New options in directed cupration: Studies in heteroleptic bis(amido)cuprate formation Dedicated to the memory of Jack Lewis.

The 2:1 combination of MPLi (MP = 2-methylpiperidide) with CuBr gives the novel complex [(MP)2CuLi(THF)2]2LiBr 12 and introduces the chiral ligand MP to the evolving field of Directed ortho Cupration reagents. Subsequent syntheses have focused on developing heteroleptic bis(amido) arrangements at Cu, with 1:1 mixtures of two out of MPLi, DMPLi and TMPLi (DMP = 2,6-cis-dimethylpiperidide; TMP = 2,2,6,6-tetramethylpiperidide) being reacted with CuI salts in the presence of THF. Resulting lithiocuprates reveal solid state dimers based on the heteroleptic bis(amido) formulations R2N(TMP)Cu(Br)Li2(THF)2 (R2N = MP 13; R2N = DMP 14). The heteroleptic Gilman lithiocuprate PIP(TMP)CuLi (PIP = piperidide) 15 has also been prepared. In each of 12–15, significant variations in the orientations of the amide ligands can be rationalized in terms of steric effects and, in the case of 15, stabilization of the alkali metal by Me…Li interaction is evidenced.This work was supported by the U.K. EPSRC through grant EP/J500380/1 (A P.)

Reactions of Trimethylaluminium: Modelling the Chemical Degradation of Synthetic Lubricants

In investigating and seeking to mimic the reactivity of trimethylaluminium (TMA) with synthetic, ester-based lubricating oils, the reaction of methyl propionate $\textbf{1}$ was explored with 1, 2 and 3 equivalents of the organoaluminium reagent. Spectroscopic analysis points to the formation of the adduct $\textbf{1}$ (TMA) accompanied only by the low level 1:1 production of Me$_{2}$AlOCEtMe$_{2}$ $\textbf{2}$ and Me$_{2}$AlOMe $\textbf{3}$ when an equimolar amount of TMA is applied. The deployment of excess TMA favours reaction to give $\textbf{2}$ and $\textbf{3}$ over $\textbf{1}$(TMA) adduct formation and spectroscopy reveals that in hydrocarbon solution substitution product $\textbf{2}$ traps unreacted TMA to yield $\textbf{2}$(TMA). The $^{1}$H NMR spectroscopic observation of two Al-Me signals not attributable to free TMA and in the ratio 1:4 suggests the formation of a previously only postulated, symmetrical metallacycle in Me$_{4}$Al$_{2}$ (μ$^{2}$-Me)(μ$^{2}$-OCEtMe$_{2}$ ). In the presence of $\textbf{3}$, $\textbf{2}$(TMA) undergoes thermally induced exchange to yield Me$_{4}$Al$_{2}$(μ$^{2}$-OMe)(μ$^{2}$-OCEtMe$_{2}$) $\textbf{4}$ and TMA. The reaction of methyl phenylacetate $\textbf{5}$ with TMA allows isolation of the crystalline product Me$_{2}$AlOCBnMe$_{2}$ (TMA) $\textbf{6}$(TMA), which allows the first observation of the Me$_{}$ Al$_{2}$(μ$^{2}$-Me)(μ$^{2}$-OR) motif in the solid state. Distances of 2.133(3) Å (Al-Me$_{bridging}$) and 1.951 Å (mean Al-Me$_{terminal}$) are recorded. The abstraction of TMA from $\textbf{6}$(TMA) by the introduction of Et$_{2}$O has yielded $\textbf{6}$, which exists as a dimer.This work was supported by Cambridge Refrigeration Technology (J.S.). The U.K. EPSRC are acknowledged for grant EP/J500380/1 (A.J.P.)

Selective hydrogenation of arenes to cyclohexanes in water catalyzed by chitin-supported ruthenium nanoparticles

The selective hydrogenation of arenes to cyclohexanes is promoted by Ru/chitin under aqueous conditions without the loss of C–O/C–N linkages.This work was financially supported by the Ichihara International Scholarship Foundation (to H. N.), the Institute for Quantum Chemical Exploration (to H. N.), MEXT (Japan) through its program “Integrated Research on Chemical Synthesis” (to H. N.) and the Royal Society through its International Exchange Scheme (to A. E. H. W. and H. N.). K. B. and B. R. K. thank the UK EPSRC (EP/J500380/1). Y. M. and A. M. acknowledge the IGER program at NU. We thank Professors R. Noyori (NU), S. Saito (NU) and K. Shimizu (Hokkaido U) for their helpful comments.This is the final version of the article. It first appeared from Royal Society of Chemistry at http://dx.doi.org/10.1039/C6CY00899B

