Synthesis, structure and reactivity of Pd and Ir complexes based on new lutidine-derived NHC/phosphine mixed pincer ligands

Coordination studies of new lutidine-derived hybrid NHC/phosphine ligands (CNP) to Pd and Ir have been performed. Treatment of the square-planar [Pd(CNP)Cl](AgCl2) complex 2a with KHMDS produces the selective deprotonation at the CH2P arm of the pincer to yield the pyridine-dearomatised complex 3a. A series of cationic [Ir(CNP)(cod)]+ complexes 4 has been prepared by reaction of the imidazolium salts 1 with Ir(acac)(cod). These derivatives exhibit in the solid state, and in solution, a distorted trigonal bipyramidal structure in which the CNP ligands adopt an unusual C(axial)–N(equatorial)–P(equatorial) coordination mode. Reactions of complexes 4 with CO and H2 yield the carbonyl species 5a(Cl) and 6a(Cl), and the dihydrido derivatives 7, respectively. Furthermore, upon reaction of complex 4b(Br) with base, selective deprotonation at the methylene CH2P arms is observed. The, thus formed, deprotonated Ir complex 8b reacts with H2 in a ligand-assisted process leading to the trihydrido complex 9b, which can also be obtained by reaction of 7b(Cl) with H2 in the presence of KOtBu. Finally, the catalytic activity of Ir–CNP complexes in the hydrogenation of ketones has been briefly assessed.CTQ2013-45011-P, CTQ2016-80814-R and CTQ2014 -51912-RE

Reduction of N2O with hydrosilanes catalysed by RuSNS nanoparticles

A series of RuSNS nanoparticles, prepared by decomposition of Ru(COD)(COT) with H2 in the presence of an SNS ligand, have been found to catalyse the reduction of the greenhouse gas N2O to N2 employing different hydrosilanes.Agencia Estatal de Investigación ID2019-104159GB-I00, MCIN/AEI/10.13039/50110001103Junta de Andalucía P18-FR-3208, US-1380604Consejo Superior de Investigaciones Científicas COOPB20604Universidad de Cádiz E-11-2019-013324

Hydrogenation of an iridium-coordinated imidazol-2-ylidene ligand fragment

An iridium complex featuring a metalated lutidine-derived CNP ligand reacts with KOt Bu to yield a dimeric species with the two metal centers bound to the opposite ligands through the CHN arms. Furthermore, reaction with H2 in the presence of KOt Bu of the same iridium derivative results in the hydrogenation of the –CHQCH– imidazolylidene moiety of the complex. NMR spectroscopy monitoring of the latter reaction supports the initial formation of a dihydride iridium complex containing an imidazolylidene ligand fragment that is hydrogenated after prolonged reaction time.Ministerio de Economía y Competitividad de España (MINECO) y fondos FEDER de la Unión Europea-CTQ2015-69568-P, CTQ2016-80814-R y CTQ2016- 81797-RED

Reactivity of TpMe2-containing hydride-iridafurans with alkenes, alkynes, and H2

The TpMe2-containing hydride-iridafurans 2a,b (TpMe2 = hydrotris(3,5-dimethylpyrazolyl)borate) cleanly reacted with ethylene to give the bicyclic derivatives 6a,b. Formation of the latter complexes is a reversible process, and it is proposed to occur by an electrocyclic ring closure that takes place between C2H4 and the 16e unsaturated intermediates A, resulting from hydride migration to the α carbon of the metallacycle. Similar reactions were observed with a variety of alkynes RC≡CR (R = H, Ph, CO2Me) and R′C≡CH (R′= CO2Me, Ph, CMe3), with the regioselectivity observed for the latter substrates depending on the nature of R′. In the case of Me3SiC≡CH the structure of an unexpected byproduct indicates that an alkyne–vinylidene rearrangement has taken place on the metal coordination sphere during the reaction, and this observation suggests that in the mechanism of all these coupling processes the corresponding π adducts are active intermediates. Finally, complexes 2a,b reacted with H2 to give products derived from the hydrogenation of their alkenyl arms.Ministerio de Ciencia e Innovación CTQ2010-17476. Consolider Ingenio 2010 CSD 2007-0006Junta de Andalucía FQM-119, P09-FQM-483

Neto-bruto-neto conversion of income

Bakalaura darbā apskatīti galvenie jautājumi, kā veicama dažādu ienākumu veidu neto-bruto-neto transformācija. Šādi pārveidojumi ir svarīgi darba pamatā aplūkotajam EU-SILC pētījumam ar mērķi iegūt salīdzināmu statistisku par visu Eiropas Savienības dalībvalstu ienākumiem un sociālajām programmām. Izmēģinājuma projekts parādīja, ka vietējo institūciju dati nav EU-SILC vajadzīgajā formātā un pastāv neskaidrības saistībā ar vietējo likumdošanu. Tāpēc tiek analizēti normatīvie akti, kas regulē ienākumu taksācijas kārtību. Bakalaura darba mērķis ir salīdzināt bruto/neto ienākumus no vietējām institūcijām un EU-SILC aptaujas. Analīze ļauj noskaidrot, vai starp dažādu avotu sniegto informāciju ir pietiekami liela korelācija, lai turpmākajos pētījumos par iedzīvotāju materiālo stāvokli varētu veikt datu imputāciju, balstoties uz iegūtajiem rezultātiem.In the diploma paper main questions of how various income net-gross-net conversions should be done are discussed, which is significant to EU-SILC, the basic research of the paper, in order to get comparable statistics of income and social programs for all European Union countries. The test project demonstrated that data from local institutions is not in a format required by EU-SILC and there exists indetermination in local legislation. Therefore normative acts, which are subject to tax system, are analyzed. The goal of this diploma paper is to compare local institutions' gross/net income to EU-SILC questionnaire. The analysis clarifies whether the correlation between data coming from various sources is sufficient in order to use data input based on achieved results in further researches about material conditions of people

