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The structure of the complex formed between trimethylamine and iodine monochloride had been redetermined by a combination of neutron powder diffraction and X-ray single crystal diffraction techniques. The structure determined using NPD shows that the geometry of the trimethylamine moiety resembles that in trimethylammonium cations rather than in the free trimethylamine molecule. The structure shows the presence of weak C–D⋯Cl hydrogen bonds, The I–Cl bond length is in agreement with that derived from an analysis of the pKb values of a series of nitrogen bases and previously determined structures containing N⋯ICl fragments.

A novel alkyne-terminated cubic-octameric POSS was synthesised in high yield (82–90%). The X-ray crystal structure revealed intra- and intermolecular hydrogen bonding between the amide groups of the arms. Hybrid biomaterials were synthesised in nearly quantitative yields via a click reaction with (i) azido-N-Fmoc-norleucine and (ii) 3′-azido-3′-deoxythymidine.

Crystal structures of the salts of 1,8-naphthalaldehydic acid (8-formyl-1-naphthoic acid) show one of two types of interaction between the functional groups. In the more commonly observed case, a carboxylate oxygen lies close to the aldehyde carbonyl carbon atom (O⋯C: 2.445–2.630 Å) and makes an n–pi* interaction. However, in two other cases the carboxylate group has rotated so that the aldehyde now directs its hydrogen atom at the face of the carboxylate group and forms a surprisingly short contact with the carbon atom (H⋯C: 2.29 and 2.42 Å). This interaction is likely to be electrostatic in nature.

A combination of NMR spectroscopy, mass spectrometry and chemical synthesis was used to elucidate the two-step hydrolytic decomposition pathway of the slow-release hydrogen sulfide (H2S) donor GYY4137 and the key decomposition product was also prepared by an independent synthetic route. The (dichloromethane-free) sodium salt of the phosphonamidodithioate GYY4137 was also produced as a pharmaceutically more acceptable salt. In contrast with GYY4137 and its sodium salt, the decomposition product did not generate H2S or exert cytoprotective or anti-inflammatory effects in oxidatively stressed human Jurkat T-cells and LPS-treated murine RAW264.7 macrophages. The decomposition product represents a useful control compound for determining the biological and pharmacological effects of H2S generated from GYY4137.

N,O-ligated Pd(II) complexes show considerable promise for the oxidation of challenging secondary aliphatic alcohols. The crystal structures of the highly active complexes containing the 8-hydroxyquinoline-2-carboxylic acid (HCA) and 8-hydroxyquinoline-2-sulfonic acid (HSA) ligands have been obtained. The (HSA)Pd(OAc)2 system can effectively oxidise a range of secondary alcohols, including unactivated alcohols, within 4–6 h using loadings of 0.5 mol%, while lower loadings (0.2 mol%) can be employed with extended reaction times. The influence of reaction conditions on catalyst degradation was also examined in these studies.

This paper reports the synthesis of a series of new half-squaraine dyes (Hf-SQ) based around a common chromophoric unit consisting of linked indoline and squaric acid moieties. Carboxylate groups have been incorporated onto this core structure at four different points to study the influence of the anchoring group position on dye-sensitized solar cell (DSC) device performance. Dyes have been linked to TiO2 directly through the squaric acid moiety, through a modified squaric acid unit where a vinyl dicyano group has replaced one carbonyl, via an alkyl carboxylate attached to the indole N or through a carboxylate attached to the 4 position of a benzyl indole. Contact angle measurements have been studied to investigate the hydrophobic/hydrophilic properties of the dyes and the results have been compared to N719 and Z907. Full characterization data of all the dyes and synthetic intermediates are reported including single-crystal X-ray structural analysis for dye precursors; the indole (2a) and the half-squarylium esters (3a) and (6b), as well as the dyes (4c), (8) and (12). Dye colours range from yellow to red/brown in solution (lambda(max) range from 430 to 476 nm) with 3 ranging from 38 000 to 133 100 M-1 cm(-1). The performance of the dyes in DSCs shows the highest efficiency yet reported for a Hf-SQ dye (eta = 5.0%) for 1 cm(2) devices with a spectral response ranging from 400 to 700 nm depending on the dye substituents. Co-sensitization of half-squarylium dye (7b) with squaraine dye (SQ2) resulted in a broader spectral response and an improved device efficiency (eta = 6.1%). Density functional theory (DFT) calculations and cyclic voltammetry have been used to study the influence of linker position on dye HOMO-LUMO levels and the data has been correlated with I-V and EQE data.

