Nanoarchitectonics of Metal-Free Porous Polyketone as Photocatalytic Assemblies for Artificial Photosynthesis

The main component of natural gas is methane, whose combustion contributes to global warming. As such, sustainable, energy-efficient, nonfossil-based methane production is needed to satisfy current energy demands and chemical feedstocks. In this article, we have constructed a metal-free porous polyketone (TPA-DPA PPK) with donor-acceptor (D-A) groups with an extensive π-conjugation by facile Friedel-Crafts acylation reaction between triphenylamine (TPA) and pyridine-2,6-dicarbonyl dichloride (DPA). TPA-DPA PPK is a metal-free catalyst for visible-light-driven CO₂ photoreduction to CH₄, which can be used as a solar fuel in the absence of any cocatalyst and sacrificial agent. CH₄ production (152.65 ppm g^-1) is ∼5 times greater than that of g-C₃N₄ under the same test conditions. Charge-density difference plots from excited-state time-dependent density functional theory (TD-DFT) calculations indicate a depletion and accumulation of charge density among the donor/acceptor functional groups upon photoexcitation. Most notably, binding energies from DFT demonstrate that H₂O is more strongly bound with the pyridinic nitrogen group than CO_2, which shed insight into mechanistic pathways for photocatalytic CO₂ reduction.

Spin crossover and structural phase transition in homochiral and heterochiral Fe[(pybox)2]2+ complexes

Spin crossover and structural phase transition were discovered in three pairs of homochiral and heterochiral [Fe(pybox)₂]²⁺ diastereomers.

2-(1,3-Oxazolin-2-yl)pyridine and 2,6-bis(1,3-oxazolin-2-yl) pyridine

The data presented in this article are related to research articles “Titanium and vanadium catalysts with oxazoline ligands for ethylene-norbornene (co)polymerization (Ochędzan-Siodłak et al., 2018). For the title compounds, 2-(1,3-oxazolin-2-yl)pyridine (Py-ox) and 2,6-bis(1,3-oxazolin-2-yl)pyridine (Py-box), the single-crystal X-ray diffraction measurement together with NMR, GC, MS, DSC analysis, like also the method of crystallization are presented.

Estimation of conventional C-Hπ (arene), unconventional C-Hπ (chelate) and C-Hπ (thiocyanate) interactions in hetero-nuclear nickel(ii)-cadmium(ii) complexes with a compartmental Schiff base

Three new heteronuclear nickel(ii)/cadmium(ii) complexes, [(SCN)(Cl)Cd(L)Ni(DMF)₂] (1), [(SCN)(CH₃CO₂)Cd(L)Ni(CH₃OH)₂] (2) and [(SCN)(Cl)Cd(L)Ni(NH₂CH₂CH₂CH₂NH₂)]_n (3) {where H₂L = N,N'-bis(3-ethoxy-salicylidene)propane-1,3-diamine is a N₂O₄ compartmental Schiff base}, have been synthesized and characterized. The structures of the complexes have been confirmed by single crystal X-ray diffraction studies. In each complex, nickel(ii) is placed in the inner N₂O₂ environment and cadmium(ii) is placed in the outer O₄ compartment of the compartmental Schiff base. Furthermore, the importance of unconventional C-Hπ (chelate) interactions in the solid state of both complexes and C-Hπ (thiocyanate) interaction in complex 2 has been described by means of DFT and MEP calculations and characterized using NCI plots. All complexes show photoluminescence at room temperature upon irradiation by ultraviolet light. The lifetimes of excited states are in the range of 2-6 ns.

Both end-on and end-to-end azide bridged tetranuclear ferromagnetic nickel(ii) Schiff base complexes

Variable temperature magnetic measurement of a tetranuclear nickel(ii) complex, consisting of two pseudo-dinuclear entities, indicates the presence of intra- and inter-dinuclear ferromagnetic interactions, corroborated by DFT calculations.

Enantioselective, Copper-Catalyzed Alkynylation of Ketimines To Deliver Isoquinolines with α-Diaryl Tetrasubstituted Stereocenters

An enantioselective, copper-catalyzed alkynylation of cyclic α,α-diaryl ketiminium ions has been developed to deliver isoquinoline products with diaryl, tetrasubstituted stereocenters. The success of this reaction relied on identification of Ph-PyBox as the optimal ligand, i-Pr₂NEt as the base, and CHCl₃ as the solvent. A broad scope and functional group tolerance were observed. Notably, the use of both aryl and silyl acetylenes results in high yields and enantioselectivities. Mechanistic experiments are consistent with a dimeric or higher order catalyst.

Spin transitions in a series of [Fe(pybox)2]2+ complexes modulated by ligand structures, counter anions, and solvents

A new family of mononuclear Fe(ii) compounds is synthesized based on pybox ligands. Their spin-crossover behaviours can be effectively mediated by ligand structures, counter anions, and solvents.

Fluorescence tuning of Zn(ii)-based metallo-supramolecular coordination polymers and their application for picric acid detection

A series of metallo-supramolecular coordination polymers displayed strong and tunable visible luminescent emission and possessed the capability for detection of picric acid (PA) with high sensitivity and selectivity.

Controlled access to a heterometallic N-heterocyclic carbene helicate

Metallation of a pentadentate diNHC proligand bearing a dipropyl-pyridine-2,6-dicarboxamide with silver and gold affords mono- and dinuclear, double-stranded bis(NHC) complexes as useful building blocks for metallo-supramolecules. The digold(I) complex acts as a metallo-bis(pincer) ligand to furnish the first example of an organometallic NHC-helicate upon coordination to cobalt.

Structural phase transition in a multi-induced mononuclear FeII spin-crossover complex

One mononuclear Fe^II complex displays a structural phase transition and a multi-induced spin-crossover behavior mediated by heat, light, pressure and solvent.

Tetrazolate–azido–copper(ii) coordination polymers: tuned synthesis, structure, and magnetic properties

Two antiferrimagnetic tetrazolate–azido–copper(ii) coordination polymers, [Cu(tz)(N₃)]_n (1) and [Cu(tz)(N₃)(NH₃)₂]_n (2) with distinct topological structures were synthesized under different reaction conditions and structurally characterized.