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Four novel Zn(ii) metal–organic frameworks (MOFs) including {[Zn(L)0.5(bimb)]·2H2O·0.5(CH3)2NH}n (1), {[Zn(L)0.5(bimmb)]·2H2O}n (2), {[Zn(L)0.5(btdpe)]·H2O}n (3), and [Zn(L)0.5(bidpe)]n (4) (H4L = 5,5′-(1,4-xylylenediamino) diisophthalic acid, bimb = 1,4-bis(imidazol-1-yl)-butane, bimmb = 1,4-bis(imidazol-1-ylmethyl)benzene, btdpe = 4,4′-bis(4H-1,2,4-triazol-4-yl)diphenyl ether, and bidpe = 4,4′-bis(imidazolyl)diphenyl ether) were solvothermally prepared and further characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis showed that complex 1 features a 3-fold interpenetrated bbf topological framework with the Schläfli symbol of (64·82)(66)2. Complex 2 displayed an unprecedented 2-nodal (4,4)-connected 3D framework with the Schläfli symbol of (86), while complexes 3 and 4 showed 3-nodal (2,4,4)-connected (4·8·104)2(4)2(84·10·12)-unprecedented frameworks. Luminescence studies revealed that complexes 1–4 can be used as high selectivity luminescence sensors for sensing Fe(iii) cations, Cr(vi) anions (Cr2O72− and CrO42−) and nitroaromatic compounds. Furthermore, a possible sensing mechanism was investigated in this paper. [ABSTRACT FROM AUTHOR]

Mixed metal halide perovskites are gaining paramount interest due to efficient band gap tenability and improved optical properties compared to their single metal halide perovskites. It is thus valuable to investigate compositional changes in lead halide perovskites to explore energy changes. Herein, we report the synthesis of a lead to lead free hybrid perovskite solid solution (CH3NH3Pb1−xCuxBr3) as nanoparticles and films. The increasing concentration of Cu2+ ions in the site of the Pb2+ ion in the perovskite shifted the diffraction peaks to a larger angle. Uniform spherically shaped nanoparticles were synthesized by a wet chemical method, the higher Cu2+ concentration leads to agglomeration, producing sheet like morphologies. However, the deposition of thin films of CH3NH3Pb1−xCuxBr3 perovskite solid solution shows that well defined morphologies begin to appear with increasing concentrations of Cu2+ in the perovskite structure. The as-prepared bulk lead free CH3NH3CuBr3 perovskite shows a band gap of 1.65 eV. A blue shift in photoluminescence (PL) was observed with copper enriched hybrid perovskites. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis, characterization, and photophysical and biological evaluation of the complexes Ln(DBM)3(RPhen) (Ln = Sm, R = H; Ln = Sm, Eu, Tb, R = 5-NH2) stabilized by three β-diketonate units (DBM) and a phenanthroline (RPhen) derivative, with the aim of contributing to the development of lanthanide-based compounds with potential application as anticancer agents. The UV-vis spectra of [Sm(DBM)3(Phen)], [Sm(DBM)3(NH2Phen)], [Eu(DBM)3(NH2Phen)] and [Tb(DBM)3(NH2Phen)] measured in DMSO and PBS showed a strong absorption band centered at ca. 350 nm in both solvents. In DMSO, all lanthanide compounds except [Sm(DBM)3(Phen)] show a ligand centered emission band at ca. 520 nm. In PBS only sharp emission peaks are detected. The complexes show similar cytotoxic effects in A2780 ovarian cancer cells, presenting IC50 values at 24 h in the range 16–27 μM. The measurement of the cellular uptake of the complexes in the A2780 cells by inductively coupled plasma mass spectrometry (ICP-MS) revealed preferential accumulation at the membrane and cytoskeleton, with the exception of [Sm(DBM)3(Phen)] that presented higher accumulation in the cytosol than in the cell membranes. All the evaluated lanthanide complexes showed low nuclear uptake, although not negligible. Spectroscopic studies on the interaction of the complexes with calf thymus DNA (ctDNA) revealed a moderate affinity with apparent binding constants in the 104 M−1 range. Complexes bind DNA not by intercalation but probably by electrostatic interactions. A morphological evaluation of the cells treated with the different complexes by electron microscopy (TEM/SEM) proved that all of them induce mitochondrial alterations, which seemed more pronounced for the NH2Phen complexes. In addition, the complex [Eu(DBM)3(NH2Phen)] presented lysosomal uptake that might explain its augmented cytotoxicity. [ABSTRACT FROM AUTHOR]