Photocatalytic N‑Methylation of Amines over Pd/TiO2 for the Functionalization of Heterocycles and Pharmaceutical Intermediates

Amines in heteroaromatic systems and pharmaceutical intermediates were functionalized through N-methylation with methanol using a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. This method provides access to a series of tertiary N-methylamines bearing N-, O-, and/or S-containing heteroaromatic functionalities from primary/secondary amines and methanol under mild reaction conditions. Facile syntheses of several pharmaceuticals containing N-methyl or ethyl groups, as well as related deuterated drugs, was achieved through the late-stage functionalization of amines.This work was supported by JSPS KAKENHI Grant Number JP26410115 (H.N.), the Tobe Maki Scholarship Foundation (H.N.), the JGC-S Scholarship Foundation (H.N.), Fusion Emergent Research Program from Integrated Research Consortium on Chemical Sciences (IRCCS, H.N. and A.E.H.W.), the JST ACT-C program (S.S.), and the UK EPSRC (EP/J500380/1, K.J.)

Morphological effects on the photocatalytic properties of SnO<inf>2</inf> nanostructures

The photocatalytic properties of SnO2 nanocrystals are tuned by varying their morphology and microstructure. SnO2 nanoparticles and nanowedges have been synthesised using hydrothermal methods, while microwave irradiation techniques have given nanospheres. Detailed structural and chemical characterization of these different morphologies has been accomplished. The influence of SnO2 morphology on photocatalytic activity has been examined by monitoring the degradation of aqueous methylene blue dye. Results demonstrate that changing the morphology of the SnO2 modulates both surface area and levels of surface defects and that these alterations are reflected in the photocatalytic properties of the materials. The degradation of methylene blue dye (98%) in the presence of SnO2 nanoparticles under simulated solar irradiation is superior to previously reported photocatalyst performance and is comparable to that of standard TiO2 (Degussa P-25). The SnO2 nanoparticles perform better than both the nanowedges and nanospheres and this is attributed to the number of surface defects available to the high surface area material. They also reveal outstanding recyclability and stability

Harnessing Surface-Functionalized Metal-Organic Frameworks for Selective Tumor Cell Capture

A platform based on a metal-organic framework (MOF) bearing free carboxylic acid groups has been developed for tumor cell capture and potential drug screening applications. A zinc-based MOF expressing uncoordinated carboxylic acids (ZnMOF-COOH) was grown on a ZnO substrate. Post-synthetic modification (PSM) of the acid groups gave a composite material that expressed peptide linkages and allowed the immobilization of anti-epithelial cell adhesion molecule (anti-EpCAM) antibody. This strategy offers a universal method for the controllable immobilization of antibodies and even enzymes on the surface of a MOF. The resulting immunotrapper exhibited excellent capture ability, demonstrating high efficiency and selectivity towards EpCAM-positive tumor cells. The promotion of tumor cell adhesion is attributed to the 3-dimentional (3D) structure of the composite, which revealed spine-like microstructures.This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 21527809 and 21575007), the China Scholarship Council and the UK EPSRC (EP/J500380/1)

Targeting low-cost type-II heterostructures: Synthesis, structure and photoreactivity

One design strategy by which to iterate the photocatalytic efficiency of semiconducting nanomaterials for harvesting solar energy involves the synthesis of type-II heterostructured materials. In this article, a straightforward, facile and environmentally benign route to heterostructures in which SnO₂ nanospheres are capped by PbS nanocubes is reported. It offers to address current limitations to photocatalytic efficiency brought about by electron-hole recombination and narrow photoresponsive ranges in many existing systems. PbS nanocubes are grown in the presence of preformed SnO₂ nanospheres by functionalizing the surface of the latter using cetyltrimethylammonium bromide (CTAB). Heterostructure formation is confirmed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area analysis, and transmission electron microscopy (TEM) analysis. Rietveld refinement has been exploited to simultaneously elucidate the atomic and microstructures of these materials, allowing the quantitative determination of particle structure and stability. The combination of narrow band-gap semiconductor (PbS) and wide band-gap semiconductor (SnO₂) endows the heterostructured nanomaterial with potential as a photocatalyst and, in the degradation of Rhodamine B (RhB) dye under solar simulation, it showed superior photocatalytic activity to that of its separate SnO₂ and PbS components. A strong type-II interaction is demonstrated by the heterostructure and a charge separation mechanism has been utilized to clarify this behaviour.A. K. acknowledges support from the Royal Society's Newton International Fellowship scheme (NF130808). B. R. K. thanks the UK EPSRC for financial support (EP/J500380/1)

Tuning porosity in macroscopic monolithic metal-organic frameworks for exceptional natural gas storage.

