12064 research outputs found
Sort by
SEROLOGICAL AND MOLECULAR CHARACTERISTICS OF ALLOIMMUNISATION TO SPECIFIC NEUTROPHIL ANTIGENS IN ALLOIMMUNE NEONATAL NEUTROPENIA
No full textAntineutrofilna (anti-HNA) aloantitijela nastaju nakon izlaganja stranim neutrofilnim
aloantigenima. Aloimuna neonatalna neutropenija (ANN) nastaje imunizacijom majke tijekom
trudnoće specifičnim humanim neutrofilnim antigenima (HNA) djeteta naslijeđenim od oca. U
oko trećine slučajeva ANN nije moguće odrediti specifičnost antitijela HNA. U ovom
istraživanju svih 10 slučajeva ANN bilo je uzrokovano antitijelima na HNA-1 sustav. U 7
slučajeva dokazana je anti-FcγRIIIb specifičnost antitijela. U 9 slučajeva imunizacija majke
bila je uzrokovana aloantitijelima nastalim nepodudarnošću s antigenom HNA-1b djeteta. Viša
vrijednost titra antitijela anti-HNA u djece bila je povezana s većim stupnjem neutropenije.
Prisutnost antitijela anti-HLA razreda I u majki ima statistički značajan utjecaj na kraće trajanje
neutropenije u djece. Ovim istraživanjem potvrđena je hipoteza da primjena osjetljive serološke
metode za dokazivanje prisutnosti antitijela anti-HNA i anti-HLA razreda I, određivanje
specifičnosti antitijela anti-HNA u plazmi majke i djeteta te molekularne metode za određivanje
genotipa HNA majke i djeteta znatno doprinose pravodobnom otkrivanju ove bolestiAntineutrophil (anti-HNA) alloantibodies are produced in response to exposure to foreign
neutrophil alloantigens. Neonatal alloimmune neutropenia (NAN) develops due to maternal
immunization during pregnancy against neonatal specific human neutrophil antigens (HNA)
inherited from the father. HNA antibody specificity cannot be identified in about one-third of
NAN cases. In this study, all 10 NAN cases were caused by HNA-1 system antibodies. AntiFcyRIIIb antibody specificity was demonstrated in 7 cases. In 9 cases, maternal immunization
was caused by alloantibodies due to incompatibility with neonatal HNA-1b antigen. Elevated
anti-HNA antibody titer in children was associated with a higher degree of neutropenia. The
presence of class I anti-HLA antibodies in mothers has a statistically significant effect on a
shorter duration of neutropenia in children. This study has confirmed the hypothesis that using
a sensitive serological method to demonstrate the presence of anti-HNA and class I anti-HLA
antibodies, determination of anti-HNA antibody specificity in maternal and neonatal plasma,
and employing molecular methods to determine maternal and neonatal HNA genotype can
contribute substantially to timely detection of this disorder
Oomycete (Oomycota) isolates from the cuticle of crayfish species in Croatia
No full textIstraživanja rasprostranjenosti i utjecaja vodenih plijesni na slatkovodne deseteronožne rakove većinom su fokusirana na patogena Aphanomyces astaci, dok su u Hrvatskoj i ostalim dijelovima Europe nedovoljno istražene druge vrste vodenih plijesni koje mogu nastanjivati kutikulu rakova, iako neke od njih također mogu imati negativan utjecaj na domaćina. Cilj ovog istraživanja bio je uzgojiti i taksonomski identificirati izolate vodenih plijesni s egzoskeleta pet različitih autohtonih i invazivnih vrsta rakova u Hrvatskoj. Vodene plijesni kultivirane su iz pereiopoda i abdominalne kutikule položene na PG1 krutu hranjivu podlogu, uz precjepljivanje hifa na nove podloge do dobivanja akseničnih kultura vodenih plijesni. Identifikacija izolata do razine vrste provedena je sekvenciranjem ITS (engl. internal transcribed spacer) regije uz naknadnu filogenijsku analizu. Utvrđene su četiri vrste vodenih plijesni izolirane s kutikule dviju vrsta rakova: izolati Saprolegnia australis i Saprolegnia turfosa s kutikule vrste Pacifastacus leniusculus te izolati Aphanomyces astaci i Aphanomyces repetans s kutikule vrsta Astacus astacus i Pacifastacus leniusculus. Neke od izoliranih