Browsing Τμήμα Χημείας / Department of Chemistry by Author "Nicolaïdes, Andrew N."
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Article
Ab Initio Calculations of the Barriers to Rotation in 1,1-Difluoroallyl Radical and an Analysis of the Factors That Govern Rotational Barriers in Fluorinated Allylic Radicals
Nicolaïdes, Andrew N.; Borden, W. T. (1992)The energies required to rotate the CF2 and the CH2 group out of conjugation in 1,1-difluoroallyl radical have been calculated at the SD-CI/6–31G*//UHF/6–31G* level of theory. In agreement with experiment, the barrier to ...
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Article
Ab Initio Calculations of the Relative Strengths of the π Bonds in Acetylene and Ethylene and of Their Effect on the Relative Energies of π-Bond Addition Reactions
Nicolaïdes, Andrew N.; Borden, W. T. (1991)Energies at the CI-SD/6-31G* level have been calculated for acetylene, ethylene, ethane, and the vinyl and ethyl anions, radicals, and cations (classical and hydrogen-bridged). From these energies, the differences between ...
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Article
CI Calculations on Didehydrobenzenes Predict Heats of Formation for the Meta and Para Isomers That Are Substantially Higher than Previous Experimental Values
Nicolaïdes, Andrew N.; Borden, W. T. (1993)CI calculations with the 6-3110** basis set on o-didehydrobenzene (1) predict a singlet-triplet energy difference of 34.4 kcal/mol, which is about 3 kcal/mol smaller than the value measured by Leopold, Miller, and Lineberger. ...
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Article
Classical and nonclassical isomers of tropylium, silatropylium, and germatropylium cations. Descending the periodic table increases the preference for nonclassical structures
Nicolaïdes, Andrew N.; Radom, L. (1997)Ab initio calculations at the G2(MP2,SVP) level predict that there is a striking transition from a preference for classical isomers on the C7H7+ surface to a preference for nonclassical isomers on the C6H7Ge+ surface. The ...
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Article
Connectivity Effects in Isomeric Naphthalenedinitrenes
Serwinski, P. R.; Walton, R.; Sanborn, J. A.; Lahti, P. M.; Enyo, T.; Miura, D.; Tomioka, H.; Nicolaïdes, Andrew N. (2001)(Matrix Presented) UV-vis, FTIR, and ESR spectroscopic studies were carried out on samples of 1,4- and 1,5-naphthalenediazide that were photolyzed at cryogenic temperatures in argon and frozen solvent matrices. Mononitrenes ...
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Article
Determination of the chirality of enantiomeric [16O, 17O, 18O] sulfate esters by IR spectroscopy: An ab initio evaluation
Nicolaïdes, Andrew N.; Radom, L. (1995)The calculated shifts accompanying oxygen isotopic substitution in the symmetric and antisymmetric >SO2 stretching vibrational frequencies of 2,2-dioxo-1,3,2-dioxothianes confirm the experimental finding that these shifts ...
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Conference Object
DFT study of optical properties of Pt-based complexes
Oprea, C. I.; Dumbravǎ, A.; Moscalu, F.; Nicolaïdes, Andrew N.; Gîrţu, M. A. (2010)We report Density Functional Theory (DFT) calculations providing the geometrical and electronic structures, as well as the vibrational and optical properties of the homologous series of Pt-pyramidalized olefin complexes ...
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Article
Dft study of the optical and vibration spectra of a series of platinum-olefin complexes
Oprea, C. I.; Moscalu, F.; Dumbravǎ, A.; Ioannou, Savvas; Nicolaïdes, Andrew N.; Gîrţu, M. A. (2011)We report Density Functional Theory calculations providing the vibrational and optical properties of the homologous series of Pt-pyramidalized olefin complexes (CH2)n-(C8H10)Pt(PX3)2, where X = H and Ph, and n = 0, 1, 2, ...
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Article
Direct observation and characterization of p-phenylenebisnitrene. A labile quinoidal diradical [11]
Nicolaïdes, Andrew N.; Tomioka, H.; Murata, S. (1998)
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Book Chapter
Distorted Alkenes
Lenoir, D.; Smith, P. J.; Liebman, J. F.; Nicolaïdes, Andrew N.; Johnson, R. P.; Konrad, K. M. (Wiley-VCH Verlag GmbH & Co. KGaA, 2009)
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Article
Effect of angle strain in conjugated cycloaikenylidenes. Singlet- triplet splitting of cyclobutenylidene and its ground-state intramolecular rearrangements
Nicolaïdes, Andrew N.; Matsushita, Takashi; Tomioka, H. (1999)The singlet and triplet states of cyclobutenylidene, cyclopenten-3- ylidene, cyclohexen,3-ylidene, and cyclohepten-3-ylidene and some of their isomers (cyclohexen-4-ylidene, cyclohepten-4-ylidene, and cyclohepten-5- ylidene) ...
