Shetty Vivekananda

SiNCO+ and SiNCS+ and their neutral counterparts

Abstract [Si,C,N,O] + and [Si,C,N,S] + cations formed upon electron ionization of trimethylsilyl isocyanate and isothiocyanate, respectively, are probed by tandem mass spectrometry. In the case of [Si,C,N,O] + , the experimental data suggest that the isocyanato group remains intact upon ionization such that silicon isocyanate SiNCO + is formed. Neutralization-reionization mass spectrometry indicates that also neutral SiNCO is a viable molecule in the gas phase. Instead, partial isomerization to SiSCN + is indicated for the sulfur analog. Because of this structural dichotomy, the nature of the [Si,C,N,S] + species giving rise to the recovery signal in the neutralization-reionization experiments remains uncertain.

Generation and characterization of ionic and neutral (methylthio)oxophosphane (CH3SP O)+·/o and (methoxy)oxophosphane (CH3OP O)+·/o by neutralizationreionization mass spectrometry☆

Abstract Results of the neutralization-reionization mass spectrometric (NRMS) experiments reveal that neutral (methythio)oxophosphane (CH3SP  O) and (methoxy)oxophosphane (CH3OP  O) are stable species in the gas phase.

Generation and characterization of ionic and neutral dihydroxy boron B(OH)2+/0 in the gas phase

The dicoordinated borinium ion, dihydroxyborinium, B(OH)(2)(+) is generated from methyl boronic acid CH3B(OH)(2) by dissociative electron ionization and its connectivity confirmed by collisional activation. Neutralization-reionization (NR) experiments on this ion indicate that the neutral B(OH)(2) radical is a viable species in the gas phase. Both vertical neutralization of B(OH)(2)(+) and reionization of B(OH)(2) in the NR experiment are, however, associated with particularly unfavorable Franck-Condon factors. The differences in adiabatic and vertical electron transfer behavior can be traced back to a particular pi stabilization of the cationic species compared to the sp(2)-type neutral radical. Thermochemical data on several neutral and cationic boron compounds are presented based on calculations performed at the G2 level of theory.

Generation and characterization of ionic and neutral (CH3OBH)+/· and (CH3BOH)+/· in the gas phase by tandem mass spectrometry

The isomeric dicoordinated borinium ions CH3O–B–H+ and CH3–B–OH+ are generated upon electron ionization of trimethylborate and methyl boronic acid, respectively. The connectivity of the ions is confirmed by collision-induced dissociation experiments on magnetic deflection type tandem mass spectrometers. Neutralization–reionization experiments on these structurally characterized ions indicate that the neutral radicals CH3O–B–H· and CH3–B–OH· are viable species in the gas phase. Calculations at the G2 level of theory were performed to obtain thermochemical data on the title isomers and their main dissociation products. The calculations also provide a rationale for the moderate yield of the neutrals generated in the experiments: the vertical electron transfer processes for both systems are associated with particularly unfavourable Franck-Condon factors.

Characterization of ammonia phosphorus oxide H3NPO+ ions and their neutral counterparts by mass spectrometry and computational chemistry

Dissociative electron ionization of O, S-dimethyl acetylphosphoramidothioate yields [N, H3, P, O]+ ions at m/z 64 whose structure was investigated by tandem mass spectrometry in combination with electronic structure calculations. Collisional activation mass spectra of source generated and low energy (MS/MS/MS) m/z 64 ions suggest that the majority of the m/z 64 ions possess the connectivity NH3PO+ (1). Neutralization-reionisation experiment on m/z 64 ions indicates that NH3PO·is a viable species in the gas phase. The relative energies of the ions and neutrals of the two isomeric species, NH3PO+/·(1) and NH2POH+/·(2) corresponding to the [N, H3, P, O]+/· potential energy surface and the fragmentation energies calculated at B3LYP/6-31G∗∗ level is used to support the interpretation of experimental results.

Characterization of iminothiosulfine-type ions [HNCS2]+/− and their neutral counterparts by mass spectrometry and computational chemistry ☆

Abstract Electron ionization of rhodanine yields iminothiosulfine ions H – N  C – S – S + , 1b + , which readily communicate with the higher energy cyclic isomer H – N  CS 2 + , 1a + . CBS-QB3 and G aussian -2 model chemistries predict that one electron reduction reverses the stability order but that the (singlet) neutrals remain connected via a negligible energy barrier. Neutralization–reionization (NR) experiments demonstrate that singlet 1a and its heterocumulene isomer 1b are stable species in the gas-phase. However, the co-generated triplet species readily dissociate into 3 S 2 + + HNC . Confirmatory experimental evidence comes from charge reversal (CR) and NR experiments on the cyclic anion H – N  CS 2 − , 1a − .

Generation and characterization of ionic and neutral thiocarbonylisocyanate [SCNCO]+/· by neutralization—reionization mass spectrometry (NRMS)☆

Abstract NRMS experiments on the structurally characterized thiocarbonylisocyanate ion, [SCNCO]+, provide evidence for the existence of its neutral counterpart in the rarefied gas phase.

Generation and characterization of ionic and neutral thiocarbonylisothiocyanate [SCNCS]+/. by neutralization-reionization mass spectrometry

Abstract In contrast to the oxygen analogue carbonylisocyanate [OCNCO], the thiocarbonylisothiocyanate [SCNCS] has been found to be a stable species on the neutralization-reionization mass spectrometry time scale.