Widespread access to greener energy is required in order to mitigate the effects of climate change. A significant barrier to cleaner natural gas usage lies in the safety/efficiency limitations of storage technology. Despite highly porous metal-organic frameworks (MOFs) demonstrating record-breaking gas-storage capacities, their conventionally powdered morphology renders them non-viable. Traditional powder shaping utilising high pressure or chemical binders collapses porosity or creates low-density structures with reduced volumetric adsorption capacity. Here, we report the engineering of one of the most stable MOFs, Zr-UiO-66, without applying pressure or binders. The process yields centimetre-sized monoliths, displaying high microporosity and bulk density. We report the inclusion of variable, narrow mesopore volumes to the monoliths' macrostructure and use this to optimise the pore-size distribution for gas uptake. The optimised mixed meso/microporous monoliths demonstrate Type II adsorption isotherms to achieve benchmark volumetric working capacities for methane and carbon dioxide. This represents a critical advance in the design of air-stable, conformed MOFs for commercial gas storage

Research data supporting "Metal exchange in lithiocuprates: implications for our understanding of structure and reactivity"

Crystallographic and multinuclear NMR spectroscopic data for a series of lithium cyanatocuprate compounds prepared and analyzed at Cambridge (UK) in 2015-2017

Metal exchange in lithiocuprates: implications for our understanding of structure and reactivity

New reagents have been sought for directed $\textit{ortho}$ cupration in which the use of cyanide reagents is eliminated. CuOCN reacts with excess TMPLi (TMP = 2,2,6,6-tetramethylpiperidide) in the presence of limited donor solvent to give crystals that are best represented as (TMP)$_2$Cu$_{0.1}$Li$_{0.9}$(OCN)Li$_2$(THF) 8, whereby both Lipshutz-type lithiocuprate (TMP)$_2$Cu(OCN)Li$_2$(THF) 8a and trinuclear (TMP)$_2$(OCN)Li$_3$(THF) 8b are expressed. Treatment of a hydrocarbon solution of TMP$_2$CuLi 9a with LiOCN and THF gives pure 8a. Meanwhile, formation of 8b is systematized by reacting (TMPH$_2$)OCN 10 with TMPH and $n$BuLi to give (TMP)$_2$(OCN)Li$_3$(THF)$_2$ 11. Important to the attribution of lower/higher order bonding in lithiocuprate chemistry is the observation that in crystalline 8, amide-bridging Cu and Li demonstrate clear preferences for di- and tricoordination, respectively. A large excess of Lewis base gives an 8-membered metallacycle that retains metal disorder and analyses as (TMP)$_2$Cu$_{1.35}$Li$_{0.65}$ 9 in the solid state. NMR spectroscopy identifies 9 as a mixture of (TMP)$_2$CuLi 9a and other copper-rich species. Crystals from which the structure of 8 was obtained dissolve to yield evidence for 8b coexisting in solution with $\textit{in situ}$-generated 9a, 11 and a kinetic variant on 9a ($i$-9a), that is best viewed as an agglomerate of TMPLi and TMPCu. Moving to the use of DALi (DA = diisopropylamide), (DA)$_2$Cu$_{0.09}$Li$_{0.91}$(Br)Li$_2$(TMEDA)$_2$ 12 (TMEDA = $N$,$N$,$N^\prime$,$N^\prime$ -tetremethylethylenediamine) is isolated, wherein (DA)$_2$Cu(Br)Li$_2$(TMEDA)$_2$ 12a exhibits lower-order Cu coordination. The preparation of (DA)$_2$Li(Br)Li$_2$(TMEDA)$_2$ 12b was systematized using (DAH$_2$)Br, DAH and $n$BuLi. Lastly, metal disorder is avoided in the 2 : 1 lithium amide : Lipshutztype monomer adduct (DA)$_4$Cu(OCN)Li$_4$(TMEDA)$_2$ 13.This work was supported by the U.K. EPSRC through grants EP/ J500380/1 and EP/K039520/1