5149-12-2Relevant academic research and scientific papers
Groups 5 and 6 terminal hydrazido(2-) complexes: Nβ substituent effects on ligand-to-metal charge-transfer energies and oxidation states
Tonks, Ian A.,Durrell, Alec C.,Gray, Harry B.,Bercaw, John E.
supporting information; experimental part, p. 7301 - 7304 (2012/06/16)
Brightly colored terminal hydrazido(2-) (dme)MCl3(NNR 2) (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 β (NR 2) nitrogen affects the energy of the lowest-energy charge-transfer (CT) transition in these complexes. For group 5 complexes, increasing the energy of the Nβ lone pair decreases the ligand-to-metal CT (LMCT) energy, except for electron-rich niobium dialkylhydrazides, which pyramidalize Nβ in order to reduce the overlap between the Nb=N α π bond and the Nβ lone pair. For W complexes, increasing the energy of Nβ eventually leads to reduction from formally [WVI≡N-NR2] with a hydrazido(2-) ligand to [WIV=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.
N,N-di(4-halophenyl)nitrenium ions: Nucleophilic trapping, aromatic substitution, and hydrogen atom transfer
Thomas, Selina I.,Falvey, Daniel E.
, p. 4626 - 4634 (2008/02/07)
(Figure Presented) The reactive intermediates N,N-di(4-chlorophenyl) nitrenium ion and N,N-di(4-bromophenyl)nitrenium ion were generated through photolysis of the corresponding N-amino(2,4,6,-collidinium) ions. The behavior of these diarylnitrenium ions was characterized by laser flash photolysis, analysis of the stable photoproducts, and ab initio calculations with density functional theory. The latter predict these species to have singlet ground states. The halogenated diarylnitrenium ions are significantly longer lived than the unsubstituted diphenylnitrenium ion. Specifically, cyclization to form carbazole derivatives occurs negligibly, if at all, with the halogenated derivatives. They do, however, carry out most of the characteristic reactions of singlet arylnitrenium ions, including combining with nucleophiles on the aryl rings, adding to arenes, and accepting electrons from readily oxidized traps. Interestingly these species also abstract H atoms from 1,4-cyclohexadiene and various phenol derivatives. The implication of the latter process in relation to the computed singlet-triplet energy gaps of ca. -12.5 kcal/mol is discussed.
Photochemical generation of nitrenium ions from protonated 1,1-diarylhydrazines
Winter, Arthur H.,Thomas, Selina I.,Kung, Andrew C.,Falvey, Daniel E.
, p. 4671 - 4674 (2007/10/03)
(Chemical Equation Presented) Laser flash photolysis experiments, chemical trapping studies, and time-dependent density functional theory calculations demonstrate that photolysis of protonated 1,1-diarylhydrazines generates N,N-diarylnitrenium ions.
An improved synthesis of camphorquinone-3-oxime
Love, Brian E.,Jones, Edward G.
, p. 2831 - 2840 (2007/10/03)
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.
