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Hydrogen-bonded H‚‚‚π complexes of C 2 H 2 and C 2 H 4 were studied both computationally and experimentally. Computationally, C 2 H 2-C 2 H 4 clusters ranging from 1:1 to 6:1 stoichiometries were identified. Using matrix isolation infrared spectroscopy, the 1:1 adduct was studied in an argon matrix. Formation of these adducts was evidenced by shifts in the vibrational frequencies of the acetylene and ethylene submolecules in the complex. The molecular structure, vibrational frequencies, and stabilization energies of the complexes were calculated at the HF, MP2, MP2(full), and B3LYP levels of theory by employing basis sets ranging from 6-31G(d,p) to 6-311++G(2d,2p). Both computations and experiments showed that two types of complexes are formed, one in which acetylene acts as a proton donor to the π cloud of ethylene and another in which ethylene acts as the proton donor to the π cloud of acetylene. Structures, interaction energies, and vibrational frequencies have also been obtained for 1:2, 1:4, and 1:6 complexes of ethylene and acetylene. This work presents a case study of hydrogen-bonded clusters formed through the H-π interaction.

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Uranium oxide was laser-ablated using the second harmonic of a Nd : YAG laser, and the products studied after trapping them in Ar and Nz matrices. The species obtained in the Ar matrix were UO, UO2 and UO3, which represent the primary products of laser ablation. Charge transfer complexes, (UO~) (O]) and (UO 2+) (022-) were also observed. In the N 2 matrix, in addition to the primary ablation products, reaction products with nitrogen were also observed; the prominent among them being UN2 and NUO, together with their complexes with N2. Charge transfer complexes were also seen in these experiments. Features due to NO, N3 and N] were identified, which clearly point to the role of nitrogen in these reactions•

The role of nitrogen, the first member of pnicogen group, as an electron donor in hypervalent non-covalent interactions, has been established long ago, while observation of its electron accepting capability...

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The conformations of trimethyl phosphite (TMPhite) were studied using matrix isolation infrared spectroscopy. TMPhite was trapped in a nitrogen matrix using an effusive source maintained at two different temperatures (298 and 410 K) and a supersonic jet source. The experimental studies were supported by ab initio computations performed at the B3LYP/6-31++G** level. Computations identified four minima for TMPhite, corresponding to conformers with C(1)(TG(±)G(±)), C(s)(TG(+)G(-)), C(1)(G(±)TT), and C(3)(G(±)G(±)G(±)) structures, given in order of increasing energy. Computations of the transition state structures connecting the C(s)(TG(+)G(-)) and C(1)(G(±)TT) conformers to the global minimum C(1)(TG(±)G(±)) structure were also carried out. The barriers for the interconversion of C(s)(TG(+)G(-)) and C(1)(G(±)TT) to the ground state C(1)(TG(±)G(±)) conformer were 0.2 and 0.6 kcal/mol, respectively. Comparison of conformational preferences of TMPhite with the related carbon compound, trimethoxymethane, and the organic phosphate, trimethyl phosphate, was also made using natural bond orbital analysis.