Tris(acetonitrile-κN){2,6-bis­[(diphenyl­phosphan­yl)amino]-4-eth­oxy-1,3,5-triazine-κ3 P,N 1,P′}iron(II) bis­(tetra­fluorido­borate) acetonitrile disolvate

In the title compound, [Fe(CH3CN)3(C29H27N5OP2)](BF4)2·2CH3CN, the FeII ion is octa­hedrally coordinated by a meridionally chelating tridentate pincer-type PNP ligand derived from 2,6-diamino-4-eth­oxy-1,3,5-triazine and by three acetonitrile mol­ecules. The four Fe—N bond lengths range from 1.9142 (12) to 1.9579 (11) Å, while the Fe—P bonds are 2.2452 (4) and 2.2506 (4) Å [P—Fe—P = 165.523 (14)°], consistent with FeII in a low-spin state. Unlike related Fe PNP complexes based on 2,6-diamino­pyridine, the BF4 anions are not hydrogen bonded to the two NH groups of the pincer ligand but show instead anion–π inter­actions with the triazine ring and acetonitrile mol­ecules in addition to ten C—H⋯F inter­actions. Most remarkable among these is an anion–π(triazine) inter­action with a short distance of 2.788 (2) Å between one F and the centroid of the π-acidic triazine ring. The corresponding shortest distance between this F atom and a triazine carbon atom is 2.750 (2) Å. The two NH groups of the pincer ligand donate N—H⋯N hydrogen bonds to the triazine N atom of a neighbouring complex and to an uncoordinated acetonitrile mol­ecule. This last mol­ecule is in a side-on head-to-tail association with the second uncoordinated acetonitrile at C⋯N distances of 3.467 (2) and 3.569 (2) Å. In contrast to several related compounds with diamino­pyridine- instead of diamino­triazine-based PNP ligands, the title crystal structure is remarkably well ordered. This suggests that the diamino­triazine moiety exerts notable crystal structure stabilizing effects

An optoelectronic sensing device for CO detection in air based on a binuclear rhodium complex

The design, fabrication and validation of an optoelectronic sensor implemented in an easy-to-use portable device for the selective and sensitive detection of CO in air is reported herein. The system is based on the colour changes observed in the binuclear rhodium complex of formula [Rh2[(C6H4)P(C6H5)2]2(O2CCF3)2](CF3CO2H)2(1) upon coordinating CO molecules in axial positions. Complex 1 is used supported on cellulose chromatography paper. In this support, colour changes to the naked eye are observed for CO concentrations above 50 ppm. The probe is also implemented in a simple portable optoelectronic device.The cellulose support containing probe 1 in this device is placed inside a small dark chamber, is illuminated with a tricolour LED emitting at 624, 525 and 470 nm, respectively corresponding to red (R), green (G) and blue (B) light, and reflected light is detected by a photodiode. With a transimpedance amplifier, the current generated by the photodiode is transformed into a voltage compatible with the 10-bit analogue-to-digital converter (ADC) port. Colour changes are measured as the distance d between the R, G and B data of the blank (probe without CO) and that for a certain CO concentration. Typical calibration curves are fitted using a bi-exponential equation. This system offers a typical response time of a few minutes (ca. 7 min) and a limit of detection of 11 ppm. The probe in the cellulose supports is also highly reversible.The optoelectronic device is portable (dimensions 14 × 8.5 × 3.5 cm; weighs approximately 270 g) and is powered by AA batteries. In addition, no variations in experimental parameter d upon exposure to CO2, N2, O2, Ar, water-saturated air and vapours of chloroform, hexane, ethanol, acetone, methane, toluene or formaldehyde are observed. Besides, colour changes are found for acetonitrile vapour, NO and NO2, but only at high concentrations. For validation purposes, the device was used to determine the CO present in the 4-shed accumulated smoke of two cigarette types after passing smokers lungs.We thank the Spanish Government (Project MAT2012-38429-C04-01), Generalitat Valenciana (Projects PROMETE02009/016 and ISIC/2012/005) and the UPV (Project INNOVA-04-10) for support. M.E.M thanks the Spanish Ministry of Education for a Doctoral FPU Fellowship.Moragues Pons, ME.; Montes Robles, R.; Ros-Lis, JV.; Alcañiz Fillol, M.; Ibáñez Civera, FJ.; Pardo Vicente, MT.; Martínez Mañez, R. (2014). An optoelectronic sensing device for CO detection in air based on a binuclear rhodium complex. Sensors and Actuators B: Chemical. 191:257-263. https://doi.org/10.1016/j.snb.2013.09.107S25726319

Ruthenium(II) and Osmium(II) Vinyl Complexes as Highly Sensitive and Selective Chromogenic and Fluorogenic Probes for the Sensing of Carbon Monoxide in Air

