Versatile packing modes of 9‐substituted 9‐fluorenols. X‐ray crystal structures of 9‐methyl‐, 9‐phenyl‐, 9‐(1‐naphthyl)‐ and 9‐(2‐biphenylyl)fluoren‐9‐ol

Ingeborg Csöregh, M. Czugler, Edwin Weber

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The four studied semi‐rigid fluorenol derivatives differ only in the size of the 9‐substituents. All four compounds crystallize with two molecules per asymmetric unit and with relatively low crystallographic symmetry [P1 for the 9‐methyl derivative (1) and P21/n for the 9‐(1‐naphthyl) (3) and 9‐(2‐biphenylyl) (4) derivatives]. Crystal data: 1, a = 8·779(1), b = 11·570(1), c = 11·747(1), α = 91·197(5), β = 104·345(4), γ = 105·848(6)° 2, a = 8·425(1), b = 13·819(1), c = 23·902(2)Å, β = 95·87(1)° 3, a = 15·679(4), b = 8·567(2); c = 23·884(17)Å, β = 92·60(6)° 4, a = 7·770(6), b = 33·766(10), c = 13·649(4)Å, β = 95·30(1)°. Nevertheless, the packing modes are different. The 9‐methylfluoren‐9‐ol molecules, forming H‐bonded tetramers with full H‐bond saturation, give rise to the lowest packing coefficient among the four compounds. The crystals of the 9‐phenyl derivative are built up of H‐bonded dimers, whereas those of the bulky 9‐naphthyl and 9‐diphenylyl derivatives consist of single molecules only. The latter two compounds, however, have a denser packing than the two that contain H‐bonded aggregates. The crystal structures are held together mainly by ordinary Van der Waals forces. In the case of 9‐biphenylyfluoren‐9‐ol, the structure seems to be stabilized also by weak H‐bond‐type interactions from the alcoholic hydroxyl group to the π‐electron cloud of an aromatic ring in the neighbouring molecule the O…centroid distances are 3·182(3) and 3·248(4)Å, and in the 9‐naphthyl derivative the OH groups are involved in some short (˜3·3Å) intermolecular approach, possibly indicating an electrostatically favourable packing for the compound.

Original languageEnglish
Pages (from-to)171-178
Number of pages8
JournalJournal of Physical Organic Chemistry
Volume6
Issue number3
DOIs
Publication statusPublished - 1993

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Versatile packing modes of 9‐substituted 9‐fluorenols. X‐ray crystal structures of 9‐methyl‐, 9‐phenyl‐, 9‐(1‐naphthyl)‐ and 9‐(2‐biphenylyl)fluoren‐9‐ol'. Together they form a unique fingerprint.

  • Cite this