CaltechTHESIS
  A Caltech Library Service

The synthesis, spectroscopic observation and chemical reactivity of N-(2,2,6,6-tetramethylpiperidyl)nitrene

Citation

Hinsberg, William Dinan, III (1980) The synthesis, spectroscopic observation and chemical reactivity of N-(2,2,6,6-tetramethylpiperidyl)nitrene. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3R32-XC97. https://resolver.caltech.edu/CaltechTHESIS:07252016-112114482

Abstract

1,1-Dialkyldiazenes (aminonitrenes, N-nitrenes) unlike their more stable 1,2-dialkyldiazetle isomers (azo compounds) have not yet been isolated or detected by spectroscopic methods, but rather are assumed intermediates based on a substantial body of chemical evidence. The first direct observation of a 1,1- dialkyldiazene is described here. The visible spectrum at -78° of N-(2,2,6,6-tetramethylpiperidyl)nitrene (33) (λmax = 541 nm) provides experimental evidence on (1) the energy required for the n + π* electronic transition, and (2) the vibrational spacing of the first electronically excited state. The infrared spectrum at -78° (14N=14N stretch at 1595 cm-1; 14N=15N stretch at 1569 cm-1) provides evidence that the 1,1- diazene has considerable N=N double bond character in the ground state.

The first kinetic study of the thermal decomposition of a 1,1-dialkyldiazene is described. The temperature dependence of the unimolecular rate (k1) of fragmentation of 33 was examined in three different solvents and kinetic evidence for a direct bimolecular pathway for the formation of 1,1 "-azo-2,2,6,6-tetra- methylpiperidine 41 from 33 is provided. The activation parameters for the unimolecular fragmentations are log A = 11.6 ± 0.5, Ea = 16.9 ± 0.7 in n-hexane, log A = 13.7 ± 0.3, Ea = 20.0 ± 0.4 in Et20, log A= 13.6 ± 0.3, Ea = 20.1 ± 0.4 kcal/mole in THF. Using computer simulation it is found that the curved portions of the tn A vs. time plots may be modelled as competitive unimolecular and bimolecular reactions (kobs = k1 + k2[33]). In Et20 at -16°, k1 = 5.03 x 10-4 sec-1 and k2 = 5.0 x 10-2 liter/mole-sec.

Also reported are proton and carbon-13 nuclear magnetic resonance data for 33, along with the results of a preliminary study of its photoreactivity.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Dervan, Peter B.
Thesis Committee:
  • Unknown, Unknown
Defense Date:31 August 1979
Funders:
Funding AgencyGrant Number
NSFUNSPECIFIED
Petroleum Research FundUNSPECIFIED
Record Number:CaltechTHESIS:07252016-112114482
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:07252016-112114482
DOI:10.7907/3R32-XC97
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9895
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:26 Jul 2016 22:48
Last Modified:21 Dec 2019 04:27

Thesis Files

[img]
Preview
PDF - Final Version
See Usage Policy.

20MB

Repository Staff Only: item control page