8,101 research outputs found
Pd/FER vs Pd/SSZ-13 Passive NOx Adsorbers: Adsorbate-controlled Location of Atomically Dispersed Pd(II) in FER Determines High Activity and Stability
No full textPd-loaded FER and SSZ-13 zeolites as
low-temperature passive NOx adsorbers (PNA) are compared under practically relevant
conditions. Vehicle cold-start exposes the material to CO under a range of concentrations,
necessitating a systematic exploration of the effect of CO on the performance
of isolated Pd ions for PNA. NO release temperature of both adsorbers decreases
gradually with the increase of CO concentration from a few hundred to a few
thousand ppm. This beneficial effect results from local nano-“hot spots”
formation during CO oxidation. Dissimilar to Pd/SSZ-13, increasing the CO
concentration above ~1,000 ppm improves the NOx storage significantly for
Pd/FER, attributed to the presence of a Pd ions in FER γ-site that is shielded from NOx. CO mobilizes
this Pd atom to the NOx accessible position where it becomes active
for PNA. This behavior explains the very high resistance of Pd/FER to
hydrothermal aging: Pd/FER materials survive hydrothermal aging at 800⁰C in 10% H2O
vapor for 16 hours with no deterioration in NOx uptake/release behavior. Thus,
by allocating Pd ions to the specific microporous pockets in FER, we have
produced very hydrothermally stable and active PNA materials with immediate practical
applications.</p
Implications of the Improvement of Teaching Quality for Professional Development (PD) of Academics at the Colleges of Applied Sciences (CASs) in the Sultanate of Oman
No full textThe Oman Accreditation Council (OAC), which is called later the Oman Academic Accreditation Authority (OAAA), designed a higher education institution (HEI) Quality Assurance (QA) framework for Omani public and private Higher Education Institutions (HEIs), starting with a quality audit process in 2008. The Colleges of Applied Sciences (CASs), as a public HEI, are required to ensure the quality of all services and activities to meet particular national standards (specified in the framework) in order to gain a HEI and programme certificate. In line with a quality audit scope, the quality of the fields of PD and related teaching quality should be ensured and enhanced by the promotion and contribution of the former field to the maintenance and improvement of the latter one.
The chief purpose of this study was to identify the uptake and implications of the growing requirement to improve teaching quality and the PD of academics at the CASs in the Sultanate of Oman especially in the context of the application of the QA framework. The study focused on examining the academics’ participation in professional development programmes (PDPs) and current perceptions of PD with respect to the improvement of teaching quality improvement at these colleges. The current study also dealt with a reorganization and prioritization of academics’ PD needs, barriers to effective PD, and factors to enhance PD of academics regarding teaching quality improvement in the colleges.
Based on the purpose and research objectives, the current study adopted both positivist (quantitative) and interpretive (qualitative) research paradigms. Because the study perused quantitative and qualitative data regarding certain variables, it chose a mixed-research design. The researcher designed survey questionnaire to collect quantitative data and a semi-structured interview and a focus group discussion to probe and interpret quantitative findings. After fulfillment of the validity and reliability measurements, a self-completion questionnaire was distributed to a stratified random sample of academics (170) over the six CASs. A total of 150 questionnaires (out of 170) were completed and returned and the response-rate reached 88.2%. The quantitative data was analyzed by appropriate analysis using the Statistical Package for Social sciences (SPSS), while the qualitative data was analyzed by appropriate qualitative analysis.
The findings of the study showed that the level of academics’ participation in PDPs to improve teaching quality in the last two years in the CASs seems to be unsatisfactorily low. The current perceptions of the PD situations in the colleges, relating to teaching quality improvement, signified a shortage in the number of available PDPs and/or a discouragement of academics’ participation in these programmes in the last two years. The study also revealed all the 22 PD needs of academics regarding the improvement of teaching quality are significantly demanded by participants; the higher rated needs focused on a development of ‘student centred’ skills, such as critical thinking and problem-solving skills.
Furthermore, the study illustrated that the highest significant perceived barriers to effective PD in the CASs, as related to teaching quality improvement, focus on a lack of a clear institutional PD policy and a lack of appropriately systematic PD plans. The study also revealed all 10 perceived factors to enhance PD regarding teaching quality improvement are very important. The most significant factors represented and stressed particular problematic issues (the high rated barriers) and a reduction of a heavy workload to enhance academics’ participation in PD regarding the improvement of teaching quality.