A new RuII based bis-heteroleptic ditopic receptor, 1[PF6]2 (C44H33F12IN10OP2Ru), having integrated anion binding iodotriazole (halogen bond donor) and urea units (–NH bond donor) is employed for selective sensing of phosphates (e.g., H2PO4− and HP2O73−). 1[PF6]2 showed superiority in phosphate sensing in CH3CN as compared to its hydrogen bond donor analogue, 2[PF6]2 (C44H34F12N10OP2Ru), non-urea halogen bond analogue, 3[PF6]2 (C38H27F12IN8P2Ru) and non-urea hydrogen bond donor analogue, 4[PF6]2 (C38H28F12N8P2Ru) in terms of enhanced binding constant values, longer excited state lifetimes and lower detection limit values. 1H-NMR, Isothermal Titration Calorimetry (ITC) and photophysical studies revealed the implementation of the combined role of both the halogen bond donor iodotriazole unit and the –NH unit of the urea moiety for selective and enhanced binding of phosphates. [ABSTRACT FROM AUTHOR]

An efficient route to obtain aromatic products based on biomass feedstock is a challenge for future biorefineries. Isobutyraldehyde is a promising feedstock available via biotechnological routes based on both carbohydrates and the direct bioconversion of CO2. Herein, we report an efficient process for the aromatisation of isobutyraldehyde over zeolite catalysts in a continuous fixed bed reactor to provide value-added aromatic compounds with a yield of 93%. Benzene, toluene and xylenes are the major compounds formed with 79% yield and a productivity of 65 mmol gcat−1 h−1. Zeolite Y, Beta and Mordenite and ZSM-5 of different modules were studied. Comprehensive catalyst characterisation using XRD, NH3-TPD, N2-physisorption, and ICP-OES enabled establishing structure–performance relationships with a major role of zeolite structure, density of strong acid sites and mesoporosity, respectively. HZSM-5 with Si/Al ratios of 15 to 49 proved effective at the aromatisation possessing a comparable density of strong acid sites of 0.37–0.52 mmol g−1. Superior stability was observed for HZSM-5 zeolites with higher mesopore volumes. The reaction is suggested to mainly proceed via catalytic cracking to C1–C4 alkanes/alkenes, which undergo further oligomerisation, cyclisation, and aromatisation to form the observed alkyl-aromatics. Emphasizing the potential of the concept, long term continuous operation was carried out by alternating 10 hours time on steam operation and catalyst regeneration via in situ calcination. [ABSTRACT FROM AUTHOR]

Aromatic hydrocarbons as a liquid fuel have unique combustion properties (high volume energy density, etc.). Thus preserving the aromatic rings while selectively cleaving the C–O bonds in the hydrodeoxygenation of lignin derived substituted phenols without additional consumption of H2 is of crucial importance. In this regard, the composite materials, which are used as the catalyst support, were prepared through the hybridization of Nb2O5 (niobium oxide) with MC (micro–mesoporous carbon). Ru NPs (nanoparticles) were loaded on the Nb2O5-MC composite supports by the incipient wetness impregnation method. And then the as-synthesized catalysts were characterized by various techniques, including XRD, SEM, TEM, BET, NH3-TPD, XPS, etc. Under mild conditions (200–250 °C and 2.0–10 bar H2), the Ru/Nb2O5-MC catalyst was proved to be highly effective for the hydrodeoxygenation (HDO) of phenol. With regard to achieving a high selectivity to benzene, the biphasic catalytic process in the decalin/water mixed solvent was superior to the monophasic processes in either the decalin or water solvent under the same conditions. Water acted as a co-solvent that prevented the occurrence of side reactions and promoted the catalytic C–O bond scission of phenol. The synergistic effect of the biphasic solvents (decalin and water) and the Ru/Nb2O5-MC composite catalysts, which might stabilize the emulsions and decrease the activation energy of HDO, was investigated. Meanwhile, other probe reactions were conducted to elucidate the mechanism of the HDO of phenol. The application of the efficient biphasic catalytic process may provide a promising approach for improving lignin valorization. [ABSTRACT FROM AUTHOR]

