pinecone/core-2020-05-10-deduplication huggingface dataset:
Synthesis, characterization, and computational analysis of the dialanate dianion, [H3Al-AlH3]2− : a valence isoelectronic analogue of ethane

C.J. and A.S. gratefully acknowledge financial support from the Australian Research Council, while C.J. thanks the U.S. Air Force Asian Office of Aerospace Research and Development (FA2386-14-1-4043) for funding. G.F. acknowledges financial support from the Deutsche Forschungsgemeinschaft.The first example of a well-defined binary, low-oxidation-state aluminum hydride species that is stable at ambient temperature, namely the dianion in [{(DepNacnac)Mg}2(μ-H)]2[H3Al-AlH3] (DepNacnac=[(DepNCMe)2CH]−, Dep=2,6-diethylphenyl), has been prepared via a magnesium(I) reduction of the alanate complex, (DepNacnac)Mg(μ-H)3AlH(NEt3). An X-ray crystallographic analysis has shown the compound to be a contact ion complex, which computational studies have revealed to be the source of the stability of the aluminum(II) dianion.PostprintPeer reviewe
Room temperature regioselective catalytic hydrodefluorination of fluoroarenes with trans-[Ru(NHC)4H2] through a concerted nucleophilic Ru−H attack pathway

The authors acknowledge the EPSRC (grant EP/J009962/1, DTA) for financial supportThe efficient and highly selective room temperature hydrodefluorination (HDF) of fluoroarenes by the trans-[Ru(IMe4)4H2] catalyst, 3 , is reported. Mechanistic studies show 3 acts directly in catalysis without any ligand dissociation and DFT calculations indicate a concerted nucleophilic attack mechanism. The calculations fully account for the observed selectivities which corroborate earlier predictions regarding the selectivity of HDF.PostprintPeer reviewe
Lithium dihydropyridine dehydrogenation catalysis : a group 1 approach to cyclisation of diamine-boranes

In reactions restricted previously to a ruthenium catalyst, a 1-lithium-2-alkyl-1,2-dihydropyridine complex is shown to be a competitive alternative dehydrogenation catalyst for the transformation of diamine boranes to cyclic 1,3,2-diazaborolidines, which can in turn be smoothly arylated in good yields. This study establishes the conditions and solvent dependence of the catalysis via NMR monitoring, with mechanistic insight provided by NMR (including DOSY) experiments and X-ray crystallographic studies of several model lithio intermediates
Stereodivergent-at-Metal Synthesis of [60]Fullerene Hybrids

Chiral fullerene–metal hybrids with complete control over the four stereogenic centers, including the absolute configuration of the metal atom, have been synthesized for the first time. The stereochemistry of the four chiral centers formed during [60]fullerene functionalization is the result of both the chiral catalysts employed and the diastereoselective addition of the metal complexes used (iridium, rhodium, or ruthenium).DFT calculations underpin the observed configurational stability at the metal center, which does not undergo an epimerization process
Chiral Brønsted Acid-Catalyzed Asymmetric Synthesis of N-Aryl-cis-aziridine Carboxylate Esters

We report a multi-component asymmetric Brønsted acid-catalyzed aza-Darzens reaction which is not limited to specific aromatic or heterocyclic aldehydes. Incorporating alkyl diazoacetates and, important for high ee's, ortho-tert-butoxyaniline our optimized reaction (i.e. solvent, temperature and catalyst study) affords excellent yields (61–98 %) and mostly >90 % optically active cis-aziridines. (+)-Chloramphenicol was generated in 4 steps from commercial starting materials. A tentative mechanism is outlined
Non-Thermal Plasma Activation of Gold-Based Catalysts for Low-Temperature Water-Gas Shift Catalysis

Acknowledgements The UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC (Portfolio Grants EP/K014706/2, EP/K014668/1, EP/K014854/1, EP/K014714/1, and EP/I019693/1). Open access data can be found via the University of Manchester research portal. We are grateful to Helen Daly (Queen's University Belfast) for discussion, to Fabio de Rosa (Queen's University Belfast) for the thermodynamic equilibrium calculations (obtained using the Convergence tool of Aspen Plus 8.0) and to Emma Gibson (Harwell Research Complex) for the BET measurements. JJ Delgado is grateful to Ramon y Cajal program and the Ce-NanoSurPhases project grant from MINECO.Peer reviewedPostprintPostprintPublisher PD
A Cationic Unsaturated Platinum(II) Complex that Promotes the Tautomerization of Acetylene to Vinylidene