Conclusions drawn from the discussion of the findings of study include a lack of a clear PD policy at national and institutional levels and absence of a particular authority/unit concerning PD issues in Omani HEIs. The two problematic issues resulted in a lack of systematic and realistic PD plans in the CASs, involving a lack of academics’ involvement in PD plans, a misconnection of academics’ PD needs to PD, inappropriate facilities and resources allocation, and inappropriate evaluation processes of PD. In addition, the conclusions also include that PD of academics regarding the improvement of teaching quality in the colleges requires more attention and focus to manage particular significant issues perceived by participants as both barriers and potential facilitators relating to PD of academics.
Based on identified conclusions, particular implications for policy and practice to enhance PD to improve teaching quality were set at three levels: governmental, institutional, and individual. Moreover, achievements of the current study according to the research questions were identified and contributions of the study to the fields of PD, teaching quality, and the context of QA and quality audit in HE were addressed. Based on the findings and conclusions, particular directions and recommended issues were suggested to be studied by further research to benefit the enhancement of PD and related teaching quality improvement
Fullerene-like WS<sub>2</sub> supported Pd catalyst for hydrogen evolution reaction
No full textHydrogen is the most desirable green energy carrier and electrocatalytic hydrogen evolution reaction (HER) from water is a promising route for hydrogen production. The search for efficient, low-cost HER catalysts is a challenging and attracting topic. In this work, we report that inorganic fullerene-like WS2 supported Pd nanoparticles (Pd/WS2), with Pd loading of 0.76 wt%, are active for electrocatalytic HER conducted in 0.5 M H2SO4 solution, with overpotential at 10 mA cm−2 current density of ~130 mV and Tafel slope of 82.4 mV dec−1, which is comparable to that of Pt/WS2 (0.88 wt% Pt loading) with higher costs. Characteristic results indicate that WO3 impurities were in-situ produced on the WS2 surface and the Pd NPs are primarily located inside the WS2 nanocages. Contrasting experiments suggest that the WO3 impurities play a crucial role in generating Hads intermediate and the Pd NPs are active sites of H2 production, and a reaction mechanism is proposed. The Pd/WS2 catalyst also shows good long-term stability owing to the location of Pd NPs inside the WS2 cages. The high HER activity, low costs and good stability make the Pd catalyst a potential alternative to Pt catalyst for HER.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Micro and Nano Engineerin
PA-Tran: Learning to Estimate 3D Hand Pose with Partial Annotation
No full textThis paper tackles a novel and challenging problem—3D hand pose estimation (HPE) from a single RGB image using partial annotation. Most HPE methods ignore the fact that the keypoints could be partially visible (e.g., under occlusions). In contrast, we propose a deep-learning framework, PA-Tran, that jointly estimates the keypoints status and 3D hand pose from a single RGB image with two dependent branches. The regression branch consists of a Transformer encoder which is trained to predict a set of target keypoints, given an input set of status, position, and visual features embedding from a convolutional neural network (CNN); the classification branch adopts a CNN for estimating the keypoints status. One key idea of PA-Tran is a selective mask training (SMT) objective that uses a binary encoding scheme to represent the status of the keypoints as observed or unobserved during training. In addition, by explicitly encoding the label status (observed/unobserved), the proposed PA-Tran can efficiently handle the condition when only partial annotation is available. Investigating the annotation percentage ranging from 50–100%, we show that training with partial annotation is more efficient (e.g., achieving the best 6.0 PA-MPJPE when using about 85% annotations). Moreover, we provide two new datasets. APDM-Hand, is for synthetic hands with APDM sensor accessories, which is designed for a specific hand task. PD-APDM-Hand, is a real hand dataset collected from Parkinson’s Disease (PD) patients with partial annotation. The proposed PA-Tran can achieve higher estimation accuracy when evaluated on both proposed datasets and a more general hand dataset
Synthesis, characterization, and reactivity of high and low valent group 10 metal complexes supported by pyridine dithiolate ligands
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-08-01The student, Giang Tran, accepted the attached license on 2021-06-24 at 22:43.The student, Giang Tran, submitted this Dissertation for approval on 2021-06-25 at 10:30.This Dissertation was approved for publication on 2021-06-29 at 09:01.Group 10 transition metals, especially palladium (Pd) and nickel (Ni), play an important role serving as catalysts for different transformations with a wide range of applications. However, beside the most commonly proposed M(0)/M(II) (M = Pd or Ni) catalytic cycles, there is still a limited understanding of the mechanisms that involve other less common key intermediates. Recent works have shown substantial evidence of the role of high valent M(III) and M(IV) species in catalytic organic transformations. Inspired by these new findings, our goal is to investigate the rarer oxidation states of these metal complexes to gain better insights into the different mechanisms. This study can potentially serve as a tool to design more efficient catalysts. Herein, we’ll discuss the +1 and +3 oxidation states of these metal centers, with a heavy focus on the low valent species.