vodenih plijesni su saprofiti (S. turfosa, A. repetans), dok su drugi oportunisti (S. australis) ili primarni patogeni (A. astaci, uzročnik račje kuge).Research on the distribution and effects of oomycetes on crayfish hosts is mostly focused on Aphanomyces astaci, the causative agent of the crayfish plague. In Croatia and other parts of Europe research on this topic is scarce, despite of the possibility of negative impacts on the host. The aim of this study was to cultivate and identify oomycete isolates from the exoskeleton of different native and invasive crayfish species present in Croatia. Oomycetes were cultivated from pereiopods and abdominal cuticle inoculated on PG1 solid growth media, with hyphal transfers to new media until pure cultures were obtained. Identification of the isolates to species level was performed by sequencing of the internal transcribed spacer (ITS) region followed by phylogenetic analysis. We detected four oomycete species originating from two crayfish species: Saprolegnia australis and Saprolegnia turfosa isolates originating from Pacifastacus leniusculus, Aphanomyces astaci and Aphanomyces repetans isolates originating from both Astacus astacus and Pacifastacus leniusculus. Some of the detected species are saprophytic (S. turfosa, A. repetans), while others are opportunistic (S. australis) or primary pathogens (A. astaci, the causative agent of crayfish plague)
CONTRIBUTION OF DNA BARCODING TO THE RESEARCH OF CROATIAN FUNGAL BIODIVERSITY
No full textCilj doktorske disertacije bio je rješavanje znanstvenih problema u sistematici gljiva metodama integrativne taksonomije koja objedinjuje evaluaciju molekularnih, morfoloških i ekoloških obilježja gljivljih organizama. Poseban naglasak stavljen je na vrednovanje znanstvenog doprinosa DNA barkodiranja u otkrivanju, razgraničenju i identifikaciji srodnih vrsta u različitim skupinama nadzemnih gljiva iz odjeljaka Ascomycota i Basidiomycota. Prikazan je znanstveni opis tri vrste nove za znanost s područja Republike Hrvatske: Inocybe brijunica, I. istriaca i Parasola papillatospora. Kao važan biogeografski doprinos ovoga rada na području Hrvatske po prvi je puta pronađeno 10 vrsta gljiva: Coprinopsis alnivora, Entonaema cinnabarinum, Parasola auricoma, P. crataegi, P. cuniculorum, P. kuehneri, P. malakandensis, P. megasperma, P. nudiceps i P. plicatilis-similis. Vrste C. alnivora i P. malakandensis ujedno su po prvi puta zabilježene i na području Europe. Integrativna taksonomska analiza roda Entonaema rezultirala je određivanjem njegovog filogenetskog i taksonomskog položaja u porodici Hypoxylaceae te izradom identifikacijskog ključa za vrste na svjetskoj razini.The aim of this dissertation was to solve scientific problems in the systematics of fungi using integrative taxonomy, which combines molecular, morphological, and ecological characteristics of fungi. Special emphasis was placed on the contribution of DNA barcoding in the discovery, delimitation, and identification of related species in different groups of epigeous fungi (Ascomycota and Basidiomycota). The scientific description of three species new to science from Croatia was presented: Inocybe brijunica, I. istriaca, and Parasola papillatospora. An important biogeographical contribution was ten species of fungi found for the first time in Croatia: Coprinopsis alnivora, Entonaema cinnabarinum and 8 species of Parasola. Coprinopsis alnivora and P. malakandensis were also recorded for the first time in Europe. The integrative taxonomic analysis of the genus Entonaema led to the determination of their phylogenetic and taxonomic position in the family Hypoxylaceae and the establishment of an identification key of worldwide species within this genus
Synthesis of multisusbstituted cyclopentadienes by zirconocene-mediated cyclization of dienynes
