The complexation between cucurbit[8]uril, Q[8], and isonicotinic acid has been studied using 1H NMR spectroscopy, UV–Vis absorption spectroscopy, Raman spectroscopy and single crystal X-ray diffraction. The results revealed that the 2:1 inclusion complex (4-PA)2@Q[8]·25H2O is formed, with two guests simultaneously encapsulated in the hydrophobic cavity; the mean planes of the guests are 3.535 Å apart.
Due to the sluggish nature of the oxygen reduction reaction (ORR), it requires electro-catalysts to speed up the kinetics of ORR at a practical level. Covalent organic frameworks (COFs)-based materials were reported to be one of the most promising electrocatalysts for ORR among the different low-cost ORR electrocatalysts. These molecular COFs-materials offer the following benefits: (i) precise control of active sites, (ii) simple understanding of structure-activity relationships, (iii) chemically adjustable and well-defined pore size architecture, and (iv) adheres to well-defined reaction pathways. Surprisingly, the importance of structure-activity correlations is well understood, and a number of strategies for improving the activity of such catalysts have been documented. The goal of this study is to simplify COFs chemistry, highlight recent comprehensive designs for ORR, and highlight some future features of COFs engineering for ORR electrocatalysis.
Background: In the movement for global health equity, increased research and funding have not yet addressed a shortage of evidence on effectively implementing context-specific interventions; one unmet need is facilitating access to specialty care within the public health sector in Mexico. Compañeros en Salud has been piloting a novel program, called Right to Healthcare (RTHC), to increase access to specialty care for the rural poor in Chiapas, Mexico. The RTHC program incorporates social work, patient navigation, referrals, direct economic support, and accompaniment for patients.
Objectives: This study evaluates the effectiveness of the RTHC program. Primary outcomes analyzed included acceptance of any referral and attendance of any appointment. Secondary outcomes included acceptance of the first referral and rate of appointment attendance for patients with an accepted referral.
Methods: Using referral process data for the years 2014 to 2019 from a public tertiary care hospital in Chiapas, 91 RTHC patients were matched using 2:1 optimal pair matching with a control cohort balancing covariates of patient age, sex, specialty referred to, level of referring hospital, and municipality.
Findings: RTHC patients were more likely to have had an accepted referral (OR 17.42, 95% CI 3.68 to 414.16) and to have attended an appointment (OR 5.49, 95% CI 2.93 to 11.60) compared to the matched control group. RTHC patients were also more likely to have had their first referral accepted (OR 2.78, 95% CI 1.29 to 6.73). Among patients with an accepted referral, RTHC patients were more likely to have attended an appointment (OR 3.86, 95% CI 1.90 to 8.57).
Conclusions: The results demonstrate that the RTHC model is successful in increasing access to specialty care by both increasing referral acceptance and appointment attendance.
In this study, based on BODIPY molecule, new calix-like structures with significant electrical and optical properties were designed. These calix-like compounds containing BODIPY seems to be highly probable and appear to be thermodynamically stable. After structural optimization, absence of imaginary frequencies and the values of cohesive energies were studied which two important evidences about their stability were obtained. Decreasing the values of Eg and improvement of optical properties as the result of enlarging the oligomers size is considerable result. Between designed structures the calix[8]BODIPY is have smallest value of Eg and is more optically active molecule which has intense absorptions in visible region of light. Two separate computational methods were used to confirm the accuracy of the obtained data. Finally, it was shown that by increasing the number of BODIPY units in calix[n]BODIPY structure, the strength of hydrogen bond in the lower rims of it increase. Although the designed compounds have not yet been synthesized, they are highly probable due to the high stability of the compounds containing BODIPY and appear to be good synthetic chemical targets.
Schiff base imine condensations are a useful tool for macrocycle synthesis and applications within supramolecular chemistry. Here we address the mixtures of products that can arise from template free synthesis using dicarbonylheterocycles and diamines, and look to develop metal-free template methods for selective macrocycle formation. A range of alkyl α,ω-diamines were combined with phenanthroline and pyridine heterocyclic dicarbaldehydes under standard literature conditions. The reaction conditions were modified to demonstrate a relationship between choice of solvent and product equilibria. It was observed that benzene and toluene could shift a mixture of products and unreacted starting materials to form predominantly one imine product for a number of systems. Once the macrocyclic products had been characterized in selected solvents, iodinated halogen bonding guest molecules were added to direct macrocycle assemblies using non-covalent interactions. Studies to investigate host – guest suitability and halogen bond interactions were conducted, and it was found that tetraiodoethylene had an influence on the formation of a phenanthroline based macrocycle. Proof of concept experiments were performed to show the influence of the guest molecule, tetraiodoethylene, on the macrocyclic products formed under competitive dynamic combinatorial chemistry conditions.
