Sara Realista

• PhD
• PhD Student at University of Lisbon

The photoreduction of CO2 offers a sustainable route for mitigating atmospheric CO2 levels while producing added‐value chemicals. This study explores the use of Ni(II) and Co(II) octaazacryptand complexes as catalysts in the presence of different ionic liquids under blue LED and solar light conditions. By employing a systematic approach to vary ion...

Scanning tunneling microscope data from a dinuclear Co(II) complex adsorbed on Au(111) are analysed using density functional theory calculations. We find that the interaction with the substrate substantially changes the geometry of the non-planar molecule. Its electronic states, however, remain fairly similar to those calculated for a gas-phase mol...

Metal-organic frameworks are materials which are constituted by an inorganic centre and organic ligand offering high crystallinity, high surface area and high permanent porosity. These structures show promising results in multiple applications due to their properties, especially their capacity for open-metal sites. The use of these structures for e...

Continuous advancements in understanding and controlling surface functionalisation and properties empower materials scientists to design materials with tailored characteristics, improved performance, and enhanced functionality, thereby expanding scientific knowledge and technological progress. This research paper presents the synthesis of two new m...

The photocatalytic efficacy of a novel mononuclear rhenium(I) complex in CO2 reduction is remarkable, with a turnover number (TONCO) of 1517 in three hours, significantly outperforming previous Re(I) catalysts. This complex, synthesized via a substitution reaction on an aromatic ring to form a bromo-bipyridine derivative, L1 = 2-Bromo-6-(1H-pyrazol...

Continuous advancements in understanding and controlling surface functionalisation and properties empower materials scientists to design materials with tailored characteristics, improved performance, and enhanced functionality, thereby expanding scientific knowledge and technological progress. This research paper presents the synthesis of two new m...

The magnetic properties of transition-metal ions are generally described by the atomic spins of the ions and their exchange coupling. The orbital moment, usually largely quenched due the ligand field, is then seen as a perturbation. In such a scheme, S = 1/2 ions are predicted to be isotropic. We investigate a Co(II) complex with two antiferromagne...

Cyclic voltammetry and bulk electrolysis showed that [Ni(II)(salphen)] [1] , [Ni(II)( t Bu-salphen)] [2] , and a binuclear Ni(II) compound combining salphen and t Bu-salphen [3] react with CO 2 to yield a metal-carbonyl species that...

Manganese catalysis has attracted significant attention in the last few years. In comparison with the extensively studied Mn complexes bearing phosphine‐based pincer ligands, catalysis with Mn containing N‐heterocyclic carbenes (NHC) is poorly developed. In this work, new manganese(I) complexes bearing an NHC ligand with picolyl wingtip substituent...

The use of N‐heterocyclic carbenes (NHCs) in manganese and rhenium catalysis is underdeveloped in comparison to other transition metals. Herein, we cover the recent and stimulating progress in homogeneous catalysis using Mn‐NHC complexes, namely in hydrosilylation, hydrogenation, and borrowing hydrogen processes. Of particular interest is the appli...

A series of new fac-[Mn(L)(CO)3Br] complexes where L is a bidentate chelating ligand containing mixed mesoionic triazolylidene-pyridine (MIC^py, 1), triazolylidene-triazole (MIC^trz, 2), and triazole-pyridine (trz^py, 3) ligands have been prepared and fully characterized, including the single crystal X-ray diffraction studies of 1 and 2. The abilit...

New manganese complexes bearing di-triazolylidene (di-trz) ligands are described. Depending on the wingtip substituents of the triazolylidene ligand and the synthetic procedure, two different ligand coordination modes were observed, i.e, bridging and chelating. A series of Mn(i) complexes of the general type fac-[Mn(di-trzR)(CO)3Br] (R = Me, Et, Me...

Reproducible materials that have detection properties towards a certain molecule are very important for applications in the fabrication of devices. Among all the substrates that are used, highly oriented pyrolytic graphite allows to clearly image a monolayer. On the other hand, cryptand molecules are versatile because they can sense certain analyte...

This chapter describes the chemistry of manganese, technetium, and rhenium complexes featuring N-heterocyclic carbene ligands (NHCs), including imidazolium derived NHCs and mesoionic carbenes. It provides a detailed account of the Group 7 NHC complexes that have appeared in the literature from 2006 to 2020. The review focus exclusively in the synth...

