Manuel Serrano-Ruiz

Visible-Light Photoisomerization and Photoaquation of trans-[Ru(1,3,5-triaza-7-phosphaadamantane)4Cl2] in Organic Solvent and Water

The interaction of the PTA (PTA = 1,3,5-triaza-7-phosphaadamantane) ruthenium complex trans-[RuCl(2)(PTA)(4)] (trans-1) with visible light in chloroform and in water has been studied at room temperature. The complex trans-1 isomerizes to the cis isomer in CHCl(3) with radiation of lambda > 416 nm (Phi(434 nm) (CHCl(3)) = 0.13 +/- 0.01). The isomerization reaction is reversible as cis-1 is transformed into trans-1 with lambda = 367 nm (Phi(367 nm) (CHCl(3)) = 0.25 +/- 0.02). Irradiation at lambda > 416 nm of a solution of trans-1 in water leads to the cis-isomer complex and to the aqua complex (OC-6-32)-[RuCl(H(2)O)(PTA)(4)]Cl (2Cl) by a photoisomerization and photoaquation reaction (Phi(434 nm) (D(2)O) = 0.27 +/- 0.02). The mole ratio of cis-1 to 2Cl is not dependent on the pH but on the concentration of the products in solution. Isomerization in water is not reversible even if only cis-1 is present in solution. Synthesis and characterization of (OC-6-32)-[RuCl(H(2)O)(PTA)(4)](CF(3)SO(3)) (2CF(3)SO(3)) are also presented.

Synthesis and Antiproliferative Activity of [RuCp(PPh3)2(HdmoPTA)](OSO2CF3)2 (HdmoPTA = 3,7-H-3,7-Dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)

The complex [RuCp(PPh3)2(HdmoPTA)](OSO2CF3)2 (2; HdmoPTA = 3,7-H-3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) was synthesized and characterized. Its crystal structure was determined by single-crystal X-ray diffraction. The complex showed a more potent antiproliferative activity than cisplatin against a representative panel of human cancer cells.

First water-soluble backbone Ru-Ru-Ni heterometallic organometallic polymer.

The water-soluble backbone heterometallic polymer {[(PTA)2 CpRu-μ-CN-RuCp(PTA)2 -μ-NiCl3 ]}n (2) is synthesized using a reproducible and robust method and fully characterized by X-ray single crystal diffraction. The Ru-Ru-Ni polymer is found to be stable in the solid state and soluble in water. Nuclear magnetic resonance (NMR) and light scattering studies show that the polymer is stable in water for several days in air.

Dearomatizing anionic cyclization of phosphonamides. A route to phosphonic acid derivatives with antitumor properties.

Deprotonation of bis(N-benzyl-N-methyl)-P-arylphosphonic diamides with s-BuLi in THF at -90 degrees C takes place selectively at the benzylic position. The anions undergo intramolecular attack to the P-aryl ring leading to dearomatized species that were trapped with a series of electrophiles (MeOH, ArOH, BnBr, aliphatic and aromatic aldehydes, and benzophenone) in very high yield, and with high regio- and stereocontrol. The dearomatized products were smoothly transformed into gamma-aminophosphonic acids under acidic conditions. Preliminary screening for antitumor activity showed promising levels of activity.

Novel polystyrene-based nanocomposites by phosphorene dispersion

Polystyrene-based phosphorene nanocomposites were prepared by a solvent blending procedure allowing the embedding of black phosphorus (BP) nanoflakes in the polymer matrix. Raman spectroscopy, X-ray Diffraction and TEM microscopy were employed to characterize the structural and morphological characteristics of the achieved hybrids, with the aim of evaluating the dispersion level of black phosphorus layers. TGA, DSC analysis as well as thermal oxidation and photo-degradation techniques were employed to investigate the thermal- and the photo-stability of the samples. The collected results showed evidence of better thermal and photostability of both the polymer matrix and dispersed layered phosphorus, suggesting really interesting polymer-nanofiller synergic effects ascribable to the presence and the good dispersion of the 2D-nanomaterial.

Binuclear ruthenium complexes containing mPTA and alkyl-bis(8-thiotheophylline) derivatives (mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane)

The water-soluble complex [RuClCp(PPh3)(mPTA)](CF3SO3) reacts with the thiopurines, bis(S-8-thiotheophylline)methane (MBTTH2), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2), and 1,3-bis(S-8-thiotheophylline)propane (PBTTH2), to lead to the binuclear ruthenium(II) complexes [{RuCp(PPh3)(mPTA)}2-μ-(L-κS7,S′7)](CF3SO3)2 where (L = MBTT2− (1), EBTT2− (2), and PBTT2− (3)). All the complexes have been fully characterized by elemental analysis, IR, and multinuclear 1H, 13C{1H}, and 31P{1H} NMR spectroscopy. The cyclic voltammetry of the complexes is characterized by two one-electron oxidative responses (RuII–RuII/RuIII–RuII; RuIII–RuII/RuIII–RuIII) that increase their redox potential when the bis(8-thiotheophylline)-alkyl-bridge growths. The reactivity against DNA and partition coefficient of the complexes were also determined. Graphical Abstract