A series of dithiolate pyridinophane ligands were employed in these studies. With the presence of S atoms as the soft atom donor, we propose that these ligands can allow us to stabilize MI species based on the Hard Soft Acid Base theory. In our first study, we attempted to isolate Pd(I) intermediates with our multidentate ligands. To further enhance the stabilizing effect, we also incorporated ancillary ligands with soft P atoms. To our delight, two monomeric Pd(I) complexes – [(N2S2)Pd(I)(PtBu3)]+ and [(NCHS2)Pd(I)(PtBu3)]+ – were structurally characterized, and both of them showed superior catalytic reactivity for the Csp2-Csp3 Kumada cross-coupling reaction vs. their Pd(0) or Pd(II) analogs.
These sulfur-based ligands were also employed to design different bioinspired Ni electrocatalysts for the study of electrochemical hydrogen evolution reaction (HER) in a non-aqueous electrolyte. These complexes are able to achieve stable catalytic currents with high turnover numbers for proton reduction, even at low acid concentration. Additionally, in contrast to the Ni(0)/Ni(II) process employed by most other reported Ni-based HER catalysts, one of our Ni species – [(NCHS2)NiOTf2 – is proposed to go through a Ni(I)/Ni(III) HER mechanism, which is similar to the natural process in [NiFe] hydrogenases. Extensive electrochemical experiments and EPR (Electron Paramagnetic Resonance) spectroscopic studies were carried out to provide evidence for the alternate Ni(I)/Ni(III) catalytic cycle.
Lastly, preliminary results also showed that the multidentate pyridine dithiolate ligands can support organometallic Pd(III) species. Excitingly, the solid state structure of complex [(NCS2)Pd(III)(PPh3)]2+ was obtained, which showed a rare four-coordinate geometry at a Pd(III) center. Prior to this, no monomeric Pd(III) complex supported by S-based ligand(s) was structurally characterized. This is an important finding as it is uncommon for a ligand system to be able to stabilize both low and high valent metal species.DSpace SAF Submission Ingestion Package generated from Vireo submission #16720 on 2022-01-12 at 13:03:41Made available in DSpace on 2022-01-12T22:51:41Z (GMT). No. of bitstreams: 3
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Studies of clinically applicable human tolerogenic dendritic cells and PD-L2 genetic modification of human islet allograft to promote graft tolerance.
