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The current discussion on whether scandium, yttrium and lanthanum should represent Group 3 in the Periodic Table or whether lutetium should replace lanthanum in the group has prompted us to further explore the structural chemistry of the Group 3 elements and compare the coordination numbers and coordination geometries adopted. The steric and electronic properties of the coordinated ligands have a major influence on the structures adopted. We report the synthesis and crystal structure determination of an unusual dinuclear scandium complex [(bipy)(NO3)2Sc(µ-OH)2Sc(NO3)2(bipy)] obtained by the reaction of hydrated scandium nitrate with 2,2'-bipyridyl (bipy) in either ethanol or nitromethane. The crystal structure of the complex shows that the scandium centers are eight coordinate, and the structure obtained contrasts with related complexes found in the lanthanide series [Ln(bipy)2(NO3)3] and [Ln(phen)2(NO3)3] (phen = phenanthroline) and in [M(terpy)(NO3)3] (M = Sc, Er-Lu), where these complexes are all mononuclear.

The crystal structure of l-threonine has been studied to a maximum pressure of 22.3 GPa using single-crystal X-ray and neutron powder diffraction. The data have been interpreted in the light of previous Raman spectroscopic data by Holanda et al. (J. Mol. Struct. (2015), 1092, 160-165) in which it is suggested that three phase transitions occur at ca. 2 GPa, between 8.2 and 9.2 GPa and between 14.0 and 15.5 GPa. In the first two of these transitions the crystal retains its P212121 symmetry, in the third, although the unit cell dimensions are similar either side of the transition, the space group symmetry drops to P21. The ambient pressure form is labelled phase I, with the successive high-pressure forms designated I′, II and III, respectively. Phases I and I′ are very similar, the transition being manifested by a slight rotation of the carboxylate group. Phase II, which was found to form between 8.5 and 9.2 GPa, follows the gradual transformation of a long-range electrostatic contact becoming a hydrogen bond between 2.0 and 8.5 GPa, so that the transformation reflects a change in the way the structure accommodates compression rather than a gross change of structure. Phase III, which was found to form above 18.2 GPa in this work, is characterised by the bifurcation of a hydroxyl group in half of the molecules in the unit cell. Density functional theory (DFT) geometry optimisations were used to validate high-pressure structural models and PIXEL crystal lattice and intermolecular interaction energies are used to explain phase stabilities in terms of the intermolecular interactions.

Research has been conducted on the group 14 trifluorovinyl compounds. The preparation of these compounds via the reaction of triphenylelement halide with trifluorovinyllithium at low temperature is described.

Research has been conducted on the organomercurial compounds. The preparation of these compounds from 2-bromobenzaldehyde and their characterization via the use of elemental analysis, NMR and infrared spectroscopy are discussed.

The pulsed EPR technique of double electron electron resonance (DEER) is used for probing the distribution of intramolecular end-to-end distances. The results have shown that porphyrin-based molecular wires are shape-persistent, but their shapes can be deformed by binding to multivalent ligands.

The design, preparation, structure and anion-binding properties of the indolocarbazole-containing interlocked structure are described. The selectivity of the [2]rotaxane for chloride is described in terms of its unique interlocked binding cavity, which is defined by the macrocycle isophthalamide and indolocarbazole N-H protons.

Coordination solids are designed and developed based on a tetrahedral organic linker, tetrakis[4-(carboxyphenyl)oxamethyl]methane, as a building block to generate metal-organic frameworks (MOFs) with metal salts and organic pillars. High selectivity for C[O.sub.2] over [H.sub.2] and [N.sub.2] is a necessity if these materials should be used for C[O.sub.2] separations from synthesis gas and flue gas mixtures.

The synthesis and separation of the 1,6- and 1,7-isomers of N,N'-bis(n-butyl)dimorpholino-3,4:9,10-perylenetetracarboxylic acid bisimide are described. The 1,7-isomer of N,N'-bis(n-butyl)dimorpholino-3,4:9,10-perylenetetracarboxylic acid bisimide has undergone a two-electron oxidation process, which is in contrast with the behavior of both the corresponding 1,6-isomer and other related amino-substituted perylene bis-imide species.

The preparation and detailed studies of five-coordinate cobalt(II) complexes, incorporating two bidentate iminopyrrolyl ligands and a P[Me.sub.3] or a THF ligand are described. The compounds show structures varying from the unusual axially compressed trigonal bipyramidal (TBP) to distorted square pyramidal (SP) geometries and different magnetic properties.

The synthesis and characterization of aluminum(III) porphyrin building blocks 1-isonic and 1-nic as well as solution and solid -state evidence for the corresponding one dimensional coordination polymers are reported. The results indicated that the ligands exhibiting other spatial relationships between oxygen and nitrogen donors could lead to the formation of a range of new geometries for the porphyrin coordination polymers.

The crystal structures of the two isostructural metal-organic salts, [(4-chloropyridinium).sub.2][Co[X.sub.4] (X - Cl, Br), are determined at different temperatures and pressures. The studies have shown that since the effect of difference in anion size is removed by application of pressure, the anisotropy in dimensions has shown that the N-H...[X.sub.2]Co hydrogen bonds and Co-X...Cl-C halogen bonds are strongly attractive for X = Cl rather than X = Br.

An alternative method is described for controlling the structure of a product in a solvothermal reaction of coordination polymers. It is shown that adding a solubilizing agent such as 2,2'-bipyridine can be used to circumvent some of the problems linked with the use of hydrophobic ionic liquids.

A study is conducted to explore the structural and electronic analogies between [Rh.sub.6][([PR.sub.3]).sub.6][H.sub.12]][[[BAr.sup.F.sub.4].sub.2]. These new cluster species arise from simple sequential addition of electrons to the low-lying set of orbitals present in the parent cluster.