Intramolecular Cyclization of Azido-Isocyanides Triggered by the Azide Anion: An Experimental and Computational Study.

This work describes the unprecedented intramolecular cyclization occurring in a set of α-azido-ω-isocyanides in the presence of catalytic amounts of sodium azide. These species yield the tricyclic cyanamides [1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-carbonitriles, whereas in the presence of an excess of the same reagent, the azido-isocyanides convert into the respective C-substituted tetrazoles through a [3 + 2] cycloaddition between the cyano group of the intermediate cyanamides and the azide anion. The formation of tricyclic cyanamides has been examined by experimental and computational means. The computational study discloses the intermediacy of a long-lived N-cyanoamide anion, detected by NMR monitoring of the experiments, subsequently converting into the final cyanamide in the rate-determining step. The chemical behavior of these azido-isocyanides endowed with an aryl-triazolyl linker has been compared with that of a structurally identical azido-cyanide isomer, experiencing a conventional intramolecular [3 + 2] cycloaddition between its azido and cyanide functionalities. The synthetic procedures described herein constitute metal-free approaches to novel complex heterocyclic systems, such as [1,2,3]triazolo[1,5-a]quinoxalines and 9H-benzo[f]tetrazolo[1,5-d][1,2,3]triazolo[1,5-a][1,4]diazepines.

Mechanically interlocked molecules in metal-organic frameworks.

Mechanically interlocked molecules (MIMs) have great potential in the development of molecular machinery due to their intercomponent dynamics. The incorporation of these molecules in a condensed phase makes it possible to take advantage of the control of the motion of the components at the macroscopic level. Metal-organic frameworks (MOFs) are postulated as ideal supports for intertwined molecules. This review covers the chemistry of the mechanical bond incorporated into metal-organic frameworks from the seminal studies to the latest published advances. We first describe some fundamental concepts of MIMs and MOFs. Next, we summarize the advances in the incorporation of rotaxanes and catenanes inside MOF matrices. Finally, we conclude by showing the study of the rotaxane dynamics in MOFs and the operation of some stimuli-responsive MIMs within MOFs. In addition to emphasising some selected examples, we offer a critical opinion on the state of the art of this research field, remarking the key points on which the future of these systems should be focused.

Chemsex Practices in PrEP: Beyond Addiction and Risk Toward a Healthy Sex Life-Baseline Experiences from a Hospital-Based PrEP Program in Barcelona, Spain.

Pre-exposure prophylaxis (PrEP) is a biomedical intervention that has demonstrated efficacy in HIV prevention in individuals at high-risk, among them chemsex users. Out of 190 PrEP users followed at Hospital Clinic of Barcelona until October 2020, 89% reported drug use, and 63% disclosed that they had engaged in chemsex practices, initiated in 64% of cases within the past year. Twenty-one percent used 3 or more drugs simultaneously, being GHB/GBL, nitrites, sildenafil, and methamphetamine the most prevalent combination. Eight percent reported slamming. Forty-one percent described having had negative experiences and 8% did not remember the last time they had sober sex. Methamphetamine, mephedrone, GHB/GBL, and having had open relationships, group sex, double penetration, and fisting were significantly more prevalent. Forty-nine percent admitted being worried about chemsex use, and 18% said they needed help. A comprehensive, interdisciplinary approach is mandatory to enable the attainment of a healthy approach to one's sex life.

RESUMEN: La PrEP es una intervención biomédica eficaz en la prevención del VIH en personas con alto riesgo, entre ellas las personas que practican chemsex. De los 190 usuarios de PrEP seguidos en el Hospital Clínic de Barcelona hasta octubre de 2020, el 89% refirió utilizar drogas y el 63% en contexto de chemsex, iniciando el consumo el 64% durante el último año. El 21% refería policonsumo, siendo GHB/GBL, nitritos, sildenafilo y metanfetamina la combinación más prevalente. El 8% reportó slamming. El 41% describió haber tenido experiencias negativas y el 8% no recordaba la última vez que tuvo sexo sobrio. Metanfetamina, mefedrona, GHB/GBL y haber tenido relaciones abiertas, sexo en grupo, doble penetración y fisting fueron significativamente más frecuentes. El 49% refirió estar preocupado por la práctica de chemsex y el 18% necesitar ayuda. Un abordaje integral e interdisciplinar mejoraría el acompañamiento global de la sexualidad en estas personas.

Mechanical insulation of aza-Pechmann dyes within [2]rotaxanes.

