Clathration by diol hosts : thermodynamics and structure

Inclusion properties of the following seven diol host compounds were investigated: Host 1 9,9'-bis(9,91-dihydroxy-fluorene) Host 2 1, 1'-binaphthyl-2,2'-bis( diphenylhydroxymethyl) Host 3 2,2'-bis(9-hydroxy-9-fluorenyl)biphenyl Host 4 trans-9, 10-dihydroxy-9,10-diphenyl-9, 10-dihydroanthracene Host 5 trans-9, 10-dihydroxy-9,10-di-p-tolyl-9,10-dihydroanthracene Host 6 trans-9, 10-dihydroxy-9, 10-di-p-tert-butylphenyl-9, 10-dihydroanthracene Host 7 trans-9, 10-dihydroxy-9, 10-di-a-naphthyl-9, 10-dihydroanthracene These compounds all possess molecular planes with bulky substituents and opposing hydroxyl moieties as probes for possible coordination to guest molecules by means of hydrogen bonding. Sixteen different inclusion compounds were formed with common organic solvents as the guests. Various characterisation techniques were used and the crystal structures of the inclusion compounds and of the a-phases of Hosts 2 and 5 were elucidated using single crystal X-ray diffraction methods. Thermal decomposition studies using thermogravimetry and differential scanning calorimetry (DSC) were carried out in order to relate the strength of the host-guest interactions to the structures of the inclusion compounds. Owing to practical limitations, the DSC technique is not suitable for the measurement of '1H for the decomposition of an inclusion compound where the guest is relatively volatile. Therefore an apparatus was devised to yield accurate '1H0 values for this process