No full textU okviru ovog diplomskog rada razvijena je metodologija priprave višesupstituiranih
ciklopentadiena u nekoliko konvergentnih sintetskih koraka pri čemu postoji mogućnost
selektivnog uvođenja i variranja veličine pojedinih supstituenata na ciklopentadienskom
prstenu. Sintetski put započinje regioselektivnom bromalilacijom disupstituiranih alkina pri
čemu nastaju odgovarajući bromdieni s reaktivnom ugljik-halogen vezom. To je ključno za
provedbu Sonogashirine reakcije s terminalnim acetilenima kako bi se generirali nekonjugirani
dienini. Ciklizacijom dienina pomoću niskovalentnog organocirkonija (Negishijev reagens)
pripravljeni su ciklopentadieni s exo-cikličkom dvostrukom. U posljednjem koraku, kiselinom
kataliziranom exo-to-endo izomerizacijom exo-cikličke dvostruke veze ciklopentadiena
pripravljeni su tetrasupstituirani ciklopentadieni. Strukture pripravljenih spojeva potvrđene su
analitičkim tehnikama i postupcima (NMR, MS).The methodology for the preparation of multisubstituted cyclopentadienes in several
convergent synthesis steps was developed within this master's thesis. This allows for the
selective introduction and varation of the size of individual substituents on the cyclopentadienyl
ring. The synthetic route starts with the regioselective bromallylation of disubstituted alkynes,
yielding the corresponding bromodienes with a reactive carbon-halogen bond, which is crucial
for carrying out the Sonogashira reaction with terminal acetylenes to generate non-conjugated
dienynes. By cyclizing the dienyne using low-valent zirconium compounds (Negishi reagent),
cyclopentadienes with an exo-cyclic double bond were prepared. In final step, through acid
catalyzed exo-to-endo isomerisation of the exo-cyclic double bond of the cyclopentadiene,
tetrasubstituted cyclopentadienes were prepared. The structures of the prepared compounds
were confirmed using analytical techniques and procedures such as (NMR, MS)
Investigation of intermolecular interactions in cocrystals of selected amino acids with 5-amino-2,4,6-triiodoisophthalic acid
No full textU proteinskoj kristalografiji se za rješavanje faznog problema koriste brojne metode. Jedna od
najčešće korištenih metoda za određivanje strukture novih proteina jest metoda izomorfne
zamjene. Za to je potrebno, uz kristale nativnog proteina, prirediti derivate koji posjeduju atome
koji značajnije anomalno raspršuju zračenje. Najčešće su to bili ioni teških metala (poput, Hg2+
,
PtCl4
2−), a u novije se vrijeme sve uspješnije koriste organske molekule koje posjeduju više
atoma halogenih elemenata. Međutim, dosad nije napravljeno istraživanje kojim bi se
specifično istražile interakcije standardnih aminokiselina s takvim organskim molekulama.
U sklopu ovog rada, kao predstavnik nove klase spojeva odabrana je 5-amino-2,4,6-
trijodizoftalna kiselina (I3C). U brojim postupcima sinteze priređeni su novi spojevi spomenute
kiseline sa standardnim aminokiselinama, a jedino je kokristalu I3C i L-histidina određena
kristalna i molekulska struktura. Ostali produkti odabranih aminokiselina i I3C karakterizirani
su infracrvenom spektroskopijom i rendgenskom difrakcijom na polikristalnom uzorku.
Također, dobiven je novi solvat I3C kojemu je određena molekulska i kristalna struktura.In protein crystallography, numerous methods are used to solve the phase problem. One of the
most commonly used methods is the isomorphous replacement method. For this, it is necessary,
along with crystals of the native protein, to prepare derivatives that possess atoms that
significantly scatter radiation (anomalously). Most often, these were heavy metal ions (such as
Hg2+, PtCl4
2−), and recently, organic molecules possessing more atoms of halogen elements
have been used successfully. However, no systematic research has been done to investigate the
interactions of standard amino acids with such organic molecules.
