Zinc and cadmium complexation of L-methionine: An infrared multiple photon dissociation spectroscopy and theoretical study.

Methionine (Met) cationized with Zn , forming Zn (Met-H) (ACN) where ACN = acetonitrile, Zn (Met-H) , and ZnCl (Met), as well as Cd , forming CdCl (Met), were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light generated from the FELIX free electron laser. A series of low-energy conformers for each complex was found using quantum-chemical calculations in order to identify the structures formed experimentally. For all four complexes, spectral comparison indicated that the main binding motif observed is a charge solvated, tridentate structure where the metal center binds to the backbone amino group nitrogen, backbone carbonyl oxygen (where the carboxylic acid is deprotonated in two of the Zn complexes), and side-chain sulfur.

Zinc and Cadmium Complexation of l-Threonine: An Infrared Multiple Photon Dissociation Spectroscopy and Theoretical Study.

Complexes of threonine (Thr) cationized with Zn and Cd were examined by infrared multiple photon dissociation action spectroscopy using light generated from a free electron laser. Low-energy conformers for Zn(Thr-H)(ACN) (where ACN = acetonitrile), Zn(Gly-H)(ACN) (formed via CO-laser irradiation of intact Zn(Thr-H)(ACN)), and CdCl(Thr) complexes were found using quantum chemical calculations in order to identify the structures formed experimentally. For all species, the predicted ground structures reproduce the experimental spectra well, where tridentate [N, CO, OH] binding motifs were dominantly observed for the intact Zn(Thr-H)(ACN) and CdCl(Thr) complexes.

Spectroscopic Identification of the Carbyne Hydride Structure of the Dehydrogenation Product of Methane Activation by Osmium Cations.

The present work explores the structures of species formed by dehydrogenation of methane (CH) and perdeuterated methane (CD) by the 5d transition metal cation osmium (Os). Using infrared multiple photon dissociation (IRMPD) action spectroscopy and density functional theory (DFT), the structures of the [Os,C,2H] and [Os,C,2D] products are explored. This study complements previous work on the related species formed by dehydrogenation of methane by four other 5d transition metal cations (M = Ta, W, Ir, and Pt).

Experimental and Theoretical Investigations of Infrared Multiple Photon Dissociation Spectra of Aspartic Acid Complexes with Zn and Cd.

Complexes of aspartic acid (Asp) cationized with Zn: Zn(Asp-H), Zn(Asp-H)(ACN) where ACN = acetonitrile, and Zn(Asp-H)(Asp); as well as with Cd, CdCl(Asp), were examined by infrared multiple photon dissociation (IRMPD) action spectroscopy using light generated from a free electron laser. A series of low-energy conformers for each complex was found using quantum chemical calculations to identify the structures formed experimentally. The main binding motif observed for the heavy-metal complex, CdCl(Asp)[N,CO,CO], is a charge-solvated, tridentate structure, where the metal center binds to the backbone amino group and carbonyl oxygens of the backbone and side-chain carboxylic acids.