Bis(1-{bis­[2-(diphenyl­phosphino­yl)eth­yl]phosphan­yl}-2-(diphenyl­phosphan­yl)ethane)dinitratoplatinum(II) methanol tetra­solvate

In the title compound, [Pt(NO3)2(C42H42O2P4)2]·4CH3OH, the Pt atom positioned on a crystallographic centre of inversion. The two symmetry-equivalent nitrate anions are weakly coordinated to the PtII ion, creating, together with four P ligand atoms, a distorted octa­hedral coordination environment. In addition, several close C—H⋯O contacts between the nitrate O atoms and phenyl H atoms are found. Hydrogen bonds from two methanol solvent mol­ecules to one of the O—P groups complete the crystal structure

Chlorido{[2-(dicyclo­hexyl­phosphano­yl)eth­yl]bis­[2-(dicyclo­hexyl­phosphan­yl)eth­yl]phosphane}platinum(II) chloride dichloro­methane hemisolvate tetra­hydrate

The title compound, [PtCl(C42H78OP4)]Cl·0.5CH2Cl2·4H2O, crystallizes as a contact ion-pair with two close inter­molecular C—H⋯Cl− contacts between CH acidic αH atoms of the phosphane ligand and the chloride anion. A chloride ligand together with three coordinating P ligand atoms create a slightly distorted square-planar coordination environment around the PtII center. An inter­molecular water O—H⋯Cl− and water O—H⋯OP hydrogen-bond network completes the coordination around the anion. In addition, a disordered CH2Cl2 solvent mol­ecule cocrystallized within a hydro­phobic cavity spanned by the dicyclo­hexyl­phosphane ligands

Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures

Self‐assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure‐encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self‐assembly pathway at a single‐component level, but in a very narrow solvent composition, a supramolecular homo‐aggregate can be non‐covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single‐crystal X‐ray diffraction and molecular simulations based on coarse‐grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures

Solvent‐Driven Supramolecular Wrapping of Self‐Assembled Structures

Self‐assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure‐encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self‐assembly pathway at a single‐component level, but in a very narrow solvent composition, a supramolecular homo‐aggregate can be non‐covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single‐crystal X‐ray diffraction and molecular simulations based on coarse‐grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures

Cryo-electron microscopy of viruses

Thin vitrified layers of unfixed, unstained and unsupported virus suspensions can be prepared for observation by cryo-electron microscopy in easily controlled conditions. The viral particles appear free from the kind of damage caused by dehydration, freezing or adsorption to a support that is encountered in preparing biological samples for conventional electron microscopy. Cryo-electron microscopy of vitrified specimens offers possibilities for high resolution observations that compare favourably with any other electron microscopical method

Glass polymorphism in glycerol–water mixtures: I. A computer simulation study

We perform out-of-equilibrium molecular dynamics (MD) simulations of water–glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA–HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/ decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration wg = 0–13% and find that, for the present mixture models and rates, the LDA–HDA transformation is detectable up to wg E 5%. As the concentration increases, the density of the starting glass (i.e., LDA at approximately wg r 5%) rapidly increases while, instead, the density of HDA remains practically constant. Accordingly, the LDA state and hence glass polymorphism become inaccessible for glassy mixtures with approximately wg 4 5%. We present an analysis of the molecular-level changes underlying the LDA–HDA transformation. As observed in pure glassy water, during the LDA-to- HDA transformation, water molecules within the mixture approach each other, moving from the second to the first hydration shell and filling the first interstitial shell of water molecules. Interestingly, similar changes also occur around glycerol OH groups. It follows that glycerol OH groups contribute to the density increase during the LDA–HDA transformation. An analysis of the hydrogen bond (HB)-network of the mixtures shows that the LDA–HDA transformation is accompanied by minor changes in the number of HBs of water and glycerol. Instead, large changes in glycerol and water coordination numbers occur. We also perform a detailed analysis of the effects that the glycerol force field (FF) has on our results. By comparing MD simulations using two different glycerol models, we find that glycerol conformations indeed depend on the FF employed. Yet, the thermodynamic and microscopic mechanisms accompanying the LDA–HDA transformation and hence, our main results, do not. This work is accompanied by an experimental report where we study the glass polymorphism in glycerol–water mixtures prepared by isobaric cooling at 1 ba

Synthetic approaches to artificial photosynthesis: general discussion

Metals in Catalysis, Biomimetics & Inorganic Material

First microwave-assisted synthesis of an electron-rich phosphane and its coordination chemistry with platinum(II) and palladium(II)

The P–O ligand 3-(di(2-methoxyphenyl)phosphanyl)propionic acid (HL) was synthesized by a microwave-assisted reaction of a secondary phosphane. The coordination of HL to PtII yielded the neutral mononuclear complex trans-[PtCl(κ2-P,O-L)(κ-P-HL)] (1), while the reaction of PdClMe(η4-COD) (COD = 1,4-cyclooctadiene) with HL in the presence of NEt3 gave the anionic PdII compound of the formula (HNEt3)[PdClMe(κ2-P,O-L)] (2). Upon crystallization of the latter compound the neutral chloride-bridged dimetallic compound cis-[Pd(μ-Cl)Me(HL)]2 (3) was obtained. HL, 1 and 3·CH2Cl2 have been characterized by single crystal X-ray structure analyses