Complexes [Fe(X-salEen)2]BPh4·DMF, with X = Br (1), Cl (2), and F (3), were crystallised from N-ethylethylenediamine with the aim of understanding the role of a high boiling point N,N′-dimethylformamide solvate in the spin crossover phenomenon. The counter ion was chosen for only being able to participate in weak intermolecular interactions. The compounds were structurally characterised by single crystal X-ray diffraction. Complex 1 crystallised in the orthorhombic space group P212121, and complexes 2 and 3 in the monoclinic space group P21/n. Even at room temperature, low spin was the predominant form, although complex 2 exhibited the largest proportion of the high-spin species according to both the magnetisation measurements and the Mössbauer spectra. Density Functional Theory calculations were performed both on the periodic solids and on molecular models for complexes 1–3 and the iodide analogue 4. While all approaches reproduced the experimental structures very well, the energy balance between the high-spin and low-spin forms was harder to reproduce, though some calculations pointed to the easier spin crossover of complex 2, as observed. Periodic calculations with the functional PBE led to very similar ΔEHS-LS values for all complexes but showed a preference for the low-spin form. However, the single-point calculations with B3LYP* showed, for the model without solvate, that the Cl complex should undergo spin crossover more easily. The molecular calculations also reflected this fact, which was more clearly defined when the cation–anion–solvate model was used. In the other models there was not much difference between the Cl, Br, and I complexes.

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The storage of guest molecules in nonporous single crystals is an important development in the field of smart materials. We describe the synthesis and characterization of the new spin crossover Fe(III) compound [Fe(3-Br,5-Cl-salEen)2]BPh4·CH3CN·H2O (salEen = N-ethyl-N-(2-aminoethyl)salicylaldiminate) and its reversible single-crystal-to-single-crystal transformation upon desolvation and resolvation of the crystals. This process affects the magnetic behavior of the compound while the desolvation of single crystals is made in several steps. The magnetic profiles of the cooling/heating routines are never coincident until the compound reaches the high-spin state after complete desolvation of the single crystals. This is further reflected in temperature-dependent Raman profiles where desolvated and high spin state spectra match after the temperature cycle. Kinetic studies gave insights on the desolvation/resolvation dynamics with the new Fe(III) compound behaving as a spin crossover sponge.

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Background The main goal of juvenile idiopathic arthritis (JIA) treatment is to achieve a long-term remission or, at least, low levels of disease activity. Objectives To evaluate disease activity, focusing on achievement inactive disease (ID) or minimal disease activity (MDA), based on Juvenile Arthritis Disease Activity Score (JADAS) score, after 5 years follow-up. Methods A cross sectional study at the 5th year of follow-up from a JIA patients cohort, diagnosed between 2000 and 2008 was carried out. Treatment strategy followed the Portuguese recommendations for the treatment of JIA patients. The data were collected using Reuma.pt, the Portuguese Register of Rheumatic Diseases. At the 5th year of follow-up JADAS was evaluated and used to identify patients who met the preliminary criteria for ID or MDA: JADAS score of 1 for ID and 2 and 3.8, for MDA, respectively, for patients with oligoarticular and polyarticular involvement. For applying the JADAS score, children with rheumatoid factor (RF)-positive polyarthritis, RF-negative polyarthritis, or extended oligoarthritis were included in the polyarthritis group and the oligoarthritis group included children with persistent oligoarthritis. Children with JIA that were classified in the remaining ILAR categories were assigned to the polyarthritis or oligoarthritis group based on the number of joints affected during disease course (>4 or <4, respectively). Cutoffs for acceptable symptom state ranged from 3.2 to 5.4 for parents. Results Eighty one JIA patients were identified with a follow-up of at least 5 years. Fourteen patients were excluded due to loss for follow-up and 2 developed criteria for systemic erythematous lupus. Forty four were female (68%), mean age at diagnosis was 7.7±4.9 years and mean follow-up was 7.6±2.6 years (minimum 5, maximum 13 years). From the 65 patients, 28 (43.1%) had persistent oligoarthritis, 11 (16.9%) RF-negative polyarthritis, 11 (16.9%) enthesitis related arthritis, 8 (12.3%) extended oligoarthritis, 3 (4.6%) RF-positive polyarthritis, 2 (3.1%) psoriatic arthritis and 2 (3.1%) systemic JIA. Seventy three percent were on methotrexate, 11% on sulphasalazine and 23% on biologics (53% etanercept, 20% adalimumab, 20% Infliximab, 7% anakinra). At the 5th year after diagnosis the mean JADAS was 0.78 for persistent oligoarthritis, 2.1 for extended oligoarthritis, 4.8 for RF-positive polyarthritis, 5.4 for RF-negative polyarthritis, 0.75 for psoriatic arthritis, 0.5 for enthesitis related arthritis and 0.3 for systemic JIA. In our population around 68% had ID criteria at the 5th year after diagnosis and 7.7% had MDA. From those patients who had ID criteria, 50% had achieved that status after 2 years of follow-up and 81% after 3 years. From the 11 cases who had neither ID nor MDA, 7 were poly JIA (4 RF negative and 3 positive). All of them except 3 had acceptable symptoms stated by the parents. Conclusions At the 5th year of follow-up, with current management strategies in daily clinical practice, around 68% of our JIA patients had ac...