Photochemical Generation of Nitrenium Ions from Protonated 1,1-Diarylhydrazines
作者:Arthur H. Winter、Selina I. Thomas、Andrew C. Kung、Daniel E. Falvey
DOI:10.1021/ol048250y
日期:2004.12.1
[reaction: see text] Laserflashphotolysis experiments, chemical trapping studies, and time-dependent density functional theory calculations demonstrate that photolysis of protonated 1,1-diarylhydrazines generatesN,N-diarylnitrenium ions.
Camphorquinone 3-oxime is prepared in 77% yield in one step from camphor. The synthesis avoids the use of toxic selenium reagents, and provides the syn compound as the major stereoisomer.
Groups 5 and 6 Terminal Hydrazido(2−) Complexes: N<sub>β</sub> Substituent Effects on Ligand-to-Metal Charge-Transfer Energies and Oxidation States
作者:Ian A. Tonks、Alec C. Durrell、Harry B. Gray、John E. Bercaw
DOI:10.1021/ja302275j
日期:2012.5.2
Brightly colored terminal hydrazido(2-) (dme)MCl3(NNR2) (dme = 1,2-dimethoxyethane; M = Nb, Ta; R = alkyl, aryl) or (MeCN)WCl4(NNR2) complexes have been synthesized and characterized. Perturbing the electronic environment of the beta (NR2) nitrogen affects the energy of the lowest-energy charge-transfer (CT) transition in these complexes. For group 5 complexes, increasing the energy of the N-beta lone pair decreases the ligand-to-metal CT (LMCT) energy, except for electron-rich niobium diallcylhydrazides, which pyramidalize N-beta in order to reduce the overlap between the Nb=N-alpha pi bond and the N-beta lone pair. For W complexes, increasing the energy of N-beta eventually leads to reduction from formally [W-VI N-NR2] with a hydraziclo(2-) ligand to [W-IV=N=NR2] with a neutral 1,1-diazene ligand. The photophysical properties of these complexes highlight the potential redox noninnocence of hydrazido ligands, which could lead to ligand- and/or metal-based redox chemistry in early transition metal derivatives.
KOJKOV, L. N.;TERENTEV, P. B.;YUFIT, D. S.;STRUCHKOV, YU. T.;ZUBAREV, V. +, ZH. ORGAN. XIMII, 1985, 21, N 9, 1820-1831
作者:KOJKOV, L. N.、TERENTEV, P. B.、YUFIT, D. S.、STRUCHKOV, YU. T.、ZUBAREV, V. +