Study of cycloplatinated complexes with isocyanide ligands: isomerism, optical properties and mechanochromism

Platinum(II) cyclometalated derivatives have attracted a great interest dueto their rich photophysical properties, with interesting applications aschemical sensors, photocatalysts or in light emitting diodes (OLEDs). Thepresence of planar ligands in these complexes improves the luminescenceand the ability to form aggregates through the formation of Pt···Pt and/or··· interactions. In this context, there are very scarce examples ofheteroleptic complexes with isocyanide and alkynyl ligands.In this work, we present the synthesis and characterization of a group ofPt(II) compounds featuring 2-phenylpyridine and 2-phenylquinoline ascyclometalated ligands and 2,6-dimethylphenyl isocyanide as auxiliaryligand. The p-tolylacetylide complexes [Pt(C^N)(CCTol)(CNXyl)] (C^N =ppy 3, pq 4) have been obtained from the chloride derivatives[Pt(C^N)Cl(CNXyl)] (C^N = ppy 1, pq 2). The isomerism of thesecompounds in which the isocyanide ligand can be trans to the nitrogen or tothe carbon of the cyclometalated ligand has been determined by differenttechniques, as NMR and X-ray diffraction.The photophysical properties (absorption and emission) of all complexeshave been studied with the aid of theoretical calculations. Interestingly, thephenylpyridine derivatives exhibit mechanical stimuli responsive colour andluminescence changes correlated with the formation of different aggregateswith ··· and/or Pt···Pt interactions

Complexes of platinum(II) containing ferrocenylethynyl ligands: synthesis, characterization and spectroscopic and electrochemical properties

A series of homoleptic and heteroleptic platinum(ii) complexes [Pt(CCFc)2(L-L)] (L-L = COD 1, 1,1- bis(diphenylphosphino)ferrocene (dppf) 2), Q2[cis/trans-Pt(C 6F5)2(C] (cis, Q = PMePh3, 3; trans, Q = NBu4, 4), (NBu4)[Pt(bzq)(CCFc) 2] 5 (Hbzq = 7,8-benzoquinoline) and (NBu4) 2[Pt(CCFc)4] 6 has been synthesized and characterized spectroscopically and the structures of 12CHCl3, 2 and 62H2O2CH2Cl2 confirmed by single-crystal X-ray studies. The anion of complex 6, shows strong O-H(CC) interactions and weaker C-Cl(CC) contacts between the protons of two water and two CH2Cl2 molecules and the CC of mutually cis alkynyl groups. In this complex the presence of additional O-HH-C(Cp) and C-ClH-C(Cp) contacts gives rise to an extended bidimensional network. The optical and electrochemical properties of all derivatives have been examined. It is remarkable that for complexes 2 and 5 a facile oxidatively induced coupling, giving rise to 1,4-diferrocenylbutadiyne, is observed, this also having been proven by chemical oxidation. © 2008 The Royal Society of Chemistry

Ground effects of the 18 October 1992, Murindo earthquake (NW Colombia), using the Environmental Seismic Intensity Scale (ESI 2007) for the assessment of intensity

The macroseismic intensity of the 18 October 1992 Murindo-Atrato earthquake that affected the northwestern states of Colombia (Choco\ub4 and Antioquia) is reassessed using the newly developed INQUA Environmental Seismic Intensity Scale (ESI 2007) which is based on the evaluation of earthquake environmental effects. To generate the ESI 2007 isoseismal map of northwestern Colombia, a geographical information system was used. Unifying the available information on the seismological and active tectonics framework including historical seismicity, hypocentral depths, foreshocks, aftershocks, focal mechanism, macroseismic data under the same GIS and the map of Quaternary faults allowed us to reinterpret the geological and environmental effects of the 1992 earthquakes sequence. A total of 24 sites from the areas of Quibdo\ub4, Bojaya\ub4, Rio Sucio, Murindo, Vig\u131\ub4a del Fuerte and Turbo were evaluated. A systematic comparison among evaluated intensities (Modified Mercalli and ESI scale) revealed differences from one to two degrees. According to the ESI 2007 scale, the epicentral intensity Io is XI. This represents one degree higher than the epicentral intensity obtained using MM and Medveded Sponhauer Karnik (MSK) intensity scales, probably due to the lack of suitable observations on building damage in this poorly populated and developed region. This information is also useful in order to shed some light on the persistent question of the exact location and dimension of the main rupture zone associated with the earthquake. The isoseismal map derived from the integration of the whole set of environmental effects with other macroseismic data strongly suggests that the causative tectonic structure is the Murindo fault. However, the rupture length derived from the distribution of ground effects is greater than the Murindo fault length, implying that other nearby fault segments were activated during the 1992 event. The new isoseismal map resulting from this work is relevant for the assessment of future seismic risk in the northwestern region of Colombia. Overall, the application of the ESI 2007 scale to the 18 October 1992 earthquake, and to similar strong events in the region, can be useful for disaster management and planning, estimation of damage, and post-earthquake recovery efforts

