Chao-Wei Zhao

Copper(I) Metal–Organic Framework: Visual Sensor for Detecting Small Polar Aliphatic Volatile Organic Compounds

A porous Cu(I)-MOF [H2O⊂Cu2(L)2I2; L = 1-benzimidazolyl-3,5-bis(4-pyridyl)benzene], which can be a visual and luminescent sensor for detecting small polar aliphatic volatile organic compounds (VOCs), such as alcohols, ketones, and halocarbons, is reported. The naked-eye and luminescent detection limitations for these VOCs are 5 and 1 ppm, respectively.

Pd@Cu(II)-MOF-Catalyzed Aerobic Oxidation of Benzylic Alcohols in Air with High Conversion and Selectivity

A new 3D porous Cu(II)-MOF (1) was synthesized based on a ditopic pyridyl substituted diketonate ligand and Cu(OAc)2 in solution, and it features a 3D NbO motif which is determined by the X-ray crystallography. Furthermore, the Pd NPs-loaded hybrid material Pd@Cu(II)-MOF (2) was prepared based on 1 via solution impregnation, and its structure was confirmed by HRTEM, SEM, XRPD, gas adsorption-desorption, and ICP measurement. 2 exhibits excellent catalytic activity (conversion, 93% to >99%) and selectivity (>99% to benzaldehydes) for various benzyl alcohol substrates (benzyl alcohol and its derivatives with electron-withdrawing and electron-donating groups) oxidation reactions in air. In addition, 2 is a typical heterogeneous catalyst, which was confirmed by hot solution leaching experiment, and it can be recycled at least six times without significant loss of its catalytic activity and selectivity.

A self-assembled Pd6L8 nanoball for Suzuki–Miyaura coupling reactions in both homogeneous and heterogeneous formats

A self-assembled nano-sized Pd6L8 (L = 1,3,5-tris(4′-pyridyloxadiazole)-2,4,6-triethylbenzene) ball was constructed based on a new oxadiazole-containing tripod. In H2O–EtOH mixed-solvent system, Pd(II)-ball displays excellent performance in Suzuki–Miyaura cross-coupling reactions at low catalyst loading under ambient conditions in a homogeneous fashion. Furthermore, it shows heterogeneous catalyst nature in o-xylene and can be reused without loss of catalytic activity.

Micro-Cu4I4-MOF: reversible iodine adsorption and catalytic properties for tandem reaction of Friedel–Crafts alkylation of indoles with acetals

We report a convenient approach, the first of its kind, to construct a microscale non-metal@MOF composite catalytic host-guest system for an organic tandem reaction. The reported porous Cu4I4-MOF is able to reversibly adsorb molecular iodine at room temperature. The obtained I2@Cu4I4-MOF host-guest system can be a highly heterogeneous catalyst to promote the Friedel-Crafts alkylation of indoles with acetals in a one-pot two-step fashion under solvent-free conditions at room temperature.

Cu(II)4L4 coordination-driven molecular container: a reusable visual colorimetric sensor for Ag(I) ions

A Cu4L4 square-like molecular container which can be a reusable visual sensor for Ag(+) is reported. The present results can be a useful stepwise approach for the construction of the heterometallic supramolecular complexes with potential applications.

Reversible visual thermochromic coordination polymers via single-crystal-to-single-crystal transformation

A thermostable Cu(II)-coordination polymer can exhibit a temperature-dependent color change in the solid state. We report the first single-crystal-to-single-crystal transformation for reversible visual thermochromism.

Fabrication of Cd(II)-MOF-based ternary photocatalytic composite materials for H2 production via a gel-to-crystal approach.

Cd(II)-MOF-based ternary composite materials of CdS@Cd(II)-MOF@TiO2 were prepared by a unique TiO2 induced gel-to-crystal approach. CdS@Cd(II)-MOF@TiO2 was demonstrated to be a highly active photocatalyst for hydrogen production under visible light based on water photolysis.

Coordination polymer-templated photoinduced [2 + 2] dimerization of pyridine-based derivative

2-Hydroxyquinoline-4-carboxylic acid (L1), an important medical intermediate, is photoinert for [2 + 2] photoaddition in solution. In this contribution, we report that the elaborately designed 1D coordination polymers, such as {M(bpa)}n (M = Zn(II), Mn(II) and Co(II), bpa = 1,2-bis(4-pyridyl)ethane) and {M(azpy)}n (M = Mn(II) and Cd(II), azpy = 4,4′-azobispyridine), are able to steer the pair of corresponding pyridyl CC bonds on L1 for photodimerization. Notably, this photodimerization is irradiated by sunlight instead of high-intensity UV-light.

Synthesis, structure and multifunctional catalytic properties of a Cu(I)-coordination polymer with outer-hanging CuBr2

A 1D Cu(I)-coordination polymer [(CuL1)(CuBr2), 1] carrying external copper bromide moieties was synthesized. The outer-hanging [CuBr2]− moiety is attached to the 1D Cu(I)-CP backbone via a Cu⋯Cu bonding interaction, which makes it look like a coordination polymer supported CuBr2 species. 1 exhibits excellent multifunctional catalytic activity for phenol acetylation, A3-coupling (aldehyde–alkyne–amine) and styrene oxide methanolysis reactions. Its heterogeneous catalytic nature was confirmed by solution leaching experiment and it can be reused without significant loss of its catalytic activity and selectivity for the above reactions.

The coordination chemistry of two symmetric fluorene‐based organic ligands with cuprous chloride

Two novel symmetric fluorene-based ligands, namely, 2,7-bis(1H-imidazol-1-yl)-9,9-dimethyl-9H-fluorene [L1 or (I), C21H18N4] and 2,7-bis(1H-imidazol-1-yl)-9,9-dipropyl-9H-fluorene (L2), have been used to construct the coordination polymers catena-poly[[dichloridodicopper(I)(Cu-Cu)]-μ-2,7-bis(1H-imidazol-1-yl)-9,9-dimethyl-9H-fluorene], [Cu2Cl2(C21H18N4)]n, (II), and catena-poly[[tetra-μ2-chlorido-tetracopper(I)]-bis[μ-2,7-bis(1H-imidazol-1-yl)-9,9-dipropyl-9H-fluorene]], [Cu4Cl4(C25H26N4)2]n, (III). There are three types of C-H···N hydrogen bonds in (I), resulting a two-dimensional network in the ab plane, including a chiral helical chain along the b axis. Compounds (II) and (III) are related one-dimensional polymers. In both, Cu(I) atoms connect the symmetric ligands (L1 or L2) into a one-dimensional chain. In (II), the {[Cu(I)Cl2](-)} unit, acting as a co-anion, adheres to the one-dimensional chain through a weak Cu···Cu interaction. However, in (III), the {[Cu(I)2Cl4](2-)} unit links two different chains into a one-dimensional rope-ladder-type chain. In addition, there are C-H···Cl hydrogen bonds and π-π interactions in the extended structures of (II) and (III), the difference is that the chains in (II) are linked into a two-dimensional network while the chains in (III) are stacked into a three-dimensional framework.