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Article
Effect of halogen substitution on o-Phenylenebiscarbene
Nicolaïdes, Andrew N. (2005)The effect of halogen (F, Cl and Br) perturbation on the geometries and relative energies of five electronic states (one quintet, two triplets and two singlets) of o-phenylenebiscarbene (1-H) is examined computationally ...
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Article
Effect of halogen substitution on p-phenylenebiscarbene
Nicolaïdes, Andrew N. (2005)The effect of halogen (F, Cl, and Br) perturbation on the geometries and relative energies of five electronic states (one quintet, two triplets, and two singlets) of p-phenylenebiscarbene (1-H) was examined computationally ...
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Article
The elusive benzocyclobutenylidene: A combined computational and experimental attempt
Nicolaïdes, Andrew N.; Matsushita, Takashi; Yonezawa, K.; Sawai, S.; Tomioka, H.; Stracener, L. L.; Hodges, J. A.; McMahon, R. J. (2001)Ab initio and density functional theory calculations predict that benzocyclobutenylidene (1) has a singlet ground state in contrast to the parent phenylcarbene and many other simply substituted arylcarbenes. Calculations ...
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Article
An evaluation of the performance of G2, G2(MP2) and G2(MP2, SVP) theories for heats of formation and heats of reaction in the case of 'large' hydrocarbons
Nicolaïdes, Andrew N.; Radom, L. (1996)Heats of formation for benzene, cyclohexane and other selected hydrocarbons, along with the heats of several isodesmic and isogyric reactions involving these species, are reported at the G2, G2(MP2) and G2(MP2, SVP) levels ...
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Article
Evidence for the formation of the (Ph3P)2Pt complex of 3,7-dimethyltricyclo[3.3.0.03,7]oct-1(5)-ene, the most highly pyramidalized alkene in a homologous series. Isolation and X-ray structure of the product of the ethanol addition to the complex
Theophanous, F. A.; Tasiopoulos, Anastasios J.; Nicolaïdes, Andrew N.; Zhou, X.; Johnson, W. T. G.; Borden, W. T. (2006)Attempts to isolate the (Ph3P)2R complex of the highly pyramidalized olefin 3,7-dimethyltricyclo[3.3.0.03,7]oct-1(5)- ene 2 by generation of 2 in the presence of (Ph3P)2RC 2H4, followed by crystallization of the complex ...
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Article
Geometrically strained carbenes: Interdependence among geometry, spin multiplicity and reactivity
Takahashi, Y.; Nicolaïdes, Andrew N.; Tomioka, H. (2001)The singlet and triplet states of cyclobutenylidene 1 and benzocyclobutenylidene 2 have been studied computationally (using ab initio and DFT methods) in order to assess the effect of angle strain on the S-T gap of vinyl- ...
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Article
Halogen derivatives of m-phenylene(carbeno)nitrene: A switch in ground-state multiplicity
Enyo, T.; Nicolaïdes, Andrew N.; Tomioka, H. (2002)m-Phenylene-coupled carbenonitrenes [(3-nitrenophenyl)methylene (2-H), (3-nitrenophenyl)fluoromethylene (2-F), (3-nitrenophenyl)chloromethylene (2-Cl), (3-nitrenophenyl)bromomethylene (2-Br)] have been investigated ...
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Article
Heats of formation from G2, G2(MP2), and G2(MP2,SVP) total energies
Nicolaïdes, Andrew N.; Rauk, A.; Glukhovtsev, M. N.; Radom, L. (1996)The translation of G2, G2(MP2), and G2(MP2,SVP) total energies to heats of formation via atomization and formation reaction procedures is evaluated. While both approaches give similar results, the former is shown to perform ...
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Article
HIV-1 integrase: From biology to chemotherapeuticsAAA
Zeinalipour-Loizidou, E.; Nicolaou, Charalambos P.; Nicolaïdes, Andrew N.; Kostrikis, Leontios G. (2007)AIDS has claimed the lives of 25 million people worldwide, an additional 40 million people are HIV-infected and new cases are being diagnosed every year. Despite the fact that HAART has moved AIDS from the category of ...