Synthesis and crystal structures of normethyl analogues of Dianin's compound

Abstract

As part of a study of inclusion behaviour, chromans (II) and (III) have been prepared, normethyl analogues of the versatile host Dianin's compound (I). Compound (II), which lacks the 2-methyl group cis to the p-hydroxyphenyl substituent, retains the ability to form clathrates. Crystals of the carbon tetrachloride clathrate of (II) are trigonal, space group R, with a= 26.936(6), c= 10.796(1)Å, and 18 host and 3 guest molecules in the hexagonal unit cell. An X-ray study has shown that the new cavity-shape is markedly different from that of the parent (I). In contrast to (II), the 4-nor-analogue (III) crystallises unsolvated in the tetragonal system, space group P2₁c, with a= 12.640(2), c= 17.254(4)Å, and Z= 8. This structure has infinite chains of molecules linked head-to-tail by O–H ⋯ O hydrogen bonds of length 2.82(1)Å.