Search results for "kationit"
showing 10 items of 12 documents
Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers
2019
Pyridine[4]arenes have previously been considered as anion binding hosts due to the electron-poor nature of the pyridine ring. Herein, we demonstrate the encapsulation of Me4N+ cations inside a dimeric hydrogen-bonded pyridine[4]arene capsule, which contradicts with earlier assumptions. The complexation of a cationic guest inside the pyridine[4]arene dimer has been detected and studied by multiple gas-phase techniques, ESI-QTOF-MS, IRMPD, and DT-IMMS experiments, as well as DFT calculations. The comparison of classical resorcinarenes with pyridinearenes by MS and NMR experiments reveals clear differences in their host–guest chemistry and implies that cation encapsulation in pyridine[4]arene…
A crystalline radical cation derived from Thiele’s hydrocarbon with redox range beyond 1 V
2021
Thiele’s hydrocarbon occupies a central role as an open-shell platform for new organic materials, however little is known about its redox behaviour. While recent synthetic approaches involving symmetrical carbene substitution of the CPh2 termini yield isolable neutral/dicationic analogues, the intervening radical cations are much more difficult to isolate, due to narrow compatible redox ranges (typically 1 V), permitting its isolation in crystalline form. Further single-electron oxidation affords borenium dication 12+, thereby establishing an organoboron redox system fully characterized in all three redox states. We perceive that this strategy can be extended to other transient organic rad…
A 2,3-dialkoxynaphthalene-based naphthocage
2019
A 2,3-dialkoxynaphthalene-based naphthocage has been synthesized. This naphthocage prefers to bind small organic cations with its low-symmetry conformation, which is in contrast to 2,6-dialkoxynaphthalene-based naphthocages. Self-sorting of these two naphthocages with two structurally similar guests tetramethylammonium and tetraethylammonium was achieved as well. peerReviewed
Towards purely inorganic clusters in medicine: Biocompatible divalent cations as counterions of cobaltabis(dicarbollide) and its iodinated derivatives
2021
Monovalent cations, Cs+, and alkylammonium ([NR4]+) salts have traditionally been used to precipitate the anions of boranes, carborane and metallocarborane clusters. In contrast, in the body and in living organisms in general, divalent cations have a special relevance. In this work, we isolate for the first time the cobaltabis(dicarbollide) salts of the biocompatible divalent cations of biological importance that can have application both in biology and in materials science. The preparation of Ca2+, Mg2+ and Fe2+ salts of anionic iodinated nido-[C2B9H12]− and cobaltabis(dicarbollide) as well as its di-, tetra- and octa-iodinated derivatives are reported. Ca2+ and Mg2+ are hard Lewis acids a…
Foldameerien isäntä-vieraskemia
2017
Tutkielman kirjallisessa osassa tarkastellaan foldameerejä isäntä-vieraskemian näkökulmasta. Foldameerit voivat sitoa rakenteeseensa erilaisia vierasmolekyylejä, jolloin muodostuu isäntä-vieraskomplekseja. Kirjallisuudesta valittiin tarkasteluun mielenkiintoisimpia anioneja, kationeja ja neutraaleja vierasmolekyylejä sitovia foldameereja ja perehdyttiin niiden vuorovaikutuksiin. Lisäksi tarkasteltiin vierasmolekyylin sitoutumisen aikaansaamia muutoksia foldameerien konformaatiossa. Kokeellisen osan tarkoituksena oli syntetisoida pitkä, 11 aromaattista rengasta sisältävä aryyliamidifoldameeri käyttäen hyväksi pääasiassa peptidikytkentäreaktioita. Koska synteesi osoittautui erittäin haasteell…
Role of Alkyl Substituent and Solvent on the Structural, Thermal, and Magnetic Properties of Binary Radical Salts of 1,2,3,5-Dithia- or Diselenadiazo…
2022
The synthesis, structural, thermal, and magnetic properties of a series of simple binary organic salts based on the radical anion of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 4-(N-alkylpyridinium-3-yl)-1,2,3,5-dithiadiazolyl (DTDA), 1R (R = Et, Pr, Bu), radical cations and their heavier selenium analogues (DSDA), 2R, are described. Single-crystal X-ray structural analyses reveal that short alkyl substituents on the pyridinium moiety of DTDA/DSDA cations lead to crystallization of isostructural acetonitrile (MeCN) solvates 1Et·MeCN, 1Pr·MeCN, 2Et·MeCN, and 2Pr·MeCN with trans-cofacial DTDA radical cation and eclipsed-cofacial TCNQ radical anion dimers. A slight increase in the substituent …
Redox-Responsive Host-Guest Chemistry of a Flexible Cage with Naphthalene Walls
2020
“Naphthocage”, a naphthalene-based organic cage, reveals very strong binding (up to 1010 M–1) to aromatic (di)cationic guests, i.e., the tetrathiafulvalene mono- and dication and methyl viologen. Intercalation of the guests between two naphthalene walls is mediated by C–H···O, C–H···π, and cation···π interactions. The guests can be switched into and out of the cage by redox processes with high binding selectivity. Oxidation of the flexible cage itself in the absence of a guest leads to a stable radical cation with the oxidized naphthalene intercalated between and stabilized by the other two. Encapsulated guest cations are released from the cavity upon cage oxidation, paving the way to futur…
Tellurium(II)-Centered Dications from the Pseudohalide “Te(OTf)2”
2009
Te for two: Supported by pyridine- or carbene-based ligands, tellurium-centered dications are prepared in high yield and include a dicationic tellurium analogue of the recently synthesized “carbodicarbene”. The key to accessing these compounds is the isolation of a base-stabilized form of TeOTf2 (see structure), a new highly electrophilic reagent for tellurium chemistry. peerReviewed
Expansion and Compression of a Helicate with Central Diol-Units as Stereocontrolling Moieties
2022
The dicatechol ester ligand 2-H4 forms the compressed helicate Li4[(2)3Ti2] which upon removal of the internally bound lithium cations expands. In the compressed form, the chiral diol units control the stereochemistry of the complex which is lost upon expansion of the system. peerReviewed
Fenyyli-ja metoksifenyylisubstituoidut karbokationit katalyytteinä
2018
Karbokationit ovat orgaanisia molekyylejä, joissa on positiivisesti varautunut hiiliatomi. Hybridisaatioteoria selittää karbokationien luonnetta ja kolmiulotteista rakennetta keskushiilen sp2-hybridisaatiolla, jossa hiiliatomin hybridisoitumaton p-orbitaali levittäytyy kolmen hybridiorbitaalin muodostaman tason ylä- ja alapuolille. Hybridisoitumaton porbitaali ei kuitenkaan ole täysin eristyksissä hybridisoituneista sidosorbitaaleista vaan se vastaanottaa helposti elektronitiheyttä keskushiileen sitoutuneilta substituenteilta. Mitä enemmän substituentit luovuttavat elektronitiheyttä positiivisesti varautuneelle hiiliatomille, sitä enemmän elektronitiheyttä siirtyy myös hybridisoitumattomall…