The half-sandwich 1,3-bis(trimethylsilyl)allyl and bis(trimethylsilyl)amido ruthenium complexes [(η5-C5Me5)RuX] (X = η3-C3H3(SiMe3)2, 1; X = N(SiMe3)2, 2) were prepared by reaction of tetranuclear [(η5-C5Me5)RuCl]4 with four equivalents of K[C3H3(SiMe3)2] or Na[N(SiMe3)2]. Complexes 1 and 2 are formally 16- and 14-electron complexes, respectively, and exhibit γ-agostic C–H…Ru interactions in the solid state, which were further investigated by density functional theory (DFT) calculations and quantum theory of atoms in molecules (QTAIM) analysis. The acid–base reaction of the amido complex 2 with 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-imine (ImDippNH) afforded the imidazolin-2-iminato complex [(η5-C5Me5)Ru(NImDipp)] (4); 4 was also obtained from the reaction of [(η5-C5Me5)RuCl]4 with the lithium reagent [(ImDippN)Li]2. 4 represents the first terminal imidazolin-2-iminato complex with a late transition metal and shows a rare one-legged piano stool (“pogo stick”) geometry with a short Ru–N bond of 1.8607(15) Å. The reaction of 4 with tert-butyl isocyanate (tBuNCO) gave the ureato complex [(η5-C5Me5)Ru{ImDippN(C=O)NtBu}] (5) by [2 + 2] cycloaddition. This reactivity together with a DFT study on the bonding situation in 4 suggest a close similarity with related half-sandwich imido complexes [(arene)M(NR)] (M = Ru, Os) and [CpM(NR)] (M = Rh, Ir). [ABSTRACT FROM AUTHOR]

We have synthesised and characterised a novel organic–inorganic hybrid crystal, [(CH3)2NH2]2KCr(CN)6. The thermal DSC, TMA, DTG and DTA analyses indicate two solid-to-solid structural phase transitions (PTs). According to the X-ray diffraction experiments, the first PT at 220 K is isostructural, since it does not involve a change of the space group. This transition occurs between the states, where the (CH3)2NH2+ cations are orientationally disordered and ordered (frozen). The other reversible PT at 481 K leads to a melt-like phase similar to the one observed in plastic crystals or polar liquids. Dielectric spectroscopy has been used to characterise the switching properties of the dipole moments in the vicinity of the PTs. Continuous-wave electron paramagnetic resonance spectroscopy was employed to investigate the effect of ordering on the local environment of the Cr3+ ions. We have also applied the quasielastic neutron scattering (QENS) technique as well as 1H NMR spectroscopy to measure the dynamics of the (CH3)2NH2+ cations residing in the inorganic framework. [ABSTRACT FROM AUTHOR]

Species with a lower ionization energy than alkali atoms are referred to as superalkalis. Typical superalkalis include a central electronegative core with excess metal ligands. We propose a new series of “non-metallic” NnH3n+1+ superalkali cations based on the results of the MP2/6-311++G(d,p) computations. These cations are designed by successive replacement of H-ligands of ammonium cations (NH4+) by ammonium (NH4) moieties. The resulting NnH3n+1+ cations, which can be expressed in the form of [NH4…(n− 1)NH3]+ complexes, possess a number of unusual N–H…N type of partially covalent H-bonds, with the interaction energy in the range of 7.8–24.3 kcal mol−1. These cations are stable against loss of a proton (NnH3n + H+) and loss of ammonia [(n− 1)NH3 + NH4+]. The vertical electron attachment energies (EAvs) of NnH3n+1+ decrease monotonically from 4.39 eV for n = 1 to 2.39 eV for n = 5, which suggests their superalkali nature. This can be explained on the basis of electron localization on the core (central) N-atom (Qc), as the EAv correlates linearly with Qc. We have also demonstrated that this series may be continued to obtain new superalkali cations with even lower EAv, by exemplifying N9H28+ with an EAv of 1.84 eV. N9H28+ is stabilized by four partially covalent H-bonds (8.5 kcal mol−1 each) and four electrostatic H-bonds (0.4 kcal mol−1 each). This led to an exponential relation between EAv and n, which may provide an approximate EAv for any value of n in the NnH3n+1+ series. [ABSTRACT FROM AUTHOR]

