Catalytic activity towards hydrogen evolution dependent of the degree of conjugation and absorption of six organic chromophores

Conjugated materials can, in many cases, absorb visible light because of their delocalized π electron system. Such materials have been widely used as a photoactive layers in organic photovoltaic devices and as photosensitizers in dye‐sensitized solar cells. Additionally, these materials have been reported for applications in solar fuel production, working as photocatalysts for the hydrogen evolution reaction (HER). The synthesis of three flexible vinyl groups‐containing chromophores is reported. The catalytic activity towards hydrogen evolution of these chromophores has been investigated and compared to their non‐vinyl‐containing analogues. The catalytic effect was confirmed using two different approaches: electrochemical, using the chromophores to modify a working electrode, and photocatalytic, using the chromophores combined with platinum nanoparticles. A relationship between the degree of conjugation and the catalytic activity of the chromophores has been observed with the electrochemical method, while a relationship between the UV absorption in the solid state and the photocatalytic effect with platinum nanoparticles was observed

Paramagnetic octahedral p-methoxyphenyldithiophosphonato nickel(II) complexes: Crystal structures of [Ni{S2P(OR)(p-CH3O-C 6H4)-κS,S′}2(L-κN) 2] (R = Et, 2,4-tBu2C6H3, L = 3-acetylpyridine)

The square-planar NiII complexes [Ni{S2P(OR)(p- CH3O-C6H4)-κS,S′}2] react with 3-acetylpyridine to give green crystals of the paramagnetic octahedral complexes [Ni{S2P(OR)(p-CH3O-C 6H4)-κS,S′}2(L-κN) 2] [R = Et (1), iPr (2), 2,4-tBu 2C6H3 (3); L = 3-acetylpyridine]. Complexes 1-3 were characterized by IR, MS, and UV-vis spectroscopy, and crystal structures were determined for 1 and 3. The magnetic moments for 1-3 are 3.04-3.15 B.M

Heterobimetallic nickel(II) complexes of ferrocenyldithiophosphonates. Molecular structures of [{FcP(OR)S2}2Ni] [Fc = Fe(η5-C5H4)(η5-C 5H5), R = Et, Pri, Bus, Bu i]

The reaction of 2,4-diferrocenyl-1,3-dithiadiphosphetane 2,4-disulfide [FcPS(μ-S)]2 [Fc = Fe(η5-C5H 4)(η5-C5H5)] with alcohols ROH gave the corresponding ferrocenyldithiophosphonic acids [FcPS(OR)(SH)], which were treated in situ with Ni(CH3COO)2·4H 2O in acetic acid to yield the square-planar heterobimetallic trinuclear complexes [{FcP(OR)S2}2Ni] (R = Me (1), Et (2), Pri (3), Bus (4) and Bui (5)). Compounds 1-5 were characterized by elemental analysis, MS, NMR (1H, 13C and 31P), IR spectroscopy, and 2-5 also by X-ray crystallography. Cyclovoltammetric studies on the heterobimetallic nickel(II) complexes 1-5 showed irreversible reduction to unstable nickel(I) complexes and an irreversible two-electron oxidation of the sulfur-containing nickel fragments, followed by a reversible one-electron oxidation of the two ferrocenyl groups

Unique anisotropic optical properties of a highly stable metal–organic framework based on trinuclear iron(III) secondary building units linked by tetracarboxylic linkers with an anthracene core

A highly stable metal–organic framework, [{Fe3(ACTBA)2}X·6DEF]n (1; X = monoanion), based on trinuclear iron(III) secondary building units connected by tetracarboxylates with an anthracene core, 2,6,9,10-tetrakis(p-carboxylatophenyl)anthracene (ACTBA), is reported. Depending on the direction of light polarisation, crystals of 1 exhibit anisotropic optical properties with birefringence Δn = 0.3 (λ = 590 nm)