Showing papers by "Gaetano Granozzi published in 1987"
31 citations
TL;DR: In this paper, the HeI and HeII photoelectron spectra of the para-substituted ω-halogenoacetophenones Y-C6H4COCH2X [Y = NO2, CN, H, OCH3, N(CH3)2; X = H, Cl, Br, I] are assigned on the basis of the composite-molecule approach, substituent effects, and intensity variations observed on changing the ionizing radiation.
Abstract: The HeI and HeII photoelectron spectra of the para-substituted ω-halogenoacetophenones Y-C6H4COCH2X [Y = NO2, CN, H, OCH3, N(CH3)2; X = H, Cl, Br, I] are assigned on the basis of the composite-molecule approach, substituent effects, and intensity variations observed on changing the wavelenght of the ionizing radiation. Ab initio minimal basis set calculations using the pseudo-potential method have been used to calculate the most stable conformation of acetophenone and its ω-bromo and ω-iodo derivatives. The first band of the iodine derivatives shows peculiar energy and intensity variations on changing the para-substituent. These findings have been ascribed to an easier interaction of the iodine lone-pair orbitals with the substrate owing to their lower ionization energy values and larger size with respect to the other halogens.
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TL;DR: In this article, the LCAO-MO-SCF calculations on the model compounds C 5 H 4 N-2-C(R 1 )=NH [R 1 = H ( 2c ) and R 1 = trans-PdCl(PH 3 ) 2 ( 4c )] indicate that the E- trans conformation is favored over the E - cis one by 16.9 kJ mol −1 for 2c and by 25.0 kJmol −1for 4c.
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TL;DR: The He I and He II gas-phase photoelectron spectra of CpCoS 2 N 2 and Cp*CoS2 N 2 (Cp*=C 5 Me 5 ) have been obtained as discussed by the authors.
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TL;DR: In this paper, several numerical calculations within the discrete variational Xα framework have been carried out on bis(2,4-pentanedionato) palladium (II) in order to find the best basis set and potential representation.
3 citations
TL;DR: In this article, the LCAO-MO-SCF calculations on the model compounds C 5 H 4 N-2-C(R 1 )=NH [R 1 = H ( 2c ) and R 1 = trans-PdCl(PH 3 ) 2 ( 4c )] indicate that the E- trans conformation is favored over the E - cis one by 16.9 kJ mol −1 for 2c and by 25.0 kJmol −1for 4c.
Abstract: Ab initio LCAO-MO-SCF calculations on the model compounds C 5 H 4 N-2-C(R 1 )=NH [R 1 = H ( 2c ) and R 1 = trans -PdCl(PH 3 ) 2 ( 4c )] indicate that the E - trans conformation is favored over the E - cis one by 16.9 kJ mol −1 for 2c and by 25.0 kJ mol −1 for 4c . One of the factors which stabilizes the E-trans arrangement for 4c is a weak bonding interaction between the palladium center and the pyridine nitrogen. On going from 2c to 4c a slight charge enrichment on the pyridine carbons and a more pronounced one on the nitrogen atoms is computed, whereas the charge density of the imino carbon atom is decreased. In 4c no π contribution to the PdC bond is observed. Protonation of the organic moiety of 4c in the E-cis configuration gives rise to a weak PdC π overlap population and to a decreased energy separation between π* 5 ( LUMO ) and the highest energy occupied π MO (π 4 ) of the pyridine-2-carbald-imino moiety. The theoretical results are qualitatively related to structural and spectroscopic data (electronic, IR and 13 C NMR ) of pyridine-2-carbaldimines and the corresponding imino-carbon palladated derivatives.