As part of this work, 5-amino-2,4,6-triiodisophthalic acid (I3C) was selected as a representative
of a new class of compounds. In numerous synthesis procedures, new compounds of I3C with
standard amino acids were prepared, and only the crystal and molecular structure of the cocrystal of I3C and L-histidine was determined. Other products of selected amino acids and I3C
were characterized by IR spectroscopy and X-ray diffraction on a polycrystalline sample. Also,
a new solvate I3C was obtained, the molecular and crystal structure of which was determined
Catecholamine concentrations in the cave and creek population of the Karst dace (Telestes karsticus)
No full textKapelska svijetlica (Telestes karsticus Marčić i Mrakovčić, 2011) stenoendemska je vrsta
dunavskog slijeva koja živi u ponoru i u potoku Sušik. Vrsta Telestes karsticus ima stalnu špiljsku
populaciju, a prisutnost specifične površinske populacije čini je potencijalno važnim modelnim
sustavom za razumijevanje početnih adaptivnih procesa koji nastaju tijekom kolonizacije špilja.
Općenito, ribe koje žive u špiljama razvile su razlike u ponašanju koje su pod kontrolom
katekolamina. Cilj ovog diplomskog rada bio je prilagoditi i validirati postojeću HPLC metodu
mjerenja razine monoamina, izmjeriti koncentracije katekolamina u uzorcima kapelske svijetlice,
utvrditi postoji li razlika u njihovim koncentracijama između špiljskih i potočnih populacija, dolazi
li do promjene u njihovim razinama u eksperimentalnim uvjetima (život u mraku/uvjeti normalnog
dnevno-noćnog ritma) te uzrokuju li spomenuti uvjeti drugačije odgovore kod špiljske i potočne
populacije. Za postizanje navedenog cilja bilo je neophodno pročišćavanje uzoraka ekstrakcijom na
čvrstoj fazi, stoga je razvijena i validirana RP-HPLC metoda za analizu spojeva s katekolnom
skupinom. Špiljska populacija kapelske svijetlice pokazuje indikativno veću koncentraciju
dopamina u mozgu od potočne populacije, što ukazuje na to da bi promjene u neurotransmiterima
mogle imati značajnu ulogu već u inicijalnim koracima naseljavanja podzemlja.Karst Dace (Telestes karsticus Marčić & Mrakovčić, 2011) is a stenoendemic species of the
Danube basin that lives in the Sušik Sinkhole and in the Sušik Creek. Telestes karsticus forms a
permanent cave population and the presence of a specific surface population makes it a potentially
important model system for understanding the initial adaptive processes that occur during the
colonization of caves. In addition, cavefish have evolved differences in behavior which are under
the control of the catecholamine systems. The aims of this thesis was to adapt and validate the
current method for measurement of monoamine concentrations by HPLC, to quantify
catecholamine concentrations in samples of brain and body tissue of the Karst Dace, to determine
whether there is a difference in catecholamine concentrations between cave and surface
populations, to determine whether there is a change in catecholamine concentrations in individuals
exposed to completely dark conditions vs. light/dark conditions and whether these conditions lead to
different responses in cave and surface populations. To achieve this goal, it was necessary to purify
samples by solid phase extraction. Therefore, the RP-HPLC method for the analysis of compounds
containing catechol moiety was developed and validated. The cave population of the Karst Dace
shows a trend of higher concentration of dopamine in the brain compared to the surface population,
indicating that changes in neurotransmitters could play an important role already in the initial
adaptive processes that occur during cave colonization
Electron microscopy characterization of iron nanoparticles used for sorption of selected lanthanides
No full textTehnološki kritični elementi poput elemenata rijetkih zemalja i aktinoida imaju široku
primjenu u modernim tehnologijama. Zbog njihove velike potražnje i godišnje proizvodnje, ti
elementi se često ispuštaju u okoliš pri čemu se akumuliraju u organizmima. U posljednjem
desetljeću provode se iscrpna istraživanja s naglaskom na nanočestice željeza kao novim
materijalima za uklanjanje lantanoida iz vodenih sustava. Kako su nanočestice željeza
