Massimo Moret

A three-dimensional nanoporous flexible network of ‘square-planar’ copper(ii) centres with an unusual topologyElectronic supplementary information (ESI) available: XRPD spectra. See http://www.rsc.org/suppdata/cc/b2/b202588d/

Cu(II) triflate reacts with 4,4′-bipyridyl in different solvents to yield the new 3D network [Cu(4,4′-bipy)2(CF3SO3)2], based on pseudo-square planar nodes and consisting of crossing layers of large rhombic meshes (22 × 22 A) fused together into an overall (two-fold interpenetrated) array, with a topology unprecedented within coordination frames and an interesting nanoporous behaviour.

Oxidation reaction of [{Cu(Hpz)2Cl}2](Hpz = pyrazole): synthesis of the trinuclear copper(II) hydroxo complexes [Cu3(OH)(pz)3(Hpz)2Cl2]·solv (solv = H2O or tetrahydrofuran). Formation, magnetic properties, and X-ray crystal structure of [Cu3(OH)(pz)3(py)2Cl2]·py (py = pyridine)

The trinuclear copper(II) complexes [Cu3(OH)(pz)3(Hpz)2Cl2]·solv (Hpz = pyrazole, pz = pyrazolate anion, solv = H2O or tetrahydrofuran) have been obtained by oxidation reactions of [{Cu(Hpz)2Cl}2]. When treated with pyridine(py), both CuII derivatives gave the related compound [Cu3(OH)(pz)3-(py)2Cl2]·py, which has been characterized by a single-crystal X-ray structure analysis. Crystals are orthorhombic, space group Pnma(no. 62), a= 19.883(3), b= 15.063(3), c= 9.495(2)A, Z= 4, R= 0.035 and R′= 0.041 for 1 472 absorption corrected reflections having I > 3σ(I).

Cationic palladium(II)–diphosphine complexes as catalysts for the carbonylation of alkenes to ketones

Cation palladium complexes of the type [(dppp)Pd(solvent)2][X]22[X = non or weakly coordinating anion; dppp = 1,3-bis(diphenylphosphino)propane] are active catalysts for the carbonylaion to ketones, e.g., for the seletive formation of E-1,5-diphenylpent-l-en-3-one from styrene; in the presence of water and depending on the acidity conditions dimerisation to the much less catalytically active [(dppp)Pd(µ-OH)2 Pd(dppp)]X23 takes place, the structure of which was determined by X-ray crystallography.

Growth and characterisation of centimetre-sized single crystals of molecular organic materials

The growth of high quality single crystals and the control of their size and shape are crucial issues for the study of the fundamental physical properties of materials. A novel floating-drop technique is here employed for the growth of centimetre-sized single crystals of different organic molecular materials, namely oligothiophenes and oligocenes dissolved in organic solvents, using water as liquid substrate. The static properties of the two-liquid system are described and their tuning for the control of the thickness of the grown crystals discussed. The quality of the samples is assessed by atomic force microscopy and optical absorption spectroscopy measurements.

Structural characterisation of single crystals and thin films of α,ω-dihexylquaterthiophene

Single crystals and thin films of the p-type organic semiconductor α,ω-dihexylquaterthiophene have been studied using X-ray diffraction and TEM, respectively. The single crystal analysis reveals the presence of monomolecular layers of quaterthiophene cores with terminally bound hexyl chains. A herringbone molecular packing akin to that exhibited by the parent quaterthiophene molecule is observed. Electron diffraction of thin films on silica clearly shows the crystalline polymorph of the solution-grown crystals and the crystallites deposited by organic molecular beam deposition are identical. However, thin film crystallites are severely affected by multiple twinning.

Directional dispersion in absorbance spectra of oligothiophene crystals

Due to the large oscillator strength of the first molecular transition in oligothiophenes, a strong directional dispersion of the b(u) exciton transition is expected originating from the macroscopic polarization field. Examining such dispersion unambiguously usually requires different faces to be accessible for the optical measurements. Alternatively, measurements carried out at different angles of incidence are met with intrinsic limits due to the peculiarities of wave propagation in such anisotropic systems. In order to demonstrate these limits along with the experimental difficulties involved, we examine refraction and absorption of light in these crystals and discuss the effects of directional dispersion on the absorbance spectra of quaterthiophene crystals.

NIR emitting ytterbium chelates for colourless luminescent solar concentrators

A new oxyiminopyrazole-based ytterbium chelate enables NIR emission upon UV excitation in colorless single layer luminescent solar concentrators for building integrated photovoltaics.

Microscopic surface processes observed during the oxidative dissolution of sphalerite

Sphalerite cleavage surface dissolution in acidic (HC1) and oxygen-saturated solutions was investigated by liquid-cell Atomic Force Microscopy (AFM). The sphalerite surface was cleaved in the laboratory and then mounted in the liquid cell at 298 K with a fast continuous renewal of the interacting solution. AFM data indicate that unreacted (110) surfaces are characterised by flat surface terraces delimited by step edges aligned along [110] crystallographic directions. AFM imaging allowed us to investigate removal of matter only at pH = 0 (HC1). Under these conditions, etch pits develop that are delimited by 1–3-nm-high step edges. However, surface terraces are covered by nanometric protrusions, while the step edges are microrough. Ex-situ solution chemistry measurements performed in flow-through-reactor indicates strong undersaturation with respect to both zinc sulphide and zinc sulphate. The reactivity of the dissolving (110) surface decreases significantly during the 24 hours of run time. Such a decrease suggests a change in the mechanism governing the overall dissolution process. We interpret nanometric protrusions as due to oxidative reactions at the interface that result in a reorganisation of the surface at the nanometric scale. The mechanism limiting the rate of sphalerite dissolution would be the process of protrusion formation and dissolution. A similar phenomenon was observed in an AFM study of the galena surface. Finally, we propose that the process of protrusion formation could be general in the oxidative dissolution of metal sulphides.

Crystal-to-crystal phase transition in α-quaterthiophene: An optical and structural study

At 191°C the organic semiconductor α-quaterthiophene is demonstrated to undergo a phase transition from the low temperature to the high temperature polymorph. Calorimetry, x-ray diffraction, optical reflectivity, and ellipsometry measurements were employed to analyze this transition and to show that this can be thermally induced on single crystals preserving the single crystalline nature of the sample over large domains.

Pentamethylcyclopentadienyl ruthenium(II) complexes containing chiral diphosphines: synthesis, characterisation and electrochemical behaviour. X-ray structure of (eta(5)-C5Me5)Ru{(S,S)-Ph2PCH(CH3)CH(CH3)PPh2}Cl

Abstract Some pentamethylcyclopentadienyl ruthenium(II) diphosphine chloride complexes have been prepared by ligand exchange starting with the parent triphenylphosphine derivatives and their reactivities compared with those of the corresponding cyclopentadienyl compounds. The pentamethyl ligand causes a greater extent of asymmetric induction when the (R)-prophos and (R)-phenphos ligands are used as well as a higher lability of the stereochemistry at the stereogenic ruthenium centre. A shift of about 200 mV in the oxidation potential is caused by the substitution at the penta-hapto ligand. The order of basicity of the diphospine ligands was also evaluated and was found to be consistent with previous determinations. The crystal structure of (η-C5Me6)Ru{(S,S)-dhiraphos}Cl shows a coordination around the ruthenium atom similar to that found for the (η5C5H5Ru{(S,S)-Chiraphos}Cl complex.