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A theoretical investigation into dimethylcarbene and its diamino and diphosphino analogs: effects of cyclization and unsaturation on the stability and multiplicity
Author(s) -
Kassaee M. Z.,
Ghambarian M.,
Musavi S. M.,
Shakib F. A.,
Momeni M. R.
Publication year - 2009
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1540
Subject(s) - chemistry , degree of unsaturation , multiplicity (mathematics) , computational chemistry , medicinal chemistry , stereochemistry , organic chemistry , mathematical analysis , mathematics
High levels of ab initio and DFT calculations (B3LYP/6‐311++G**, B3LYP/AUG‐cc‐pVTZ, and CCSD(T)/6‐311++G** levels) coupled with isodesmic reactions are used to compare and contrast the multiplicities and relative stabilities of singlet (s) and triplet (t) acyclic carbenes, including: dimethylcarbene, diaminocarbene, and diphosphinocarbene along with their saturated and unsaturated cyclic ones. Cyclization is unfavorable for all acyclic carbenes while unsaturation of cyclic analogs appears favorable. The simultaneous cyclization and unsaturation of dimethylcarbene increases the singlet–triplet energy gap (Δ E s–t ), while for diphosphinocarbene the situation is reversed. For diaminocarbene the increase of Δ E s–t is encountered only during cyclization. Copyright © 2009 John Wiley & Sons, Ltd.