ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
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.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610060308
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