Synthesis And Structure Of Pyridyl-containing Organic Molecular Cage And Macrocyclic NHC Precursor

In recent years,organic molecular cages as supermolecular host compounds and N-heterocyclic carbene act as an important ligand for metal organic chemistry,which has received high attention from researchers.Firstly,here in,an organic molecular cage containing pyridyl groups was designed and prepared by Schiff base reaction.A pair of cylindrical chiral molecular were synthesized by imine condensation reaction with chiral cyclohexanediamine and 4,4'-?1,4-phenylene?bis?pyridine-2,6-diformaldehyde?.The Schiff base molecular cage is further reduced to a more flexible and stable secondary amine molecular cage.The molecular structure of the R-imine chiral cage was tested by single crystal X-ray and found to have a cylindrical internal cavity with an inner diameter of 9.4?and a length of 12.4?.A series of carboxyl-containing azospiropyran compounds as guest molecules were also designed and synthesized.It is hoped that the protonated reduced-state organic cage can stabilize the colorless closed-loop state or open-loop coloration state of the guest molecule at a certain pH.Secondly,a pair of different mono-chiral pyridyl-containing macrocyclic NHC precursor compounds were synthesized using 2,6-pyridinedicarbaldehyde and R/S cyclohexanediamine with a single chirality,and subjected to ¹H-NMR,¹³C-NMR,ESI-MS and circular dichroism characterization provide precursor compounds that can be exploited to investigate the coordination chemistry and catalytic properties of macrocyclic NHCs.Finally,a pair of single chirality[3+3]type NHC precursor compound bridges with fluorenyl were prepared by 9,9-diethyl-9H-2,7-fluorenyldialdehyde and 1S,2S or 1R,2R cyclohexanediamine.From the molecular structure obtained by single crystal test and its weakly interacting dimer,it is known that the single triimidazoline cationic group is in the form of a barrel,and the barrel length is about 5?,inner diameter of about 9¹3?;Moreover,the group can self-assemble into a dimer of a polar,medium-waist hydrophobic at both ends by the hydrophobic action of the cyclohexane group only in a polar solvent.The dimer has a length of about 7.2?,which also maintains the presence of chirality and large caliber,to explore the host-guest chemistry,separation of chiral molecules,and coordination of macrocyclic NHCs chemical related performance studies provide precursor compounds that are available.