Photoinduced electron transfer (PET) with the formation of stable radicals plays an important role in many areas. In this work, PET and color change of two sulfone-based donor–acceptor molecules were observed for the first time in the solid state. Generation of radicals was confirmed by experimental and theoretical data. The radicals could be stable in the air and at high temperature (e.g. 105 °C) in the solid state. Introducing an electron-donating substituent (such as –NH2) increases the molecular dipole moment and promotes the PET process. Sulfone-based molecules observed in this work and their analogs may be applied in several potential applications such as photoswitching, photochromism, energy conversion, and photocatalysis. [ABSTRACT FROM AUTHOR]

Herein, we synthesized CH3NH3PbBr3 nanoparticles using succinic acid and oleylamine at a fixed ratio as ligands. The formed stable CH3NH3PbBr3 NCs exhibit narrow green photoluminescence with high quantum yield as compared to the perovskites formed through oleic acid. Moreover, a fluorescent keypad lock security device authorizing password entries was constructed based on the output emission signal. The fluorescent keypad lock could be unlocked upon entering the correct sequence of password, i.e. MPDSOC. Furthermore, characterizations and morphology studies have been performed using UV, PL, XRD, TCSPC and TEM. In addition, stability tests were monitored using fluorescence spectra. [ABSTRACT FROM AUTHOR]

Not only do theoretical studies predict that doping graphene with nitrogen can tailor its electronic properties and chemical reactivity but practical results have also shown that tuning the shapes of graphene could make it more applicable in electronic devices. However, the successful transfer of lab procedures to commercialization and scale-up fabrication of N-doped graphene with specific architectures still faces great challenges at the moment. Herein, we report a smart approach to rationally design and deliberately construct 3D N-doped honeycomb-structured graphene, denoted as 3D-NHrGO, by a (NH4)2SO4-templated self-assembly method in which (NH4)2SO4 plays the role of “a choice that serves three purposes”. (NH4)2SO4 can not only facilitate the ultrafast separation of GO from the obtained mixed liquor of Hummers’ method, but also act as a nitrogen source and a green template to tailor the electronic properties as well as control the morphology of 3D-NHrGO, respectively. Particularly, (NH4)2SO4 can be recovered with simple recrystallization at the end of the synthesis, which makes the process environment-friendly and resource-effective. The compositions, structures, and morphologies of the samples during overall evolution of the synthetic procedure were investigated, and the substitution of N in the graphene framework is also evidenced. When evaluated as an anode material for Li-ion battery, the 3D-NHrGO gives high rate capability and stable cycle life. This research inspires new methodologies in addressing the enormous problems associated with the traditional graphene preparation process while using GO as the precursor, and sheds light on the great potential of industrially viable manufacturing of 3D N-doped graphene architectures for other applications. [ABSTRACT FROM AUTHOR]

A family of lanthanide-based MOFs (Ln-MOFs) with high thermal and chemical stability have been successfully synthesized by a solvothermal method. Owing to the intrinsic robustness of the framework and temperature-dependent luminescence behaviour of lanthanides, Eu3+/Tb3+-mixed MOFs ([(CH3)2NH2]Eu0.036Tb0.964BPTC) have also been successfully synthesized and targeted for developing excellent luminescent thermometers. The obtained mixed Ln-MOF exhibits ratiometric temperature sensing based on the distinguished characteristic emission of lanthanides with a wide temperature range from 77 K to 377 K. Particularly, the temperature sensor shows good linear responses from 220 K to 310 K with the maximum relative sensitivities (Sm) of 9.42% per K at 310 K. This value is comparable to those of the most excellent Ln-MOF thermometers reported. Besides, the temperature-dependent luminescent colours could also be systematically tuned from green, through yellow to red with increasing temperature, which can be clearly and directly observed even by the naked eye or a camera, thus also allowing colorimetric luminescence thermometry. [ABSTRACT FROM AUTHOR]

