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The synthesis of a new bis‐NHP complex (NHP=N‐heterocyclic phosphenium) of chromium via salt metathesis and studies of its reactivity are reported. Photochemical reactions with H2 and selected olefins give rise to non‐isolable H2‐ and π‐alkene complexes identified spectroscopically, while internal alkynes react via activation of the triple bond to yield isolable metalla‐phospha‐cyclobutenes characterized by spectroscopic and XRD data. DFT studies give a preliminary account of the bonding in H2‐ and alkene‐complexes and explain the different reactivity towards alkenes and alkynes as the consequence of kinetic effects. Photolysis of the bis‐NHP‐complex in the presence of H2 and olefins or alkenes enables the catalytic hydrogenation of the organic substrates, while the π‐ethene complex mediates the catalytic hydrogenation of ethene in a dark reaction. The similarities and differences between both catalytic processes are shortly discussed. [ABSTRACT FROM AUTHOR]

The article titled "Cover Feature: The Noble Addendum of a Phosphenium Ligand to a Base Metal: Coordination, Activation, and Hydrogenation of Alkenes and Alkynes on a Chromium Complex" explores the chemical diversity and reactivity of a bis‐phosphenium complex of chromium. The research focuses on the catalytic hydrogenation of alkenes through two molecular pathways: a photochemical route and a dark reaction. The dark reaction involves a ligand exchange reaction with alkynes, resulting in the production of metallacycles. The article provides further details on these processes and their implications. [Extracted from the article]

Objective: To determine whether capture-recapture analysis provides more reliable estimates of the cumulative incidence and prevalence of leg ulcers in Auckland, New Zealand. Methods: A population-based, cross-sectional study was conducted in the Central and North Auckland health districts of New Zealand in 1998. Cases were identified through health professional referral and by self-notification. All ages and ulcer types were investigated. Both traditional and capture-recapture methods of analysis were used to estimate the cumulative incidence and prevalence of leg ulcers in the study population. Results: Four hundred and twenty-six people with current leg ulcers were identified during the 12-month study period. Using traditional methods of analysis, the annual cumulative incidence rate of leg ulcers in Auckland was 32 per 100,000, with a point prevalence of 39 per 100,000 and a period prevalence of 79 per 100,000 per year. Results from capture-recapture analysis, however, suggest an annual cumulative incidence rate of 252 per 100,000, with a point prevalence of 248 per 100,000 and a period prevalence of 530 per 100,000 per year. Conclusions: The traditional method of calculating cumulative incidence and prevalence clearly under-estimates the frequency of leg ulcers in the Auckland region. Capture-recapture analysis provides a more reliable estimate of disease frequency, since cases that remain unidentified in the population are considered.

A chromium complex carrying two benzanellated N-heterocyclic phosphenium (bzNHP) ligands was prepared by a salt metathesis approach. Spectroscopic studies suggest that the anellation enhances the π-acceptor ability of the NHP-units, which is confirmed by the facile electrochemical reduction of the complex to a spectroscopically characterized radical anion. Co-photolysis with H2 allowed extensive conversion into a σ-H2-complex, which shows a diverse reactivity towards donors and isomerizes under H-H bond fission and shift of a hydride to a P-ligand. The product carrying phosphenium, phosphine and hydride ligands was also synthesized independently and reacts reversibly with CO and MeCN to yield bis-phosphine complexes under concomitant Cr-to-P-shift of a hydride. In contrast, CO2 was not only bound but reduced to give an isolable formato complex, which reacted with ammonia borane under partial recovery of the metal hydride and production of formate. Further elaboration of the reactions of the chromium complexes with CO2 and NH3BH3 allowed to demonstrate the feasibility of a Cr-catalyzed transfer hydrogenation of CO2 to methanol. The various complexes described were characterized spectroscopically and in several cases by XRD studies. Further insights in reactivity patterns were provided through (spectro)electrochemical studies and DFT calculations., (© 2024 Wiley‐VCH GmbH.)

Unprecedented metalated phosphonite boranes were prepared from PH-substituted precursors and silyl amides. Although potassium derivatives were thermally stable and could even be isolated and structurally characterised, lithiated analogues proved to be unstable towards self-condensation under cleavage of LiOR at ambient temperature. Reaction studies revealed that the metalated phosphonite boranes exhibit ambiphilic character. Their synthetic potential as nucleophilic building blocks was demonstrated in the synthesis of the first stannylated phosphonite representing a new structural motif in phosphine chemistry., (© 2021 The Authors. Published by Wiley-VCH GmbH.)

Aim: To describe the age at onset, recurrence rate, and provision of care for people with leg ulcers in New Zealand., Methods: Between 1997 and 1998, people with current leg ulcers were identified from the North Auckland and Central Auckland health districts via notification from relevant health professionals and by self-referral. All ulcer types were investigated. Identified cases, aged between 40 and 99 years and on the general electoral roll, were interviewed as part of a case-control study. Descriptive information relating to interviewed cases is presented., Results: 241 people with leg ulcers were interviewed. The average age was 75 years and almost 60% were women. The average age at ulcer onset was 65 years, 59% of people had recurrent ulcers, and 24% had been hospitalised in the last five years because of their leg ulcers. Those people with recurrent leg ulcers had lived with their condition for an average of fifteen years, with an average time to healing for their last ulcer of thirteen months. Treatment of this condition was largely community-based, with 136 different treatment options employed., Conclusions: Leg ulceration remains a chronic and recurring condition, with substantial practice variation in terms of treatment. Urgent attention needs to be given to the management of leg ulcer patients in this country, particularly given that New Zealand has a rapidly ageing population.

Aim: To estimate the cumulative incidence rate and prevalence of leg ulcers in Auckland., Methods: A cross-sectional study was conducted to identify all individuals who had or developed a leg ulcer in the North Auckland and Central Auckland health districts between 1997 and 1998. Cases were identified through multiple sources, including community-based and hospital-based health professionals and by self-notification. All ulcer types were investigated., Results: 611 individuals with healed or current leg ulcers were identified during the study period, of whom 426 had current leg ulcers. The annual cumulative incidence rate was 32 per 100,000. The point prevalence of current leg ulcers was 39 per 100,000, with a period prevalence of 79 per 100,000 per year. Men had lower age-adjusted incidence rates than women, but a higher age-adjusted point prevalence of leg ulceration, indicating that ulcers take longer to heal in men. Annual cumulative incidence rates increased steeply with age (< 60 years = 4, 60-69 years = 62, 70-79 years = 191, 80+ years = 466 per 100,000 per year), as did point prevalence (< 60 years = 5, 60-69 years = 76, 70-79 years = 238, 80+ years = 564 per 100,000)., Conclusions: These data indicate that the risk of developing leg ulcers increases dramatically with age, with individuals aged 60 years and over particularly at risk. Given New Zealand's rapidly ageing population, the number of older people with leg ulcers each year is expected to double in the next 25 years.