Templated polar order of a guest in a quasiracemic organic host

Abstract

A quasiracemic mixture of Dianin's compound and its thiol derivative enforces additional anisotropy of the guest-accessible space, thus facilitating a net polar arrangement of guest molecules; guest alignment is rationalized in terms of van der Waals volume considerations.

Organic alloys of room temperature liquids thiophenol and selenophenol

“…7 In contrast, the diversity in shapes and structural complexity in organic molecules make the design of organic alloys a hard task. The known examples of organic alloys or solid solutions may be classified into two types: (i) structures for which the component molecules are very similar in size, 8 shape, 9 and interaction propensity, 10 and (ii) those which form host-guest type crystal structures 11 with porous frameworks 12 that allow variable stoichiometry of the guest molecules. For the known examples of solid solutions at least one of the molecular components is a room temperature-solid, and to our knowledge there are no examples of organic alloys formed by two room-temperature liquids.…”

Total CCl4 guest alignment in a quasiracemic clathrate closely related to Dianin's compound

“…Interestingly, in this case the clathrate features a novel [OH ... SH] 3 hexamer replacing the conventional [OH] 6 host hexamer. 10 NQR has also been employed to study the motion of the CCl 4 guest molecule in host 1 itself 11 . We now present detailed single-crystal X-ray analyses at 100K of these earlier prototypal quasiracemic polar structures, space group R3, which reveal a novel complete guest orientation phenomenon and an unprecedented host conformation.…”

Engineering robust polar chiral clathrate crystals

“…11 In a recent paper Jacobs et al presented a quasiracemic organic host prepared from the cocrystallisation of the resolved enantiomers of Dianin's compound 1a and its mercapto analogue 1b. 12 Cocrystallisation of (R)-1a and (S)-1b from CCl 4 produced a CCl 4 clathrate structure in the polar and chiral space group R3 featuring an [SHÁ Á ÁOH] 3 hexamer replacing the [OH] 6 and [SH] 6 hexamers of racemic 1a and 1b respectively. The reduction in symmetry from R% 3 to R3 allowed for the polar ordering of the CCl 4 guest molecules, (two per cage), such that a preferential alignment of the C-Cl bonds along the polar axis toward the host phenolic moiety was achieved in the ratio of 85 : 15.…”

“…[18][19][20] The hydroxyl oxygen atoms in structure 5 are referred to as O2A and O2B for the chroman and thiachoman components respectively. Alternating molecules of 3 and 4 self-assemble to form the expected R 6 6 (12), [OH] 6 hydrogen bonded hexamer at each end of the classical 'hourglass' cavity with O2A donor Á Á ÁO2B acceptor and O2B donor Á Á ÁO2A acceptor = 2.821(2) and 2.901(2) Å respectively. The single CCl 4 guest moiety is disordered over two sites on the three-fold axis within the hourglass cavity.…”

“…The goodness of fit on F 2 was 1.002. Flack parameter = 0.002 (12). [18][19][20] All crystal structures were solved and refined using the SHELX suite of programs.…”