Chromium Complexes with Benzanellated N-Heterocyclic Phosphenium Ligands-Synthesis, Reactivity and Application in Catalytic CO Reduction.

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 H allowed extensive conversion into a σ-H-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 Noble Addendum of a Phosphenium Ligand to a Base Metal: Coordination, Activation, and Hydrogenation of Alkenes and Alkynes on a Chromium Complex.

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 H and selected olefins give rise to non-isolable H- 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 H- and alkene-complexes and explain the different reactivity towards alkenes and alkynes as the consequence of kinetic effects.

Annellated 1,3,4,2-Triazaphospholenes-Simple Modular Synthesis and a First Exploration of Ligand Properties.

The successful use of 1,3,4,2-triazaphospholenes (TAPs) as organo-catalysts stresses the need for efficient synthetic routes to these molecules. In this study, we establish the [1 + 4]-cycloaddition of PBr to azo-pyridines as a new approach to preparing pyrido-annellated TAPs in a single step from easily available precursors. The modular assembly of the azo-component via condensation of primary amines and nitroso compounds along with the feasibility of post-functionalization at the P-Br bond under conservation of the heterocyclic structure allows, in principle, to address a wide range of target molecules, which is illustrated by prototypical examples.

A neutral analogue of a phosphamethine cyanine.

Reaction of an imidazolio-phosphide with an N-heterocyclic bromo-borane and NaH afforded a neutral analogue of a phosphamethine cyanine cation. DFT studies were used to analyse the dative bonding across P-C/B bonds and the conformational preferences and imply that the observed conformation is imposed by sterics.

A PH-functionalized dicationic bis(imidazolio)diphosphine.

Reaction of the iodide salt of a secondary imidazolio-iodophosphine [(L)PHI]I (L = 1,3-diarylimidazolium-yl) with an imidazolio-phosphide (L)PH in the presence of GaI afforded the isolable salt of a dicationic, bis(imidazolio)-substituted dihydro-diphosphine [(L)PH][GaI]. Non-preparative formation of the cationic diphosphines was also observed upon spontaneous "dehalo-coupling" of [(L)PHI], or in reactions of [(L)PHI]I and (L)PH in the absence of GaI. Further reaction of [(L)PH] with (L)PH produced an iodide salt of a known (bis)imidazolio-diphosphide monocation [(L)PH].

Reversible cooperative dihydrogen binding and transfer with a bis-phosphenium complex of chromium.

The reversible reaction of H with a bis-phosphenium complex of chromium provides a rare example of 3d transition metal/phosphenium cooperativity. Photolysis induces the activation of H and yields a spectroscopically detectable phosphenium-stabilized (σ-H)-complex, readily showing exchange with gaseous H and D. Further reaction of this complex affords a phosphine-functionalized metal hydride, representing a unique example of reversible H cleavage across a 3d M[double bond, length as m-dash]P bond.

Synthesis and Ambiphilic Reactivity of Metalated Diorgano-Phosphonite Boranes.

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.

Proton transfer vs. oligophosphine formation by P-C/P-H σ-bond metathesis: decoding the competing Brønsted and Lewis type reactivities of imidazolio-phosphines.

Studies of the protonation and alkylation of imidazolio-phosphides and deprotonation of imidazolio-phosphines reveal a complex behaviour that can be traced back to an interplay of Brønsted-type proton transfers and Lewis-type P-P bond formation reactions. As a consequence, the expected (de)protonation and (de)alkylation processes compete with reactions producing cyclic or linear oligophosphines. A careful adjustment of the conditions allows us to selectively address each reaction channel and devise specific synthesis methods for primary, secondary and tertiary imidazolio-phosphines, imidazolio-alkylphosphides, and cyclic oligophosphines, respectively.

Long-term effect of methotrexate for childhood atopic dermatitis.

Aim: To evaluate methotrexate (MTX) for paediatric atopic dermatitis (AD) while on and post-treatment.

Methods: Medical records of children prescribed MTX for AD between 2011 and 2016 at Starship Children's Hospital, Auckland, New Zealand, were reviewed for demographics, dose and duration of MTX and hospitalisations for AD. In the follow-up by telephone in 2017, parents of the patients reported response on MTX, AD relapses and use of additional systemic treatment and completed a patient-oriented eczema measure (POEM).

A randomized, controlled trial of oral propranolol in infantile hemangioma.

