Serendipity and four polymorphic structures of benzidine, C 12H12N2

Michal Rafilovich, Joel Bernstein

Research output: Contribution to journalArticlepeer-review

92 Scopus citations


The search for a co-crystal of benzidine as a bifunctional hydrogen-bond donor with potential hydrogen-bond acceptors has instead revealed four polymorphs of the source material benzidine for which, somewhat surprisingly, no structure has been reported as of the November 2005 update of the CSD. All four structures are characterized by a rather unusual number of molecules in the asymmetric unit (Z = 1.5, 3, and 4.5), which are found in only 0.25%, 0.4%, and 0.002% of structures in the CSD. Forms I and IV (Z = 4.5) exhibit very similar crystal habits and are not distinguishable visually. In all forms except Form II (Z = 3), one of the molecules lies on a crystallographic inversion center, requiring the molecule to be planar; other molecules are nonplanar. Spectroscopic and thermodynamic characterizations of the system, including at least two possible additional forms of benzidine obtained by HT polymorph screening are reported.

Original languageEnglish
Pages (from-to)12185-12191
Number of pages7
JournalJournal of the American Chemical Society
Issue number37
StatePublished - 20 Sep 2006

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


Dive into the research topics of 'Serendipity and four polymorphic structures of benzidine, C 12H12N2'. Together they form a unique fingerprint.

Cite this