Molecular surface modification of silver chalcogenolate clusters.

This study presents a molecular surface modification approach to synthesizing a family of silver chalcogenolate clusters (SCCs) containing the same [Ag12S6] core and different surface-bonded organic ligands (DMAc or pyridines; DMAc = dimethylacetamide), with the aim of tuning the luminescence properties and increasing the structural stability of the SCCs. The SCCs displayed strong and tuneable luminescence emissions at 77 K (from green to orange to red) as influenced by the peripheral pyridine ligands. In addition, SCC 5 protected by pyridine molecules was stable in ambient air, humid air and even liquid water for a long time (up to 1 week), and it was more structurally stable than SCC 1 bonded with DMAc molecules under the same conditions. The high structural stability of SCC 5 can be explained by the ability of pyridine molecules to form strong coordination bonds with silver atoms. This study offers a new way of designing structurally stable metal nanoclusters with tuneable physicochemical properties.

Self-assembly and guest-induced disassembly of triply interlocked [2]catenanes.

Two fascinating triply interlocked [2]catenanes and one simple triangular prism metallacage were constructed by tuning the widths of the organometallic dinuclear building blocks. Notably, the interlocked architectures were disassembled in the presence of large aromatic molecules to form their corresponding monomeric host-guest complexes.

A new supramolecular catalytic system: the self-assembly of Rh8 cage host anthracene molecules for [4 + 4] cycloaddition induced by UV irradiation.

The supramolecular assembly, used as a molecular reactor, is of great significance in host-guest chemistry. In this work, we used a tetratopic pyridyl ligand as a building block to hierarchically combine a slightly twisted cuboid with half-sandwich rhodium fragments. The cuboid directionally self-assembled hydrophobic pockets that can encapsulate conjugated molecules like anthracene (ANT) as guests in solutions, by supramolecular interactions including hydrogen bonding and hydrophobic interactions. The array of the ANT molecules in the confined pockets was subjected to a [4 + 4] photocycloaddition reaction under UV light irradiation as an external stimulus in a methanol solution. Furthermore, the mechanism underlying the process was proposed. The cuboid was fully characterized by 1H NMR, single-crystal X-ray diffraction (SCXRD), and mass spectrometry (MS), and its host-guest and cycloaddition processes were monitored by 1H NMR spectroscopy and UV-visible spectrophotometry.

Assembly of Discrete Chalcogenolate Clusters into a One-Dimensional Coordination Polymer with Enhanced Photocatalytic Activity and Stability.

Interlinking discrete supertetrahedral chalcogenolate clusters with conjugated bipyridine linkers form a one-dimensional coordination polymer, [Cd6Ag4(SPh)16(DMF)(H2O)(bpe)]n (1a), displaying a broader visible-light absorption and a narrower band gap than those of the discrete cluster. More importantly, the coordination polymer demonstrates enhanced activity and stability for the photocatalytic degradation of organic dye in water.

Interlinking supertetrahedral chalcogenolate clusters with bipyridines to form two-dimensional coordination polymers for photocatalytic degradation of organic dye.

Chalcogenolate clusters Cd6Ag4(EPh)16(DMF)3(CH3OH) (E = S, Se) with supertetrahedral structures are isolated. Further interlinking the clusters with organic linker 4,4'-trimethylenedipiperidine in the stepwise assembly approach forms two-dimensional coordination polymers. The clusters and the coordination polymers show tunable band gaps and efficient photocatalytic activities for the degradation of aqueous dye solution. This study demonstrates the great potential of using chalcogenolate clusters and their coordination polymers in photocatalysis applications.

Electrocatalytic oxygen evolution with a cobalt complex.

The development of an earth-abundant, first-row water oxidation catalyst that operates at a high TOF and a low overpotential remains a fundamental chemical challenge. Cobalt complexes are important members of water oxidation catalysts. Herein, we report a cobalt-based robust homogeneous water oxidation catalyst, which can electrocatalyze water oxidation at a high pH and a low overpotential (η = 520 mV) in phosphate buffer. This homogeneous system exhibits a high turnover frequency (about 5 s-1) of catalyzing water oxidation to produce oxygen at η = 720 mV. We speculate the mechanism of the reaction that O-O bond formation prefers a HO-OH coupling in catalytic water oxidation.

Photodimerization behaviour of 1D-3D Zn(II) coordination polymers with tetrazolyl styrylpyridine.

The [2 + 2] photodimerization of tetrazolyl styrylpyridine leads to single-crystal-to-single-crystal transformations of four Zn(II) coordination polymers with 1D-3D structures, exhibiting controllable reaction extent, luminescence decrease or blue shift, and a two-step reaction process with a phase transition point.

