Chiral resolution of a racemic macrocyclic complex by recognition of one enantiomer over the other: structures and DFT calculations.

The enantiopure agents d- and l-leucine, selectively bind RR and SS enantiomers from a racemate [Ni(alpha-rac-L)](2+) to give {[Ni(RR-L)(d-HLeu)](ClO(4))(2)}(n) (Delta-) and {[Ni(SS-L)(l-HLeu)](ClO(4))(2)}(n) (Lambda-), respectively, and leave the corresponding uninteracted SS and RR enantiomers of [Ni(alpha-SS-L)](ClO(4))(2) (S-) and [Ni(alpha-RR-L)](ClO(4))(2) (R-). Occasionally, a few crystals of {[Ni(RR-L)(l-HLeu)](ClO(4))(2)}(n) (Delta-) and {[Ni(SS-L)(d-HLeu)](ClO(4))(2)}(n) (Lambda-) were found to have accreted with the crystals of Lambda-/R-, and Delta-/S-, respectively (the yields are less than 2%). The results of X-ray crystal structural analysis reveal that Delta- and Lambda-, S- and R-, and Delta- and Lambda- are enantiomers, in which Delta- and Delta- possess 1D right-handed helical chains, while Lambda- and Lambda- exhibit a motif of 1D left-handed helical chains.

Ester hydrolysis by a cyclodextrin dimer catalyst with a tridentate N,N',N''-zinc linking group.

A new beta-cyclodextrin dimer, 2,6-dimethylpyridine-bridged-bis(6-monoammonio-beta-cyclodextrin) (pyridyl BisCD, L), is synthesized. Its zinc complex (ZnL) is prepared, characterized, and applied as a catalyst for diester hydrolysis. The formation constant (log K(ML)=7.

Assembly of CdI2-type coordination networks from triangular ligand and octahedral metal center: topological analysis and potential framework porosity.

Reaction of a rigid triangular ligand 2,4,6-tris[4-(1H-imidazole-1-yl)phenyl]-1,3,5-triazine (TIPT) with Cd2+ ions affordedrare non-interpenetrating CdI2-type networks which display high thermostability and potential porosity; the topological character of the CdI2-type networks have been analyzed in comparison with three common uniform (4,4), (6,3) and (3,6) plane nets.