Terpyridine Zn(ii), Ru(iii) and Ir(iii) complexes as new asymmetric chromophores for nonlinear optics: first evidence for a shift from positive to negative value of the quadratic hyperpolarizability of a ligand carrying an electron donor substituent upon coordination to different metal centres

2002 ◽  
pp. 846-847 ◽  
Author(s):  
Dominique Roberto ◽  
Francesca Tessore ◽  
Renato Ugo ◽  
Silvia Bruni ◽  
Amedea Manfredi ◽  
...  
Keyword(s):  
Nonlinear Optics ◽  
Electron Donor ◽  
Donor Substituent ◽  
Electron Donor Substituent

Gold-Catalyzed Partial Hydrogenation of Activated Alkynes Mediated by Triphenylphosphine

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2379-2386
Author(s):  
Susana Porcel ◽  
Ana Patricia Cocoletzi-Xochitiotzi ◽  
Miguel Hernández-Hernández ◽  
Ignacio Medina-Mercado ◽  
Williams de Jesús Jiménez-Martínez ◽  
...  
Keyword(s):  
Electron Donor ◽  
Cooperative Effect ◽  
Partial Hydrogenation ◽  
Aryl Ring ◽  
Activated Alkynes ◽  
Donor Substituent ◽  
Electron Donor Substituent

Gold(I) can exhibit a cooperative effect with triphenylphosphine, accelerating the triphenylphosphine-mediated partial hydrogenation of activated alkynes. In this protocol, 3-arylpropiolates are selectively reduced to the Z-isomer when the aryl ring bears an electron-donor substituent, whereas 3-arylpropynones are reduced to the E-isomers.

Recent Advances in the Chemistry of Doubly Activated Cyclopropanes: Synthesis and Reactivity

2019 ◽  
Vol 23 (3) ◽  
pp. 276-312 ◽  
Author(s):  
Purushothaman Gopinath ◽  
Srinivasan Chandrasekaran
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Electron Donor ◽  
Ring Opening ◽  
Dipolar Cycloaddition ◽  
Recent Advances ◽  
Donor Acceptor ◽  
Synthesis Reactions ◽  
Donor Substituent ◽  
Electron Donor Substituent

Diactivated cyclopropanes containing two geminal electron withdrawing groups, commonly called as ‘Doubly Activated Cyclopropanes’ are useful synthons for the synthesis of many interesting natural products and functionalized molecules. These geminal electron withdrawing groups (EWG’s) facilitate the regioselective ring opening of cyclopropanes by polarizing the C-C bond adjacent to it. This polarization also allows them to undergo 1,3 dipolar cycloaddition reactions when substituted with a suitable electron donor substituent at the adjacent carbon (donor-acceptor cyclopropanes) in the presence of suitable dipolarophiles. In this review, we discuss the recent advances in the chemistry of doubly activated cyclopropanes: their synthesis, reactions and applications in total synthesis.

Solvent Dynamics Regulated Electron Transfer in S2-Excited Sb and Ge Tetraphenylporphyrins with an Electron Donor Substituent at the Meso-Position

2014 ◽  
Vol 118 (22) ◽  
pp. 3926-3933 ◽  
Author(s):  
Mamoru Fujitsuka ◽  
Tsutomu Shiragami ◽  
Dae Won Cho ◽  
Sachiko Tojo ◽  
Masahide Yasuda ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Solvent Dynamics ◽  
Meso Position ◽  
Donor Substituent ◽  
Electron Donor Substituent

scholarly journals N/N Bridge Type and Substituent Effects on Chemical and Crystallographic Properties of Schiff-Base (Salen/Salphen) Niii Complexes

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 616 ◽  
Author(s):  
Cynthia S. Novoa-Ramírez ◽  
Areli Silva-Becerril ◽  
Fiorella L. Olivera-Venturo ◽  
Juan Carlos García-Ramos ◽  
Marcos Flores-Alamo ◽  
...  
Keyword(s):  
Substituent Effects ◽  
Planar Geometry ◽  
X Ray ◽  
Half Wave ◽  
Square Planar ◽  
Bridge Type ◽  
Aliphatic Bridge ◽  
Aromatic Bridge ◽  
Donor Substituent ◽  
Electron Donor Substituent

