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2 Polish Journal of Chemistry

2 1998

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X-ray structural investigation of three 4-aryl-substituted [2.2]paracyclophanes

Jones P.G., Kuś P.

Polish Journal of Chemistry

1998

Vol. 72, nr 8

1999-2008

The low-temperature crystal structures of 4-methylphenyl[2.2]paracyclophane (1), C23H22, orthorhombic, Pbca, a=12.880(2), b=7.4234(12), c=34.425(6) A, Z=8; 2,6-dimethyl-phenyl[2.2]-paracyclophane (2), C24H24, orthorhombic, P2-12-12-1, a=8,593(3), b=12.550(4), c=15.745(4) A, Z=4, and 2,4,5-trimethylphenyl[2.2]paracyclophane (3), C25H26, monoclinic, P2-1/c, a=13.737(2), b=17.883(2), c=15.230(2) A, beta= 103.423(8)degree, Z=8 (two independent molecules) have been determined. Surprisingly, only small differences from the normal paracyclophane structure were found in the three sterically hindered species; the paracyclophane rings are mutually rotated and twisted by a few degrees, and the torsion angle between paracyvlophane and aryl rings is slightly increased in 2 and 3 compared to 1.

Crystal structure of meso-4,4'-Di[2.2]paracyclophane

Jones P.G., Kuś P.

Polish Journal of Chemistry

1998

Vol. 72, nr 6

1106-1111

Of the two possible racemates formed on the dimerization of [2.2]paracyclophane, the title compound C32H30 is the meso (RS/SR) isomer. It crystallizes in moniclinic system in space group P2-1/n with Z=4 and unit cell dimensions: a=13.7612(12), b= 11.2530(10), c=14.6974(12) A, beta=99.668(8)degree (at-100degree C). The conformation is described by interplanar angle between the linked rings, 48.67(8)degree. Some widened angles in the region of C4-C4' may indicate steric congestion.