New acyclic diaminocarbenes cycloplatinated(II) complexes: synthesis, photophysical properties and cytotoxic activity

Among all phosphorescent molecules, cyclometalated platinum(II) complexes have receivedconsiderable attention because of their photophysical properties and potential applications asdopants in OLEDs, LECs, photocatalysts or bioimaging. Another research of relevant interest istheir employment as anticancer drugs with a broader spectrum of action against differenttumours and fewer side effects than the well-known cisplatin. For that reason, the choice of thecyclometalated group and ancillary ligands play an important role not only in emissive behaviorbut also on the biological activity.1N-acyclic diaminocarbenes (ADCs) show several appealing characteristics; they display strongelectron-donating ability with structural flexibility and can be easily prepared. However, thereare only a few examples of ADC-platinum complexes used as perspective metal-based drugs inthe literature.2In this contribution, we describe a series of new luminescent ADC cycloplatinated(II) compoundsfeaturing 2-(2,4-difluorophenyl)pyridine (3) and 2-phenylquinoline (4) cyclometalated groups[Pt(C^N)Cl{C(NHXyl)(NHR)}] (R = Pr a, Benzyl b) obtained by nucleophilic addition of primarypropyl and benzyl amines, to the isocyanide ligand of the corresponding precursors[Pt(C^N)Cl(CNXyl)] (1, 2) recently reported by our group.3 Their optical properties haveexamined and interpreted with the aid of DFT/TD-DFT calculations and, finally, all newcompounds have been screened for their cytotoxic activity against various cancer cell lines

[Pt]2Pb Trinuclear Systems: Impact of the Anionic Platinum Fragment on the Lead Environment and Photoluminescence

A comparison of the solid structures of three novel trinuclear sandwich R2Pb systems (NBu4)2[{Pt(CCTol) 4}2Pb(OH2)2] 1, [{Pt(bzq) (CCPh)2}2Pb] 2, and (NBu4)[{Pt(bzq) (CCC6H4-CF3-4)2} 2Pb(O2ClO2)] 4 (NBu4[3· (O2ClO2)]) with that of the previously reported (NBu 4)2[{Pt(C6F5)4} 2Pb] 5 showed that the local environment of PbII is highly sensitive to the nature of the anionic platinate(II) precursors. The photoluminescence (PL) studies of all 1-5 complexes revealed a dependence of PL on the structure type. Thus, complexes 1 and 5 exhibit metal centered emissions (1, 497 nm, 77 K; 5, 539 nm, ø = 0.43, 298 K) related to the linear (5) or bent (1 Pt-Pb-Pt 149.9°) trinuclear entities. However, in complexes 2-4, that have unprecedented PbII1(CCR) bonding interactions and very short PtPb and PtPt distances, the emissive state in solid state (77 K) is attributed to a 3MLM'CT [Pt(1)(CCR)Pt(2)/Pb(sp)*(CCR)] state mixed with some * excimeric character in neutral complexes 2 (R = Ph) and 3 (R = C6H4-CF3-4), and in the case of the adduct (NBu4)[{Pt(bzq)(CCC6H4-CF 3-4)2}2Pb(O2ClO2)] 4 modified also by PbIIO (O2ClO2 -) contacts. © 2008 American Chemical Society

Indicadores bibliométricos para investigadores y revistas de impacto en el área de la salud

Las publicaciones científicas en revistas especializadas y losautores evaluados a través de métricas, deben conocer losparámetros y funcionalidad en procesos de indexación y categorización.Este artículo tiene por objetivo presentar argumentosde expertos en la temática, igualmente las institucionesy plataformas en indicadores bibliométricos, la importanciade las redes para la comunidad académica e investigativay científica. La metodología está fundamentada en la revisiónliteraria desde la investigación documental. Se concluye queWos, Scopus y Google Scholar constituyen los principalesíndices y Orcid, Publons y Researchgate las redes para ladivulgación de productos