Anilido-oxazoline-ligated rare-earth metal dialkyl complexes have been synthesized and structurally characterized. The complexes exhibited strong fluorescence emissions and good catalytic performance on isoprene polymerization with high cis-1,4-selectivity. The treatment of anilido-oxazoline precursors ortho-C6H4[NH(2,6-R12C6H3)][C=NC(R2,R3)CH2O] (R1 = R2 = R3 = Me (HL1); R1 = iPr, R2 = R3 = Me (HL2); R1 = R2 = iPr, R3 = H (HL3); and R1 = iPr, R2 = R3 = H (HL4)) with an equimolar amount of Ln(CH2SiMe3)3(THF)2 (Ln = Sc, Y) afforded rare-earth metal complexes L1–4-Ln(CH2SiMe3)2(THF)n (L1-Sc (1), n = 1; L2-Sc (2), n = 0; L1-Y (3), n = 1; L2-Y (4), n = 1; L3-Y (5), n = 1; and L4-Y (6), n = 1) in good yields. The complexes are stable in both the solid state and solution. Single crystal X-ray diffraction study showed that complexes 1, 3 and 4 exhibit a distorted trigonal bipyramidal configuration, while complex 2 is pseudo-tetrahedral without coordinated THF. The luminescence properties of complexes 1–4 were investigated and the emission maxima were found in the range of 465–477 nm. DFT and TD-DFT studies were carried out to explore their characteristic electronic structures and gain insight into their optical properties. Upon activation with organic borates, the reported complexes exhibited high activity and cis-1,4-selectivity for isoprene polymerization. The nature of the central metal and substituent groups in oxazoline have an influence on the cis-1,4-selectivity. [ABSTRACT FROM AUTHOR]

NH3, synthesized by the Haber–Bosch process, is essential for fertilisers in order to feed the world's growing population, however, it causes massive energy consumption and generates large amounts of greenhouse gases. Electrochemical N2 reduction reaction (NRR) at ambient conditions is highly desirable for energy-efficient and sustainable NH3 production but this requires an efficient catalyst. In this work, we report a defect-rich fluorographene nanosheet synthesised via fluorination of graphene for NRR electrocatalysis. Such an electrocatalyst shows an NH3 formation rate of 9.3 μg h−1 mgcat.−1 and a faradaic efficiency of 4.2% at −0.7 V vs. reversible hydrogen electrode in 0.1 M Na2SO4. Density functional theory calculations reveal that the fluorination of graphene induces defects, which not only provide reaction sites for NRR but effectively activate N2 molecules. [ABSTRACT FROM AUTHOR]

Oxygenative cleavage of an inert CAr–NH2 bond with concomitant 1,2 amine migration in 8-aminoquinoline derivatives is reported in water at room temperature. The reaction is highly atom- and step-economical as both C- and N-containing fragments of the C–N bond cleavage are incorporated into the target molecule and is effected without the need for N-oxide. The reaction is scalable to gram level, and the products are useful as electrophilic partners for coupling reactions, ligands in catalysis and bioactive compounds. [ABSTRACT FROM AUTHOR]

The thiaboranes closo-1-SB11H11 (1a) and 12-I-closo-1-SB11H10 (1b) react with 4-(dimethylamino)pyridine under inert conditions upon the formation of the nido-type thiaboranes 9-B{(4-Me2N)C5NH4}2(H)-7-SB10H11 and 9-B{(4-Me2N)C5NH4}2(H)-5-I-7-SB10H10 containing an exoskeletal B–H group. The same type of B–H moiety is also stabilised by one bipyridine molecule in a chelating fashion. These complexes are unstable in solution, and in air and hydrolyse to monodeboronated ionic compounds having [nido-7-SB10H11]− or [5-I-nido-7-SB10H10]− anions which are also products of the reactions of 1a and 1b with other N-bases such as pyridine, ammonia and DABCO. The extrusion of one boron and one sulphur atom takes place when 1a reacts with 2,6-di-tert-butylpyridine to yield decaborane. [ABSTRACT FROM AUTHOR]

Industrial NH3 synthesis mainly relies on the carbon-emitting Haber–Bosch process operating under severe conditions. Electrocatalytic N2-to-NH3 fixation under ambient conditions is an attractive approach to reduce energy consumption and avoid direct carbon emission. In this communication, sulfur-doped graphene (S-G) is proposed as an efficient and stable electrocatalyst to drive the nitrogen reduction reaction (NRR) under ambient conditions. In 0.1 M HCl, this S-G attains a remarkably large NH3 yield of 27.3 μg h−1 mgcat.−1 and a high Faradaic efficiency of 11.5% at −0.6 and −0.5 V vs. a reversible hydrogen electrode, respectively, much higher than those of undoped G (6.25 μg h−1 mgcat.−1; 0.52%). Density functional theory calculations reveal that carbon atoms close to substituted sulfur atoms are the underlying catalytic active sites for the NRR on S-G, and the related NRR mechanism is also explored. [ABSTRACT FROM AUTHOR]