B3LYP/6-31G* calculations were carried out on adducts formed by the interaction of a cyclic unsaturated aminocarbene with carbenoid moieties CH2, SiH2, NH, PH, O or S. The bonding mode has been described using the Natural Bond Orbital (NBO) partitioning schemes, the Charge-Decomposition Analysis (CDA) and the topological analysis of the Electron Localization Function (ELF). A donor–acceptor int...

In this article, we analyze the stability, reactivity, and possible aromatic behavior of two recently reported clusters (Reveles, J. U.; Khanna, S. N.; Roach, P. J.; Castleman, A. W., Jr. Proc. Natl. Acad. Sci. 2006, 103, 18405), viz., Al(7)C(-) and Al(7)O(-) in the light of the principles of the maximum hardness and minimum electrophilicity as well as the nucleus-independent chemical shift val...

Hydrogen storage capacity of some Li(+)/F(-) doped neutral and charged aromatic/antiaromatic systems is studied at the B3LYP, M05-2X, MPW1K and MP2 levels of theory. Various conceptual density functional theory based global and local reactivity descriptors, nucleus independent chemical shift (NICS), NICS-rate, interaction energy per H(2) molecule, reaction enthalpy and reaction electrophilicity...

The lack of detect technology hinders the understanding host-guest (H-G) chemical properties for thiolate-protected tiara-like structural nanoclusters (Mn(SR)2n). In this work, NMR spectroscopy is demonstrated as a powerful tool to probe H-G structure Mn(SR)2n both experimentally and theoretically. A low-field shifting wide shift (CS) signal H nucleus in CH2Cl2 observed spectrum mixture Pd8(PET...

Using the bidirectional NICS scan method in conjunction with two-photon absorption (TPA) measurements, it has proved possible to determine the relationship between pi-conjugation and aromaticity in two structurally related expanded porphyrin systems, sapphyrin and inverted sapphyrin, and establish that differences in these defining factors depend on the presence or absence of a key sp3 hybrid m...

nowadays nmr spectroscopy becomes a powerful tool in chemistry because of the nmr chemical shifts. hartree–fock theory and the gauge-including atomic orbital (giao) methods are used in the calculation of 29si nmr chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. calculations have been performed at geo...

Trinuclear transition-metal complexes such as Re(3)X(9) (X = Cl, Br, I), with their uniquely featured structure among metal halides, have posed intriguing questions related to multicenter electron delocalization for several decades. Here we report a comprehensive study of the technetium halide clusters [Tc(3)(μ-X)(3)X(6)](0/1-/2-) (X = F, Cl, Br, I), isomorphous with their rhenium congeners, pr...

The structural and electronic properties of C24-2nBn Nn and M@ C24-2nBn Nn (M= alkaline and earth alkaline metals; n=3 and 6) molecules are studied using the Density Functional Theory (DFT). It was found that the most interaction is in M@ C24-2nBn Nn complexes (M=Be, Mg; n=3 and 6). The negative nucleus-independent chemical shifts confirm that C24-2nBn Nn (n=3 and 6) cages exhibit aromatic char...

Chemical shifts reflect the structural environment of a certain nucleus and can be used to extract structural and dynamic information. Proper calibration is indispensable to extract such information from chemical shifts. Whereas a variety of procedures exist to verify the chemical shift calibration for proteins, no such procedure is available for RNAs to date. We present here a procedure to ana...