Alkane Metathesis over Immobilized Pincer-ligated Iridium Complexes: Effect of Support Nature

In this work, catalytic alkane metathesis has been evaluated as a suitable approach to upcycle hydrocarbons (polyolefins) at moderate temperatures. To this end, a pincer-ligated iridium complex (dehydrogenation catalyst) has been combined with a rhenium-based (metathesis) catalyst, being the effect of immobilizing the Ir complex over different supports deeply investigated. FTIR spectroscopy has been used to confirm the complex grafting and to elucidate the anchoring site to the support. Additionally, the supports have been dehydroxylated at different conditions to evaluate its possible impact in both the complex grafting and the catalytic activity. The influence of the support nature and its participation in the catalytic reaction have been clearly evidenced.European Union (UE). H2020 101022598Agencia Estatal de Investigación PID2019–104159GB-I00, TED2021-129181B-I00Junta de Andalucía US-1380604Consejo Superior de Investigaciones Científicas COOPB2060

Ruthenium Nanoparticles Stabilized by 1,2,3-Triazolylidene Ligands in the Hydrogen Isotope Exchange of E-H Bonds (E = B, Si, Ge, Sn) Using Deuterium Gas

A series of ruthenium nanoparticles (Ru·MIC) stabilized with different mesoionic 1,2,3-triazolylidene (MIC) ligands were prepared by decomposition of the Ru(COD)(COT) (COD = 1,5-cyclooctadiene; COT = 1,3,5-cyclooctatriene) precursor with H2 (3 bar) in the presence of substoichiometric amounts of the stabilizer (0.1-0.2 equiv.). Small and monodisperse nanoparticles exhibiting mean sizes between 1.1 and 1.2 nm were obtained, whose characterization was carried out by means of transmission electron microscopy (TEM), including high resolution TEM (HRTEM), inductively coupled plasma (ICP) analysis and X-ray photoelectron spectroscopy (XPS). In particular, XPS measurements confirmed the presence of MIC ligands on the surfaces of the nanoparticles. The Ru·MIC nanoparticles were used in the isotopic H/D exchange of different hydrosilanes, hydroboranes, hydrogermananes and hydrostannanes using deuterium gas under mild conditions (1.0 mol% Ru, 1 bar D2, 55 °C). Selective labelling of the E-H (E = B, Si, Ge, Sn) bond in these derivatives, with high levels of deuterium incorporation, was observed.Agencia Estatal de Investigación PID2019-104159GB-I00Junta de Andalucía P18-FR-3208, US-1380604, EMC21_00427Universidad de Sevilla USE-22972-

Functionalization of 3-Iridacyclopentenes

Members of a series of iridacyclopentenes of composition [TpMe2Ir(k2-C,C-CH2CR′=CRCH2)(CO)] (TpMe2=hydrotris(3,5-dimethylpyrazolyl)borate; R=R′=H, 1; R=Me, R′=H, 2; R=R′=Me, 3) have been subjected to common organic chemistry procedures for hydrogenation, cyclopropanation, epoxidation, water addition through hydroboration, cis-dihydroxylation, and ozonolysis. The stability of metallacycles 1–3, imparted by the presence of the co-ligands TpMe2 and CO, directs the reactivity towards the C=C double bonds, and furthermore the stereochemistry of the products formed is strongly dictated by the steric demands of the TpMe2 ligand. While the products obtained in some of the above-mentioned reactions are the expected ones from an organic chemistry point of view, in other cases the results differ from the outcomes of similar reactions carried out with the all-carbon counterparts.Peer reviewe

Selective hydrodeoxygenation of levulinic acid to γ-valerolactone over Ru supported on functionalized carbon nanofibers

In this work, carbon nanofibers (CNFs) have been successfully functionalized by using different approaches and finally used for the preparation of Ru based catalysts. The organometallic approach has been demonstrated to be suitable for CNF functionalization, leading to well-defined Ru NPs (by adding organosilane, amino or mercapto functionalities, among others) in comparison with mineral acid treatments conventionally used to activate and/or functionalize carbonaceous solids. All catalysts have been tested in levulinic acid hydrodeoxygenation to γ-valerolactone under mild conditions, with the impact of CNF functionalization on the catalysts' performance fully discussed in comparison with unmodified commercial CNFs