In total, 13 ligands R-salen (N,N’-bis(5-R-salicylidene)ethylenediamine (where R = MeO, Me, OH, H, Cl, Br, NO2) and R-salphen (N,N’-bis(5-R-salicylidene)-1,2-phenylenediamine (where R = MeO, Me, OH, H, Cl, Br) and their 13 nickel complexes NiRsalen and NiRsalphen were synthesized and characterized using IR (infrared) spectroscopy, mass spectrometry, elemental analysis, magnetic susceptibility, NMR (nuclear magnetic resonance), UV-vis (ultraviolet-visible) spectroscopy, cyclic voltammetry, and X-ray crystal diffraction. Previous studies have shown that all complexes have presented a square planar geometry in a solid state and as a solution (DMSO). In electrochemical studies, it was observed that in N/N aliphatic bridge complexes, the NiII underwent two redox reactions, which were quasi-reversible process, and the half-wave potential followed a trend depending on the ligand substituent in the 5,5’-R position. The electron-donor substituent—as -OH, and -CH3 decreased the E1/2 potential—favored the reductor ability of nickel. The crystals of the complexes NiMesalen, NiMeOsalen, NiMeOsalphen, and Nisalphen were obtained. It was shown that the crystal packaging corresponded to monoclinic systems in the first three cases, as well as the triclinic for Nisalphen. The Hirshfeld surface analysis showed that the packaging was favored by H∙∙∙H and C∙∙∙H/H∙∙∙C interactions, and C-H∙∙∙O hydrogen bridges when the substituent was -MeO and π-stacking was added to an aromatic bridge. Replacing the N/N bridge with an aromatic ring decreased distortion in square-planar geometry where the angles O-Ni-N formed a perfect square-planar.

Pentacyanoiron(II) as an Electron Donor Group for Nonlinear Optics:  Medium-Responsive Properties and Comparisons with Related Pentaammineruthenium(II) Complexes

2006 ◽  
Vol 128 (37) ◽  
pp. 12192-12204 ◽  
Author(s):  
Benjamin J. Coe ◽  
Josephine L. Harries ◽  
Madeleine Helliwell ◽  
Lathe A. Jones ◽  
Inge Asselberghs ◽  
...  
Keyword(s):  
Nonlinear Optics ◽  
Electron Donor ◽  
Donor Group

scholarly journals The alkyl group is a -I + R substituent

2018 ◽  
Vol 28 (4) ◽  
Author(s):  
Luis Salvatella
Keyword(s):  
Alkyl Group ◽  
Dipole Moments ◽  
Substituent Effects ◽  
Uv Spectra ◽  
Substitution Effects ◽  
Resonance Effects ◽  
Alkyl Groups ◽  
Alkyl Substitution ◽  
Donor Substituent ◽  
Electron Donor Substituent

Electronic substituent effects are usually classified as inductive (through σ-bonds) and resonance effects (via π-bonds). The alkyl group has been usually regarded as aσ -electron donor substituent (+I effect, according to the Ingold’s classification). However, a σ-withdrawing, π-donor effect (-I + R pattern) allows explaining the actual electron-withdrawing behavior of alkyl groups when bound to sp³ carbon atoms as well as their well-known electron-releasing properties when attached to sp² or sp atoms. Alkyl substitution effects on several molecular properties (dipole moments, NMR, IR, and UV spectra, reactivity in gas phase and solution) are discussed.

scholarly journals Oxidative Aromatization of 4,7-Dihydro-6-nitroazolo[1,5-a]pyrimidines: Synthetic Possibilities and Limitations, Mechanism of Destruction, and the Theoretical and Experimental Substantiation

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4719
Author(s):  
Daniil N. Lyapustin ◽  
Evgeny N. Ulomsky ◽  
Ilya A. Balyakin ◽  
Alexander V. Shchepochkin ◽  
Vladimir L. Rusinov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Oxidative Degradation ◽  
Chemical Calculation ◽  
Oxidative Aromatization ◽  
Donor Substituent ◽  
Experimental Substantiation ◽  
Electron Donor Substituent ◽  
Chemical Experiment

The reaction tolerance of the multicomponent process between 3-aminoazoles, 1-morpholino-2-nitroalkenes, and aldehydes was studied. The main patterns of this reaction have been established. Conditions for the oxidation of 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines were selected. Previous claims that the 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines could not be aromatised have now been refuted. Compounds with an electron-donor substituent at position seven undergo decomposition during oxidation. The phenomenon was explained based on experimental data, electro-chemical experiment, and quantum-chemical calculation. The mechanism of oxidative degradation has been proposed.

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