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Abstract The cavity inside fullerene C60 provides a highly symmetric and inert environment for housing atoms and small molecules. Here we report the encapsulation of formaldehyde inside C60 by molecular surgery, yielding the supermolecular complex CH2O@C60, despite the 4.4 Å van der Waals length of CH2O exceeding the 3.7 Å internal diameter of C60. The presence of CH2O significantly reduces the cage HOMO-LUMO gap. Nuclear spin-spin couplings are observed between the fullerene host and the formaldehyde guest. The rapid spin-lattice relaxation of the formaldehyde 13C nuclei is attributed to a dominant spin-rotation mechanism. Despite being squeezed so tightly, the encapsulated formaldehyde molecules rotate freely about their long axes even at cryogenic temperatures, allowing observation of the ortho-to-para spin isomer conversion by infrared spectroscopy. The particle in a box nature of the system is demonstrated by the observation of two quantised translational modes in the cryogenic THz spectra.

Abstract This work demonstrates a large area process for atomically thin 2D semiconductors to unlock the technological upscale required for their commercial uptake. The new atomic layer deposition (ALD) and conversion technique yields large area performance uniformity and tunability. Like graphene, 2D Transition Metal Dichalcogenides (TMDCs) are prone to upscaling challenges limiting their commercial uptake. They are challenging to grow uniformly on large substrates and to transfer on alternative substrates while they often lack in large area electrical performance uniformity. The scalable ALD process of this work enables uniform growth of 2D TMDCs on large area with independent control of layer thickness, stoichiometry and crystallinity while allowing chemical free transfers to application substrates. Field effect transistors (FETs) fabricated on flexible substrates using the process present a field effect mobility of up to 55 cm2/Vs, subthreshold slope down to 80 mV/dec and on/off ratios of 107. In addition, non-volatile memory transistors using ferroelectric FETs (FeFETs) operating at ±5 V with on/off ratio of 107 and a memory window of 3.25 V are demonstrated. These FeFETs demonstrate state-of-the-art performance with multiple state switching, suitable for one-transistor non-volatile memory and for synaptic transistors revealing the applicability of the process to flexible neuromorphic applications.

This paper explores and revisits in detail the formation and characterization of sugar-based aminonitriles, whose ultimate origin can be traced to the interaction of biomolecules with cyanide. Although the synthesis and spectroscopic data of 2-amino-aldononitriles were reported long ago, there are both contradictory and confusing results among the published data. We have now addressed this concern through an exhaustive structural elucidation of acylated 2-amino- and 2-alkyl(aryl)amino-2-deoxyaldonitriles using mass spectrometry and FT-IR, FT–Raman, and NMR spectroscopies. Several structures could be unambiguously determined through single-crystal X-ray diffraction, which allowed us to correct other misassignments. Moreover, this study unveils how steric and electronic effects influence the acylation outcome of the amino, (alkyl, aryl)amino, or acetamido group at C-2. The chirality at the latter, which was assigned tentatively through optical rotation correlation, and hence the preferential threo stereochemistry generated during the cyanohydrin synthesis of 2-amino-2-deoxy aldononitriles have now been established with confidence.

This paper reports the preparation and herbicidal evaluation of a small library of acylhydrazones based on the synthetic herbicide metribuzin. The hydrazone linkage easily obtained by reaction of metribuzin with aliphatic and aromatic aldehydes, masks efficiently the exocyclic amino group, thereby altering significantly H-bonding with the receptor and increasing the lipophilicity relative to the parent herbicide. The structures of all compounds, including key stereochemical issues on conformation and E/Z configuration around the CN bond were thoroughly elucidated by spectroscopic methods, and unambiguously corroborated by X-ray diffraction analysis. The herbicidal assays using an aliphatic and an aromatic acylhydrazone were performed on tomato and rapeseed plants grown in greenhouse. Our results demonstrate, regardless of rate application, that such acylhydrazone formulations do not alter the selectivity of metribuzin. Moreover, the herbicide activity was even higher in the alkyl derivative than that achieved by commercial metribuzin, thus suggesting that this substance can be applied with no need of combination with chemical coadjuvants, unlike most formulations of commercially available herbicides. Therefore, the study shows the promising effect of chemical derivatization of a common herbicide as metribuzin, to improve the herbicide activity without compromising selectivity, and allowing the farmers its use in crop protection safely and effectively.

