A Shape-Persistent Cryptand for Capturing Polycyclic Aromatic Hydrocarbons

Abstract

A shape-persistent cryptand 1, containing two face-to-face oriented electron-deficient 2,4,6-triphenyl-1,3,5-triazine units separated by approximately 7 Å, and bridged by two rigid 1,8-naphthyridine linkers and a pentaethylene oxide loop, is created for capturing polycyclic aromatic hydrocarbons. Cryptand 1 formed 1:1 complexes with PAH guest molecules, such as phenanthrene (6), anthracene (7), pyrene (8), triphenylene (9), and tetraphene (10). The single-crystal structure of complex 6⊂1 revealed that 6 was included in the cavity of 1 via face-to-face π···π stacking interactions. Soaking crystalline 1 in a toluene solution of anthracene resulted in anthracene from the toluene solution being picked up by the crystalline solid of 1.

Self-Assembly of Fluorinated Boronic Esters and 4,4′-Bipyridine into 2:1 N→B Adducts and Inclusion of Aromatic Guest Molecules in the Solid State: Application for the Separation of o,m,p-Xylene

“…(iv) More complex systems with confined cavities can be achieved by enhancing the nuclearity of the adduct, e.g., by using tri-or tetra-amine ligands. These perspectives illustrate that this class of molecules could constitute an interesting alternative to Stoddart's X-boxes and -cages, 30,31 Peinador's and Fujita's palladium and platinum-based metallacycles and -cages, 32,33 Severin's and Iwasawa's oligonuclear boron cages, 23,34 among others, 35,36 all of which have shown high selectivity for the inclusion of large PAHs.…”

Synthesis, Structure and Supramolecular Properties of a Novel C3 Cryptand with Pyridine Units in the Bridges

“…Cryptands exhibiting C 3 symmetry have been exciting synthetic targets, due to their high ability to form stable “host–guest” supramolecular assemblies (i.e., as result of the macrobicyclic effect [ 1 ]) either with ions (cations and anions) [ 2 , 3 , 4 ] or neutral organic molecules [ 5 , 6 , 7 , 8 , 9 ]. Many aromatic tripodand units were employed to access this type of cryptand.…”

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

“…Cryptands with C 3 -symmetric aromatic reference groups are exciting targets, on the one hand due to the challenges encountered in their synthesis and on the other due to their ability (macrobicyclic effect [ 1 ]) to form supramolecular assemblies with cations, anions or neutral guests, e.g., aromatic molecules [ 2 – 6 ]. The supramolecular architectures involving cryptands (including metallomacrocycles) and aromatic guests are targeted for investigations of aromatic–aromatic contacts [ 7 – 8 ] and for various applications in molecular electronics [ 9 – 10 ].…”

“…The synthesis of cryptands with C 3 symmetry by peculiar reactions (acetylenic coupling [ 16 – 18 ], CuAAC [ 19 – 22 ], double or triple bond metathesis [ 23 – 25 ], aromatic nucleophilic substitutions [ 26 – 33 ], or via the amplification of a cryptand belonging to DCC libraries [ 2 , 25 , 34 – 35 ]) allowed accessing of more sophisticated architectures. In a previous work [ 32 ] we reported the formation of a host–guest complex between a cryptand having pyridine units in the bridges and 1,3,5-triphenylbenzene caps ( 1 , Fig.…”