Inclusion compounds of a diol host with xylidines: controlled stoichiometries.
The diol host, 1,1'-bis-(4-hydroxyphenyl)cyclohexane (DHPC) and a number of xylidine isomers as guests formed a series of inclusion compounds that gave rise to various host:guest ratios controlled by crystallization temperatures. For the host DHPC with a particular xylidine isomer, the number of guests included generally decreases as the crystallization temperature increases. The crystal structures of these host-guest compounds were elucidated using single-crystal X-ray diffraction. Their thermal stabilities were characterized by TG and DSC analysis. The selectivity of enclathration by the host was measured by carrying out a series of competition experiments. The kinetics of guest decomposition were studied using isothermal and non-isothermal methods and reconciled with the crystal structures.
Disorder as adaptation of the crystal structure to increase the crystallization temperature. X‐ray crystal structure of the host–guest complexes between 1,1′‐binaphthyl‐2,2′‐dicarboxylic acid and dimethyl sulphoxide obtained at 50 and 60 °C
The complex formation of 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA) with dimethyl sulphoxide (DMSO) at different temperatures was investigated. The crystal structures of the α- and β-form [triclinic, P1, a = 9.614(2), b = 11.743(2), c = 12.029(2) A, α = 99.35(3), β = 93.58(3), γ = 110.51(3)°, V = 1244.5(4) A3, Z = 2, R = 0.053 for 4879 reflections] host–guest complexes obtained at 50 and 60 °C, respectively, were determined by x-ray structure analysis (the crystal structure of the α-form obtained at room temperature was studied previously). There is disorder of the guest molecules characteristic of the α-form of the 1:1 BNDA·DMSO complex obtained at 50 °C and the host carboxylic groups in the β-form of the 1:2 BNDA·DMSO, considered a consequence of the changed conditions for crystal preparation. By disordering of the crystal structure the interaction of the solvent molecule with its environment, especially with nearest BNDA molecules, is improved. The new orientation leads to the formation of a more compact host–guest associate which resists the escape of the guest molecules from the growing crystal during crystallization and may exist even in the nucleation step. Thus disordering of the solvent molecules (α-form) and disordering of the carboxyl groups of the host molecules (β-form) are the two modes of operation in this system. Copyright © 1999 John Wiley & Sons, Ltd.
Host-guest binding in two coordinatoclathrates of 1,1′-binaphthyl-2,2′-dicarboxylic acid. x-ray crystal structures of the inclusion compounds with 1-propanol (2 : 1) andt-butanol (1 : 1)
Abstract1,1'-Binaphthyl-2,2'-dicarboxylic acid (1) forms crystalline inclusion compounds with 1-PrOH (2:1) andt-BuOH (1:1). X-ray crystal structures of the two inclusion compounds are reported. Crystals of1·1-PrOH (2: 1) show triclinic (
$$P\bar 1$$
) symmetry with the unit cell dimensionsa = 10.160(1),b = 14.050(2),c = 15.167(1) Åα = 100.37(1),β = 104.40(1), andγ =94.82(1)°. Crystals of1s·t-BuOH (1: 1) are monoclinic (P21/n) with the cell dimensionsa = 10.603(5),b = 14.377(4),c = 15.664(7) Å,β = 104.24(4)°. In both structures, H-bonded loops involving host −000H functions and guest −OH groups establish the supramolecular association. They relate these coordinatoclathrates to previous alcohol inclusions of1. Due to the unusual 2:1 (host: guest) stoichiometry, additional dimer-like interactions between −000H groups of host molecules are found in the 1-PrOH inclusion compound. From the point of view of topology these structures can be referred to as channel inclusion compounds.