Competitive H-bonding in bicyclic bis-lactams: self-assembly in nanotubes or in unbalanced chiral threefold interpenetrated diamondoid network

The first example of an H-bonded diamondoid network formed by a chiral molecule is reported. Diamondoid networks in the crystal structure of the described bicyclic bis-lactam are homochiral and threefold interpenetrated, two of them being of one chirality and the third of the other. Thus, imbalanced chiral packing with ee 33% is observed. A slight change in the structural formula leads to an entirely different crystal structure with nanosize channels.     

Autoassembling of the cage structures

Enantiomeric dilactones ((1R,4R)-(+)-1 and (1S,4S)-(-)-1) of αα′-dihydroxy-αα′-di-tert-butylglutaric acid have been prepared. The Cotton effect sign of the n→π*-transition of the lactone chromophore in enantiomers1 is determined by the contribution of the uncompensated bonds of the δ-dilactone ring, but not by that of the γ-monolactone ring of1. The correlation of the Cotton effect sign of the n→π*-transition with the chirality of the cage structure and the absolute configuration for the series of 1,4-dialkyldilactones of type1 has been suggested. The contribution of the pseudo-a-oriented amide group to, the Cotton effect sign of the lactone n→π*-transition (the effect of the third chiral sphere) in diastereomeric lactonamides2a,b predominates over that of the nonplanar bonds of the heterocycle (over the effect of the second chiral sphere).     

RESTRICTED LIE ALGEBRAS WITH MAXIMAL 0-PIM

In this paper it is shown that the projective cover of the trivial irreducible module of a finite-dimensional solvable restricted Lie algebra is induced from the one dimensional trivial module of a maximal torus. As a consequence, the number of the isomorphism classes of irreducible modules with a fixed p-character for a finite-dimensional solvable restricted Lie algebra L is bounded above by p ^MT(L), where MT(L) denotes the maximal dimension of a torus in L. Finally, it is proved that in characteristic p > 3 the projective cover of the trivial irreducible L-module is induced from the one-dimensional trivial module of a torus of maximal dimension, only if L is solvable.     

Asymmetric nitrogen

Reactions of the Tröger base (1) with HgBr₂ and Mel proceed with the participation of only one N atom. According to the data of X-ray diffraction analysis, the complex [(±)-1]₂·HgBr₂ crystallizes in the achiral space groupP _n . Unlike the complex [(+)-1]₂·HgBr₂, methiodide of (+)-1 in MeOH undergoes racemization at 20°C. The virtual spin-spin coupling constants⁴ J _HH observed for the base (C ₂ symmetry) are transformed into the “usual” constants in the case of the desymmetrized methiodide system.