Complex [PtMe(PMeAr)] (1), which contains a tethered terphenyl phosphine (Ar =2,6-(2,6-PrCH)CH), reacts with [H(EtO)]BAr (BAr =B[3,5-(CF)CH] ) to give the solvent (S) complex [PtMe(S)(PMeAr)] (2⋅S). Although the solvent molecule is easily displaced by a Lewis base (e.g., CO or CH) to afford the corresponding adducts, treatment of 2⋅S with CH yielded instead the allyl complex [Pt(η-CH)(PMeAr)] (6) via the alkyne intermediate [PtMe(η-CH)(PMeAr )] (5). Deuteration experiments with CD, and kinetic and theoretical investigations demonstrated that the conversion of 5 into 6 involves a Pt-promoted HC≡CH to :C=CH tautomerization in preference over acetylene migratory insertion into the Pt−Me bond.Fondos FEDER, Subprogramas Ramón y Cajal and Juan de la Cierva  BES - 2011 - 048035Ministerio de Ciencia e Innovación CTQ2013 - 42501- P, CTQ2014 -51912 - REDC, CTQ - 2014 - 52769 - C3 - 3 - RJunta de Andalucía FQM - 119 and project P09 - FQM - 4832  and  FQM - 212
Expansion of the ADOR strategy for the synthesis of new zeolites : the synthesis of IPC-12 from zeolite UOV

R.E.M. thanks the Royal Society and the Engineering and Physical Sciences Research Council (Grants EP/K025112/1, EP/K005499/1, EP/L016419/1) for funding work in this area and for providing a Ph.D. studentship to S.E.R. through the Criticat Centre for Doctoral training. R.E.M. and M. O. acknowledge the OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. J.Č., V.K., and M.T. acknowledge the Czech Science Foundation for the project of the Centre of Excellence (P106/12/G015) and J.Č has received funding from the European Union's Horizon2020 research and innovation programme under grant agreement No 640979. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement No. 312483—ESTEEM2 (Integrated Infrastructure Initiative–I3).The assembly-disassembly-organisation-reassembly (ADOR) process has been used to disassemble a parent zeolite with the UOV structure type and then reassemble the resulting layers into a novel structure, IPC-12. The structure of the material has previously been predicted computationally and confirmed in our experiments using X-ray diffraction and atomic resolution STEM-HAADF electron microscopy. This is the first successful application of the ADOR process to a material with porous layers.Publisher PDFPeer reviewe
Mixed-matrix membranes

Article In Press title was: New directions for mixed-matrix membranes. Also published in German in Angewandte Chemie, 2017; 129(32):9420-9439.Research into extended porous materials such as metal-organic frameworks (MOFs) and porous organic frameworks (POFs), and their molecular analogues, metal-organic polyhedra (MOPs) and porous organic cages (POCs), has blossomed over the last decade. Given their chemical and structural mutability and notable porosity, MOFs have been proposed as novel adsorbents for industrial gas separations. In this context they have also been identified as promising filler components for high-performance mixed matrix membranes (MMMs). Research in this area has focused on enhancing the chemical compatibility between the MOF and polymer phase by judiciously functionalising the organic linkers of the MOF, modifying the MOF surface chemistry and, more recently, exploring how particle size, morphology and distribution enhance separation performance. Other filler materials, including POFs, MOPs and POCs, are also being explored as additives for MMMs and have shown, unexpectedly, remarkable anti-aging performance and excellent chemical compatibility for commercially available polymers. This review briefly outlines the state-of-the-art in MOF-MMM fabrication, and the more recent use of porous organic frameworks and molecular additives for MMMs.Janina Dechnik, Jorge Gascon, Christian J. Doonan, Christoph Janiak and Christopher J. Sumb
Total synthesis of phenolic natural products

