Wikipedia:Good article reassessment/Persistent carbene/1

Persistent carbene

 * • [//en.wikipedia.org/w/index.php?title=Wikipedia:Good_article_reassessment/Persistent_carbene/1&action=watch Watch article reassessment page] • GAN review not found
 * Result: No significant improvement, even giving the extra allotted time. Delisted. AirshipJungleman29 (talk) 22:11, 2 March 2023 (UTC)

Quite a lot of uncited material including and many more. These will need to be cited. Onegreatjoke (talk) 22:12, 9 February 2023 (UTC)
 * the Molecular orbitals and persistent carbenes section and its subsections
 * Diaminocarbenes have diagnostic 13C NMR chemical shift values between 230 and 270 ppm for the carbenic atom. The X-ray structure of dihydroimidazole-2-ylidene shows a N–C–N bond angle of about 106°, whilst the angle of the acyclic carbene is 121°, both greater than those seen for imidazol-2-ylidenes.
 * Exposure to oxygen (a triplet diradical) converts this carbene to the corresponding benzophenone. The diphenylmethane compound is formed when it is trapped by cyclohexa-1,4-diene. As with the other carbenes, this species contains large bulky substituents, namely bromine and the trifluoromethyl groups on the phenyl rings, that shield the carbene and prevent or slow down the process of dimerization to a 1,1,2,2-tetra(phenyl)alkene. Based on computer simulations, the distance of the divalent carbon atom to its neighbors is claimed to be 138 picometers with a bond angle of 158.8°. The planes of the phenyl groups are almost at right angles to each other (the dihedral angle being 85.7°).
 * The Mesoionic carbenes section