This paper thoroughly explores the formation of Schiff bases derived from salicylaldehydes and a conformationally restricted amino alcohol (1-amino-2-indanol), as well as the generation of 1,3-oxazolidines, a key heterocyclic core present in numerous bioactive compounds. We provide enough evidences, both experimental-including crystallographic analyses and DFT-based calculations on imine/enamine tautomerism in the solid state and solution. In the course of imine formation, a pentacyclic oxazolidine–oxazine structure could be isolated with complete stereocontrol, whose configuration has been determined by merging theory and experiment. Mechanistic studies reveal that, although oxazolidines can be obtained under kinetic conditions, the prevalence of imines obeys to thermodynamic control as they are the most stable structures. The stereochemical outcome of imine cyclization under acylating conditions leads to formation of 2,4-trans-oxazolidines.

The Lucite Alpha process is the predominant technology for the preparation of acrylics. This two-stage process involves the palladium-catalysed formation of methyl propanoate from ethene, CO, and methanol, followed by the oxidative formylation of methyl propanoate into methyl methacrylate. A range of bis-1,2-disubstituted aminomethylferrocenes has been prepared and characterised. These complexes serve as precursors to a variety of bulky ferrocenylmethyldiphosphanes that, in turn, function as ligands in the palladium-catalysed process. We describe the crystal structures of five ligand precursors and provide a rationale for their design. In situ catalyst testing on palladium complexes derived from ferrocenylphosphanes demonstrates that these are highly selective (>99.5%) catalysts for the formation of methyl propanoate from ethene, CO, and methanol and have turnover numbers exceeding 50,000. This article credits those researchers who worked on this project in the early days, who received little or no credit for their achievements and endeavours.

Materials that combine flexibility and open metal sites are crucial for myriad applications. In this article, we report a 2D coordination polymer (CP) assembled from CuII ions and a flexible meta-carborane-based linker [Cu2(L1)2(Solv)2]•xSolv (1-DMA, 1-DMF, and 1-MeOH; L1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane). 1-DMF undergoes an unusual example of reversible phase transition on solvent treatment (i.e., MeOH and CH2Cl2). Solvent exchange, followed by thermal activation provided a new porous phase that exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 301 m2 g−1 and is capable of a CO2 uptake of 41 cm3 g−1. The transformation is reversible and 1-DMF is reformed on addition of DMF to the porous phase. We provide evidence for the reversible process being the result of the formation/cleavage of weak but attractive B−H∙∙∙Cu interactions by a combination of single-crystal (SCXRD), powder (PXRD) X-ray diffraction, Raman spectroscopy, and DFT calculations.

A core 4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridine-4-one scaffold is elaborated at C-3(Me) by base-mediated aldol condensation to give new 3-alkenyl-4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridine-4-ones, which are masked forms related to the acylpyridone natural products.

The conformational properties of 1,3-diindolylureas and thioureas were studied by a combination of heteronuclear NMR spectroscopy and quantum mechanics calculations. NOE experiments showed that the anti–anti conformer along the C7–N7α bonds was predominant in DMSO-d6 solution in the absence of anions. Anion-induced changes in the 1H and 15N chemical shifts confirm the weak binding of chloride anions with negligible conformational changes. Strong deshielding of ureido protons and moderate deshielding of indole NH was observed upon the addition of acetate, benzoate, bicarbonate and dihydrogen phosphate, which indicated that the predominant hydrogen bond interactions occurred at the urea donor groups. Binding of oxo-anions caused conformational changes along the C7–N7α bonds and the syn–syn conformer was preferred for anion–receptor complexes. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations.

Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar enediyne (1), the helical stiff stilbene (2), or the semi-rigid glycoluril motif fused to the porphyrins (3), are compared. Binding constants Ka = 104–106 M−1 reveal subtle differences between these tweezers, that are discussed in terms of porphyrin dislocation modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

The coordination chemistry of 2,5-dicarbothioamidopyrrole ligands, namely N2,N5-dibutyl-3,4-diphenyl-1H-pyrrole-2,5-bis(carbothioamide) and N2,N5,3,4-tetraphenyl-1H-pyrrole-2,5-bis(carbothioamide), has been investigated with Cu(ii) metal centres by means of X-ray crystallography. This resulted in the formation of the expected planar S,N,S′ coordinated complex for the former ligand and unexpected ring-closure reactions, with formation of benzothiazole sidearms, for the latter. Both Cu(ii) and Cu(i), used in large excess, were found to favour the ring-closure reaction, although the structural characterisation of the resulting complexes contained only Cu(ii) cations, with varying coordination geometries ranging from square planar and square-based pyramidal to tetrahedral. By repeating the reaction using a slight excess of Cu(ii) (2 : 1) two more different structures were obtained where the metal was coordinated to the original ligand, N2,N5,3,4-tetraphenyl-1H-pyrrole-2,5-bis(carbothioamide), or to the mixed ligand where only one of the thioamide substituents had converted to a benzothiazole. The essential role of Cu for the ring closure reaction was also established by comparing its complex with structural features of the analogous Co(ii) complex, the latter revealing no ring closure to give benzothiazole substituents and co-crystallisation of a mixed Co(ii)/Co(iii) complex. Finally, the structure and photophysical properties of the corresponding 3,4-diphenyl-2,5-bis(benzothiozol-5-yl)-pyrrole ligand, obtained viatreatment of the thioamide with K3[Fe(CN)6], were also investigated revealing a blue-centered emission. [ABSTRACT FROM AUTHOR]

The syntheses of new o-carboranyl alcohols bearing N-aromatic rings, 1-[R(hydroxy)methyl]-2-methyl-1,2-dicarba-closo-dodecaborane (R = 6-methyl-2-pyridyl 1b, 3-pyridyl 1c, 2-quinolyl 1e, 4-quinolyl 1f), 1-[R(hydroxy)methyl]-1,2-dicarba-closo-dodecaborane (R = 2-pyridyl 2a, 6-methyl-2-pyridyl 2b, 3-pyridyl 2c, 4-pyridyl 2d, 2-quinolyl 2e, 4-quinolyl 2f)), are reported. The crystal structures of all compounds, except that for 1b, are reported and compared with those related compounds previously synthesized by us (1-[R(hydroxy)methyl]-2-methyl-1,2-dicarba-closo-dodecaborane (R = 2-pyridyl 1a, 4-pyridyl 1d)). We provide an analysis of these compounds by means of X-ray crystallography, NMR/IR spectroscopies, thermal analyses and gas phase calculations in the context of crystal engineering. The results show that the crystal packings of these alcohols are dominated by the supramolecular O–HN heterosynthon, but also include other weaker interactions such as C–HO hydrogen bonds, HH contacts and some degree of (C/B)–Hπ interactions. There are four types of O–HN hydrogen bonded chains, two giving rise to high melting point compounds (1c, 1d, 1f, 2c, 2d, and 2f) and two affording lower melting point compounds (1a, 2aand 2b). The lowest melting compounds (1eand 2e) show no such infinite O–HN hydrogen bonding networks and only intramolecular O–HN hydrogen bonds. We correlate the presence of the infinite O–HN hydrogen bonding network in the crystal structure for the pyridine derivatives with their melting points. Gas phase calculations show that the energy for the O–HN interactions in hydrogen bonded dimers is in the range 4–8 kcal mol−1. [ABSTRACT FROM AUTHOR]