This thesis is regarded with the biomimetic total synthesis of phenolic natural products\ud
and describes two different projects.\ud
Chapter 1 introduces phenolic natural products, the most important biosynthetic\ud
pathways for their formation and some examples of relevant biomimetic syntheses. A\ud
short introduction to dimeric and pseudo-dimeric natural products can also be found\ud
in this chapter. Specific introductions can be found at the start of Chapters 2 and 3.\ud
Chapter 2 describes the total synthesis of a dimeric thymol derivative isolated from\ud
Arnica sachalinensis (which we have named “thymarnicol”). Inspired by the\ud
biosynthesis proposed by Passreiter and co-workers, we tested and confirmed the\ud
feasibility of a key hetero-Diels–Alder dimerisation step. During our investigations,\ud
we gained significant new insights into the origin and reactivity of thymarnicol. The\ud
final oxidative cyclisation has been found to occur spontaneously upon exposure to\ud
visible light in air.\ud
Chapter 3 discusses our efforts to develop a divergent biomimetic synthetic strategy\ud
towards a family of prenylated phenylpropanoid natural products isolated from\ud
Illicium genus plants. Our first biomimetic approach revealed the chemical instability\ud
of our proposed key intermediates. Therefore, a revised approach was trialled,\ud
allowing the total synthesis of a small set of natural products and related structures.\ud
We envisage that this strategy could be exploited by accessing a large number of\ud
members of this family of compounds
The Ti3AlC2 MAX-phase as an efficient catalyst for oxidative dehydrogenation of n-butane

H. F. G. and W.Z. thank the EPSRC for a Capital Equipment Grant EP/L017008/1.Light alkenes are important raw materials for the synthesis of polymers and other chemical products. Traditionally they are obtained mainly from steam cracking and catalytic cracking units. However, dehydrogenation or oxidative dehydrogenation (ODH) of alkanes is gaining more importance to produce alkenes directly from natural gas/shale gas. Here we report that Ti3AlC2, a MAX phase, which hitherto had not used in catalysis, efficiently catalyses the ODH of n-butane to butenes and butadiene, important intermediates for the synthesis of polymers and other compounds. The catalyst, which combines both metallic and ceramic properties, is stable for at least 30 h on stream, even at low O2:butane ratios without suffering from coking. This material has neither lattice oxygens nor noble metals, yet a unique combination of numerous defects and a thin surface Ti1-yAlyO2-y/2 layer that is rich in oxygen vacancies makes it an active catalyst. Given the large number of compositions available, MAX phases may find applications in several heterogeneously catalyzed reactions.Publisher PDFPeer reviewe
Lanthanide complexes that respond to changes in cyanide\ud
concentration in water.

Cyanide ions are shown to interact with lanthanide complexes of phenacylDO3A derivatives in aqueous solution, giving rise to changes in the luminescence and NMR spectra. These changes are the consequence of cyanohydrin formation, which is favored by the coordination of the phenacyl carbonyl group to the lanthanide center. These complexes display minimal affinity for fluoride and can detect cyanide at concentrations less than 1 μm. By contrast, lanthanide complexes with DOTAM derivatives display no affinity for cyanide in water, but respond to changes in fluoride concentration
Morphological control of heteroleptic cis- and trans-Pd2L2Lʹ2 cages

Control over the integrative self-sorting of metallo-supramolecular assemblies has recently generated significant interest as it opens up possibilities of introducing increased complexity and function into a single self-assembled architecture. Here, the relationship between the geometry of three ligand components and morphology of three self-sorted heteroleptic [Pd2L2Lʹ2]4+ cages is examined. Pd-mediated assembly of two bis-monodentate pyridyl ligands with native bite angles of 75° and 120° affords a cis-[Pd2L2Lʹ2]4+ cage while the same reaction with two ligands bearing bite angles of 75° and 60° forces an anti-conformation for latter ligand, leading to an unprecedented, self-penetrating structural motif; a trans-[Pd2(anti-L)2Lʹ2]4+ heteroleptic cage bearing a “doubly-bridged figure-eight” topology. Each heteroleptic assembly can be accessed through cage-to-cage conversion of their homoleptic precursors, and notably, morphological control of [Pd2L2Lʹ2] cages is achieved through selective ligand displacement transformations in a system of three ligands and at least six possible cage products
Expanding the Boundary of Water-Tolerant Frustrated Lewis Pair Hydrogenation: Enhanced Back Strain in the Lewis Acid Enables the Reductive Amination of Carbonyls

The development of a boron/nitrogen-centered frustrated Lewis pair (FLP) with remarkably high water tolerance is presented. As systematic steric tuning of the boron-based Lewis acid (LA) component revealed, the enhanced back-strain makes water binding increasingly reversible in the presence of relatively strong base. This advance allows the limits of FLP's hydrogenation to be expanded, as demonstrated by the FLP reductive amination of carbonyls. This metal-free catalytic variant displays a notably broad chemo-selectivity and generality
Hyperconjugation is the source of helicity in perfluorinated n-alkanes