podložne oksidaciji, proučava se i površinska modifikacija s ciljem poboljšanja selektivnosti i
efikasnosti sorpcije metalnih iona. U ovom radu promatrana je efikasnost sorpcije iona Nd3+
,
Eu3+, Er3+, Gd3+, UO2
2+
na nanočestice elementarnog željeza te nanočestice modificirane
piridin-2,6-dikarboksilnom kiselinom. Pomoću spektrometrije masa uz induktivno spregnutu
plazmu (ICP-MS) promatrana je efikasnost sorpcije odabranih iona. Kako bi se utvrdila sama
morfologija nanočestica, provedena je strukturna analiza pomoću skenirajuće elektronske
mikroskopije (SEM) i mikroskopije atomskih sila (AFM). Utvrđeno je da sorpcija odabranih
iona na nanočestice te površinska modifikacija uvelike utječu na njihovu veličinu i strukturu.Technologically critical elements such as rare earth elements and actinides are widely used in
modern technologies. Due to demanding production technologies and widespread use, these
elements are often released in the environment and bioaccumulated. Over the last decade,
zero-valent nanoparticles have been the focus of research in removal of lanthanides from
aqueous systems. However, nanoparticles tend to oxidize, therefore nanoparticles are often
surface modified in order to enhance selectivity and efficiency of sorption. In this work,
efficiency of neutral nanoparticles and nanoparticles modified with pyridine-2,6-dicarboxylic
acid for sorption of selected lanthanides (Nd3+, Eu3+, Er3+, Gd3+, UO2
2+
) was examined.
Efficiency of sorption from aqueous solutions was analyzed by inductively coupled plasma
mass spectrometry (ICP-MS). In order to determine the morphology of iron nanoparticles,
scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis were
performed. The obtained results showed that adsorption of selected ions on nanoparticles and
surface modification affect their size and structure
Uloga tumorskog endotelnog markera 1 u metastaziranju pluća
No full textCancer relapse is driven by dormant tumor cells that are able to reactivate after perturbations in
the microenvironmental niche. Endothelium-derived protein multimerin 2 (MMRN2) is
hypothesized to induce tumor reawakening through the interaction with tumor endothelial
marker 1 (TEM1). The main objective of this study was to assess the MMRN2-TEM1 axis in
reactivation and proliferation of B16F10 melanoma and E0771 breast cancer cells, and
elucidate function of TEM1 in lung metastasis. The MMRN2-TEM1 axis, induced by a coculture system comprised of endothelial cells and tumor cells, has demonstrated to stimulate
phosphorylation of ERK1/2. Individual addition of PDGFB and MMRN2 fragments to dormant
tumor cells caused their reactivation, conceivably through the TEM1-PDGFRB pathway. In
vivo results have shown that absence of TEM1 does not influence primary tumor growth nor
extravasation, but reduces macrometastasis formation in both intravenous and resection models
of lung metastasis. These in vivo results suggest that TEM1 could be implicated in tumor mass
dormancy. Computational models have shown significant correlation of TEM1 and PDGFRB
as a prediction marker of low survival rates and higher relapse in various tumor types.
Therefore, this study presents a pioneering research in defining the MMRN2-TEM1
reactivation axis as a potential target for state-of-the-art, personalized therapies intended for
patients in remission.Ponovnu pojavu tumora uzrokuju dormantne tumorske stanice koje su sposobne reaktivirati se
uslijed promjena u mikrookolišnoj niši. Za endotelni protein multimerin 2 (MMRN2) se
pretpostavlja da inducira nastanak tumora, stupanjem u interakciju s tumorskim endotelnim
markerom 1 (TEM1). Glavni cilj ovoga rada bio je procijeniti ulogu osi MMRN2-TEM1 u
reaktivaciji i proliferaciji stanica melanoma B16F10 i stanica tumora dojke E0771 te razjasniti
funkciju proteina TEM1 u metastaziranju pluća. Pokazano je da os MMRN2-TEM1, inducirana
kokulturom endotelnih stanica i tumorskih stanica, može stimulirati fosforilaciju proteina
ERK1/2. Pojedinačni dodaci proteina PDGFRB i fragmenata MMRN2 dormantnim tumorskim
stanicama uzrokovali su njihovu reaktivaciju, potencijalno signalnim putem TEM1-PDGFRB.