No full textIslet transplantation is a developing therapy for type 1 diabetic patients (T1D), which has been limited by problems associated with hypoxia, poor revascularisation and allograft rejection. Immunosuppressive agents used to prevent rejection are associated with severe side effects including islet toxicity, increased susceptibility to the development of cancer, infections and cardio-vascular problems. In order for islet transplantation to be used widely as a potentially curative treatment for T1D there is a need to develop novel therapies to treat allograft rejection without the use of immunosuppressive agents. In chapter 3, the immunomodulatory effects of IFN-γ on human monocyte-derived DC were investigated, using a standard 7-day in vitro DC propagation protocol. IFN-γ was shown to exert its immunomodulatory function on monocytes early during DC differentiation (IFNγ-DC[subscript]D0), resulting in an immature DC (iDC) phenotype with reduced expression of maturation markers CD83 and RelB. IFNγ-DC[subscript]D0 induced a state of T-cell hyporesponsiveness in a MLR, whilst IFN-γ treatment at day 5 (IFNγ-DC[subscript]D5) did not modulate DC function. The ability of IFN-γ to promote the generation of maturation arrested DC, could potentially serve as a cellular therapy for transplant rejection. However DC propagation using the standard 7-10 day protocol is not clinically applicable in the islet transplant setting. In chapter 4, a 'FAST-DC' protocol to promote the rapid generation of tolerogenic DC was investigated and used to generate IFNγ modulated DC in 48h. These IFNγ-DC featured an iDC phenotype similar to that seen in chapter 3. Maturation arrested IFNγ-DC caused significant T-cell hyporesponsiveness and promoted a higher frequency of CD4+CD25+ Foxp3[superscript]HI T-regulatory cells. IFNγ-DC primed T-cells were shown to be functionally suppressive in an antigen specific manner. It was also confirmed that IFN-γ reduced the phosphorylation of IL-4 activated STAT-6, which in turn affected the downstream gene expression of Interferon regulatory factor 4 (IRF4). IFNγ-DC were also investigated in vivo, where a humanised model of islet allo-transplantation model was developed. Diabetic NOD-SCID mice were transplanted with human islets and challenged with donor-derived DC and allogeneic PBMNC. After 21 days post transplantation, there was no significant change to euglycaemic state, between the tested groups. Genetic modification of the allograft is an alternative therapy to protecting the graft from the recipient‟s immune system. In chapter 5, human islets were genetically modified with programmed cell death ligand 2 (PD-L2), an inhibitory molecule known inhibit T-cell immune responses. Two recombinant adenovirus constructs carrying the PD-L2 gene were generated. One construct encoded a soluble isoform, while the other expressed a full transmembrane PD-L2 molecule. Adenoviral transduction did not affect the viability or insulin producing capacity of islets. Interestingly, soluble PD-L2 was more efficient at inducing signalling by 1000 fold, compared to the transmembrane isoform. In summary, this thesis demonstrated the timing of IFN-γ exposure is crucial in determining the function of DC and their maturational state, where IFN-γ exposure only during DC differentiation resulted in the inhibition of DC maturation. Secondly, the combination of IFN-γ and a FAST-DC protocol, enabled the generation of tolerogenic DC in 48h, making DC therapy more clinically applicable. Finally, the induced expression of soluble PD-L2 by human islets potently signals through human PD-1, which may provide the basis for the protection of islets from allo- and auto T-cell responses.Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 201
Enhanced T-Cell Immunity to Osteosarcoma Through Antibody Blockade of PD-1/PD-L1 Interactions
No full textabstract: Osteosarcoma is the most common bone cancer in children and adolescents. Although 70% of patients with localized disease are cured with chemotherapy and surgical resection, patients with metastatic osteosarcoma are typically refractory to treatment. Numerous lines of evidence suggest that cytotoxic T lymphocytes (CTLs) limit the development of metastatic osteosarcoma. We have investigated the role of PD-1, an inhibitory TNFR family protein expressed on CTLs, in limiting the efficacy of immune-mediated control of metastatic osteosarcoma. We show that human metastatic, but not primary, osteosarcoma tumors express a ligand for PD-1 (PD-L1) and that tumor-infiltrating CTLs express PD-1, suggesting this pathway may limit CTLs control of metastatic osteosarcoma in patients. PD-L1 is also expressed on the K7M2 