magistrsko delo
Tjaša Podlogar (Avtor), Martin Gazvoda (Mentor), Jurij Lah (Član komisije za zagovor), Janez Košmrlj (Član komisije za zagovor)

Povzetek

Cilj magistrskega dela je bila sinteza različnih s piridinom funkcionaliziranih triazolijevih soli in poskus priprave kompleksov med omenjenimi triazolijevimi solmi in kovinami prehoda, v katerih bi triazolijeve soli predstavljaje Py-tzNHC bidentatne karbenske ligande. Sinteze smo začeli s klik reakcijo med ustrezno izbranima acetilenom in azidom ter nato po literaturnih postopkih pripravili ustrezne trizolijeve soli. Pripravili smo 4 nove, v literaturi še neopisane, triazolijeve soli. Pripravili smo s piridinom funkcionalizirano triazolijevo sol, ki ima na triazolna dušika N 1 in N 3 vezani metilni skupini. Sintetizirana sol nam je služila kot prekurzor za ligand v paladijevemu kompleksu z dvem tovrstnima Py-tzNHC ligandoma, ki smo ga pripravili z deprotoniranjem omenjene soli s srebrovim(I) oksidom. Kompleks smo uporabili kot katalizator pri Sonogashirovem pripajanju brez bakra, žal se je izkazal slabše aktiven kot njegov analog, ki ima na N 1 vezano aromatsko, 4-Me-C 6 H 4 -, skupino. Omenjen paladijev kompleks z dvema Me skupina je tudi manj obstojen kot njegov analog, saj je po enem dnevu pri sobni temperaturi razpadel. Pripravili smo tudi s piridinom funkcionalizirano triazolijevo sol, ki ima 2-piridinski substituent vezan na triazolni obroč preko -CH mostička. Na mostovni ogljik je bila vezana še hidroksilna oziroma acetiloksi skupina. To triazolijevo sol smo poskusili uporabiti kot prekurzor za ligand pri pripravi ustrezenega paladijevega kompleksa, a ta triazolijeva sol že pod blagimi bazičnimi pogoji razpade na 3-metil-1-(p-tolil)-1H-1,2,3-triazol-3-ijev tetrafluoroborat. Razpad najverjetneje poteče po retro-aldolni reakciji, vendar nam tega ni uspelo nedvoumno potrditi niti z detekcijo 2-formilpiridina oziroma 2-pikolinske kisline niti z obratno, aldolno reakcijo 2-formilpiridina na 3-metil-1-(p-tolil)-1H-1,2,3-triazol-3-ijev tetrafluoroborat. Pri sintezi omenjene triazolijeve soli dobimo racemno zmes dveh enantiomerov, katera smo poskusili ločiti z resolucijo s pomočjo kristalizacije. Poleg opisanih triazolijevih soli smo pripravili tudi s piridinom funkcionalizirano kiralno triazolijevo sol. Sintezno smo začeli iz (R)-2-(1-azidoetil)piridina, v optično čisti obliki, ki je po klik reakciji z 1-etinil-4-metilbenzenom in nadaljni pretvorbi do ustrezne triazolijeve soli, vodil do prve takšne optično čiste spojine. Omenjena triazolijeva sol predstavlja prekurzor za kiralen karbenski Py-tzNHC ligand, ki bi po vezavi na kovino prehoda vodil do kiralnega organokovinskega kompleksa. Takšen kompleks bi lahko služil kot katalizator za stereoselektivne pretvorbe pri katalitskih reakcijah.

Ključne besede

organska sinteza;triazol;triazolijeve soli;kovine prehoda;paladij;kiralni organokovinski kompleksi;Sonogashirova reakcija;magistrska dela;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UL FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik: [T. Podlogar]
UDK: 547.79:546.98(043.2)
COBISS: 1538506947 Povezava se bo odprla v novem oknu
Št. ogledov: 831
Št. prenosov: 209
Ocena: 0 (0 glasov)
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Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: Structure and reactivity of palladium complexes with different triazolylidene ligands
Sekundarni povzetek: The goal of master thesis was the synthesis of different pyridine- functionalized triazolium salts and attempt to prepare their corresponding complexes with transition metals in which triazolium salts would represent Py-tzNHC bidentate carbene ligands. We started the synthesis with click reaction between appropriately selected acetylenes and azides and then we followed literature procedures to prepare corresponding triazolium salts. We synthesized 4 new triazolium salts. We prepared pyridine-functionalized triazolium salt with methyl group at the triazole nitrogens N 1  and N 3 . This salt was used as a ligand in palladium complex with two Py-tzNHC which was made by deprotonation with silver(I) oxide. Palladium complex was tested as a catalyst for copper-free Sonogashira reaction but it turned out to be less efficient than its analogue with aromatic, 4-Me-C 6 H 4 -, group bonded to nitrogen N 1 . Mentioned palladium complex with 2 methyl groups is also less stable than its arylated analogue as it decomposes at room temperature in one day. We also prepared pyridine functionalized triazolium salt which had 2-pyridine substituents bonded to triazolium ring over a –CHbridge, with additional OH or OAc group on the CH linker. We tried to use this triazolium salt as a precursor for ligand for the corresponding palladium complex but this triazolium salt decomposed already under mild basic conditions into 3methyl1(ptolyl)-1H-1,2,3-triazol-1-ium tetrafluoroborate. Decomposition probably occures through a retro-aldol reaction, however, we were unable to prove this neither with detection of 2-formylpyridine or 2-picolinic acid nor with reversed, aldol reaction of 2-fromylpyridine and 3-methy-1-(p-tolyl)-1H-1,2,3-triazol-3-ium tetrafluoroborate. The synthesis of the above mentioned triazolium salt furnished racemic mixture of 2 enantiomers which we tried to separate by resolution with help of crystalization. In addition, we also prepared optically pure pyridine-functionalized triazolium salt. We started the synthesis from optical pure (R)-2-(1-azidoethyl)pyridine which we reacted with 1-etynyl-4-methylbenzene and then further converted to the corresponding triazolium salt by methylation. This is the first prepared optical pure compound of this type. This triazolium salt represents a precursor for chiral carbene Py-tzNHC ligand which would after bonding to transition metal lead to chiral organometallic complex. This kind of complex could serve as a catalyst for stereoselective transformations.
Sekundarne ključne besede: triazole;triazolium salt;transition metals;palladium;chiral organometallic complex;
Vrsta dela (COBISS): Magistrsko delo/naloga
Študijski program: 1000375
Konec prepovedi (OpenAIRE): 1970-01-01
Komentar na gradivo: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemija
Strani: 72 str.
ID: 11332765