Rezultati in vivo su pokazali da nedostatak proteina TEM1 ne utječe na rast primarnog tumora
ni proces ekstravazacije, ali smanjuje formaciju makrometastaza u intravenoznom i
resekcijskom modelu plućnog metastaziranja. Navedeni rezultati in vivo upućuju na to da
protein TEM1 može biti uključen u regulaciju tumorske mase tijekom dormancije. Računalni
modeli su ukazali na značajnu povezanost proteina TEM1 i proteina PDGFRB kao
predikcijskog markera smanjenog preživljenja i češće ponovne pojave tumora kod brojnih
tipova tumora. Ovaj rad predstavlja inicijalno istraživanje u definiranju reaktivacijske osi
MMRN2-TEM1, kao potencijalne mete suvremenih, personaliziranih terapija namijenjenih
pacijentima u remisiji
Enhancement of Raman scattering on gold nanoparticiples prepared in hepes buffer
No full textIstražena je SERS (spektroskopija površinski pojačanog Ramanova raspršenja) učinkovitost i
stabilnost koloida zlata pripravljenih redukcijom tetraklorozlatne(III) kiseline 4–(2–
hidroksietil)–1–piperazinetilensulfonskom kiselinom (pufer HEPES) pomoću modelnih
molekula rodamina 6G (R6G), (E)-1,2-di(piridin-4-il)etena (BPE) i dinatrijeva fluoresceinata
(Na2Fl). Koloidi su sintetizirani na dva načina: sinteza „bez sjemena“ u kojoj su samo
pomiješani metalna sol i pufer, te sinteza „sa sjemenom“ u koju se dodaje, osim metalne soli i
pufera, i srebrov nitrat. Istražen je i utjecaj dodatka polimera poli(vinil-pirolidona) (PVP) na
stabilnost pripravljenih koloida i pojačanje raspršenja zračenja. U svim koloidima zlata najjače
pojačanje raspršenja nađeno je za molekulu BPE, vrlo vjerojatno zbog njezine neutralnosti i
strukturnih značajki. Modelne molekule s nabojem elektrostatski odbija HEPES koji stabilizira
nanočestice i nalazi se na površini zlata u obliku zwitter iona. Uvođenje stabilizirajućeg
polimera PVP u sustav stvara steričku barijeru i dobiveni spektri modelnih molekula pokazuju
vrlo slabe vrpce. No, takvi modificirani koloidi su najstabilniji kroz vrijeme.The SERS (surface–enhaced Raman scattering) efficiency and stability of gold colloids prepared
by reduction of tetrachloroauric(III) acid with 4-(2-hydroxyethyl)-1-piperazineethylenesulfonic
acid (HEPES buffer) were investigated using rhodamine 6G (R6G), (E)-1,2-di(pyridin-4-yl)ethene
(BPE) and disodium fluoresceinate (Na2Fl). Colloids were synthesized in two ways: the "seedless"
synthesis, in which the metal salt and buffer are mixed, and the "seeded" synthesis, in which, in
addition to the metal salt and buffer, silver nitrate was added. The influence of the poly(vinylpyrrolidone) - PVP addition on the stability of the prepared colloids and the scattering enhancement
were investigated. In all gold colloids, the strongest SERS effect was found for the BPE molecules,
most likely due to its neutrality and structural features. The charged model molecules are
electrostatically repelled by HEPES, which stabilizes the nanoparticles and was located on the gold
surface as zwitter ion. Introduction of the polymer PVP into the system resulted with a steric barrier
and the obtained spectra of the model molecules show very weak bands. However, such modified
colloids are the most stable over time
Synthesis and catalytic potential of molybdenum(VI) complexes with hydrazone ligand obtained from 5-nitrosalicylaldehide and benzhydrazide ; Choosing demonstration for homogenous catalysis
No full textOvaj diplomski rad sastoji se od dvije cjeline: istraživačkog i metodičkog dijela. U istraživačkom dijelu
pripravljen je hidrazonski ligand izveden iz 5-nitrosalicilaldehida i benzhidrazida (H2L). Reakcijom
[MoO2(acac)2] i hidrazonskog liganda (H2L), pripravljeni su kompleksni spojevi molibdena(VI).