Stepwise assembly of a semiconducting coordination polymer [Cd8S(SPh)14(DMF)(bpy)]n and its photodegradation of organic dyes.

Chalcogenolate clusters can be interlinked with organic linkers into semiconducting coordination polymers with photocatalytic properties. Here, discrete clusters of Cd8S(SPh)14(DMF)3 were interlinked with 4,4'-bipyridine into a one dimensional coordination polymer of [Cd8S(SPh)14(DMF)(bpy)]n with helical chains. A stepwise mechanism for the assembly of the coordination polymer in DMF was revealed by an ex situ dynamic light scattering study. The cluster was electrostatically neutral and showed a penta-supertetrahedral structure. During the assembly each cluster was interlinked with two 4,4'-bipyridine molecules, which replaced the two terminal DMF molecules of the clusters. In their solid-state forms, the cluster and the coordination polymer were semiconductors with wide band gaps of 3.08 and 2.80 ev. They photocatalytically degraded rhodamine B and methylene blue in aqueous solutions. The moderate conditions used for the synthesis could allow for further in situ studies of the reaction-assembly of related clusters and coordination polymers.

Anion-directed self-assembly of two half-sandwich ruthenium-based metallamacrocycles as catalysts for water oxidation.

The binuclear [η(6) -(cymene)Ru(L)]2 (OTf)2 (TfO(-) =trifluoromethanesulfonate) and tetranuclear [η(6) -(cymene)Ru(L)]4 (NO3 )4 metallacycles were prepared by treating the pyridyl-substituted 8-hydroxyquinoline ligand (E)-2-[2-(pyridin-3-yl)vinyl]quinolin-8-ol (HL) with [(p-cymene)Ru(µ-Cl)Cl]2 in the presence of AgOTf or AgNO3 . The molecular structures of these complexes were confirmed by single-crystal X-ray diffraction, which revealed that both complexes have macrocycle frameworks induced by the TfO(-) and NO3 (-) counteranions, respectively. The electrochemical properties of the two metallacycles were investigated by cyclic voltammetry, which showed that they have great potential as catalysts for water oxidation. Good efficiency was obtained by utilizing the nitrate complex as a water oxidation catalyst in the presence of a Ce(IV) salt as an oxidant at high pH values.

A new copper species based on an azo-compound utilized as a homogeneous catalyst for water oxidation.

A new azo-complex [(L)Cu(II)(NO3)] [L = (E)-3-(pyridin-2-yldiazenyl)naphthalen-2-ol (HL)], was prepared via a one-pot synthetic method at 60 °C and was structurally characterized by IR, EA, PXRD and single crystal X-ray diffraction. In addition, TGA studies indicated that the complex was stable in air. The redox properties were determined by cyclic voltammetry, which revealed that the complex could be utilized as a catalyst for water oxidation under mild conditions. Subsequently, the complex was employed as a catalyst to take part in water oxidation reaction in the presence of a Ce(IV) salt utilized as an oxidant at pH 11 in PBS (Phosphate Buffered Saline) solution. The results suggested that the catalyst exhibited a high stability and activity toward water oxidation reaction under these conditions with an initial TOF of 4.0 kPa h(-1). Calculation methodology was performed to study the mechanism of the reaction, which revealed that in this catalytic process, the initial oxidation of Cu(II) to Cu(III) occurred by the formation of an intermediate "Cu(III)-O-O-Cu(III)". The formation of this intermediate, resulted in a release of oxygen and closing of the catalytic cycle.

Pyrolytic cavitation, selective adsorption and molecular recognition of a porous Eu(III) MOF.

A channel-equipped metal-organic framework (1-pyr), resulting from the pyrolysis of [(CH3)2NH2]@[Eu2L3(HCOO)] (1) (L(2-) = isophthalate), showed the preferable absorption of CO2 and the Eu(III)-based emission quenched by aromatics.

Water oxidation catalysts and pH sensors based on azo-conjugated iridium/rhodium motifs.

Herein we report the molecular structures and electronic properties of ionic, hydrophobic half-sandwich complexes with formula [η(5)-Cp*Ir(L)(Cl)](OTf) (), [η(5)-Cp*Rh(L)(Cl)](OTf) (), [η(5)-Cp*Ir(L)(H2O)](OTf)2 () and [η(5)-Cp*Rh(L)(H2O)](OTf)2 (), where L is 1-(2-pyridylazo)-2-naphthol. The electrochemical properties of these complexes have been investigated, and they displayed good electronic properties for use as water oxidation catalysts. Interestingly, the color of their solutions is unambiguously transformed from brown to green at pH = 12; the color changes of , and are especially apparent. For this reason, their use as pH sensors for detecting solution pH values can be explored.