Tetrahedral cobalt(II) complexes stabilized by the aminodiphosphine PNP ligand [PNP = CH3CH2CH2N(CH2CH2PPh2)2]

The reaction of CoCl2·6H2O and PNP [PNP = 1,1-bis(diphenylphosphinoethyl)-n-propylamine (CH3CH2CH2)N(CH2CH2PPh2)2] in ethanol affords the blue Co(II) complex [CoCl3{η1-PPPh2CH2CH2N(CH2CH2CH3)(H)(CH2CH2P(O)Ph2)}] (1), which has been characterized by spectroscopic methods and X-ray diffraction analysis. The structure of 1 consists of a tetrahedral cobalt atom coordinated by three chlorides and by an η1-P-PNP ligand bearing a dangling PO end and quaternised at the nitrogen atom. EPR measurements and a detailed analysis of the magnetic behaviour of 1 are consistent with a tetrahedral Co(II) ion and accordingly support the protonation of the PNP nitrogen atom. A mechanistic picture accounting for the formation of 1 has been proposed from the isolation and characterization of three reaction intermediates along the pathway leading to 1 which involve either η2-P,P- and η2-P,N-PNP cobalt complexes.

Benign Chlorine-Free Approaches to Organophosphorus Compounds

Organophosphorus compounds have widespread use throughout the world, as agricultural chemicals, medicinal agents, flame retardants, plasticizing and stabilizing agents, selective extractants for metal salts from ores, additives for petroleum products and corrosion inhibitors. Moreover, they are also endowed with metal binding properties, for this reason they have a paramount role in catalysis, being able to direct the activity and selectivity of a metal. Currently, organophosphorus compounds are produced on industrial scale using white phosphorus and chlorine, through an environmentally harmful process which generates equimolar amount of chlorinated waste. In the quest for alternative environmentally benign technology, several routes have been envisaged starting either from elemental phosphorus or from one of its direct low-valent derivative as hypophosphite.

Polymer-Based Black Phosphorus (bP) Hybrid Materials by in Situ Radical Polymerization: An Effective Tool To Exfoliate bP and Stabilize bP Nanoflakes

Black phosphorus (bP) has been recently investigated for next generation nanoelectronic multifunctional devices. However, the intrinsic instability of exfoliated bP (the bP nanoflakes) toward both moisture and air has so far overshadowed its practical implementation. In order to contribute to fill this gap, we report here the preparation of new hybrid polymer-based materials where bP nanoflakes (bPn) exhibit a significantly improved stability. The new materials have been prepared by different synthetic paths including: (i) the mixing of conventionally liquid-phase exfoliated bP (in dimethyl sulfoxide, DMSO) with poly(methyl methacrylate) (PMMA) solution; (ii) the direct exfoliation of bP in a polymeric solution; (iii) the in situ radical polymerization after exfoliating bP in the liquid monomer (methyl methacrylate, MMA). This last methodology concerns the preparation of stable suspensions of bPn–MMA by sonication-assisted liquid-phase exfoliation (LPE) of bP in the presence of MMA followed by radical polymerization. The hybrids characteristics have been compared in order to evaluate the bP dispersion and the effectiveness of the bPn interfacial interactions with polymer chains aimed at their long-term environmental stabilization. The passivation of the bPn is particularly effective when the hybrid material is prepared by in situ polymerization. By using this synthetic methodology, the nanoflakes, even if with a gradient of dispersion (size of aggregates), preserve their chemical structure from oxidation (as proved by both Raman and 31P-solid state NMR studies) and are particularly stable to air and UV light exposure. The feasibility of this approach, capable of efficiently exfoliating bP while protecting the bPn, has been then verified by using different vinyl monomers (styrene and N-vinylpyrrolidone), thus obtaining hybrids where the nanoflakes are embedded in polymer matrices with a variety of intriguing thermal, mechanical, and solubility characteristics.

Phosphorus oxide gate dielectric for black phosphorus field effect transistors

The environmental stability of the layered semiconductor black phosphorus (bP) remains a challenge. Passivation of the bP surface with phosphorus oxide, POx, grown by a reactive ion etch with oxygen plasma is known to improve photoluminescence efficiency of exfoliated bP flakes. We apply phosphorus oxide passivation in the fabrication of bP field effect transistors using a gate stack consisting of a POx layer grown by reactive ion etching followed by atomic layer deposition of Al2O3. We observe room temperature top-gate mobilities of 115 cm2/Vs in ambient conditions, which we attribute to the low defect density of the bP/POx interface.