Linked Life Data

20812698

Source:http://linkedlifedata.com/resource/pubmed/id/20812698

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2010-9-24
pubmed:abstractText
Triplet carbenes t-butylpentadiynylidene (t-BuC(5)H, 1a) and dimethylpentadiynylidene (MeC(5)Me, 1b) have been produced photochemically from their corresponding diazo compound precursors and studied spectroscopically in cryogenic matrices (N(2) or Ar) at 10 K. The infrared, electronic absorption, and electron paramagnetic resonance spectra of these species exhibit numerous similarities to the spectra of pentadiynylidene (HC(5)H) and methylpentadiynylidene (MeC(5)H) recorded previously. EPR spectra yield zero-field splitting parameters that are typical for triplet carbenes with axial symmetry (t-BuC(5)H, 1a: |D/hc| = 0.61 cm(-1), |E/hc| ? 0 cm(-1); MeC(5)Me, 1b: |D/hc| = 0.62 cm(-1), |E/hc| ? 0 cm(-1)). Electronic spectra are characterized by weak absorptions (T(1) ? T(0)) in the near-UV and visible region (350-430 nm) with extended vibronic progressions. The electronic transitions of several -C(5)- carbenes are compared, and an apparent dependence of the transition wavelength on the level of alkyl substitution of the carbon chain is found. Chemical trapping of triplet 1a in an O(2)-doped matrix affords carbonyl oxides derived predominantly from attack at C-3. Both t-BuC(5)H (1a) and MeC(5)Me (1b) undergo photochemical rearrangement upon UV irradiation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1520-6904
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6372-81
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Dialkynyl carbene derivatives: generation and characterization of triplet tert-butylpentadiynylidene (t-Bu-C?C-C?-C?C-H) and dimethylpentadiynylidene (Me-C?C-C?-C?C-Me).
pubmed:affiliation
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.