Cocrystallization and configurations of myo-inositol-1,2-L-camphor acetals in two crystal structures

The inositol rings in (1S,2R,3R,4S,5S,6R,7S,8S,11S)-myo-inositol-1,2-camphor acetal {systematic name: (1R,2S,3S,4R,5S,6R)-5,6-[(1S,2S,4S)-1,7,7-trimethyl­bicyclo­[2.2.1]heptane-2,2-diyldi­oxy]cyclohexane-1,2,3,4-tetrol}, C₁₆H₂₆O₆, and (1R,2S,3S,4R,5R,6S,7R/S,8S,11S)-myo-inositol-1,2-camphor acetal trihydrate {systematic name: (1S,2R,3R,4S,5R,6S)-5,6-[(1S,4S,6R/S)-1,7,7-trimethyl­bicyclo­[2.2.1]heptane-2,2-diyldi­oxy]cyclohexane-1,2,3,4-tetrol trihydrate}, C₁₆H₂₆O₆·3H₂O, adopt flattened chair conformations with the latter crystal containing two stereoisomers in a 0.684 (2):0.316 (2) ratio, similar to that found both in solution and by calculation. Both mol­ecules pack in the crystals in similar two-dimensional layers, utilizing strong O—H...O hydrogen bonds, with the trihydrate cell expanded to incorporate the additional hydrogen-bonded water mol­ecules.

[1L-3,4-Bis-O-(diphenyl­phosphino)-1,2,5,6-tetra-O-methyl-chiro-inositol-κ²P,P′][η⁴-(Z,Z)-cyclo­octa-1,5-diene]rhodium(I) tetra­fluorido­borate chloro­form solvate

The title compound, [Rh(C₈H₁₂)(C₃₄H₃₈O₆P₂)]BF₄·CHCl₃, a novel asymmetric hydrogenation catalyst, crystallizes with two independent almost identical cations and anions. Cell-packing inter­actions are provided by nonclassical hydrogen bonding between phenyl and chloro­form H atoms and fluoro and chloro donors of the BF₄⁻ anion and the chloro­form solvent mol­ecule.

Geometry and bond-length alternation in nonlinear optical materials. I. Standard parameters in two precursors

2-{3-Cyano-4-[4-(N-formyl­anilino)-trans-1,3-butadien­yl]-5,5-dimethyl-2,5-dihydro­furan-2-yl­idene}propane­dinitrile, C₂₂H₁₈N₄O₂, (I), and 2-{3-cyano-4-[6-(N-formyl­anilino)-trans,trans-1,3,5-hexa­trien­yl]-5,5-dimethyl-2,5-dihydro­furan-2-yl­idene}propane­dinitrile, C₂₄H₂₀N₄O₂, (II), show the alternating single/double-bond behaviour of push–pull chromophores. In the two structures, the planar polyene chains are twisted with respect to the furanyl­idene ring by 18.2 (2) and 12.4 (2)°, respectively. Comparison with structures of related and parent mol­ecules shows subtle but consistent bond-length variations consistent with charge-delocalized structures. Crystal cohesion is provided by various sets of hydrogen bonds, viz. C—H_methyl...N_cyano and bifurcated (C=C—H)₂...O=C in (I), and C—H_{methyl/phenyl}...O and C=C—H...N_cyano in (II).