Nitrosyl Isocyanate (ONNCO): Gas-Phase Generation and a HeI Photoelectron Spectroscopy Study

The nitrosyl isocyanate (ONNCO) has been generated from a heterogeneous reaction of gaseous nitrosyl chloride with silver isocyanate and studied for the first time in the gas phase. This structurally and energetically novel transient specimen is characterized by HeI photoelectron spectroscopy combined with DFT calculations. Both the calculations and the spectroscopic results suggest that the molecule adopts an open-chain trans structure. The observed decomposition products indicate the formation of ONNCO and further confirm the previously reported decomposition pathway

Bis(trifluoroaceto) Disulfide (CF₃C(O)OSSOC(O)CF₃): A HeI Photoelectron Spectroscopy and Theoretical Study

Bis(trifluoroaceto) disulfide CF3C(O)OSSOC(O)CF3 was prepared and studied by Raman, photoelectron spectroscopy (PES), and theoretical calculations. This molecule exhibits gauche conformation with both CO groups cis to the S−S bond; the structure of the OSSO moiety is characterized by dihedral angle δOSSO = −95.1° due to the sulfur−sulfur lone pair interactions. The contracted S−S bond (1.979 Å) and relatively high rotational barrier (19.29 kcal mol-1 at the B3LYP/6-31G* level) of the δOSSO indicate the partial resonance-induced double bond character in this molecule. After ionization, the ground cationic-radical form of CF3C(O)OSSOC(O)CF3•+ adopts a trans planar main-atom structure (δOSSO = 180° and δOCOS = 0°) with C2h symmetry. The S−S bond elongates to 2.054 Å, while the S−O bond shortens from 1.755 Å in neutral form to 1.684 Å in its corresponding cationic-radical form. The adiabatic ionization energy of 9.91 eV was obtained accordingly. The first two HOMOs correspond to the electrons mainly localized on the sulfur 3p lone pair MOs:  3pπ {36a (nAS)}-1 and 3pπ* {35b (nBS, nBO(CO))}-1, with an experimental energy separation of 0.16 eV. The first vertical ionization energy is determined to be 10.81 eV

Gas-Phase Generation and Electronic Structure Investigation of Chlorosulfanyl Thiocyanate, ClSSCN

The chlorosulfanyl thiocyanate molecule, ClSSCN, was generated in the gas phase through heterogeneous reaction of SCl2 on the surface of finely powdered AgSCN for the first time. The reaction products were detected and characterized in situ by ultraviolet photoelectron and photoionization mass spectrometry. The molecular geometry and electronic structures of ClSSCN were investigated by a combination of PES experiment and theoretical calculations with the density functional theory and ab initio methods. It was found that the outermost electrons of ClSSCN reside in the Cl−S antibonding π orbital, predominantly localized on the sulfur atom, and the experimental first vertical ionization potential of ClSSCN is 10.20 eV. The dominant fragment SSCN+ in the mass spectrum indicates that the ClSSCN cation prefers the dissociation of the Cl−S bond

HeI Photoelectron Spectroscopy and Theoretical Study of Trichloromethanesulfenyl Acetate, CCl₃SOC(O)CH₃, and Trichloromethanesulfenyl Trifluoroacetate, CCl₃SOC(O)CF₃

Two novel species, trichloromethanesulfenyl acetate, CCl3SOC(O)CH3, and trichloromethanesulfenyl trifluoroacetate, CCl3SOC(O)CF3, have been generated in situ by the heterogeneous reactions between trichloromethanesulfenyl chloride, CCl3SCl, and corresponding silver salts, silver acetate (AgOC(O)CH3) and silver trifluoroacetate (AgOC(O)CF3), respectively. Photoelectron spectroscopy and quantum chemical calculations are performed to investigate these two molecules, together with their precursor, CCl3SCl. Both of these two compounds may exist in the gas phase as a mixture of gauche and trans conformations. As for the dihedral angles δRSOR‘ of the gauche conformers, 107.0° and 108.5° are derived by theoretical calculations (at the B3LYP/6-311+G(3df) level) for CCl3SOC(O)CH3 and CCl3SOC(O)CF3, respectively. The first vertical ionization energies of CCl3SOC(O)CH3 and CCl3SOC(O)CF3, which have been determined by photoelectron spectroscopy, are 9.67 and 10.34 eV, respectively. According to the experimental results and theoretical analysis, the first ionization energy of these two molecules both come from the ionization of the lone pair electron of S atom

Geometrical and Electronic Structure of the Pt₇ Cluster: A Density Functional Study

We present a study on the structural and electronic properties of the Pt7 cluster by using density functional theory within the generalized gradient approximation for the exchange and correlation. The structures, relative stabilities, and vibrational frequencies of various isomers are calculated and compared with the well-studied Au7 cluster. The ground state of the Pt7 cluster favors a three-dimensional geometrytwo-dimensional local minima are not locatedwhereas for its neighbor, gold heptamer, a two-dimensional geometry is favored. The most stable isomer of Au7 is found to be an edge-capped rhombus structure and an edge-capped tetrahedron structure is found to be the most stable three-dimensional local minimum. The ground state of the Pt7 cluster is found to be a coupled tetragonal pyramid structure with the quintet state in contrast to a pentagonal bipyramid structure obtained by semiempirical molecular dynamics calculation. The natural orbital analysis shows that the overall charge transfer is from 6s to 5d orbitals in the Pt7 cluster, whereas in Au7 cluster it is from 5d to 6s. The molecular orbital picture shows that the bonding orbitals are due to the hybridization between 5d and 6s molecular orbitals in Pt7 cluster, and the nonbonding and antibonding orbitals lie close to the highest occupied molecular orbital. This may be compared with the Au7 electronic structure, where the nonbonding and antibonding orbitals mainly consists of 5d6s hybridized molecular orbitals