical Chemistry, Department of Chemistry, University of Texas , Austin, Texas 78712, United States.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Lopez
authors.affiliation: Harvard-Smithsonian Center for Astrophysics and School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Kyle N
authors.initials: KN
authors.lastname: Crabtree
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Caroline C
authors.initials: CC
authors.lastname: Womack
authors.affiliation: Institute for Theoretical Chemistry, Department of Chemistry, University of Texas , Austin, Texas 78712, United States.
authors.forename: Thanh L
authors.initials: TL
authors.lastname: Nguyen
authors.affiliation: I. Physikalisches Institut, Universität zu Köln , 50937 Köln, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Thorwirth
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Cummins
authors.affiliation: Institute for Theoretical Chemistry, Department of Chemistry, University of Texas , Austin, Texas 78712, United States.
authors.forename: John F
authors.initials: JF
authors.lastname: Stanton
authors.affiliation: Harvard-Smithsonian Center for Astrophysics and School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: McCarthy