David James Young

Ligand-Controlled Copper(I)-Catalyzed Cross-Coupling of Secondary and Primary Alcohols to α-Alkylated Ketones, Pyridines, and Quinolines

One hexanuclear Cu(I) cluster of 4,6-dimethylpyrimidine-2-thiolate efficiently catalyzes the dehydrogenative cross-coupling of secondary and primary alcohols to α-alkylated ketones with high selectivity. This transformation proceeds through a one-pot sequence of dehydrogenation of alcohols, condensation of aldehydes and ketones, hydrogenation of the resulting α,β-unsaturated ketones, and dehydrogenation of the α-alkylated alcohols to generate α-alkylated ketones. This catalytic system also displays high activity for the annulation reaction of secondary alcohols with γ-amino- and 2-aminobenzyl alcohols to yield pyridines and quinolines, respectively.

Efficient ring-opening polymerization (ROP) of ε-caprolactone catalysed by isomeric pyridyl β-diketonate iron(iii) complexes

A series of Fe(III) complexes of β-diketonate ligands, 1-(2-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L1), 1-(2-pyridyl)-3-(2-pyridyl)-1,3-propanedione (L2), 1-(2-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L3), 1-(3-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L4), 1-(3-pyridyl)-3-(3-pyridyl)-1,3-propanedione (L5) and 1-(4-pyridyl)-3-(4-pyridyl)-1,3-propanedione (L6), viz. [Fe(L1)3] (1), [Fe(L2)3] (2), [Fe(L3)3] (3), [Fe(L4)3] (4), [Fe(L5)3] (5) and [Fe(L6)3] (6) have been structurally characterized. All but one complex (1) catalyzed the ring-opening polymerization (ROP) of e-caprolactone (e-CL) in near quantitative yield at 110 °C to give polymers with relatively narrow polydispersities (PDI). The comparison of in situ reaction and a reaction with preformed 1 indicated that the latter was a better catalyst, giving a higher molecular weight. Complex 2 catalyzed this reaction in a more modest yield reflecting its greater thermal stability, shorter Fe–O bonds and minimal distortion in fold angle among the isomeric complexes, suggesting that ligand dissociation is important for catalytic activity.

Rectangle and [2]catenane from cluster modular construction

Reaction of [Et4N][Tp*WS3] (1) with [Cu(MeCN)4]PF6, CsCl, isonicotinic acid and CuCN, and treatment of [Et4N][Tp*WS3(CuCl)3] (2)/[Et4N][{Tp*WS3Cu3Cl}2(μ-Cl)2(μ4-Cl)] (3) with AgOTf and bpp (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; bpp = 1,3-di(4-pyridyl)propane) give rise to [Et4N]2[{Tp*WS3Cu3(CN)0.5}2(μ-Cl)2(μ4-Cl)]2(PF6)2 (4) and [(Tp*WS3Cu3)2(μ3-Cl)2(bpp)3]2(OTf)4 (5), respectively. Compounds 4 and 5 feature cluster-based rectangle and [2]catenane architecture, and both exhibit enhanced third-order nonlinear optical responses relative to those of 1.

(2Z)-3-Hy­droxy-1-(pyridin-2-yl)-3-(pyridin-3-yl)prop-2-en-1-one: crystal structure and Hirshfeld surface analysis

The title molecule, featuring an intramolecular O—H⋯O hydrogen bond, is non-planar as seen in the dihedral angle between the pyridyl rings of 7.45 (7)°. In the crystal, supramolecular chains are formed via π(pyridin-2-yl)–π(pyridin-3-yl) interactions.

4-[(1-Benzyl-1H-1,2,3-triazol-4-yl)meth­oxy]benzene-1,2-dicarbo­nitrile: crystal structure, Hirshfeld surface analysis and energy-minimization calculations

The terminal rings in the title compound have an anti disposition in contrast to a syn conformation calculated in the energy-minimized structure. Supramolecular layers in the ab plane and sustained by methylene-C—H⋯N(triazolyl) and carbonitrile-N⋯π(benzene) interactions feature in the molecular packing.

Crystal structure of bis­[(phenyl­methanamine-κN)(phthalocyaninato-κ4N)zinc] phenyl­methan­amine tris­olvate

A pentacoordinated Zn2+ ion is found in each independent complex molecule of the title compound; the asymmetric unit is completed by three conformationally flexible non-coordinating benzylamine molecules. Supramolecular layers sustained by N—H⋯N and N—H⋯π interactions are found in the crystal packing; these are connected by π–π contacts.

Post-synthetic Modification of a Two-Dimensional Metal–Organic Framework via Photodimerization Enables Highly Selective Luminescent Sensing of Aluminum(III)

Reaction of Cd(NO3)2·4H2O with 5-fluoro-1,3-bis[2-(4-pyridyl)ethenyl]benzene (5-F-1,3-bpeb) and 1,3-benzenedicarboxylic acid (1,3-H2BDC) under the solvothermal conditions gave rise to a two-dimensional metal-organic framework (MOF) [{Cd2(5-F-1,3-bpeb)2(1,3-BDC)2}·0.5DMF·2H2O] n (1). Compound 1 was postmodified by a photodimerization reaction between 5-F-1,3-bpeb ligands to yield [{Cd2( syn-dftpmcp)(1,3-BDC)2}·0.5DMF·H2O] n ( syn-dftpmcp = syn-3,4,12,13-tetrakis(4-pyridyl)-8,17-bisfluoro-1,2,9,10-diethano[2.2]metacyclophane) (2). Compounds 1 and 2 have 2D networks built from linking one-dimensional [Cd2(1,3-BDC)2] n chains via 5-F-1,3-bpeb or syn-dftpmcp bridges. After such a post-synthetic modification, compound 2, relative to 1, can probe Al3+ by using a luminescent quenching approach with much higher selectivity and sensitivity.

Hydrogels as Emerging Materials for Translational Biomedicine

Hydrogels have been extensively investigated as biomaterials because of their excellent biocompatibility, and recent developments such as 3D printing and the incorporation of dynamic crosslinks have advanced the field considerably. However, the next step of in vivo translational biomedicine requires an understanding of essential hydrogel properties so that they can be designed to overcome the challenges of the living environment. In this review, the stringent design criteria required for in vivo applications are highlighted and recent advances in the repair of organ tissues (heart, bone, eye, etc.) and the therapeutic delivery of bioactive molecules are described. Commercially available hydrogel systems that can be used for translational biomedicine are also discussed, as is the long and sometimes fraught journey from the laboratory to the clinic.