Design and photophysical studies of iridium(iii)–cobalt(iii) dyads and their application for dihydrogen photo-evolution

We report several new dyads constituted of cationic iridium(iii) photosensitizers and cobalt(iii) catalyst connected via free pendant pyridine on the photosensitizers.

A Bisamide Ruthenium Polypyridyl Complex as a Robust and Efficient Photosensitizer for Hydrogen Production

A photosensitizer based on a ruthenium complex of a bisamide-polypyridyl ligand gives rise to a large improvement in photocatalytic stability, rate of activity, and efficiency in photocatalytic H₂ production compared to [Ru(bpy)₃ ]²⁺ (bpy=2,2'-bpyridine). The bisamide ruthenium polypyridyl complex combined with a cobaltoxime-based photocatalyst was found to be highly efficient under blue-light (turnover number (TON)=7800) and green-light irradiation (TON=7200) whereas [Ru(bpy)₃ ]²⁺ was significantly less effective with a TON of 2600 and 1100, respectively. The greatest improvement was under red-light-emitting diodes, with bisamide ruthenium polypyridyl complex and cobaltoxime exhibiting a TON of 4200 compared to [Ru(bpy)₃ ]²⁺ and cobaltoxime at a TON of only 71.

Improved photocatalytic hydrogen evolution driven by chloro(terpyridine)platinum(ii) derivatives tethered to a single pendant viologen acceptor

Chloro(terpyridine)platinum(ii) derivatives tethered to a single pendant viologen acceptor exhibit drastically improved turnover number in the photocatalytic H₂ evolution reaction from water.

A tricarboxylated PtCl(terpyridine) derivative exhibiting pH-dependent photocatalytic activity for H2 evolution from water

A ‘negatively charged’ PtCl(terpyridine) derivative was found to be the first example of a Pt(ii)-based molecular photocatalyst capable of driving H₂ evolution coupled with a PCET process at the ligand geometry.

Red-light-driven photocatalytic hydrogen evolution using a ruthenium quaterpyridine complex

The ruthenium tris-quaterpyridine complex, obtained in quantitative yield, is an excellent photosensitiser for photocatalytic hydrogen production, especially under red-light irradiation.

A new Ru,Ru,Pt supramolecular architecture for photocatalytic H2 production

New RuRuPt complexes photocatalytically reduce H₂O to H₂ with enhanced efficiency and stability compared to Ru₂RuPt analogues.

Syntheses, characterization, and photo-hydrogen-evolving properties of tris(2,2'-bipyridine)ruthenium(II) derivatives tethered to an H2-evolving (2-phenylpyridinato)platinum(II) unit

With the aim of developing new molecular devices having higher photo-hydrogen-evolving activity, Pt(ppy)ClX units (ppy = 2-phenylpyridinate, X = Cl^- or DMSO; DMSO = dimethylsulfoxide) have been employed as an H₂-evolving site, as the catalytic activity of [Pt(ppy)Cl₂]^- was confirmed to be higher than those of other mononuclear platinum(II) complexes. In the present study, two new heterodinuclear Ru(II)Pt(II) complexes, produced by condensation of [Ru(bpy)₂(5-amino-phen)]²⁺ (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) with [Pt(cppy)Cl₂]^- and Pt(cppy)(DMSO)Cl (cppy = 9-carboxy-phenylpyridinate), respectively, have been prepared and their photo-hydrogen-evolving activities have been evaluated in detail. The ineffectiveness of these systems as photo-hydrogen-evolving molecular devices are interpreted in terms of their negative driving forces for the photoinduced electron transfer from the triplet MLCT excited state of the Ru chromophore to the π*(ppy) orbital of the catalyst moiety.

Bis(2,2'-bipyridine){ethyl 4'-[N-(4-carbamoylphen-yl)carbamo-yl]-2,2'-bi-pyridine-4-carboxyl-ate}ruthenium(II) bis-[hexa-fluorido-phosphate(V)]

In the title compound, [Ru(C(10)H(8)N(2))(2)(C(21)H(18)N(4)O(4))](PF(6))(2), the Ru(II) complex cation reveals a slightly distorted octa-hedral coordination. The coordination bonds of the 4,4'-substituted bipyridyl donors [Ru-N = 2.038 (3) and 2.051 (3) Å] are shorter than those of the 2,2'-bipyridyl donors [Ru-N1 = 2.065 (3)-2.077 (3) Å], due to the electron-withdrawing effects of the substituents at the 4,4'-positions. The angles between the pyridyl planes of the three bipyridyl ligands are 1.5 (2), 6.3 (3) and 8.7 (2)°, respectively. The cations are connected by anions via N-H⋯F inter-actions.

Chlorido(dimethyl sulfoxide-κS)[2-(2-pyrid-yl)phenyl-κN,C]platinum(II)

In the title compound, [Pt(C(11)H(8)N)Cl(C(2)H(6)OS)], the S atom of dimethyl sulfoxide is trans to the pyridyl N atom [Pt-S = 2.2181 (11) Å] and the chlorido ligand is trans to the carbon donor of 2-(2-pyrid-yl)phenyl [Pt-Cl = 2.4202 (10) Å]. The [2-(2-pyrid-yl)phen-yl]platinum(II) unit forms a one-dimensional stack along the c axis with two independent inter-planar separations of 3.44 (9) and 3.50 (2) Å.

N-(1,10-Phenanthrolin-5-yl)-4-(2-pyridyl)-benzamide monohydrate

In the title mol­ecule, C₂₄H₁₆N₄O·H₂O, the benzene ring of the 1,10-phenanthroline group and that of the 2-phenyl­pyridine group are respectively twisted by 67.9 (1) and 15.3 (3)° from the carbamoyl group defined by the plane of the O=C—N group of atoms. The water mol­ecule is hydrogen bonded to one of the phenanthroline N atoms. In the crystal structure, significant π–π stacking inter­actions occur, with centroid-to-centroid separations in the range 3.567–3.681 (2) Å.