Aza-Pechmann derivatives have emerged as interesting building blocks for the preparation of organic electronic devices. The development of methodologies aimed to enhance their chemical stability and modulate their physical and chemical properties constitutes an interesting goal. Here we report the synthesis of mechanically interlocked aza-Pechmann dyes with benzylic amide macrocycles, along with the study of how the mechanical bond impacts their stability, photophysical and redox properties. Rotaxanes composed of Pechmann dilactams as threads exhibit one of the highest energy barriers for macrocyclic ring rotation, highlighting the strength of the attractive interactions ring-thread within the interlocked structure. Their enhanced thermal stability, compared to the non-interlocked counterparts, evidences the protective role of the macrocycle. Computational and electrochemical analyses indicate that the benzylic amide macrocycle improves the stability of the HOMO and LUMO orbitals of the interlocked dyes. Finally, spectroscopic and electrochemical data reveal that the macrocycle subtly modulates the optoelectronic and redox behaviour of the Pechmann dilactams.

Mechanical bonding of rigid MORFs using a tetratopic rotaxane.

The preparation of highly rigid cobalt(II)- and copper(II)-organic frameworks incorporating a tetralactam [2]rotaxane as a ligand is described. The interlocked ligand is functionalized with two pairs of carboxylate groups placed at each counterpart, thus limiting its dynamics within the crystal. The solid structure of the metal-organic rotaxane frameworks showed different, unprecedented polycatenation modes of grids, depending on the employed metal, providing great rigidity to the structures. This rigidity has been evaluated by using single crystal X-ray diffraction analyses of the cobalt(II)-organic frameworks embedded in different solvents, observing that the lattices remain unchanged. Thus, this research demonstrates that rigid and robust materials with permanent porosity can be achieved using dynamic ligands.

PrEP program experience in a hospital HIV unit. Description of baseline user profile and identification of opportunities for improvement.

INTRODUCTION: Pre-Exposure Prophylaxis (PrEP) is a biomedical intervention to prevent HIV infection in seronegative people at high risk of becoming infected. This strategy was endorsed in October 2019 by the Spanish Ministry of Health. OBJECTIVE: To present the PrEP initial experience in the HIV Unit of the Hospital Clínic of Barcelona, paying special attention to the analysis of the vulnerability factors in the cohort. MATERIALS AND METHODS: Retrospective, descriptive study. The epidemiological, sociodemographic, and clinical characteristics of the users included in the program during the first year are analyzed, paying particular attention to Infections, risky practices, and substance use. RESULTS: 190 individuals were included, 177 men and 12 trans women with a mean age of 35 years (8 SD). 70% had higher education, and half had Spanish nationality. An average of 10 couples per trimester and 60% reported unprotected anal sex. 31% had at least one positive PCR for STIs, with N. gonorrhoeae being the most prevalent microorganism (51%) and the rectal sample the most affected (21%). 63% reported chemsex use, 19% polydrug use, and 8% "slamming". Half expressed concern about consumption and/or sexual practices and 25% the need for help. CONCLUSIONS: The PrEP user profile attended in our Hospital Unit justifies the creation of multidisciplinary teams that allow us to provide holistic attention to the sexual life of these people.

PrEP program experience in a hospital HIV unit. Description of baseline user profile and identification of opportunities for improvement. / Experiencia de un programa de profilaxis preexposición en una unidad de virus de la inmunodeficiencia humana hospitalaria. Descripción del perfil basal del usuario e identificación de oportunidades de mejora.

INTRODUCTION: Pre-Exposure Prophylaxis (PrEP) is a biomedical intervention to prevent HIV infection in seronegative people at high risk of becoming infected. This strategy was endorsed in October 2019 by the Spanish Ministry of Health. OBJECTIVE: To present the PrEP initial experience in the HIV Unit of the Hospital Clínic of Barcelona, paying special attention to the analysis of the vulnerability factors in the cohort. MATERIALS AND METHODS: Retrospective, descriptive study. The epidemiological, sociodemographic, and clinical characteristics of the users included in the program during the first year are analyzed, paying particular attention to Infections, risky practices, and substance use. RESULTS: 190 individuals were included, 177 men and 12 trans women with a mean age of 35 years (8 SD). 70% had higher education, and half had Spanish nationality. An average of 10 couples per trimester and 60% reported unprotected anal sex. 31% had at least one positive PCR for STIs, with N. gonorrhoeae being the most prevalent microorganism (51%) and the rectal sample the most affected (21%). 63% reported chemsex use, 19% polydrug use, and 8% "slamming". Half expressed concern about consumption and/or sexual practices and 25% the need for help. CONCLUSIONS: The PrEP user profile attended in our Hospital Unit justifies the creation of multidisciplinary teams that allow us to provide holistic attention to the sexual life of these people.