The preparations and spectroscopic characterisation of the hydrolytically unstable As(iii) complexes, [AsF3(OPR3)2] (R = Me or Ph) and [AsF3{Me2P(O)CH2P(O)Me2}] are described and represent the first examples of complexes of AsF3with neutral ligands. The crystal structure of [AsF3{Me2P(O)CH2P(O)Me2}] contains dimers with bridging diphosphine dioxide, but there are also long contacts between the dimers to neighbouring phosphine oxide groups, completing a very distorted six-coordination at arsenic and producing a weakly associated polymer structure. The reaction of AsF3with OAsPh3affords Ph3AsF2, and no arsine oxide complex was formed. Reaction of SbF3with OER3(R = Me or Ph, E = P or As), Me2P(O)CH2P(O)Me2and Ph2P(O)(CH2)nP(O)Ph2(n= 1 or 2) in MeOH produces [SbF3(OER3)2], [SbF3{Me2P(O)CH2P(O)Me2}] and [SbF3{Ph2P(O)(CH2)nP(O)Ph2}] respectively. The X-ray structures reveal that the complexes contain square pyramidal SbF3O2cores with apical F and cisdisposed pnictogen oxides. However, whilst [SbF3(OER3)2] (R = Ph: E = P or As; R = Me: E = As) and [SbF3{Ph2P(O)CH2P(O)Ph2}] are monomeric, [SbF3{Me2P(O)CH2P(O)Me2}] is a dimer with bridging diphosphine dioxides producing a twelve-membered ring, and [SbF3{Ph2P(O)(CH2)2P(O)Ph2}] is a chain polymer with diphosphine dioxide bridges. In the OAsR3reactions with SbF3, R3AsF2are also formed. Notably the Sb–O(P) bonds are shorter than As–O(P), despite the covalent radii (As < Sb), consistent with very weak coordination of the AsF3. IR and multinuclear (1H, 19F and 31P) NMR data are reported and discussed. BiF3does not react with pnictogen oxide ligands under similar conditions and halide exchange of bismuth chloro complexes with Me3SnF gave BiF3. [ABSTRACT FROM AUTHOR]

The structure, synthesis and magnetic properties of three new complex cobalt hydroxyl oxalates are presented, showing a modification of the 2-D double layer hydroxide structure. Co12(OH)18(ox)3(pip) [ox = oxalate, C2O42−; pip = piperazine, C4N2H10] (1), is essentially built from brucite-like layers with a one ninthdepletion of the octahedral sites and a preservation of a trigonal crystallographic symmetry. ACo28(OH)43(ox)6Br2(H2O)2[A = Na (2), K (3)] are similarly composed of a brucite-like layer with three nineteenthsdepletion of octahedral sites, again preserving a trigonal symmetry. Both 2and 3show a small degree of structural disorder within the framework. All of these compounds have alternating layers of a mineral-like metal hydroxide structure and a metal oxalate coordination network, with the depletion in the hydroxyl layers being templated by the coordination network. Magnetic studies of 1reveal a metamagnetic character, with the onset of an antiferromagnetic phase below Tc= 23.5 K (H= 0 G), and a first order antiferromagnet to metamagnet transition at Hc= 500–1000 G (T= 20–6 K). Compound 3shows a more conventional ferrimagnetic ordering below 33(±1) K with a small coercive field of 107(±5) G at 10 K. [ABSTRACT FROM AUTHOR]

