Synthesis and properties of the inclusion compound 2-phenyl-3-p-(2,2,4-trimethylchroman-4-yl)phenylquinazolin-4(3H)-one; use of quartets in the crystal structure determination of the methylcyclohexane clathrate

Abstract

The title compound (III) has been found to form stable adducts with a wide range of solvents, important classes of guest being cycloalkanes, cyclic ethers and ketones, alcohols, and aromatic molecules. An X-ray investigation of the inclusion compound formed with methylcyclohexane has been carried out. A key feature of the solution of this complex structure, which has 79 non-hydrogen atoms in the asymmetric unit, was the use of quartet relationships in the direct-method analysis. Crystals are triclinic, space group P, with a= 18.649(25), b= 19.443(25), c= 9.390(15)Å, α= 78.88(5), β= 98.97(5), γ= 118.16(10)°, with four host and two guest molecules in the unit cell. The structure was refined by least-squares methods to a final R of 0.098, employing 3 432 significant diffractometer data. The packing of host molecules of (III) is such that large closed cages are formed : in each of these clathrate voids two methylcyclohexane guest molecules are accommodated. Compound (V), a thio-analogue of (III), has also been prepared and found to exhibit inclusion behaviour.