Background: Oral propranolol has been used to treat complicated infantile hemangiomas, although data from randomized, controlled trials to inform its use are limited.

Methods: We performed a multicenter, randomized, double-blind, adaptive, phase 2-3 trial assessing the efficacy and safety of a pediatric-specific oral propranolol solution in infants 1 to 5 months of age with proliferating infantile hemangioma requiring systemic therapy. Infants were randomly assigned to receive placebo or one of four propranolol regimens (1 or 3 mg of propranolol base per kilogram of body weight per day for 3 or 6 months).

Isotretinoin 5 mg daily for low-grade adult acne vulgaris--a placebo-controlled, randomized double-blind study.

Background: Despite acne persisting into adulthood in up to 50% of the population, very few therapeutic studies have been performed in this age group.

Objectives: To assess the efficacy of 5 mg/day isotretinoin in adult acne.

Methods: An investigator initiated, industry-sponsored, randomized, double-blind, placebo-controlled, parallel-group clinical study of isotretinoin 5 mg/day in the treatment of low-grade adult acne for 16 weeks followed by an open-label phase of 16 weeks.

Changes in mood predict disease activity and quality of life in patients with psoriasis following emotional disclosure.

Objective: The present study examined the effects of emotional disclosure (ED) intervention on both disease severity and quality of life in patients with psoriasis.

Methods: Fifty-nine patients were recruited (mean age, 50 years; 32 men and 27 women; mean length of diagnosis, 22 years). Individuals were randomly assigned to receive ED intervention or standard control writing intervention.

Cutis verticis gyrata: three cases with different aetiologies that demonstrate the classification system.

Cutis verticis gyrata describes a scalp condition where there are convoluted folds and deep furrows that resemble the surface of the cerebral cortex. We report three cases of cutis verticis gyrata that demonstrate the current classification structure. The first case is the most commonly described primary non-essential acquired form, appearing in the scalp of an 11-year-old girl with mental retardation.

Leg ulceration and perceived health: a population based case-control study.

Objectives: To quantify the effect of leg ulceration on health-related quality of life and to estimate a health state value for leg ulceration.

Design: Population based case-control study.

Setting: Two New Zealand health districts (population 540,468 people).

Leg ulceration as a long-term complication of deep vein thrombosis.

Objective: To evaluate the role of deep vein thrombosis as a cause of leg ulcers.

Patients And Methods: A population-based, case-control study was conducted in Central and North Auckland, New Zealand. Cases comprised 241 people aged 40 to 99 years and on the electoral roll, with current leg ulcers (all types).

Acute and maintenance treatment of atopic dermatitis in children - two comparative studies with fluticasone propionate (0.05%) cream.

Background: Two multicentre, randomised, parallel group, double-blind, comparative studies in children (2-14 yr) evaluated fluticasone propionate (FP) 0.05% cream for both acute and maintenance treatment of moderate to severe atopic dermatitis (AD).

Methods: One study compared FP with hydrocortisone (HC) 1% cream (FP 70, HC 67) and the other with hydrocortisone butyrate (HCB) 0.

Does capture-recapture analysis provide more reliable estimates of the incidence and prevalence of leg ulcers in the community?

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.

Leg ulcers in New Zealand: age at onset, recurrence and provision of care in an urban population.

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.

The occurrence of leg ulcers in Auckland: results of a population-based study.

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.

The peripheral lymphoid compartment is disrupted in flaky skin mice.

Flaky skin (fsn) is an autosomal recessive mutation on mouse chromosome 17 that causes severe anaemia, forestomach papillomatosis and a papulosquamous skin disease that resembles psoriasis in humans. In the present paper, it is reported that fsn causes peripheral lymphadenopathy, CD4/CD8 imbalance and hyperresponsiveness to T cell growth factors. Peripheral lymph nodes (PLN) of adult mutant (fsn/fsn) mice were found to contain almost 10-fold more leucocytes than PLN from phenotypically normal littermates (+/fsn or +/+, hereafter referred to as +/?).

The impact of acne: a study of adolescents' attitudes, perception and knowledge.

Aim: To assess adolescent students' attitudes to, perceptions and knowledge of acne and to assess the effect of acne on daily living.

Method: Students from Auckland sixth and seventh form classes were selected from ten Auckland secondary schools using a randomisation process which ensured proportional representation by socioeconomic group and gender. Eight hundred and forty-seven students completed a written questionnaire on the subject of acne vulgaris and had their acne examined.