From molecules to materials : Engineering new ionic liquid crystals through halogen bonding

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid crystals (ILCs). Taking advantages of the high specificity of XB for haloperfluorocarbons and the ability of anions to act as XB-acceptors, we obtained supramolecular complexes based on 1-alkyl-3-methylimidazolium iodides and iodoperfluorocarbons, overcoming the well-known immiscibility between hydrocarbons (HCs) and perfluorocarbons (PFCs). The high directionality of the XB combined with the fluorophobic effect, allowed us to obtain enantiotropic liquid crystals where a rigid, non-aromatic, XB supramolecular anion acts as mesogenic core. X-ray structure analysis of the complex between 1-ethyl-3-methylimidazolium iodide and iodoperfluorooctane showed the presence of a layered structure, which is a manifestation of the well-known tendency to segregation of perfluoroalkyl chains. This is consistent with the observation of smectic mesophases. Moreover, all the reported complexes melt below 100 °C, and most are mesomorphic even at room temperature, despite that the starting materials were non-mesomorphic in nature. The supramolecular strategy reported here provides new design principles for mesogen design allowing a totally new class of functional materials

The Effect of Age and NT-proBNP on the Association of Central Obesity with 6-Years Cardiovascular Mortality of Middle-Aged and Elderly Diabetic People: The Population-Based Casale Monferrato Study

BACKGROUND: Among people with type 2 diabetes the relationship between central obesity and cardiovascular mortality has not been definitely assessed. Moreover, NT-proBNP is negatively associated with central obesity, but no study has examined their combined effect on survival. We have examined these issues in a well-characterized population-based cohort. METHODS AND FINDINGS: Survival data of 2272 diabetic people recruited in 2000 who had no other chronic disease have been updated to 31 December 2006. NT-proBNP was measured in a subgroup of 1690 patients. Cox proportional hazards modeling was employed to estimate the independent associations between cardiovascular and all-cause mortality and waist circumference. Mean age was 67.9 years, 49.3% were men. Both age and NT-proBNP were negatively correlated with waist circumference (r = -0.11, p<0.001 and r = -0.07, p = 0.002). Out of 2272 subjects, 520 deaths (221 for CV mortality) occurred during a median follow-up of 5.4 years. Central obesity was not associated with CV mortality (hazard ratio, HR, adjusted for age, sex, diabetes duration, 1.14, 95% CI 0.86-1.52). NTproBNP was a negative confounder and age a strong modifier of this relationship (p for interaction<0.001): age<70 years, fully adjusted model HR = 3.52 (1.17-10.57) and age ≥70 years, HR = 0.80 (0.46-1.40). Respective HRs for all-cause mortality were 1.86 (1.03-3.32) and 0.73 (0.51-1.04). CONCLUSIONS: In diabetic people aged 70 years and lower, central obesity was independently associated with increased cardiovascular mortality, independently of the negative effect of NT-proBNP. In contrast, no effect on 6-years survival was evident in diabetic people who have yet survived up to 70 years

The dissolution of monosodium urate monohydrate crystals: formulation of a biocompatible buffer solution with potential use in the treatment of gouty arthropathies

The dissolving abilities (DAs) of several aqueous media for microcrystalline monosodium urate monohydrate (MSU, NaC5N4O3H3·H2O) have been investigated using UV spectrophotometry for quantitative analytical determinations and X-ray diffraction, scanning electron microscopy and polarized light optical microscopy to assess structural aspects. High DAs were found for a buffer labeled TMT which contains tris(hydroxymethyl)aminomethane (TRIS), tris(hydroxymethyl)aminomethane hydrochloride (TRIS·HCl), D-mannitol (MAN) and taurine (TAU) and gave DA30=1298(5) mg/L for synthetic MSU after 30 min incubation at 37°C and pH 7.4, most of the dissolution taking place within the first 5-10 min. Semiempirical molecular modelling techniques (ZINDO/1) show a favorable energy balance for the formation of a TRIS-urate-TRIS adduct which might explain the high DA values. Buffers containing linear or dendrimeric polyamines gave DA values which suggest that complex formation toward sodium cations is less important. An ex vivo MSU sample was found to have a significantly lower DA value (DA30=1124(5) mg/L in TMT) as well as a lower crystallinity than its synthetic counterpart, possibly related to the presence of a non-crystalline impurity such as endogenous proteins. Cytotoxicity tests based on the MTT assay were used to check the biocompatibility of the TMT buffer and showed only moderate cell mortality after 24 h contact with the buffer solution

Halogen bonding in hypervalent iodine and bromine derivatives: Halonium salts

Halogen bonds have been identified in a series of ionic compounds involving bromonium and iodonium cations and several different anions, some also containing hypervalent atoms. The hypervalent bromine and iodine atoms in the examined compounds are found to have positive Ï\u83-holes on the extensions of their covalent bonds, while the hypervalent atoms in the anions have negative Ï\u83-holes. The positive Ï\u83-holes on the halogens of the studied halonium salts determine the linearity of the short contacts between the halogen and neutral or anionic electron donors, as usual in halogen bonds

C–halogen…O supramolecular synthons:in situcryocrystallisation of 1,2-dihalotetrafluoroethane/HMPA adducts

The in situ cryocrystallisation technique has been used to obtain four adducts between hexamethylphosphortriamide and 1,2-dihalotetrafluoroethanes having iodine, bromine and chlorine as halogen-bonding donor atoms. These systems allowed for a precise comparison of different C-X···O synthons. The effectiveness and reliability of the pharmacologically important C-Cl···O synthons are proven. © 2013 Copyright Taylor and Francis Group, LLC

The Halogen Bond

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design

Circulating anti-Hsp70 levels in nascent metabolic syndrome: the Casale Monferrato Study.

The metabolic syndrome (MetS) confers an increased risk of both type 2 diabetes and cardiovascular diseases (CVD). Heat shock protein 70 (Hsp70), an intracellular polypeptide, can be exposed on the plasma membrane and/or released into the circulation, eliciting both native and immune responses that may contribute to vascular damage. Our aim was to assess if serum anti-Hsp70 antibody levels were cross-sectionally associated with uncomplicated MetS. A cross-sectional case–control study from the nondiabetic cohort of the Casale Monferrato Study was performed. Subjects with established CVD and/or abnormal renal function were excluded. Case subjects (n = 180) were defined as those fulfilling the criteria for the diagnosis of MetS. Control subjects (n = 136) were completely free of any component of the MetS. Serum anti-Hsp70 levels were measured by immunoenzymatic assay. We found that anti-Hsp70 antibody levels were significantly higher in cases than in control subjects [122.6 (89.5–155.6) vs 107.1 (77.3–152.4) μg/ml, p = 0.04], even after age and sex adjustment. In logistic regression analysis, higher levels of log-anti-Hsp70 conferred greater odds ratio (OR) for MetS, independently of age and sex. There was a statistically significant trend of ORs across quartiles of anti-Hsp70 and values greater than 108.0 μg/ml conferred a 77 % increased OR of MetS as compared with values in the lower quartiles. The strength of the association slightly decreased after further adjustment for apolipoprotein B, smoking, and albumin excretion rate. In conclusion, our results show that serum anti-Hsp70 antibody levels are independently associated with nascent MetS

Halogen bond directionality translates tecton geometry into self-assembled architecture geometry

The structures of halogen-bonded infinite chains involving two diiodoperfluoroalkanes and a bent bis(pyrid-4′-yl)oxadiazole show that the geometry of the pyridyl pendant rings is translated into the angle between the formed halogen bonds. © 2013 The Royal Society of Chemistry