The syntheses of new o-carboranyl alcohols 1-[R(hydroxy)methyl]-2-methyl-1,2-dicarba-closo-dodecaborane (R = 9-anthracenyl 2, 4-pyridyl 4), 1-[R(hydroxy)methyl]-2-phenyl-1,2-dicarba-closo-dodecaborane (R = 3-phenyl-2-propen-1-ol 6, 2-furanyl 7) are reported. Their crystal structures, along with those for the related 1-[R(hydroxy)methyl]-2-methyl-1,2-dicarba-closo-dodecaborane (R = phenyl 1, 2-pyridyl 3) and 1-[phenyl(hydroxy)methyl]-2-phenyl-1,2-dicarba-closo-dodecaborane (5) derivatives are reported. We provide an analysis of these compounds by means of X-ray crystallography, NMR/IR spectroscopies, thermal analyses and gas phase calculations in the context of crystal engineering. The results show that the crystal packing for these alcohols can be described in terms of three major supramolecular synthons based on hydrogen bonding of OH groups with themselves (O–HO homosynthons: 1, 6and 7), with the pyridine nitrogen atom (O–HN heterosynthons: 3and 4) or with aromatic rings (O–Hπ: 2). The latter shows an unusual combination of O–Hπ and π–π interactions. The supramolecular heterosynthons are clearly favoured over their respective supramolecular homosynthons. In the absence of a nitrogen atom, the bulkiness around the OH groups seems to play a key role in the formation or not of full O–HO hydrogen bonding. The supramolecular arrays are finally supported by both, weak dihydrogen or hydrophobic interactions, due to the presence of o-carboranyl fragments in these molecules. These compounds display good thermal stabilities, with compound 4showing an unexpectedly high melting temperature of 256 °C probably arising from an infinite O–HN hydrogen bonding network. Gas phase calculations demonstrate that O–HN hydrogen bonded dimers are 3.5 kcal mol−1more stable than analogous for O–HO hydrogen bonded ones. [ABSTRACT FROM AUTHOR]

The present paper summarizes a straightforward synthesis of 4,5-dihydro-1,3,4-thiadiazoles by the 1,3-dipolar cycloaddition of thioisomünchnones. These reactions have been carried out in dichloromethane and are essentially complete within 60 min at room temperature. Under such mild conditions the asymmetric version has been explored as well. Unequivocal structure elucidation has been accomplished by means of one- and two-dimensional NMR techniques as well as X-ray structure analysis. [ABSTRACT FROM AUTHOR]

Crystal structures of ten homoleptic platinum (II) complexes with N-methylthiourea, N,N′-dimethylthiourea and 1-methyl-1H-imidazole-2(3H)-thione ligands and squarate, croconate, rhodizonate, terephthalic acid monocarboxylate and 1,4-naphthalene dicarboxylic acid monocarboxylate were determined by X-ray diffraction. The coordinated ligands display hydrogen bonding interactions with the counter anions, leading to the formation of a variety of different hydrogen bonded networks. The thiourea groups adopt different conformations around the metal centre, with a 1,2-alternate arrangement most frequently encountered. Discrete hydrogen bonds are the dominant interactions as a result of the disposition of the alkyl groups preventing the DDAA contacts usually displayed by thiourea ligands and carboxylates. [ABSTRACT FROM AUTHOR]

Metal complexes of 2,5-dicarboxamidopyrroles and 2,5-dicarbothioamidopyrroles have been structurally characterised for the first time, complementing the significant amount of work that has been reported for the analogous pyridine ligands. N,N′-Bis(3,5-dinitrophenyl)-3,4-diphenyl-1H-pyrrole-2,5-dicarboxamide forms octahedral bis(tridentate) complexes with cobalt(iii) and nickel(ii), where the ligands are bound to the metal centres through deprotonated pyrrole and amide N atoms. N,N′-Dibutyl-3,4-diphenyl-1H-pyrrole-2,5-dicarboxthioamide and N,N′-diphenyl-3,4-diphenyl-1H-pyrrole-2,5-dicarboxthioamide also form bis(tridentate) cobalt complexes but are only deprotonated at the pyrrole N atom, the remainder of the coordination sphere comprising the thioamide S atoms. The dibutyl derivative was isolated as a Co(ii) complex, whereas the diphenyl system deposited a Co(iii) complex. In contrast, N,N′-dibutyl-3,4-dichloro-1H-pyrrole-2,5-dicarboxamide was found to act as a bidentate ligand, in an octahedral cobalt(ii) complex comprising of two bidentate pyrrole ligands, and two aqua ligands. Synthesis of N,N-bis(pyridin-2-ylmethyl)-3,4-diphenyl-1H-pyrrole-2,5-carboxamide gave a pyrrole ligand with increased denticity. Reaction with cobalt(ii) chloride resulted in the isolation of a dinuclear helicate complex. The ligand was found to have undergone addition of a methoxy group to one of the linking methylene carbons, presumably as a result of the oxidative addition of solvent methanol. [ABSTRACT FROM AUTHOR]

