Amidinate Ligands in Zinc coordination sphere: Synthesis and structural diversity

A one-pot reaction involving neosilyllithium and three different carbodiimides (RN=C=NR, R=cyclohexyl, isopropyl and tert-butyl) in diethyl ether, followed by the addition of anhydrous ZnCl2, afforded, in high yield, corresponding homoleptic zinc amidinate complexes having the molecular formulae [Zn{CyN =C(CH2SiMe3)NCy}2] (1), [Zn{ i PrN =C(CH2SiMe3)N i Pr}2] (2) and [Zn{ t BuN =C(CH2SiMe3) N t Bu}2] (3), respectively, and amidinato moieties in the zinc coordination sphere. Solid state structures of complexes 1-3 are reported thereafter - all the three complexes are isostructural, and each of them consists of two four-membered metallacycles

Synthesis, structure and reactivity study of magnesium amidinato complexes derived from carbodiimides and N,N′-bis(2,6-diisopropylphenyl)-1,4-diaza-butadiene ligands

We report an amidinato ligand-supported series of magnesium complexes obtained from the insertion of a magnesium–carbon bond into a carbon–nitrogen double bond of different carbodiimides and α-diimine ligands. The magnesium complexes [Mg(CH2Ph){CyN[double bond, length as m-dash]C(CH2Ph)NCy}]2 (1), [Mg(CH2Ph){iPrN[double bond, length as m-dash]C(CH2Ph)NiPr}]2 (2) and the homoleptic [Mg{tBuN[double bond, length as m-dash]C(CH2Ph)NtBu}2] (3) (Cy = cyclohexyl, iPr = isopropyl, tBu = tert-butyl) were prepared by the reaction of dibenzyl magnesium [Mg(CH2Ph)2(Et2O)2] with the respective carbodiimides either in 1 : 1 or 1 : 2 molar ratio in toluene. The analogous reaction of [Mg(CH2Ph)2(Et2O)2] with the N,N′-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (Dipp2DAD) ligand afforded the corresponding homoleptic magnesium complex [Mg{DippN[double bond, length as m-dash]C(CH2Ph)CH2NDipp}2] (4) (Dipp = 2,6 diisopropylphenyl) in good yield. The solid-state structures of magnesium complexes 1–4 were confirmed by single-crystal X-ray diffraction analysis. It was observed that in each case, a magnesium–carbon bond was inserted into the carbon–nitrogen double bond of either carbodiimides or Dipp2DAD resulting in a monoanionic amido–imino ligand. In a further reaction between 1 and N-aryliminopyrrolyl ligand 2-(2,6-iPr2C6H3N[double bond, length as m-dash]CH)C4H3NH (ImpDipp-H) in 1 : 2 molar ratio, a new magnesium complex [Mg(ImpDipp)2{CyN[double bond, length as m-dash]C(CH2Ph)NHCy}] (5), with one amidinato and two aryliminopyrrolyl ligands in the coordination sphere, was obtained in good yield. In contrast, the homoleptic magnesium complex 4 reacted with one equivalent of N-aryliminopyrrolyl ligand (ImpDipp-H) to produce another mixed ligated magnesium complex [Mg{DippN[double bond, length as m-dash]C(CH2Ph)CH2NDipp}(ImpDipp)] (6), with a benzylated DAD ligand and aryliminopyrrolyl ligands in the coordination sphere. Further reaction of complex 4 with benzyl alcohol (PhCH2OH) afforded the third mixed ligated magnesium complex [Mg{DippN[double bond, length as m-dash]C(CH2Ph)CH2NDipp}(OCH2Ph)2] (7) in very good yield. The magnesium complexes 5–7 were characterised using standard analytical/spectroscopic techniques and their solid-state structures were established by single-crystal X-ray diffraction analysis

Syntheses and solid state structures of zinc (II) complexes with Bi-dentate N-(Aryl)imino-acenapthenone (Ar-BIAO) ligands