The synthesis, structural and magnetic characterisation of a family of related Cr(iii) cages are reported. Each member comprises {Cr(iii)3O(O2CR1)3(R2-sao)3}2- (R1 = H, CH3, C(CH3)3, C14H9; R2 = Me, Ph, tBu, C10H8) triangles linked by Na+ cations, resulting in either the discrete complexes [H3O][NEt4]2[NaCr(iii)6O2(O2C-C14H9)6(Naphth-sao)6] (1) and [Na4Cr(iii)6O2(O2CC(CH3)3)6(3,5-di-tBu-sao)6(MeCN)6] (3); or the extended networks [H3O]2[Na2Cr(iii)6O2(O2CH)6(Ph-sao)6(MeCN)2(H2O)2]n·4MeCN (2); [H3O][Na3Cr(iii)6O2(O2CCH3)6(Me-sao)6(MeCN)]n (4) and [Na2Cr(iii)3O(O2CCH3)3(Me-sao)3(H2O)6]n·3MeCN (5). Magnetic susceptibility data obtained for 2 and 4 reveal weak antiferromagnetic exchange between the Cr(iii) ions in the triangles.

A combination of single-crystal X-ray (at 110 and 200 K) and high-resolution neutron powder diffraction (110 K only) using perdeuterated samples has been used to re-determine the crystal structure of the well-known acetone–Br2 complex. The results indicate a significant interaction between the carbonyl oxygen and the nearest Br atom leading to a marked elongation of the molecular Br–Br bond. In the earlier widely cited crystal structure, no such elongation was reported. Furthermore, the new structure indicates the presence of additional weaker C–H⋯O and C–H⋯Br interactions. In this simple complex, in which the halogen bonding is strong compared to the hydrogen bonding (C–H⋯O), the former interaction is found to occur close (~12°) to the plane of the carbonyl group, with the C–H⋯Br complementing the stronger halogen bond.

A crystallographic systematic study of a series of 6 anion receptor complexes has been performed, with the accurate atomic positions and displacement parameters of the hydrogen atoms for two complexes determined by neutron diffraction studies. The N–H⋯anion hydrogen bonding interaction is shown to be central to the geometry of the urea unit. Contributions of the intermolecular interactions to the packing of the molecule are highlighted by correlation to the Hirshfeld surfaces and their fingerprint plots, with alterations to the position and amount of nitro substitution on the receptor shown to affect the π⋯π stacking motifs observed across the structures.

This paper describes the synthesis of a new, yellow triphenylamine dye, 4-[2-(4-diphenylaminophenyl)vinyl]benzoic acid] (6), with a sorption maximum at 380 nm in solution for which EQE data show shifts to 420 nm on sorption to TiO2. The performance of this dye has been measured in dye-sensitized solar cell (DSC) devices, showing η = 2.6% for 1 cm2 devices. Light soaking of (6) shows excellent long-term stability with

The triptycene skeleton has been used to measure (1,5) interactions between aldehyde groups, placed at both sp3 centres, and hydroxy or methoxy groups, placed at the respective ortho position on a benzene ring; HO⋯CHO interactions of 2.621–2.624 A and MeO⋯CHO interactions of 2.528–2.584 A were observed with the O⋯C vector making angles of 105.3–133.7° with the carbonyl bond. The lack of a competing conjugation with the framework for the electrophilic group is a favourable factor compared to the use of peri-naphthalene systems.