Sara Realista

Dr. Sara Realista

ITQB NOVA, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras Portugal
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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 January 2015 in Dalton Transactions
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Journal Article
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Carla D. NunesCarla D. Nunes
Carla D. Nunes
Pedro D. VazPedro D. Vaz
Pedro D. Vaz
VFVítor Félix
Vítor Félix
LVLuís Filipe Veiros
Luís Filipe Veiros
Tânia MonizTânia Moniz
Tânia Moniz
MCMaria José Calhorda
Maria José Calhorda
Three new mononuclear oxovanadium(IV) complexes [VO(acac)(R-BIAN)]Cl (BIAN = 1,2-bis{(R-phenyl)imino}acenaphthene, R = H, 1; CH3, 2; Cl, 3) 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(−)- and R(+)-pinene, and S(−)- and R(+)-limonene) selectively to their epoxides, with tbhp as the oxidant. The TOFs for styrene epoxidation promoted by complex 3 with H2O2 (290 mol mol−1 V h−1) and for cis-cyclooctene epoxidation by 2 with tbhp (248 mol mol−1 V h−1) are particularly good. Conversions reached 90% for several systems with tbhp, and were lower with H2O2. A preference for the internal CC bond, rather than the terminal one, was found for limonene. Kinetic data indicate an associative process as the first step of the reaction and complex [VO(acac)(H-BIAN)]+ (1+) was isolated in an FTICR cell after adding tbhp to 1. EPR studies provide evidence for the presence of a V(IV) species in solution, until at least 48 hours after the addition of tbhp and cis-cyclooctene, and cyclic voltammetry studies revealed an oxidation potential above 1 V for complex 1. DFT calculations suggest that a [VO(H-BIAN)(MeOO)]+ complex is the likely active V(IV) species in the catalytic cycle from which two competitive mechanisms for the reaction proceed, an outer sphere path with an external attack of the olefin at the coordinated peroxide, and an inner sphere mechanism starting with a complex with the olefin coordinated to vanadium.

1 April 2020 in Advanced Synthesis & Catalysis
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SSSara C. A. Sousa
Sara C. A. Sousa
SRSara Realista
Sara Realista
Beatriz RoyoBeatriz Royo
Beatriz Royo

18 November 2016 in Journal of Coordination Chemistry
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Journal Article
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SRSara Realista
Sara Realista
SQSusana Quintal
Susana Quintal
Paulo MartinhoPaulo Martinho
Paulo Martinho
AMAna I. Melato
Ana I. Melato
AGAdrià Gil-Mestres
Adrià Gil-Mestres
MCMaria José Calhorda
Maria José Calhorda
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 dipyridylamine ligand (~6 μM). Complex 6, also with a benzimidazole backbone, displayed slightly higher values (~11 μM). Cyclic voltammetry studies show that while the non-cytotoxic ferrocene derivatives 1, 2, and 5 follow a ferrocene-based redox behavior, derivatives 3, 4, 6, and 7 exhibit a more complex mechanism. These complex mechanisms are consistent with a more effective cytotoxic activity. Mössbauer spectroscopy parameters reflect a very small influence of the substituents.

13 July 2016 in Dalton Transactions
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SRSara Realista
Sara Realista
AFAnthony J. Fitzpatrick
Anthony J. Fitzpatrick
GSG. Santos
G. Santos
LFLiliana Maria Pires Ferreira
Liliana Maria Pires Ferreira
Sónia BarrosoSónia Barroso
Sónia Barroso
Paulo MartinhoPaulo Martinho
Paulo Martinho
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-field splitting (D = −4.73 cm−1), HF-EPR reveal two distinct large axial Ds (D = −4.60 cm−1 for unit A and D = −4.18 cm−1 for unit B), thus resulting in the largest D known to date for a Mn(III) single ion magnet. AC magnetic measurements at 2000 Oe allowed determination of the energy barrier for spin reversal (10.19 K) and spin reversal relaxation time (1.476 × 10−6 s) for the Mn(III) ion. Computational studies were used to characterise the electronic structure and substantiate the zero field splitting in the Mn(III) complex.

1 June 2014 in Journal of Organometallic Chemistry
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Paulo MartinhoPaulo Martinho
Paulo Martinho
AVAna I. Vicente
Ana I. Vicente
SRSara Realista
Sara Realista
MSMarta S. Saraiva
Marta S. Saraiva
AMAna I. Melato
Ana I. Melato
MCMaria de Deus Carvalho
Maria de Deus Carvalho

24 April 2020 in Organometallics
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Journal Article
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JPJan Pecak
Jan Pecak
WEWolfgang Eder
Wolfgang Eder
BSBerthold Stöger
Berthold Stöger
SRSara Realista
Sara Realista
Paulo MartinhoPaulo Martinho
Paulo Martinho
KKKarl Kirchner
Karl Kirchner
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 through a solution of [Co(PCPNMe-iPr)Cl], [Co(PCPO-iPr)Cl] or [Co(PCPCH2-iPr)Br] led to the formation of the low-spin complex [Co(PCP-iPr)(NO)X] with a strongly bent NO ligand. Treatment of the latter species with (X = Cl, Br) AgBF4 led to chloride abstraction and formation of cationic square-planar Co(I) complexes of the type [Co(PCP-iPr)(NO)]+ featuring a linear NO group. This reaction could be viewed as a formal two electron reduction of the metal center by the NO radical from Co(III) to Co(I), if NO is counted as NO+. Hence, these systems can be described as {CoNO}8 according to the Enemark–Feltham convention. X-ray structures, spectroscopic and electrochemical data of all nitrosyl complexes are presented. Preliminary studies show that [Co(PCPNMe-iPr)(NO)]+ catalyzes efficiently the reductive hydroboration of nitriles with pinacolborane (HBpin) forming an intermediate {CoNO}8 hydride species.