Regionaal voedsel in Arnhem : naar meer regionaal voedsel in Arnhem

In dit rapport staat de vraag centraal hoe de voedselvoorziening van Arnhem en omgeving momenteel georganiseerd is en hoe het aandeel regionaal voedsel kan worden vergroot. Wat is het huidige gebruik van regionaal voedsel, hoe kunnen we dat veranderen en waarom eigenlijk

Smakelijk eten : aandacht voor eten bij het Leger des Heils

Het Leger des Heils wil meer aandacht voor eten. Het wil voedselverspilling tegengaan door reststromen voedsel uit de voedselindustrie te gebruiken bij de productie van warme maaltijden en waar mogelijk de kwaliteit en beleving van maaltijden verbeteren. Het voorliggend onderzoek gaat in op mogelijkheden om deze ambitie te bereiken

Regionaal voedsel in Arnhem : naar meer regionaal voedsel in Arnhem

In dit rapport staat de vraag centraal hoe de voedselvoorziening van Arnhem en omgeving momenteel georganiseerd is en hoe het aandeel regionaal voedsel kan worden vergroot. Wat is het huidige gebruik van regionaal voedsel, hoe kunnen we dat veranderen en waarom eigenlijk

Ruthenium-decorated lipid vesicles: light-induced release of [Ru(terpy)(bpy)(oh2)]2+ and thermal back coordination

Electrostatic forces play an important role in the interaction between large transition metal complexes and lipid bilayers. In this work, a thioether-cholestanol hybrid ligand (4) was synthesized, which coordinates to ruthenium(II) via its sulfur atom and intercalates into lipid bilayers via its apolar tail. By mixing its ruthenium complex [Ru(terpy)(bpy)(4)]2+ (terpy = 2,2′;6′,2′′-terpyridine; bpy = 2,2′-bipyridine) with either the negatively charged lipid dimyristoylphosphatidylglycerol (DMPG) or with the zwitterionic lipid dimyristoylphosphatidylcholine (DMPC), large unilamellar vesicles decorated with ruthenium polypyridyl complexes are formed. Upon visible light irradiation the ruthenium−sulfur coordination bond is selectively broken, releasing the ruthenium fragment as the free aqua complex [Ru(terpy)(bpy)(OH2)]2+. The photochemical quantum yield under blue light irradiation (452 nm) is 0.0074(8) for DMPG vesicles and 0.0073(8) for DMPC vesicles (at 25 °C), which is not significantly different from similar homogeneous systems. Dynamic light scattering and cryo-TEM pictures show that the size and shape of the vesicles are not perturbed by light irradiation. Depending on the charge of the lipids, the cationic aqua complex either strongly interacts with the membrane (DMPG) or diffuses away from it (DMPC). Back coordination of [Ru(terpy)(bpy)(OH2)]2+ to the thioether-decorated vesicles takes place only at DMPG bilayers with high ligand concentrations (25 mol %) and elevated temperatures (70 °C). During this process, partial vesicle fusion was also observed. We discuss the potential of such ruthenium-decorated vesicles in the context of light-controlled molecular motion and light-triggered drug delivery

η6-Coordination of a ruthenium(II) organometallic fragment to the arene ring of N,C,N-pincer metal complexes

Stable heterobimetallic complexes of the type [MX(NCN)Ru(C5R5)]+ (R = H or Me), where the phenylene ring of an NCN-pincer ligand coordinates first to a platinum or palladium center via a σ-bond, and second to a ruthenium organometallic fragment via a π-bond, are synthesized in a single step involving electrophilic attack of a cationic Ru species on the aryl metal complex. X-ray crystal structures and solution NMR agree on the simultaneous presence of orthogonal η6- and η1-coordination axes. 195Pt NMR and electrochemistry show that the η6-coordinated ruthenium fragment has a strong electron-withdrawing effect on the pincer metal, which leads to a diminished nucleophilicity of the platinum center toward electrophiles such as SO2

η6-Coordination of a ruthenium(II) organometallic fragment to the arene ring of N,C,N-pincer metal complexes

Stable heterobimetallic complexes of the type [MX(NCN)Ru(C5R5)]+ (R = H or Me), where the phenylene ring of an NCN-pincer ligand coordinates first to a platinum or palladium center via a σ-bond, and second to a ruthenium organometallic fragment via a π-bond, are synthesized in a single step involving electrophilic attack of a cationic Ru species on the aryl metal complex. X-ray crystal structures and solution NMR agree on the simultaneous presence of orthogonal η6- and η1-coordination axes. 195Pt NMR and electrochemistry show that the η6-coordinated ruthenium fragment has a strong electron-withdrawing effect on the pincer metal, which leads to a diminished nucleophilicity of the platinum center toward electrophiles such as SO2

SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated to the phenyl ring of the NCN-pincer platinum fragment (cf . [2]+ and [3]+, see Scheme 1), the characteristic orange coloration (pointing to h1- SO2 binding to Pt) of a solution of the parent NCN-pincer platinum complex 1 in dichloromethane upon SO2-bubbling is not observed. However, when the ruthenium center is h6-coordinated to a phenyl substituent linked in para-position to the carbon-to-platinum bond, i.e. complex [4]+, the SO2-binding property of the NCN-platinum center seems to be retained, as bubbling SO2 into a solution of the latter complex produces the characteristic orange color. We performed theoretical calculations at the MP2 level of approximation and TD-DFT studies, which enabled us to interpret the absence of color change in the case of [2]+ as an absence of coordination of SO2 to platinum. We analyze this absence or weaker SO2-coordination in dichloromethane to be a consequence of the relative electron-poorness of the platinum center in the respective h6-ruthenium coordinated NCN-pincer platinum complexes, that leads to a lower binding energy and an elongated calculated Pt–S bond distance. We also discuss the effects of electrostatic interactions in these cationic systems, which also seems to play a destabilizing role for complex [2(SO2)]+

Bimetallic η6,η1 NCN-pincer ruthenium palladium complexes with η6-RuCp coordination: synthesis, X-ray structures, and catalytic properties

The synthesis, structure, and catalytic activity of a series of bimetallic η6,η1-NCN-pincer ruthenium palladium complexes, [3]+−[5]+, have been studied, in which η6-coordination of [Ru(C5R5)]+ (R = H or Me) is realized either directly to the central arene ring of the NCN-pincer palladium complex ([3]+ and [4]+) or to the para-phenyl substituent ([5]+). The X-ray structures of [4]+ and [5]+, as well as the regioselectivity observed in the synthesis of [5]+, provide clear evidence of intramolecular steric interactions in [4]+ between the amine arms of the pincer moiety and the methyl groups of the cyclopentadienyl ligand. Cyclovoltammetry data point to strong electronic interactions between the two metal fragments in [3]+ and [4]+ and only limited interactions in [5]+. Catalytic studies in the cross-coupling reaction between trans-phenylvinylboronic acid and vinyl epoxide show that the catalytic activity of the palladium center is enhanced by η6-coordination of the ruthenium fragment. These modifications of the catalytic activity of palladium are not correlated to the decreased electron density on palladium, as confirmed by DFT calculations. We hence propose a mechanism in which transmetalation is the rate-determining ste

Smakelijk eten : aandacht voor eten bij het Leger des Heils

Het Leger des Heils wil meer aandacht voor eten. Het wil voedselverspilling tegengaan door reststromen voedsel uit de voedselindustrie te gebruiken bij de productie van warme maaltijden en waar mogelijk de kwaliteit en beleving van maaltijden verbeteren. Het voorliggend onderzoek gaat in op mogelijkheden om deze ambitie te bereiken