magistrsko delo
Abstract
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.
Keywords
organska sinteza;triazol;triazolijeve soli;kovine prehoda;paladij;kiralni organokovinski kompleksi;Sonogashirova reakcija;magistrska dela;
Data
Language: |
Slovenian |
Year of publishing: |
2019 |
Typology: |
2.09 - Master's Thesis |
Organization: |
UL FKKT - Faculty of Chemistry and Chemical Technology |
Publisher: |
[T. Podlogar] |
UDC: |
547.79:546.98(043.2) |
COBISS: |
1538506947
|
Views: |
831 |
Downloads: |
209 |
Average score: |
0 (0 votes) |
Metadata: |
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Other data
Secondary language: |
English |
Secondary title: |
Structure and reactivity of palladium complexes with different triazolylidene ligands |
Secondary abstract: |
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. |
Secondary keywords: |
triazole;triazolium salt;transition metals;palladium;chiral organometallic complex; |
Type (COBISS): |
Master's thesis/paper |
Study programme: |
1000375 |
Embargo end date (OpenAIRE): |
1970-01-01 |
Thesis comment: |
Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemija |
Pages: |
72 str. |
ID: |
11332765 |