Strained thiacyclophanes: Reducing properties and gauge of transannular interactions.

The current study involves the investigation of reducing properties of disulfide bonded heteraphanes. The calculated adiabatic electron affinity (AEA) values of heteraphanes are found comparable to that of cystine molecule and are capable of undergoing reversible redox reactions. In aqueous phase, these show high propensity to get reduced.

Antiproliferative studies of transition metal chelates of a pyrazolone based hydrazone derivative.

Pyrazolone derivatives play a significant role in the treatment of cancer. The synergic effect which emerges from the combination of pyrazolone moiety with hydrazone functionality was investigated. The objective of this study was to explore the antiproliferative potential of copper(II), cobalt(II), nickel(II) and zinc(II) metal chelates synthesized from pyrazolone based hydrazone derivative.

Computational study on atom-economic alkyne hydrotelluration reaction using benchmarked ECP for Te.

Geometry and energy calibration studies are done for arriving at a proper ECP for tellurium containing compounds. Among the various d-function included ECPs cc-pwCVTZ-PP and def2-TZVP give more reliable results. Non-catalytic and base/radical initiated hydrotelluration reactions are computationally studied using the calibrated def2-TZVP, with a special focus on the regio-and stereoselective formation of vinyl tellurides.

Cationic closo-carboranes 2. Do computed 11B and 13C NMR chemical shifts support their experimental availability?

(11)B and (13)C NMR spectra of so-far experimentally unknown carbon-rich cationic closo-carboranes C(3)B(n-3)H(n)(+) (n = 5, 6, 7, 10, 12) have been calculated at the GIAO-MP2 level and subsequently analyzed to reveal the nature of bonding in these potentially weakly coordinating cations. All previous rules derived for understanding (11)B NMR spectra of borane derivatives can be applied to realistically account for the corresponding shieldings. The correlated wavefunction for n = 5 and, to a lesser extent, for n = 10 seems to be decisive when trying to compute realistic shielding tensors, which is in agreement with the corresponding known dicarbaboranes.

Theoretical study of the effect of coordinating solvent on ion pair SN2 reactions: the role of unsymmetrical transition structures.

Computations are reported at the HF/6-31+g* level for ion pair SN2 reactions of methyl, ethyl, n-propyl, isopropyl, and allyl halides with LiX.E, LiX.2E, and LiX.

Hypercarbons in polyhedral structures.

Though carbon is mostly tetravalent and tetracoordinated, there are several examples where the coordination number exceeds four. Structural varieties that exhibit hypercarbons in polyhedral structures such as polyhedral carboranes, sandwich complexes, encapsulated polyhedral structures and novel planar aromatic systems with atoms embedded in the middle are reviewed here. The structural variety anticipated with hypercoordinate carbon among carboranes is large as there are many modes of condensation that could lead to large number of new patterns.

The rearrangement of dicarboranyl methyl cation: a possible synthetic strategy toward cationic closo-tricarbaboranes.

A quantitative study on cationic closo-tricarbaboranes proved their stability and a possible use for them as weakly coordinating ions due to the dispersal of positive charge throughout the cage. The current study explores computationally a synthetic strategy toward their realization in parallel with the benzyl cation-tropylium ion rearrangement. This study shows that cage expansion along with the incorporation of a carbon atom into the cage starting from the dicarboranyl methyl cation is in the realm of the possible.

Analogies between boron and carbon.

The structural connections between the compounds of boron and carbon are extended using the mno rule beyond the borane-carbocation continuum, the lithium boride-polycarbyne analogy, and the magnesium boride (MgB(2))-graphite equivalence to beta-rhombohedral boron and fullerenes. The structural similarity of the pentagonal pyramidal C(6)H(6)(2+) and MgB(4) is established. An interesting electronic structural relationship between the B(84) fragment of the beta-rhombohedral boron and the fulleride anion, C(60)(12-), is derived by replacing the 12 pentagonal pyramidal B(6)(4-) units by isoelectronic C(5)(-) units and removing the central B(12) from the electron-deficient B(84) unit.