Ferrocene-functionalised anion receptors based on an ortho-phenylenediamine scaffold have been shown to undergo anion-triggered electrochemical deposition. This process may offer a new way of detecting anionic species in solution. [ABSTRACT FROM AUTHOR]

The synthesis of a N-confused calix[4]pyrrole-α-carbaldehyde is reported, together with its Knoevenagel reaction derivatives. The X-ray crystal structure of the aldehyde and two derivatives are reported showing the macrocycles adopting ‘confused 1,3-alternate’ conformations in all cases. The affinity of these macrocycles for a range of anionic guests has been measured in DMSO-d6/0.5% water, and the results compared with the parent N-confused calix[4]pyrrole parent macrocycle. These studies show that the derivatives have a significantly higher affinity for anionic guests than the parent system. [ABSTRACT FROM AUTHOR]

An isomeric series of seven, square-planar, neutral dichloropalladium(ii) complexes cis-PdCl2{P,P-C6H3N(CH2PPh2)2(CO2H)(OH)} 2a–2g have been synthesised in high yields (70–99%) from PdCl2(cod) (cod = cycloocta-1,5-diene) and the appropriate ligands C6H3N(CH2PPh2)2(CO2H)–(OH) 1a–1g in CH2Cl2. The new ditertiary phosphine C6H3N(CH2PPh2)2(3-CO2H)(4-CO2H) 3, bearing two remote carboxylic acid groups on the N-arene backbone, was prepared by condensation of H2NC6H3(3-CO2H)(4-CO2H) with 2 equiv. of Ph2PCH2OH in MeOH. The palladium(ii) complex cis-{P,P-PdCl2C6H3N(CH2PPh2)2(3-CO2H)(4-CO2H)} 4 was synthesised in an analogous fashion to 2a–2g. Solution NMR (31P{1H}, 1H), FT-IR, ms and microanalytical data are in full agreement with the proposed structures. Single crystal X-ray studies confirm that, in each case, compounds 2a–2e and 4 are square-planar with normal Pd–P [range 2.2255(11)–2.2529(5) Å]/Pd–Cl [range 2.3292(14)–2.3640(16) Å] bond lengths and P–Pd–P [range 91.586(18)–97.25(4)°] bond angles. These studies also demonstrate the importance of predisposition, with respect to the –N(CH2PPh2)2, –CO2H and –OH (or a second –CO2H as in 4) functionalities around the benzene core, and the choice of recrystallisation solvent used with regards to the supramolecular structures observed here for the palladium(ii) complexes 2a–2e and 4. Hence in 2a·MeOH, intermolecular O–H⋯Cl hydrogen bonding associates two molecules into a dimer pair with the formation of a 20-membered ring. Two different hydrogen bonded motifs are observed in 2b·0.5Et2O namely an intermolecular O–H⋯O dimer pair and a 1-D polymeric chain through bifurcated O–H⋯Cl hydrogen bonding. Both 2c·MeOH and 2d·CHCl3 have 1-D chain structures using intermolecular O–H⋯Cl hydrogen bonding between neighbouring molecules (for 2d·CHCl3) or a combination of O–H⋯O (with a MeOH solvent) and O–H⋯Cl hydrogen bonding (for 2c·MeOH). The structures of 2e·CHCl3 and 2a·CHCl3 have similar features in common namely a classic H-bonded head-to-tail arrangement of carboxylic acid groups between molecules and additional intermolecular O–H⋯Cl H-bonds giving rise to ladder structures. Each ring is either 38- (for 2e·CHCl3) or 34-membered (for 2a·CHCl3) in size. In 4·2.5MeOH dimers are connected via MeOH solvates to give a 2-D infinite H-bonded network. The X-ray structures of 4·3DMSO, 2e·2DMSO and 2a·DMSO have also been determined. Whilst 4·3DMSO and 2e·2DMSO form discrete structures, 2a·DMSO forms a 1-D chain through O–H⋯Cl hydrogen bonding. The Pd⋯Pd contacts for all these palladium(ii) complexes lie clearly within the non bonding range [7.35–20.69 Å]. [ABSTRACT FROM AUTHOR]

