This article records the diversely reported melting temperatures of 3,6-diamino-9H-carbazole (DAC) and 3,6-dinitro-9H-carbazole (DNC), and reports a reinvestigation on their melting phenomena, and associated specific observations. A rationalization of these reports has been attempted on the basis of IR spectroscopic, X-ray diffraction, thermal response, solubility behavior, and differential scanning calorimetric data on DAC and DNC. The data indicate that an exothermic inter-molecular deaminative self-condensation involving N9 H and NH2 sets in prior to melting of DAC, which obscures the actual melting process. An extrapolated onset melting temperature of 241.0 .C and a peak temperature of 296.5 .C at zero heating rate have been assigned for DAC from DSC measurements. A possible structure of the polymeric self-condensation product is also presented. For DNC, a peak melting temperature of 296.5 +-1.8 .C, but no onset melting temperature could be assigned.
Compounds
#
Formula
Name
1
C12H11N3
3,6-diamino-9H-carbazole
2
C12H7N3O4
3,6-dinitro-9H-carbazole
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.