Supramolecular Assembly Through Intermolecular n → π* Interactions through a Coordinated Perrhenate Formed via Superoxidation of Re(I) to Re(VII) in the Formation of Substituted Re(CO)3 Complexes Bearing Diimine Ligands

We report the structural, spectroscopic, and computational studies of two new Re(I) tricarbonyl complexes bearing 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenanthrene (Ph4TAP) and 4,5-diazafluoren-9-one (Dafone) having a coordinated perrhenate group obtained via in situ superoxidation of Re(I) to Re(VII); intramolecular and intermolecular n→π* interactions are dominant and stabilize the molecular geometry and crystal packing

The impact of hydrogen bonding on 100% photo-switching in solid-state nitro-nitrito linkage isomers

Two crystal systems: [Pd(Et4dien)(NO2)]OTf [1] and [Pt(Et4dien)(NO2)]OTf [2] (Et4dien = N,N,N′,N′-tetraethyldiethylene-triamine, OTf = trifluoromethanesulfonate) are investigated by steady-state photocrystallographic methods. Both structures contain intermolecular hydrogen bonds to the ground state nitro-(η1-NO2) isomer, which are previously shown to limit the achievable level of nitro → nitrito photo-conversion. Irradiation at 100 K induces a mixture of endo-ONO and exo-ONO isomers in 1 and 2, with overall incomplete photo-activation. In contrast, irradiation at higher temperatures leads to much higher conversion, with 100% excitation in 1 at 150 K. The results show that the detrimental effects of hydrogen bonding on the photo-reaction are overcome at higher temperature, adding a new dimension of control to the isomerisation process

Prior Likelihoods and Space-Group Preferences of Solvates

For a range of organic solvents, the likelihood of the solvent forming solvates has been estimated using the recrystallization solvent (RS) data in the Cambridge Structural Database (CSD). Although RS data are viewed with caution by some crystallographers, most of the likelihood estimates are shown to have good precision. Strong trends are apparent in the results. For example, high likelihoods are found for aromatic solvents with electron-withdrawing substituents and low likelihoods for acyclic aliphatic hydrocarbons. Results for different CSD subsets, such as organic and metalloorganic, are highly correlated. The likelihood that a solvent will form solvates is almost always higher when the solvent is part of a mixture than when it is pure. The likelihood of two solvents forming a heterosolvate (i.e., both solvents in the structure) can be well estimated by the product of the likelihoods of the solvents forming normal solvates (i.e., only one solvent in the structure). The space-group preferences of solvates vary significantly with the nature of the cocrystallized solvent. Those of nonsolvates vary significantly with the solvent(s) from which they were crystallized. Solvents with inversion centers favor solvate crystallization in centrosymmetric space groups, and solvents with 2-fold rotational symmetry promote crystallization in space groups with 2-fold proper rotational axes. The inclusion of cyclohexane and carbon tetrachloride in a lattice can facilitate crystallization in trigonal and tetragonal space groups, respectively. Our results can: (a) guide solvent selection when solvates are undesired; (b) assist in predicting solvate formation, e.g., using Bayesian algorithms; (c) assist in the choice of space groups for solvate crystal structure prediction; and (d) suggest ways in which solvent incorporation can be used to influence space groups.</p

Zeolites fit for a crown:Studying organic-framework host-guest interactions through thermogravimetric techniques

Every year millions of tons of zeolites are produced, being used as molecular sieves, hydrocracking catalysts, gas-capture materials and for emerging novel applications. There is a demand to synthesise new zeolites with bespoke frameworks, which are tailor-made for a chosen application. To achieve these ‘designer zeolites’ it is crucial to fully understand the host-guest interactions between organic additives and zeolitic frameworks. Here we have studied four different zeolites, synthesised with the same organic additive, 18-crown-6 ether, which show observable differences in the host-guest interactions. We demonstrate that the framework geometry dominates the decomposition temperature, enthalpy and mechanism. The zeolites show unique decomposition features, emphasising experimental differences in how the organic additive and framework interact.</p

A Comparison of the Structural Chemistry of Scandium, Yttrium, Lanthanum and Lutetium: A contribution to the Group 3 debate

Data deposited in the Cambridge Structural Database (CSD) for compounds of scandium, yttrium, lanthanum and lutetium(III) have been analysed to assess the structural similarities of complexes of the different metal ions. 29 sets of compounds of Sc, Y, La and Lu where at least three of the elements form compounds with the same ligands have been identified and their crystal structures analysed. In 14 of them, scandium and lutetium have the same coordination number; in the remaining 15 they do not. Similarly, there are 10 examples where there is a difference in coordination number between Lu and Y for compounds with the same ligands. For the other 19 either the coordination numbers are the same or that compounds for both the elements under consideration have not been reported. Overall structural differences correlate well with the size of the metal ions and provide no true chemical basis for arranging Lu rather than La in one triad with Sc and Y

Reluctant educators and self‐advocates: Older trans adults’ experiences of health‐care services and practitioners in seeking gender‐affirming services

Background Trans-identifying individuals experience unique barriers and challenges in negotiating health-care systems due to the cisnormative attitudes and practices which obstruct the receipt of trans-inclusive care. To date, there has been little exploration of older trans consumers’ experiences of contemporary health-care services when seeking to transition medically in later life. Objectives Qualitative findings are presented from a study of trans ageing and trans-related health and social care needs in Wales, UK (2016-18). The objectives are to (1) examine supportive and obstructive points of interaction with health-care professionals, and (2) identify key learning messages for improving trans-related health care from the perspectives of trans-identifying adults in later life. Design Trans-identifying participants self-selected to take part in two interviews—a life-history interview and a semi-structured interview. Interview data were analysed thematically using the framework method approach. Setting and participants This paper focuses on the accounts of 19 participants (50-74 years of age) who identified as trans and were seeking to transition medically in mid- to later life. Results Findings indicate how older trans patients are positioned as reluctant educators for GPs in primary care settings and illustrate the transphobic practices and cisnormative assumptions encountered across health-care interactions and systems that impede their journey of transitioning in later life. Discussion and conclusions Messages from this study speak to the importance of improving professionals’ knowledge of gender identity diversity across the life course and making changes at a systemic level in redressing cisnormative assumptions and systems that reinforce inequities on the basis of gender identity

Systematic approaches towards template-free synthesis of EMT-type zeolites

Presently it is understood that 18-crown-6 ether is necessary as an organic template to synthesise pure and well crystalline EMT-type zeolites. This is problematic for optimisation of organic-free synthesis of zeolites. We report a new method to synthesise pure zeolite EMC-2 using a lower amount of 18-crown-6 ether than previously reported. At these low 18-crown-6 ether concentrations, FAU-type zeolites were not seen to co-crystallise. We observe that the crystallinity of the EMT-type zeolite is proportional to the amount of 18-crown-6 ether added in the synthesis. The as-synthesised zeolites were characterised using X-ray powder diffraction, scanning electron microscopy and solid state nuclear magnetic resonance. These findings are a crucial step towards understanding template roles and designing syntheses for zeolites without the use of toxic organic templates