0000000000597885
AUTHOR
Jouni Pursiainen
X-Ray and NMR Studies on Host-Guest Inclusion Complex Formation between Crown Ethers and Pyridinium Compounds
Aromatic–aromatic, π–π, and cation–π interactions can be exploited in the preparation of molecular complexes between benzene-substituted crown ethers and pyridium cations. These complexes have been studied in the gas phase, in solution, and in the solid state; the structure of one of the complexes is depicted on the right.
The complexation of tetraphenylborate with organic N-heteroaromatic cations
Complexation studies of eleven N-heteroaromatic cations with tetraphenylborate are reported. Tetraphenylborate forms complexes with five cations and reacts to form Lewis-base boranes with six cations. The complexes and the displacement reaction products were characterised by 1H NMR spectroscopy, elemental analysis and crystallographic methods. In the complexes C–H⋯π or N–H⋯π hydrogen bonds are the principal intermolecular interactions. The stability constants for the complexes are determined by 1H NMR titration in acetonitrile–methanol (1 ∶ 1) solution. Crystal structures of four of the complexes and three of the Lewis-base triphenylborane products are reported.
Synthesis, characterization, and complexation of tetraarylborates with aromatic cations and their use in chemical sensors.
Five aromatic borate anions, namely tetrakis(4-phenoxyphenyl)borate (1), tetrakis(biphenyl)borate (2), tetrakis(2-naphthyl)borate (3), tetrakis(4-phenylphenol)borate (4), and tetrakis(4-phenoxy)borate (5), have been prepared and tested as ion-recognition sites in chemical sensors for certain aromatic cations and metal ions. To gain further insight into the complexation of the cations, some complexes have been prepared and structurally characterized. The complexation behavior of 1 and 2 towards N-methylpyridinium (6), 1-ethyl-4-(methoxycarbonyl)pyridinium (7), tropylium (8), imidazolium (9), and 1-methylimidazolium (10) cations has been studied, and the stability constants of the complexes o…
Synthesis and characterization of new aromatic tweezers and complex formation with tropylium ion in 1,2-dichloroethane
A series of benzene and pyridine tweezers bearing phenyl, naphthyl and anthryl receptor units was prepared and characterized. The x-ray crystal structure of the 1,3-bis(9-methanolanthracene)methylbenzene ligand (5) is reported. UV–visible and NMR spectroscopy were used to investigate the host–guest chemistry of the new ligands in complexation with tropylium tetrafluoroborate as a model aromatic cationic guest in 1,2-dichloroethane. The appearance of coloured charge-transfer absorption bands demonstrates the complex formation with a tropylium ion. The enlargement of aryl receptor size from phenyl and naphthyl to anthryl increases the stability of complexes. Electron donor–acceptor interactio…
Complexation of planar, organic, five-membered cations with crown ethers
Complexation of six aromatic, nitrogen-containing cations with various crown ethers has been studied using 1H NMR, mass spectrometric and crystallographic methods. Hydrogen bonding appears to be the most important interaction in complexation, but minor effects such as π-stacking or cation–π interactions have also been observed. The stability constants of five different imidazolium perchlorate ·crown ether complexes and five other similar cation·DB18C6 complexes were determined by 1H NMR titration in acetonitrile solution. The stability of these complexes in solution and in the gas phase is discussed. The crystal structures of seven complexes were determined in order to study complexation in…