We have synthesized five zinc complexes of molecular formulae [ZnCl 2 (2,6-dimethylphenyl- BIAO)] 2 ( 1a ), [ZnBr 2 (2,6-dimethylphenyl-BIAO)] 2 ( 1b ), [ZnI 2 (2,6-dimethylphenyl-BIAO)] 2 ( 1c ), [ZnBr 2 (mes- BIAO)] 2 ( 2b) and [ZnBr 2 (dipp-BIAO)] ( 3b) with rigid unsymmetrical imi noacenaphthenone ligands, (2,6- dimethylphenyl-BIAO) ( 1 ), (mesityl-BIAO) ( 2 ) and (2,6-diisopropylphenyl-BIAO) ( 3 ).Thezinccomplex 1a was prepared by the reaction of ZnCl 2 and neutral (mesityl-BIAO) ( 1 ). However, complexes 1b , 2b and 3b were obtained by the treatment of ZnBr 2 and neutral ligands 1 – 3 respectively in 1:1 molar ratio in dichloromethane at ambient temperature. In a similar reaction of ZnI 2 with (2,6-dimethylphenyl-BIAO) ( 1 ) in dichloromethane the corresponding iodo-complex 1c was obtained in good yield. All the zinc (II) complexes are characterized by FT-IR, 1 Hand 13 C{ 1 H} NMR spectroscopic techniques. The solid state structures of the complexes 1a , 1b , 1c , 2b and 3b are confirmed by single crystal X-ray diffraction analysis. The molecular structures of com- plexes 1a , 1b , 1c and 2b reveal the dimeric nature of the complexes and subsequently the centre atom zinc is penta-coordinated to adopt distorted trigonal bipyr amidal geometry around it. In contrast, the complex 3b is in monomeric in nature due to bulkier size of the ligand and zinc ion is tetra coordinated to adopt distorted tetrahedral geometry

Synthesis and Structures of Dimeric Zinc Complexes Supported by Unsymmetrical Rigid Bidentate Imino- acenapthenone Ligand

We report two zinc complexes of molecular formulae [ZnCl 2 (Mes - BIAO)] 2 ( 3 ) and [ZnCl 2 (Dipp - BIAO)] 2 ( 4 ) ( Mes = Mesityl, Dipp = 2,6 - diisopropylphenyl) of rigid unsymmetrical bidentate iminoacenapthenone ligands (Mes - BIAO) ( 1 ) and Dipp - BIAO) ( 2 ). The zinc complexes 3 and 4 can be achieved by the reaction of ZnCl 2 and neutral [ N - (mesityl) - iminoacenapthenone] ( 1 ) and [ N - (2,6 - diisopropylphenyl) - iminoacenapthenone] ligand ( 2 ) respectively in dichloromethane at ambient temperature. The solid state structures of the complexes 3 and 4 were established by single crystal X – ray diffraction analysis. In the solid state structures, bo th the complexes are dimeric in nature. In complexes 3 and 4 , each of the zinc coordination polyhedron is formed by the ligation of imine nitrogen, carbonyl oxygen atoms of the ligand 1 and 2 respectively along with three chlorine atoms. Out these three ch lorine atoms, two are 2 bridged with adjacent zinc atom to form the dimer. Thus overall zinc atom is penta - coordinated and the geometry can be best described as a distorted trigonal bipyramidal or a distorted square pyramidal

Direct and indirect costs of nephrolithiasis in an employed population: Opportunity for disease management?

