New palladium and platinum complexes with bioactive 3,5-diacetyl-1,2,4- triazol bis(4-cyclohexyl thiosemicarbazone) ligand: Chemistry, antiproliferative activity and preliminary toxicity studies

Dalton Transactions 41.40 (2012): 12538-12547. Reproduced by permission of The Royal Society of ChemistryThe preparation and characterization of the new 3,5-diacetyl-1,2,4-triazol bis(4-cyclohexyl thiosemicarbazone) ligand, H5L1, is described. Treatment of H5L1 with K2PtCl 4 gave the dinuclear complex [Pt(H3L1)] 2, 1, but using MCl2(PPh3)2 where M = Pd or Pt, mononuclear complexes 2 and 3, of general formula [M(H 3L1)PPh3], were obtained. Subsequent reaction of the [Pd(H3L1)PPh3] complex with PdCl 2(PPh3)2 yielded a new dinuclear complex [(PPh3)Pd(H2L1)PdCl], 4. All compounds have been characterized by elemental analysis and FAB+ spectrometry and by IR and NMR spectroscopy. The molecular structures of mononuclear complexes 2 and 3 and dinuclear complex 4 have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, HepG2, MCF-7, A2780 and A2780cisR human cancer cell lines. The cytotoxicity data suggest that the H5L1 ligand and [Pt(H3L1)]2, complex 1, may be endowed with important cytotoxic properties since they are capable of not only circumventing cisplatin resistance in A2780cisR but also exhibit antiproliferative activity in NCI-H460. The interactions of these compounds with calf thymus DNA were investigated by UV-vis absorption and a nephrotoxic study, in LLC-PK1 cells, has also been carried outWe are grateful to Ministerio de Economía y Competitividad, Instituto de Salud Carlos III (PI080525 and PI1100659), of Spain for financial suppor

A convergent growth approach to electroactive ferrocene rich carbosilane- and siloxane-based dendrons, dendrimers, and dendronized polymers

The construction of the first members of a novel family of structurally well-defined, ferrocenyl rich, dendritic macromolecules based on carbosilane skeletons and siloxane linkages has been achieved via a convergent growth approach. Starting from triferrocenylvinylsilane Fc3SiCHvCH2 (1) (Fc = Fe(η5 -C5H4)(η5 - C5H5) as the key monomer, the sequential utilization of platinum-catalyzed hydrosilylation and alkenylation steps with Grignard reagents (allylmagnesium bromide) can be applied to prepare three different branched structures: multiferrocenyl-terminated dendrons 2 and 3, dendrimers 4 and 5, and dendronized polymers 7n–9n. All of the dendritic metallomacromolecules have been thoroughly characterized using a combination of elemental analysis, multinuclear (1 H, 13C, 29Si) NMR spectroscopy, FT-IR and MALDI-TOF mass spectrometry, to establish their chemical structures and properties. The molecular structures of G1- dendron 3 and dendrimer 4, containing six and nine ferrocenyl units, respectively, have been successfully determined by single-crystal X-ray analysis, compound 4 being the branched multiferrocenyl-containing siloxane with the highest number of Fc substituents whose structure has been reported so far. Electrochemical studies (using cyclic voltammetry (CV) and square wave voltammetry (SWV) performed in dichloromethane solution with [PF6] − and [B(C6F5)]4− as supporting electrolyte anions of different coordinating abilities) reveal that all the macromolecular compounds obtained exhibit a three-wave redox pattern, suggesting appreciable electronic interactions between the silicon-bridged triferrocenyl moieties as they are successively oxidized. In addition, dendrimer 5 and dendronized polymers 7n–9n, with 12 and 4 < n < 14 ferrocenyl units, respectively, linked in threes around the periphery, undergo remarkable oxidative precipitation in CH2Cl2/[n-Bu4N][PF6] and are able to form chemically modified electrodes with stable electroactive filmsWe thank the Ministerio de Ciencia e Innovación (MICINN) of Spain for its financial support through projects PGC2018- 094644-B-C21 and PID2021-125207NB-C3

Crystal structure dependence of the energy transfer from tb(III) to yb(III) in metal–organic frameworks based in bispyrazolylpyridines

Luminescent mixed lanthanide metal−organic framwork (MOF) materials have been prepared from two polyheterocyclic diacid ligands, 2,6-bis(3-carboxy-1-pyrazolyl)pyridine and 2,6- bis(4-carboxy-1-pyrazolyl)pyridine. The crystal structures of the two organic molecules are presented together with the structures for the MOFs obtained by hydrothermal synthesis either with Yb(III) or mixed Tb(III)/Yb(III) ions. Different coordination architectures result from each ligand, revealing also important differences between the lanthanides. The mixed lanthanide metal−organic frameworks also present diverse luminescent behavior; in the case of 2,6-bis(4-carboxy-1- pyrazolyl)pyridine, where no coordinated water is present in the metal environment, Tb(III) and Yb(III) characteristic emission is observed by excitation of the bispyrazolylpyridine chromophoreThe research leading to these results has received funding from ERCROS S.A. (Aranjuez, Spain

Structural study of the compounds formed in the reactions of FeCl3·6H2O with Ni(OH)2 in the presence of dithiolenes HSRSH (R = C6H2Cl2 or C6H4)

