Substituent effects on gas-phase homolytic Fe-N bond energies of m-G-C6H4NHFe(CO)(2)((5)-C5H5) and m-G-C6H4N(COMe)Fe(CO)(2)((5)-C5H5) studied using density functional theory methods
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
Authors: Zeng, Qing; Li, Zucheng; Wang, Yi-Bo
Abstract
One of the most fundamental properties in chemistry is the bond dissociation energy, the energy required to break a specific bond of a molecule. In this paper, the Fe-N homolytic bond dissociation energies [H-homo(Fe-N)'s] of 2 series of (meta-substituted anilinyl)dicarbonyl((5)-cyclopentadienyl) iron [m-G-C(6)H(4)NHFp (1)] and (meta-substituted -acetylanilinyl)dicarbonyl((5)-cyclopentadienyl) iron [m-G-C6H4N(COMe)Fp (2)] were studied using density functional theory methods with large basis sets. In this study, Fp is ((5)-C5H5)Fe(CO)(2), and G is NO2, CN, COMe, CO2Me, CF3, Br, Cl, F, H, Me, MeO, and NMe2. The results show that Tao-Perdew-Staroverov-Scuseria, Minnesota 2006, and Becke's power-series ansatz from 1997 with dispersion corrections functionals can provide the best price/performance ratio and accurate predictions of H-homo(Fe-N)'s. The H-homo(Fe-N)'s (1 and 2) conform to the captodative principle. The polar effects of the meta-substituents show the dominant role to the magnitudes of H-homo(Fe-N)'s. sigma and sigma(c) values for meta-substituents are all related to polar effects. Spin-delocalization effects of the meta-substituents in H-homo(Fe-N)'s are small but not necessarily zero. RE plays an important role in determining the net substituent effects on H-homo(Fe-N)'s. Insight from this work may help the design of more effective catalytic processes.
Oligogermanes Containing Only Electron-Withdrawing Substituents: Synthesis and Properties
ORGANOMETALLICS
Authors: Zaitsev, Kirill V.; Lam, Kevin; Zhanabil, Zhaisan; Suleimen, Yerlan; Kharcheva, Anastasia V.; Tafeenko, Viktor A.; Oprunenko, Yuri F.; Poleshchuk, Oleg Kh.; Lermontova, Elmira Kh.; Churakov, Andrei V.
Abstract
A series of germanes Ar3GeX, containing electron-withdrawing substituents [Ar = p-FC6H4, 1a-d, 1a (X = CO, 1b (X = Br), 1c (X = H), 1d (X = NMe2); p-F3CC6H4, 2a-d, 2a (X = Cl), 2b (X = Br), 2c (X = H), 2d (X = NMe2)], was synthesized and used to prepare symmetrical digermanes Ar3Ge-GeAr3, (p-FC6H4)(3)GeGe(C6H4F-p)(3) (3), and (p-F3CC6H4)(3)GeGe(C6H4CF3-p)(3) (4) and trigermane [(p-F3CC6H4)(3)Ge](2)Ge(C6F5)(2) (5) by hydrogermolysis reaction. The properties of all compounds were investigated by multinuclear NMR and for oligogermanes by UV/vis and fluorescence spectroscopy, as well as by electrochemical methods. In addition, the molecular structures of 1a, 1b, 2b, 2c, and 3-5 were studied by X-ray diffraction analysis. Compound 5 showed a significantly shifted UV/visible absorption to the red field in comparison with previously described derivatives.