The authors thank FAPESP and EaStCHEM funding agencies.Hyperconjugative, steric and electrostatic effects were evaluated as possible sources of the helicity in linear perfluorinated alkanes through analysis of natural bond orbitals and classical electrostatics. Contrary to previous rationalisations, which indicate dominating steric or electrostatic effects, this analysis indicates that hyperconjugative stabilisation through σCC-> σ*CF interactions are the underlying driving force for the origin of the observed helicity in perfluoroalkanesPostprintPeer reviewe
Advancing a methodology for implant-triggered cancer treatment with Bioorthogonal Palladium-Labile prodrugs

Chemotherapeutics are potent molecules capable of systematically treating cancer. As healthy\ud
tissues contain features also inherent to cancer cells, treatment often results in unwanted sideeffect.\ud
As chemotherapeutic side-effect produces significant harm and often limits optimal drug\ud
dosing, new strategies must be developed to improve treatment selectivity. A prodrug strategy\ud
provides one option to improve the selectivity of an established chemotherapeutic. By\ud
modifying a pharmaceutically active drug, interaction with biology may be functionally masked.\ud
Subsequent ‘un-masking’ the prodrug exclusively at the intended treatment site may direct\ud
treatment only to where the anticancer effect is required.\ud
This thesis progresses the novel approach of bioorthogonal organometallic (BOOM) prodrug\ud
activation. A metal catalyst and masked chemotherapeutic constitute reaction partners to\ud
provide a new strategy for intratumoural prodrug activation. Whereby the prodrug and metal\ud
catalyst are independently non-cytotoxic, in combination the prodrug undergoes catalytic\ud
activation to deliver an anticancer affect. By positioning the metal catalyst within a tumour (i.e.\ud
by microsurgery), an administered masked prodrug sensitive to catalyst-mediated activation\ud
could allow for ‘targeted’ chemotherapy localised to the tumour site.\ud
The design, synthesis and study of new BOOM prodrug candidates are reported herein. Novel\ud
protecting groups are developed to enhance drug masking to biology and subsequent catalyst-mediated\ud
activation. Prodrug screening studies are carried out in cancer cell culture models,\ud
with zebrafish and in ex vivo rodent model tumour explants. The catalyst, a palladium (Pd0)\ud
functionalised bead system, is optimised for enhanced activation, drug release and in vivo\ud
implantation. The potentially infinite generation of active chemotherapeutics exclusively in\ud
tumour would increase the efficacy of treatment whilst reducing harmful effect on healthy\ud
tissue
Pac13 is a small, monomeric dehydratase that mediates the formation of the 3′-deoxy nucleoside of pacidamycins

This work was supported by the EPSRC council (Grant number 1398501), Wellcome Trust (Investigator Award) and GlaxoSmithKline.The uridyl peptide antibiotics (UPAs), of which pacidamycin is a member, have a clinically unexploited mode of action and an unusual assembly. Perhaps the most striking feature of these molecules is the biosynthetically unique 3′-deoxyuridine that they share. This moiety is generated by an unusual, small and monomeric dehydratase, Pac13, which catalyses the dehydration of uridine-5’-aldehyde. Here we report the structural characterisation of Pac13 with a series of ligands, and gain insight into the enzyme’s mechanism demonstrating that H42 is critical to the enzyme’s activity and that the reaction is likely to proceed via an E1cB mechanism. The resemblance of the 3′-deoxy pacidamycin moiety with the synthetic anti-retrovirals, presents a potential opportunity for the utilisation of Pac13 in the biocatalytic generation of antiviral compounds.Publisher PDFPeer reviewe
LiTMP trans-metal-trapping of fluorinated aromatic molecules : a comparative study of Al and Ga carbanion traps

Fluoro aromatic scaffolds pose a challenge to lithiation due to low stability of lithiated intermediates. Here we apply trans-metal-trapping (TMT) to a series of key fluorinated aromatics. In TMT, LiTMP performs the metallation, while an organometallic trap intercepts the emergent carbanion. This study contrasts the trapping abilities of iBu2AlTMP and Ga(CH2SiMe3)3, structurally mapping their TMT reactions and probing relative stabilities of metallated fluoroaromatic intermediates by NMR studies. Results show the installed Al-C(aryl) bonds are more prone to decomposition by benzyne formation and Li-F liberation, than the Ga-C(aryl) species. The latter are thus better for onward reactivity as demonstrated in cross-coupling reactions with benzoyl chloride that produce ketones
Multitarget-directed ligands combining cholinesterase and monoamine oxidase inhibition with histamine H3R antagonism for neurodegenerative diseases