osteosarcoma tumor cell line that establishes metastases in mice, and PD-1 is expressed on tumor-infiltrating CTLs during disease progression. Blockade of PD-1/PD-L1 interactions dramatically improves the function of osteosarcoma-reactive CTLs in vitro and in vivo, and results in decreased tumor burden and increased survival in the K7M2 mouse model of metastatic osteosarcoma. Our results suggest that blockade of PD-1/PD-L1 interactions in patients with metastatic osteosarcoma should be pursued as a therapeutic strategy.This is a non-final version of an article published in final form as Lussier, Danielle M., O'Neill, Lauren, Nieves, Lizbeth M., McAfee, Megan S., Holechek, Susan A., Collins, Andrea W., Dickman, Paul, Jacobsen, Jeffrey, Hingorani, Pooja, & Blattman, Joseph N. (2015). Enhanced T-Cell Immunity to Osteosarcoma Through Antibody Blockade of PD-1/PD-L1 Interactions. JOURNAL OF IMMUNOTHERAPY, 38(3), 96-106. http://dx.doi.org/10.1097/CJI.000000000000006
Modeling of Surface Segregation for Binary Alloys in Vacuum and Gas Environments: Applied to Pd-alloys
No full textComputational modeling offers the possibility to design alloys in a cheaper and faster way. A model for surface segregation for binary alloys in vacuum and by adsorption and absorption of gases was developed and applied. The proposed model was used in conjunction with the Miedema semi-empirical model for the calculation of enthalpies of solution and formation of binary alloys and with the cluster variation method (CVM) for the calculation of the ? and ? phase boundaries in the ternary Pd-M-H systems. The models for segregation were applied in a temperature range from 298K to 600K, considering the surface plane (111) of the FCC crystal structure. The model for segregation in vacuum was applied to Pd-Au, Pd-Ag, Pd-Cu, Pd-Ni and Pd-Pt. For this case Pd is segregated for the Pd-Pt alloys only. By increasing the temperature from 298K to 600K, the surface concentrations of Pd decreased for all of the alloys. By varying the plane from (111) to (100) few changes were observed. The calculated results compared to experiments were found to be in good agreement for Pd-Au and Pd-Ag. For the model of surface segregation by adsorption and chemisorption, H2, CO and O2 gases on Pd-Ag, Pd-Cu, Pd-Ni and Pd-Pt were considered. In the presence of adsorbed or chemisorbed hydrogen, segregation of Pd was found for Pd-Ag, Pd-Cu and Pd-Pt alloys. For adsorbed O2 and CO on Pd-Ag and Pd-Cu alloys gases, segregation of Pd was enhanced. The model for segregation by absorption of hydrogen was applied for Pd-Ag, Pd-Cu, Pd-Ni and Pd-Pt alloys, using a hydrogen (bulk) concentration of 0.50 H/M. No Pd segregation was found for Pd-Ag alloys. For Pd-Pt alloys, Pd segregation was observed. For Pd-Cu alloys with large concentrations of Pd, a surface enrichment of Pd was calculated, while for alloys with low concentration of Pd a slight Cu surface enrichment was observed. Enhanced segregation of Ni was found for Pd-Ni alloys. The H/M fractions at the boundaries of the ? and ? phase obtained with the CVM for the Pd85Ag15H system were used as input values to calculate the surface concentration of Ag. As the hydrogen concentration was increased, the surface segregation of Pd also increased. For the surface segregation by adsorption and absorption combined, segregation of Pd was observed for Pd-Ag, Pd-Cu and Pd-Pt alloys. Surface enrichment of Ni was found for Pd-Ni alloys. The proposed model enables to predict surface segregation under various conditions and the results show that it is affected by many parameters.Master Materials Science and EngineeringDepartment of Materials Science and EngineeringMechanical, Maritime and Materials Engineerin
Mapping Ambiphile Reactivity Trends in the Anti-(Hetero)annulation of Non-Conjugated Alkenes via Pd(II)/Pd(IV) Catalysis
No full textIn this study, we systematically evaluate different ambiphilic organohalides for their ability to participate in anti-selective carbo- or heteroannulation with non-conjugated alkenyl amides under Pd catalysis. Detailed optimization of reaction conditions has led to protocols for synthesizing tetrahydropyridines, tetralins, pyrrolidines, and other carbo/heterocyclic cores via [n+2] (n = 3–5) (hetero)annulation. Expansion of scope to otherwise unreactive ambiphilic haloketones through Pd(II)/amine co-catalysis is also demonstrated. Compared to other annulation processes, this method proceeds via a distinct Pd(II)/Pd(IV) mechanism involving Wacker-type directed nucleopalladation. This distinction results in unique reactivity and selectivity patterns, as revealed through assessment of reaction scope and competition experiments