In our attempts to prepare coordination polymers by reaction of FeCl3·6H2O and Ni(OH)2 in the presence of dithiolenes HSC6H2X2SH (X = Cl or H), several ion pairs of compounds containing the anionic entity [Ni(SC6H2X2S)2]⁻ were obtained instead. It was also found that other species without dithiolene ligands were formed in these reactions, giving rise to different ion pairs and a tetrametallic cluster. The careful isolation of the different types of crystalline solids allowed the characterization of all of the resulting compounds by single crystal X-ray diffraction (SCXRD). In order to establish the amount of nickel and iron present in the crystals, complementary total reflection X-ray fluorescence (TXRF) analyses were performed. The eight different structural types that were obtained are described and compared with related ones found in the literaturaThis research was funded by the Spanish Ministerio de Economía y Competitividad, grand number (MAT2016-77608-C3-1-P) and Ministerio de Ciencia, Innovación y Universidades (PGC2018-094644-B-C21

The flexibility of CuI chains and the functionality of pyrazine-2-thiocarboxamide keys to obtaining new Cu(I)-I coordination polymers with potential use as photocatalysts for organic dye degradation

This research focuses on two interesting aspects in the synthesis of new coordination polymers (CPs) taking advantage of the lability of coordination bonds. The first is the use of multifunctional and flexible building blocks, such as pyrazine-2-thiocarboxamide (Pyrtca) and CuI, and the second is the modification of the synthetic conditions to expand the amount of different crystalline phases. This means that starting from the same building blocks, we can increase the number of compounds obtained and diversify their final properties, as well as their possible applications. Furthermore, Cu(I)-halogen coordination polymers have been extensively studied for a long time due to their interesting optoelectronic properties. However, despite being usually semiconductors, research related to their possible behavior as photocatalysts is almost non-existent. In this work, we present five compounds, four coordination compounds with formulas [CuI(Pyrtca)]n (CP1), [Cu3I3(Pyrtca)7] (2) [Cu2I2(Pyrtca)]n (CP4 and CP4′) and a transformation of the starting ligand to a cationic imidazole derivative (compound 3) where copper iodine serves as a catalyst. All the compounds have been characterized by different techniques including single-crystal X-ray diffraction. The antibacterial behavior of CP1 against E. Coli DH5, E. Coli BL21, and C. glabrata (CECT 1448), as well as their optoelectronic properties, are also discussed in the work. The value of the band gap obtained (1.91 eV) for the two-dimensional coordination polymer of formula [Cu2I2(Pyrtca)]n (CP4) allows us to study its behavior as a photocatalyst in the degradation of persistent dyes in water with interesting results, achieving a total degradation of Methylene Blue and Rhodamine B in 40 min under UV–visible lightThis work was supported by the Spanish Ministerio de Ciencia e Innovación (Agencia Estatal de Investigación) (MCIN/AEI/10.13039/501100011033; PID2019- 108028GB-C22 and TED2021-131132B-C22

Taming C60 fullerene: Tuning intramolecular photoinduced electron transfer process with subphthalocyanines

Two subphthalocyanine-C60 conjugates have been prepared by means of the 1,3-dipolar cycloaddition reaction of (perfluoro) or hexa(pentylsulfonyl) electron deficient subphthalocyanines to C60. Comprehensive assays regarding the electronic features-in the ground and excited state-of the resulting conjugates revealed energy and electron transfer processes upon photoexcitation. Most important is the unambiguous evidence-in terms of time-resolved spectroscopy-of an ultrafast oxidative electron transfer evolving from C60 to the photoexcited subphthalocyanines. This is, to the best of our knowledge, the first case of an intramolecular oxidation of C60 within electron donor-acceptor conjugates by means of only photoexcitationFinancial support from the MICINN and MEC, Spain (CTQ- 2011-24187/BQU and PRI-PIBUS-2011-1128) is acknowledged. D.M.G. appreciates funding by the DFG (GU 517/14-1) and “Solar Technologies Go Hybrid” – an initiative of the Bavarian State Ministry for Science, Research, and Ar

Structural and theoretical study of copper(ii)-5-fluoro uracil acetate coordination compounds: Single-crystal to single-crystal transformation as possible humidity sensor

This paper describes the synthesis and characterization of seven different copper(II) coordination compounds, as well as the formation of a protonated ligand involving all compounds from the same reaction. Their synthesis required hydrothermal conditions, causing the partial in situ transformation of 5-fluoro uracil-1-acetic acid (5-FUA) into an oxalate ion (ox), as well as the protonation of the 4,4′-bipyridine (bipy) ligand through a catalytic process resulting from the presence of Cu(II) within the reaction. These initial conditions allowed obtaining the new coordination compounds [Cu2(5-FUA)2(ox)(bipy)]n·2n H2O (CP2), [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3), as well as the ionic pair [(H2bipy)+2 2NO3−] (1). The mother liquor evolved rapidly at room temperature and atmospheric pressure, due to the change in concentration of the initial reagents and the presence of the new chemical species generated in the reaction process, yielding CPs [Cu(5-FUA)2(bipy)]n·3.5n H2O, [Cu3(ox)3(bipy)4]n and [Cu(ox)(bipy)]n. The molecular compound [Cu(5-FUA)2(H2O)4]·4H2O (more thermodynamically stable) ended up in the mother liquor after filtration at longer reaction times at 25 °C and 1 atm., cohabiting in the medium with the other crystalline solids in different proportions. In addition, the evaporation of H2O caused the single-crystal to single-crystal transformation (SCSC) of [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3) into [Cu(5-FUA)2(bipy)]n·2n H2O (CP4). A theoretical study was performed to analyze the thermodynamic stability of the phases. The observed SCSC transformation also involved a perceptible color change, highlighting this compound as a possible water sensorPID2019-108028GB-C22, TED2021-131132B-C2