The reaction of coordinatively unsaturated Co(II) PCP pincer complexes with nitric oxide leads to the formation of new, air-stable, diamagnetic mono nitrosyl compounds. The synthesis and characterization of five- and four-coordinate Co(III) and Co(I) nitrosyl pincer complexes based on three different ligand scaffolds is described. Passing NO throug...

Selective reduction of esters to alcohols was accomplished through Mn(I)‐mediated hydrosilylation reaction. The manganese tricarbonyl complex [Mn(bis‐NHC)(CO)3Br] resulted an active pre‐catalyst for the reduction of a variety of esters using phenylsilane and the cheap and readily available polymethylhydrosiloxane. An in situ examination of the cata...

A new type of asymmetric binuclear Zn(II) complex was synthesized from a suitable mononuclear precursor. One Zn(II) was coordinated to a salphen ligand (salphen = N,N′-disalicylidene-1,2-phenylenediamine) and the other to a modified salphen bearing OC12H25 chain in the 4,4’ positions, the two being joined by phenylene rings. The molecular structure...

CoII cryptates bearing several substituents can photoreduce catalytically CO2 to CO and, under longer irradiation times, to CH4, under visible light at room temperature in the presence of water. The cryptate with Br substituents showed the maximum activity, followed by the one with NO2. This work emphasizes how small differences are crucial to fine...

Three CoII octaazacryptates, with different substituents on the aromatic rings (Br, NO2, CCH), were synthesised and characterised. These and the already published non‐substituted cryptate catalysed CO2 photoreduction to CO and CH4 under blue visible light at room temperature. Although CO was observed after short irradiation times and a large range...

An amphiphilic iron(III) complex with a tridentate Schiff-base ligand was prepared by condensation of a hexadecyloxy functionalised salycylaldehyde with a diamine followed by complexation with FeCl2 and anion methathesis with NaClO4. The complex shows spin crossover both in the solid state and solution. However in solution self-assembly and consequ...

Several ferrocene derivatives (five mononuclear and two binuclear), including the new N-(p-chlorophenyl)-carboxamidoferrocene (1), were synthesized and their anticancer activity investigated. Two of them, 3 and 7, bearing a benzimidazole backbone were the most active against HeLa cells achieving IC50 values of ~5 μM along with 4 with a dipyridylami...

Single ion magnet behaviour is reported for a mononuclear Mn(iii) ion with tridentate Schiff-base ligands which exhibits a tetragonal Jahn-Teller elongation along the Namine-Mn-Namine axis and crystallises with two crystallographically distinct Mn(iii) cations (unit A and unit B). While magnetic measurements show a large and negative axial zero-fie...

New Cu(ii)/Ni(ii) heterodinuclear complexes with salphen-type ligands were synthesised via a stepwise template method. DFT studies were performed to understand their electronic properties, showing localisation of the HOMO on the Ni(ii) fragment, while in the oxidised species the spin density was high at some carbon phenolate atoms. These new comple...

Treatment of anhydrous FeX2 (X = Cl, Br) with 1 equiv of the asymmetric chiral PNP pincer ligands PNP-R,TAD (R = iPr, tBu) with an R,R-TADDOL (TAD) moiety afforded complexes of the general formula [Fe(PNP)X2]. In the solid state these complexes adopt a tetrahedral geometry with the PNP ligand coordinated in 2P,N-fashion, as shown by X-ray crystall...

New asymmetric Cu(II)/Cu(II) and Ni(II)/Ni(II) binuclear Schiff base complexes were synthesised via a one-pot reaction introducing two different aldehyde building blocks (R = H, t-Bu). These complexes were successfully electropolymerised to afford new metallopolymers using different sweep scan rates (50, 100 and 200 mV s-1) between 0 and 1.4 V. Sur...

Three new mononuclear oxovanadium(iv) complexes [VO(acac)(R-BIAN)]Cl (BIAN = 1,2-bis{(R-phenyl)imino}acenaphthene, R = H, ; CH3, ; Cl, ) were prepared and characterized. They promoted the catalytic oxidation of olefins such as cyclohexene, cis-cyclooctene, and styrene with both tbhp (tert-butylhydroperoxide) and H2O2, and of enantiopure olefins (S(...

Reaction of [Co(eta(5)-C5H5)(CO)(2)], 1, with 1,1'-bis(diphenylphosphino)ferrocene (dppf) yields the new trinuclear complex [Co(eta(5)-C5H5)(CO)](2)(mu-dppf), 2, which was structurally characterised by single crystal X-ray diffraction and showed two Co(eta(5)-C5H5)(CO) moieties covalently linked by a dppf bridge. Electrochemical studies in dichloro...