Simple epoxide ring opening chemistry using the cyclic secondary amine 1,4-diazacycloheptane or the related linear species N,N′-dimethylethylenediamine, and racemic (±)−3,3-dimethyl-1,2-epoxybutane gives access to the pendant alcohol functionalised ditertiary amine pro-ligands [HOCH(tBu)CH2N(R)CH2]2 (H2L1: R2 = CH2CH2CH2; H2L2: R2 = Me2). The contrasting reactions of H2L1 and H2L2 towards homoleptic group 4 alkoxides highlight the crucial role of ligand backbone flexibility in complex formation. Thus, the chemistry of the more conformationally rigid system (L1)2− appears to be constrained by the cyclic ligand core, such that it adopts a bridging (μ2:η2,η2) mode of coordination towards Ti(iv), leading to dinuclear metal systems [e.g.L1Ti2(OiPr)6]. By contrast, the more flexible linear system (L2)2− binds to both Ti(iv) and Zr(iv) in a chelating fashion leading, for example, to the synthesis of the C2 symmetric mononuclear complex rac-L2Ti(OiPr)2. Thus, a simple synthesis of diastereomerically pure, C2 symmetric, geometrically cis octahedral Ti(iv) complexes from racemic precursors is presented. [ABSTRACT FROM AUTHOR]

The anion complexation properties of a trans-functionalised platinum(ii) complex have been studied revealing a high affinity for sulfate in solution and 3 : 2 receptor : sulfate complex formation in the solid state with the anion bound in a pocket lined with 6 NH and 8 CH hydrogen-bond-donating groups. [ABSTRACT FROM AUTHOR]

Neutral 1,3-di(1H-indol-7-yl)ureas are selective dihydrogen phosphate receptors in polar solvent mixtures (DMSO-d6–25% water). [ABSTRACT FROM AUTHOR]

Sulfonamide groups, commonly used as neutral hydrogen bond donors in a wide variety of anion receptors, deprotonate upon addition of certain basic anionic guests in two simple functionalised ureas. [ABSTRACT FROM AUTHOR]

Two cleft-like anion receptors have been synthesised that contain indole hydrogen-bond donors and show fluoride selectively in a DMSO–water solution with crystallographic studies showing a ‘twisted’ binding mode for fluoride in the solid state. [ABSTRACT FROM AUTHOR]

Replacement of the central isophthalamide core in a synthetic HCl receptor, with a 2,6-dicarboxamidopyridine, leads to a more preorganised molecular structure that exhibits higher chloride affinity and membrane transport flux. [ABSTRACT FROM AUTHOR]

The interaction of a variety of acridinone derivatives containing hydrogen-bond donor groups in the 4- and 5-positions with anions demonstrate the potential of this new scaffold in anion receptor and sensor design. [ABSTRACT FROM AUTHOR]