In this work, a new macrocyclic cadmium complex, [Cd(ACE)I]2[CdI4] (1); ACE: 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane, was prepared by template method and characterized by elemental analysis, FT-IR spectroscopy and single-crystal X-ray diffraction. Structural analysis of the complex 1 revealed an ionic complex containing two cadmium atoms with tetrahedral (in anionic portion) and square-pyramidal (in cationic portion) geometries. Using the DFT calculations, thermodynamic stability of the first-row and group 12 metal complexes containing ACE ligand was investigated and then validated by comparing with the CSD analogues. Charge distribution pattern of ACE ligand was compared with cationic unit of 1 by NBO analysis to study of the charge variation of ligand after complexation.
Cancer is one of the leading causes of death worldwide, and the limited success of currently used anticancer drugs is a driving force for the search for new compounds with anticancer potential. Calixarenes make up a fascinating class of macrocycles that find a wide range of biological applications in supramolecular chemistry. Especially in recent years, the anticancer activity of various calixarene derivatives has been reported by many researchers. The aim of this review article is to find relatively simple, efficient, and synthetic methods for the preparation of macrocyclic compounds containing various pharmacophoric groups to produce new and effective anticancer materials in cancer research and to investigate the usability of calixarene-based supramolecular in cancer research.
The crystal structures are reported for 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-6,17-dione, (C12H22N2O6), (I), dibenzo[e,q][1,4,10,13,7,16] tetraoxadiazacyclooctadecine-6,13-dione, (C20H22N2O6), (II) and 1,4-dioxa-10,13-dithia-7,16-diazacyclooctadecane-8,15-dione, (C12H22N2O4S2), (III). Solid-state structures show different types of hydrogen bonding for all three structures. In I, there are two intermolecular hydrogen bonds between an amide and carbonyl [N–H···O = 2.8206(11) Å and 2.8637(11) Å] and two intermolecular hydrogen bonds between an amide and ether [N–H···O = 2.9570(11) Å and 3.0067(11) Å]. There are two intramolecular hydrogen bonds between amide and ether oxygens [N–H···O = 2.589(3) Å and 2.623(4) Å] in II. Molecule III has a mixture of intramolecular hydrogen bonds between an amide and thioether [N–H···S = 3.0501(18) Å] and intermolecular hydrogen bonds between an amide and carbonyl [N–H···O = 2.835(2) Å].
Calixarene derivatives are excellent host compounds for ionic species in liquid–liquid extraction. However, many studies using calixarene derivatives have been conducted using highly toxic chloroform as a solvent because of their poor solubility in typical hydrocarbons. In the present study, aromatic ethers were developed as solvents for calixarene derivatives to enhance their industrial applicability. The solubility of the calix[6]arene carboxylic acid derivative tOct[6]CH2COOH in 1-octoxybenzene (OB) and 1-butoxybenzene (BB) was 11.3 mM and 24.9 mM, respectively. The cationic guest molecule tryptophan methyl ester was extracted using the tOct[6]CH2COOH host in OB and BB. The cationic lysine-rich protein cytochrome c was also extracted using tOct[6]CH2COOH in BB as shown for tOct[6]CH2COOH in chloroform in previous studies. However, cytochrome c was not extracted using tOct[6]CH2COOH in OB and instead, precipitated. As tOct[6]CH2COOH stabilizes the ammonium group of biomolecules because of its suitable cavity size, the extraction of the tryptophan ester and cytochrome c using tOct[6]CH2COOH was much higher than those using the corresponding calix[4]arene and calix[8]arene derivatives. These results confirm that aromatic ethers are potential solvents for calixarene derivatives for the extraction of biomolecules.
This review introduces the synthesis, properties and applications of CoIIIcorroles. The synthesis methods are containing A2B type, A3 type, ABC type, Hangman H3corrole and H3biscorrole synthesis and their metal-inserting reactions. Also, the spectroscopic and electrochemical properties of CoIIIcorroles were also described. However, the most important part of this paper is about the application of CoIIIcorroles, including the development of sustainable and pollution-free chemical energy sources, the degradation of environmentally harmful organochlorides, and the oxidation of alkanes.
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