Mononuklearni kompleksni spojevi, [MoO2(L)(MeOH)], [MoO2(L)(H2O)], [MoO2(L)(EtOH)],
dobiveni su iz metanolne, acetonitrilne i etanolne otopine, a dinuklearni, [(MoO2(L))2(4,4'-bipiridin)],
iz acetonitrilne otopine uz dodatak 4,4'-bipiridina. Kompleksni spojevi su karakterizirani i identificirani
metodom infracrvene spektroskopije, elementnom i termogravimetrijskom analizom. Difrakcijom
rentgenskog zračenja na jediničnom kristalu određena je molekulska i kristalna struktura
mononuklearnih i dinuklearnog kompleksnog spoja molibdena(VI). Katalitička aktivnost pripravljenog
mononuklearnog spoja [MoO2(L)(MeOH)], ispitana je u reakciji (ep)oksidacije cikloheksena i transcikloheksan-1,2-diola uz vodikov peroksid kao oksidacijsko sredstvo s ciljem dobivanja adipinske
kiseline.
Metodički dio rada usmjeren je na paramatre koji su bitni pri odabiru pokusa koji će biti temelj
nastavnog sata učenja otkrivanjem na temu katalize. Poseban osvrt dan je na pokus koji se desetljećima
u međunarodnoj literaturi navodi kao primjer homogene katalize – na potencijalnu reakciju tartaratnih
iona s molekulama vodikovog peroksida u prisustvu kobaltovih(II) iona. Na temelju detaljne analize
dostupne literature i provedenih pokusa ovu kemijsku promjenu bolje je opisati terminom sparene
reakcije nego je navoditi kao primjer katalitičkog pokusa.This Diploma thesis consists of two parts: the research part and the methodical part. In the research part
a hydrazone ligand derived from 5-nitrosalicyaldehyde and benzhydrazide (H2L) was prepared. By the
reaction of [MoO2(acac)2] and hydrazone ligand (H2L), complexes of molybdenum(VI) were
synthesized. Mononuclear complexes [MoO2(L)(MeOH)], [MoO2(L)(H2O)], [MoO2(L)(EtOH)], were
syntesised from methanol, acetonitrile and ethanol solutions, and dinuclear one, [(MoO2(L))2(4,4'-
bipyridine)], from an acetonitrile solution with the addition of 4,4'-bipyridine. All complexes were
characterized and identified by infrared spectroscopy, element and thermogravimetric analysis. The
molecular and crystal structure of mononuclear and dinuclear molybdenum(VI) complex was
determined by the single crystal X-ray diffraction. Catalytic activity of mononuclear complex
[MoO2(L)(MeOH)], was tested in the (ep)oxidation reaction of cyclohexene and trans-cyclohex-1,2-an
diole, with hydrogen peroxide as an oxidant, with the aim of obtainig apidic acid.
Methodological part of the thesis is focused on parameters that should be addressed when one is
choosing a demonstration experiment that should serve as a basis to design a lesson based on guided
inquiry learning on the subject of catalysis. Special attention is given to the experiment that is for
decades quoted in international literature as an example of homogenous catalysis – potential reaction of
tartarate ions and hydrogen peroxide molecules in presence of cobalt(II) ions. Detailed analysis of
available literature and conducted experiments showed that it would be better to consider this chemical
change as an example of coupled reactions than to use it as demonstration of homogenous catalysis