A semiconducting microporous framework of Cd6Ag4(SPh)16 clusters interlinked using rigid and conjugated bipyridines.

Ternary supertetrahedral chalcogenolate clusters were interlinked with bipyridines into a microporous semiconducting framework with properties qualitatively different from those of the original clusters. Both the framework and the clusters were effective photocatalysts, and rapidly degraded the dye rhodamine B.

Azo-conjugated half-sandwich Rh/Ru complexes for homogeneous water-oxidation catalysis.

Herein we report the molecular structures and electronic properties of ionic, hydrophobic, half-sandwich complexes of the formula [η(5)-Cp*Rh(L)(MeOH)] (1) and [η(6)-CyRu(L)(H2O)] (2), where L is azo-dye compound of (p-(2-hydroxy-1-naphthylazo)benzenesulfonic acid sodium salt). Both these complexes have been investigated electrochemically and found to display good electronic properties for use as water-oxidation catalysts potentially.

Chlorido[2,2'-[1,2-phenyl-enebis(nitrilo-methanylyl-idyne)]diphenolato-κ(4) O,N,N',O']manganese(III) methanol monosolvate.

In the title complex, [Mn(C20H14N2O2)Cl]·CH3OH, the central Mn(III) atom displays a distorted square-pyramidal coordination by two N and two O atoms from the tetradentate 2,2'-[1,2-phenyl-enebis(nitrilo-methanylyl-idyne)]diphenolate ligand and one chloride ligand. The Mn(III) atom is 0.525 (4) Šout of the square basal N2O2 least-squares plane. The complex mol-ecule is hydrogen bonded to the methanol solvent mol-ecule.

µ-(Acetic acid)-di-µ-chlorido-bis[tri-phenyl-tellurium(IV)] monohydrate.

The asymmetric unit of the title compound, C38H34Cl2O2Te2·H2O, contains two independent Te(IV) cations, each coordinated by three phenyl ligands, two Cl(-) anions and one acetic acid mol-ecule in a distorted octa-hedral C3Cl2O geometry; the longer Te⋯Cl distances ranging from 3.2007 (11) to 3.4407 (11) Šand the longer Te⋯O distances of 3.067 (3) and 3.113 (3) Šindicate the weak bridge coordination. The Cl(-) anion and acetic acid mol-ecule bridge the two independent Te(IV) cations, forming the dimeric complex mol-ecule, in which the Te⋯Te separation is 3.7314 (4) Å. In the crystal, the water molecules of crystallization link the Te(IV) complex mol-ecules into chains running along the b-axis direction via O-H⋯O and O-H⋯Cl hydrogen bonds.

Tris(aceto-nitrile-κN)dichlorido(tri-phenyl-phosphane-κP)ruthenium(II) aceto-nitrile monosolvate.

In the title complex, [RuCl2(CH3CN)3(C18H15P)]·CH3CN, the coordination geometry of the Ru(II) atom is distorted octa-hedral, defined by one P atom from a tri-phenyl-phosphane ligand, three N atoms from three aceto-nitrile ligands and two Cl atoms. The three acetronitile ligands linearly bind to the Ru(II) atom, with Ru-N-C angles of 172.6 (2), 179.9 (2) and 171.4 (2)°.

Tris(diisopropyl di-thio-phosphato-κ(2) S,S')ruthenium(III).

In the title complex, [Ru(C6H14O2PS2)3], the coordination environment of the Ru(III) atom is distorted octa-hedral, defined by six S atoms from three S,S'-bidentate diisopropyl di-thio-phosphate ligands. The average Ru-S bond length is 2.41 (1) Šand the average S-Ru-S bite angle is 81.13 (19)°.

catena-Poly[[(tri-phenyl-phosphane-κP)silver(I)]-µ-4,4'-bi-pyridine-κ(2) N:N'-[(tri-phenyl-phosphane-κP)silver(I)]-di-µ-chlorido].

In the title coordination polymer, [Ag2Cl2(C10H8N2)(C18H15P)2] n , the Ag(I) cation is coordinated by a 4,4'-bi-pyridine N atom, a tri-phenyl-phosphane P atom and two Cl(-) anions in a distorted tetra-hedral geometry. The 4,4-bi-pyridine and Cl(-) anions bridge the Ag(I) cations, forming polymeric chains running along [21-1]. In the crystal, weak C-H⋯Cl inter-actions link the polymeric chains into a three-dimensiona supra-molecular architecture.