Direct and indirect costs of nephrolithiasis in an employed population: Opportunity for disease management?BackgroundMore than 5% of the United States population has been diagnosed with nephrolithiasis and about one half of (first-time) stone formers will have a recurrence within 5 years. The prevalence of nephrolithiasis is concentrated among working age adults, yet little prior work has examined the economic burden of the disease on employers and their employees. We sought to estimate the direct and indirect costs of nephrolithiasis for working age adults (18-64) with employer-provided insurance.MethodsThis was an observational study using retrospective claims data. Detailed medical and pharmacy claims from 25 large employers and absentee data from a subset of firms were used to estimate the direct and indirect costs associated with nephrolithiasis in a privately insured, nonelderly population. Multivariate regression models were used to predict health care expenditures for persons with and without the condition, controlling for differences in patient (health status) and plan characteristics.ResultsMore than 1% of working-age adults were treated for nephrolithiasis in 2000. Prevalence was considerably higher among men and employees age 55 to 64. About one third of employees treated for nephrolithiasis in 2000 missed work due to the condition, with an average work loss for the entire treated population of 19 hours per person. Conditional on receiving treatment, the incremental costs of nephrolithiasis were $3,494 per person in 2000.ConclusionThe direct and indirect costs of nephrolithiaisis are substantial among working-age adults. Interventions that prevent recurrence among known stone formers may be a cost-effective component of disease management programs

Alkali Metal Complexes Having Sterically Bulky Bis-Iminopyrrolyl Ligands – Control of Dimeric to Monomeric Complex

We report the syntheses and structural diversity of three different bis-iminopyrrole ligands and their alkali metal (Li, Na, K) complexes featuring a shift from dimeric to monomeric nature by a simple tuning of the steric control of the imine nitrogen substitutions. The bis-iminopyrrole ligands having molecular formula [(ArN=CH)2C4H2NH] [Ar = CHPh2 (1-H), Ad (2-H), Ad = adamentyl, and CPh3 (3-H)], were prepared through the reaction of 2,5-pyrrole-dicarbaldehyde with corresponding amines (ArNH2) in 1:2 molar ratio and under acidic conditions. Using ligand 1-H, the lithium [{Li(Ph2CHN=CH)2C4H2N}2] (1-Li), sodium [{Na(Ph2CH-N=CH)2C4H2N}2(THF)] (1-Na) and potassium [{3-(Ph2CHN=CH)2C4H2N}-K(THF)2] (1-K) complexes were obtained through either alkane elimination (for Li) or amine elimination (for Na, K). The alkali metal complexes [{2-(Ph3CHN=CH)2C4H2N}M(THF)n] [n = 2, M = Li (3-Li), Na (3-Na); n = 3, M = K (3-K)] were synthesized using the ligand 3-H. Molecular structures of ligands 1-3-H, and alkali metal complexes 1-Li, 1-Na, 1-K, 3-Li, 3-Na and 3-K, in solid state were established. The complexes 1-Li and 1-Na were found to be dimeric in the solid state whereas the complexes 1-K, 3-Li, 3-Na and 3-K were all monomeric – either due to a larger ionic radius (for 1-K) or because of the presence of the bulky triphenylmethyl group in the imine nitrogen

The impact of advocacy and community mobilization on the utilization of health services at the Comprehensive Health Centre, Gindiri.

Primary Health Care facilities provide promotive, preventive, curative and rehabilitative services to a community. They may be well built and equipped with adequate resources but grossly underutilized due to several factors. Health records at the Comprehensive Health Centre Gindiri for 2005 were compared with those of 2007 after a wellcoordinated advocacy and mobilization programme in that community. The results show that the total out patient attendance in 2007 increased by 220.6% when compared to that of 2005. 293 patients were admitted into the wards in 2005 compared to 813 in 2007(277%). There was no surgery carried out in the whole of 2005, whereas in 2007 there were 98 surgeries. Advocacy and community mobilization could be important factors in the utilization of primary health service

The functional, social and economic impact of acute encephalitis syndrome in Nepal--a longitudinal follow-up study.

notes: PMCID: PMC3772013Open Access JournalOver 133,000 children present to hospitals with Acute Encephalitis Syndrome (AES) annually in Asia. Japanese encephalitis (JE) accounts for approximately one-quarter of cases; in most cases no pathogen is identified and management is supportive. Although JE is known to result in neurological impairment, few studies have examined the wider impact of JE and AES on patients and their families.Wellcome TrustUniversity of Liverpool Clinical Fellowshi

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century