Search results for "Benzonitrile"

A DFT study for the regioselective 1,3-dipolar cycloadditions of nitrile N-oxides toward alkynylboronates

2003

Abstract The mechanism for the 1,3-dipolar cycloaddition of benzonitrile oxide toward ethynyl and propynylboronate has been studied by using density functional theory (DFT) at B3LYP/6-31G* level. These cycloadditions are concerted [3+2] processes. The presence of the two oxygens on the boronic ester precludes the participation of the boron atom on [3+3] processes. The two regioisomeric channels associated to the formation of the isoxazoles bearing the boronic ester unit on the 4- or 5-positions have been characterized. The B3LYP/6-31G* activation parameters are in acceptable agreement with the experiments, allowing to explain the factors controlling these regioselective cycloadditions.

Pt(II) nitrile complexes: New insights on old complexes from a combined experimental and theoretical study

2017

Abstract The spectroscopic characterization of cis - and trans -[PtCl 2 (NCR) 2 ] (R = CH 3 , Ph, CH 2 Ph) was reported in solid state and solution phase. Moreover, the X-ray structures of cis -[PtCl 2 (NCCH 3 ) 2 ], cis - and trans -[PtCl 2 (NCPh) 2 ] were redetermined at low temperature. FT-IR and NMR showed a blue-shift and a slight shielding of the νCN and δ ( 13 C CN ) values, respectively, in a counterintuitive way with respect to the well known improved reactivity towards nucleophiles of nitriles ligands coordinated to platinum(II), when compared to their free forms. These spectroscopic behaviors were also confirmed by theoretical experiments at DFT level. Moreover, DFT approach show…

Clarification of the oxidation state of cobalt corroles inheterogeneous and homogeneous catalytic reduction of dioxygen

2008

Co(III) corroles were investigated as efficient catalysts for the reduction of dioxygen in the presence of perchloric acid in both heterogeneous and homogeneous systems. The investigated compounds are (5,10,15-tris(pentafluorophenyl)corrole)cobalt (TPFCor)Co, (10-pentafluorophenyl-5,15-dimesitylcorrole)cobalt (F 5PhMes 2Cor)Co, and (5,10,15-trismesitylcorrole)cobalt (Mes 3Cor)Co, all of which contain bulky substituents at the three meso positions of the corrole macrocycle. Cyclic voltammetry and rotating ring-disk electrode voltammetry were used to examine the catalytic activity of the compounds when adsorbed on the surface of a graphite electrode in the presence of 1.0 M perchloric acid, a…

Persistent electron-transfer state of a pi-complex of acridinium ion inserted between porphyrin rings of cofacial bisporphyrins

2006

A free-base cofacial bisporphyrin, H(4)DPOx, forms a pi-complex with acridinium ion (AcH(+)) by pi-pi interaction in benzonitrile (PhCN). Formation of the H(4)DPOx-AcH(+) pi-complex was probed by UV-vis and NMR spectroscopy. The binding constant between AcH(+) and H(4)DPOx is determined as 9.7 x 10(4) M(-)(1). Photoinduced electron transfer (ET) from the H(4)DPOx to the AcH(+) moiety occurred efficiently in the pi-complex to form the ET state (H(4)DPOx(*)(+)-AcH(*)). The ET state is successfully detected by laser flash photolysis. The lifetime of the ET state is 18 mus in PhCN at 298 K, and the quantum yield of the ET state is 90%. The temperature dependence of the ET state lifetime has bee…

Mechanism of four-electron reduction of dioxygen to water by ferrocene derivatives in the presence of perchloric acid in benzonitrile, catalyzed by c…

2004

The selective two-electron reduction of dioxygen occurs in the case of a monocobalt porphyrin [Co(OEP)], whereas the selective four-electron reduction of dioxygen occurs in the case of a cofacial dicobalt porphyrin [Co(2)(DPX)]. The other cofacial dicobalt porphyrins [Co(2)(DPA), Co(2)(DPB), and Co(2)(DPD)] also catalyze the two-electron reduction of dioxygen, but the four-electron reduction is not as efficient as in the case of Co(2)(DPX). The micro-superoxo species of cofacial dicobalt porphyrins were produced by the reactions of cofacial dicobalt(II) porphyrins with dioxygen in the presence of a bulky base and the subsequent one-electron oxidation of the resulting micro-peroxo species by…

Synthesis and reactivity of .sigma.-bonded silicon metalloporphyrins. Spectroscopic characterization and electrochemistry of (P)Si(R)2, (P)Si(R)X, an…

1988

CCDC 743661: Experimental Crystal Structure Determination

2010

Related Article: B.Therrien, Trieu-Tien Thai, J.Freudenreich, G.Suss-Fink, S.S.Shapovalov, A.A.Pasynskii, L.Plasseraud|2010|J.Organomet.Chem.|695|409|doi:10.1016/j.jorganchem.2009.10.033

CCDC 1542456: Experimental Crystal Structure Determination

2018

Related Article: Maude Desroches, Paula Mayorga Burrezo, Joël Boismenu-Lavoie, Miriam Peña Álvarez, Carlos J. Gómez-García, Jon M. Matxain, David Casanova, Jean-François Morin, Juan Casado|2017|Angew.Chem.,Int.Ed.|56|16212|doi:10.1002/anie.201708740

CCDC 295282: Experimental Crystal Structure Determination

2006

Related Article: E.Schweizer, A.Hoffmann-Roder, K.Scharer, J.A.Olsen, C.Fah, P.Seiler, U.Obst-Sander, B.Wagner, M.Kansy, F.Diederich|2006|ChemMedChem|1|611|doi:10.1002/cmdc.200600015

CCDC 295281: Experimental Crystal Structure Determination

2006

Related Article: E.Schweizer, A.Hoffmann-Roder, K.Scharer, J.A.Olsen, C.Fah, P.Seiler, U.Obst-Sander, B.Wagner, M.Kansy, F.Diederich|2006|ChemMedChem|1|611|doi:10.1002/cmdc.200600015