Nanocatalisadores metálicos de paládio e prata estabilizados com novos líquidos iônicos piridínicos para aplicação em reações de Heck e redução
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2015.Este trabalho foi dividido em: (i) síntese de novos líquidos iônicos (LIs) piridínicos para utilização na estabilização de nanopartículas de prata (Ag-NPs) para aplicação na reação de redução do p-nitrofenol (NIP) e (ii) a introdução da ciclização do N-(o-iodobenzoil)-3-metilindol (MIAc), como modelo de reação de Heck para avaliação in situ, por espectroscopia UV-visível (UV-vis), da atividade de catalisadores a base de paládio molecular ou coloidal. Nove LIs foram sintetizados variando-se a cadeia alquílica ligada ao nitrogênio piridínico (metil, butil e octil) e contra-íons (haletos, tetrafluoroborato (BF4) e bis(trifluorometilsulfonil)imidato (NTf2)) e utilizados na estabilização de Ag-NPs. Para comparar os nove sistemas Ag-NPs/LI, verificou-se sua atividade catalítica na reação de redução do NIP, cujo progresso é facilmente monitorado por UV-vis. Todos os nanocatalisadores apresentaram atividade na redução do NIP sendo que, em geral, as maiores constantes de velocidade foram obtidas quando LIs metilados foram utilizados como estabilizante. Na reação de ciclização do MIAc, três sistemas catalíticos foram testados: nanopartículas de paládio (Pd-NPs/LI-Me(I)) pré-formadas e estabilizadas pelo LI N-metilpiridínico (LI-Me(I)); Pd(OAc)2 e Pd(OAc)2 com adição de LI-Me(I) (Pd(OAc)2/LI-Me(I)). Diversos experimentos foram realizados como variação da quantidade do catalisador, da concentração e natureza da base, do solvente e do LI, além de análises por microscopia eletrônica de transmissão (TEM) em diferentes tempos de reação e envenenamento com Hg. Após essa série de experimentos, pode-se dizer que a ciclização do MIAc foi introduzida com êxito como modelo de reação de Heck uma vez que seu progresso foi acompanhado in situ por UV-vis facilitando a realização de diversos experimentos para obtenção dos parâmetros cinéticos TON (mol de catalisador/mol de produto) e TOF (TON/tempo), com os quais comparou-se a atividade e aplicabilidade de sistemas catalíticos a base de paládio. Além disso, demonstrou ser uma reação relativamente branda ocorrendo em meio aquoso, na ausência de atmosfera inerte e a 80 ºC. O sistema Pd(OAc)2/LI-Me(I), com 1x10-3 mmol L-1 de LI-Me(I), resultou nos maiores parâmetros TON e TOF e maior conversão ao produto de ciclização.Abstract : The present work is divided in: (i) synthesis of new pyridinium ionic liquids (LIs) to use as stabilizing agents of silver nanoparticles (Ag-NPs), whose application was the reduction reaction of p-nitrophenol (NIP) and (ii) the introdution of (2-iodophenyl)(3-methyl-1H-indol-1-yl)methanone (MIAc) ciclization as a model reaction, for the in situ evaluation by UV-vis Spectroscopy (UV-vis) of Pd catalysts based on molecular or colloidal palladium. Nine LIs were synthesized modifying the alkyl chain bounded to the pyridine nitrogen (methyl, butyl and octyl) and the counteranion (halides, tetrafluoroborate (BF4-) and bis(trifluoromethylsulfonyl)imidate (NTf2-)). To compare the nine Ag-NPs/LI systems, their catalytic activity was evaluated in the NIP reduction reaction, whose progress can be easily monitored by UV-vis. All Ag-NPs/LI catalyst showed a good catalytic activity for the NIP reduction but, in general, the highest rate constants were obtained with methylic LIs. For the MIAc ciclization, three catalytic systems were evaluated: as-formed palladium nanoparticles (Pd-NPs/LI-Me(I)) stabilized by N-methylpyridinic LI, Pd(OAc)2, and Pd(OAc)2 with LI-Me(I) addition (Pd(OAc)2/LI-Me(I)). A series of experiments was carried out including varying the amount of catalyst, the concentration and nature of the base, solvent, and LI, analysis by transmission electronic microscopy (TEM) at different times of the reaction and poisoning tests with Hg. After this series of experiments, it can be said that the cyclization of MIAc was successfully introduced as a model for Heck reaction since its progress was easily monitored in situ by UV-vis, facilitating the implementation of several experiments and obtaining the kinetic parameters TON (mol of product/mol of catalyst) and TOF (TON/time), in which the activity and applicability of the catalytic systems could be compared. Furthermore, the reaction was carried out at relatively mild conditions once it occurs in aqueous medium, in the absence of inert atmosphere, and at 80 ° C. The Pd(OAc)2/LI-Me(I) system with 1x10-3 mmol L-1 of LI-Me(I) resulted in both, highest kinetic parameters TON and TOF and ciclization product conversion
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