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Updated: Aug 15, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Isatin 3-semicarbazone and 1-methylisatin 3-semicarbazone
G Pelosi1, C Pelizzi, M Belicchi Ferrari
1Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Parco Area delle Scienze 17/A, 43100 Parma, Italy. giorgio@unipr.it
Abstract:
The two title semicarbazones, namely 2,3-dihydro-1H-indole-2,3-dione 3-semicarbazone, C9H8N4O2, (I), and 1-methyl-2,3-dihydro-1H-indole-2,3-dione 3-semicarbazone, C10H10N4O2, (II), show the same configuration, viz. Z around the imine C=N bond and E around the C(O)-NH2 bond, stabilized by two intramolecular hydrogen bonds. The presence of a methyl group on the isatin N atom determines the difference in the packing; in (I), the molecules are linked into chains which lie in the crystallographic (102) plane and run perpendicular to the b axis, while in (II), the molecules are arranged to form helices running parallel to a crystallographic screw axis in the a direction.
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