magistrsko delo
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: |
2019 |
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
|
Št. ogledov: |
831 |
Št. prenosov: |
209 |
Ocena: |
0 (0 glasov) |
Metapodatki: |
|
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 |