J.M.C. thanks MINECO (SAF2012-33304 and SAF2015-65586-R). J.M.C., F.L.M., and A.R. thank UCJC for grants 2015-12, 2014-35, and 2015-21, respectively. J.E. thanks the Fondo de Investigaciones Sanitarias (FIS) (ISCIII/FEDER) (Programa Miguel Servet: CP14/00008 and PI16/00735) and Fundación Mutua Madrileña. O.S. and J.J. thank MHCZ-DRO (UHHK 00179906) for support. R.R.R., H.S., and J.M.C. acknowledge the EU COST Actions CM1103 and CM15135. E.P. and H.S. thank the German Research Foundation (DFG; PRO 1405/2-2, PRO 1405/4-1, SFB 1039 A07, and INST208/664-1).The therapy of complex neurodegenerative diseases requires the development of multitarget-directed drugs (MTDs). Novel indole derivatives with inhibitory activity towards acetyl/butyrylcholinesterases and monoamine oxidases A/B as well as the histamine H3 receptor (H3R) were obtained by optimization of the neuroprotectant ASS234 by incorporating generally accepted H3R pharmacophore motifs. These small-molecule hits demonstrated balanced activities at the targets, mostly in the nanomolar concentration range. Additional in vitro studies showed antioxidative neuroprotective effects as well as the ability to penetrate the blood–brain barrier. With this promising in vitro profile, contilisant (at 1 mg kg−1 i.p.) also significantly improved lipopolysaccharide-induced cognitive deficits.PostprintPeer reviewe
Visible-light-mediated selective arylation of cysteine in batch and flow

A mild visible-light-mediated strategy for cysteine arylation is presented. The method relies on the use of eosin Y as a metal-free photocatalyst and aryldiazonium salts as arylating agents. The reaction can be significantly accelerated in a microflow reactor, whilst allowing the insitu formation of the required diazonium salts. The batch and flow protocol described herein can be applied to obtain a broad series of arylated cysteine derivatives and arylated cysteine-containing dipeptides. Moreover, the method was applied to the chemoselective arylation of a model peptide in biocompatible reaction conditions (room temperature, phosphate-buffered saline (PBS) buffer) within a short reaction time
Beyond Bleaney's theory : experimental and theoretical analysis of periodic trends in lanthanide induced chemical shift.

A detailed analysis of paramagnetic NMR shifts in a series of isostructural lanthanide complexes relavant to PARASHIFT contrast agents reveals unexpected trends in the magnetic susceptibility anisotropy that cannot be explained by the commonly used Bleaney's theory. Ab initio calculations reveal that the primary as-sumption of Bleaney's theory - that thermal energy is larger than the ligand field splitting - does not hold for the lanthanide complexes in question, and likely for a large fraction of lanthanide complexes in general. This makes the orientation of the magnetic susceptibility tensor differ significantly between complexes of different lanthanides with the same ligand: thus, one of the most popular assumptions about isostructural lanthanide series is incorrect
Spin changes accompany ultrafast structural interconversion in the ground state of a cobalt nitrosyl complex.

Ultrafast, reversible intersystem crossing (ISC) is reported under ambient conditions for the electronic ground state of the pentacoordinate cobalt nitrosyl complexes, [CoX2(NO)(PMePh2)2] (X=Cl, Br), in solution. ISCs on such short timescales are more typically observed in electronically excited states reached by absorption of ultraviolet or visible light. Singlet and triplet electron spin states of the complex, corresponding to two different isomers, are populated at room temperature, and the two isomers exchange on a timescale of a few picoseconds. Ultrafast two-dimensional infrared spectroscopy observes the change in wavenumber of the NO ligand band accompanying the isomerization and associated ISC on the (spin) adiabatic ground potential energy surface. Comparison of the dynamics of the chloro- and bromo-complexes shows that inertial effects of the ligand motion have a greater effect than spin–orbit coupling on determining the forward and reverse isomerization and ISC rates
Radical enhanced charge transport in single-molecule phenothiazine electrical junctions.

We studied the single-molecule conductance through an acid oxidant triggered phenothiazine (PTZ-) based radical junction using the mechanically controllable break junction technique. The electrical conductance of the radical state was enhanced by up to 200 times compared to the neutral state, with high stability lasting for at least two months and high junction formation probability at room-temperature. Theoretical studies revealed that the conductance increase is due to a significant decrease of the HOMO–LUMO gap and also the enhanced transmission close to the HOMO orbital when the radical forms. The large conductance enhancement induced by the formation of the stable PTZ radical molecule will lead to promising applications in single-molecule electronics and spintronics