[EN] The detection of carbon monoxide in solution and air has been achieved using simple, inexpensive systems based on the vinyl complexes [M(CH=CHR)Cl(CO)(BTD)(PPh3)2] (R=aryl, BTD=2,1,3-benzothiadiazole). Depending on the nature of the vinyl group, chromogenic and fluorogenic responses signalled the presence of this odourless, tasteless, invisible, and toxic gas. Solutions of the complexes in CHCl3 underwent rapid change between easily differentiated colours when exposed to air samples containing CO. More significantly, the adsorption of the complexes on silica produced colorimetric probes for the naked-eye detection of CO in the gas phase. Structural data for key species before and after the addition of CO were obtained by means of single X-ray diffraction studies. In all cases, the ruthenium and osmium vinyl complexes studied showed a highly selective response to CO with exceptionally low detection limits. Naked-eye detection of CO at concentrations as low as 5 ppb in air was achieved with the onset of toxic levels (i.e., 100 ppm), thus resulting in a remarkably clear colour change. Moreover, complexes bearing pyrenyl, naphthyl, and phenanthrenyl moieties were fluorescent, and greater sensitivities were achieved (through turn-on emission fluorescence) in the presence of CO both in solution and air. This behaviour was explored computationally using time-dependent density functional theory (TDDFT) experiments. In addition, the systems were shown to be selective for CO over all other gases tested, including water vapour and common organic solvents. Supporting the metal complexes on cellulose strips for use in an existing optoelectronic device allows numerical readings for the CO concentration to be obtained and provision of an alarm system.The authors wish to express their gratitude to the Spanish Government (project MAT2012-38429-C04) and Generalitat Valenciana (project PROMETEOII/2014/047) for their support. M.E.M. is grateful to the Spanish Ministerio de Ciencia e Innovacion for an FPU grant and a short-stay fellowship, which allowed this profitable collaboration. C.M.-H. thanks the Spanish Ministry of Economy and Competitiveness for her grant. A.T. gratefully acknowledges the support of the Leverhulme Trust (Grant RPG-2012-634) for a studentship. The authors thank Prof. C. K. Williams, Prof. N. J. Long, and Dr P. Hunt (Imperial College, UK) for the use of apparatus and assistance.Toscani, A.; Marín-Hernández, C.; Moragues Pons, ME.; Sancenón Galarza, F.; Dingwall, P.; Brown, NJ.; Martínez-Máñez, R.... (2015). Ruthenium(II) and Osmium(II) Vinyl Complexes as Highly Sensitive and Selective Chromogenic and Fluorogenic Probes for the Sensing of Carbon Monoxide in Air. Chemistry - A European Journal. 21(41):14529-14538. https://doi.org/10.1002/chem.201501843S1452914538214

An Organic Spin Crossover Material in Water from a Covalently Linked Radical Dyad

A covalently linked viologen radical cation dyad acts as a reversible thermomagnetic switch in water. Cycling between diamagnetic and paramagnetic forms by heating and cooling is accompanied by changes in optical and magnetic properties with high radical fidelity. Thermomagnetic switches in water may eventually find use as novel biological thermometers and in temperature-responsive organic materials where the changes in properties originate from a change in electronic spin configuration rather than a change in structure

Low-coordinate first-row transition metal complexes in catalysis and small molecule activation

Enforcing unusually low coordination numbers on transition metals with sterically demanding ligands has long been an area of interest for chemists. Historically, the synthesis of these challenging molecules has helped to elucidate fundamental principles of bonding and reactivity. More recently, there has been a move towards exploiting these highly reactive complexes to achieve a range of transformations using cheap, earth-abundant metals. In this Perspective, we will highlight selected examples of transition metal complexes with low coordination numbers that have been used in catalysis and the activation of small molecules featuring strong bonds (N2, CO2, and CO)

Relationship between self-reported dietary intake and physical activity levels among adolescents: The HELENA study

Background Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. Therefore it is important to investigate associations between dietary and physical activity behavior, the two most important lifestyle behaviors influencing our energy balance and body composition. The objective of the present study is to describe the relationship between energy, nutrient and food intake and the physical activity level among a large group of European adolescents. Methods The study comprised a total of 2176 adolescents (46.2% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Dietary intake and physical activity were assessed using validated 24-h dietary recalls and self-reported questionnaires respectively. Analyses of covariance (ANCOVA) were used to compare the energy and nutrient intake and the food consumption between groups of adolescents with different physical activity levels (1st to 3rd tertile). Results In both sexes no differences were found in energy intake between the levels of physical activity. The most active males showed a higher intake of polysaccharides, protein, water and vitamin C and a lower intake of saccharides compared to less active males. Females with the highest physical activity level consumed more polysaccharides compared to their least active peers. Male and female adolescents with the highest physical activity levels, consumed more fruit and milk products and less cheese compared to the least active adolescents. The most active males showed higher intakes of vegetables and meat, fish, eggs, meat substitutes and vegetarian products compared to the least active ones. The least active males reported the highest consumption of grain products and potatoes. Within the female group, significantly lower intakes of bread and cereal products and spreads were found for those reporting to spend most time in moderate to vigorous physical activity. The consumption of foods from the remaining food groups, did not differ between the physical activity levels in both sexes. Conclusion It can be concluded that dietary habits diverge between adolescents with different self-reported physical activity levels. For some food groups a difference in intake could be found, which were reflected in differences in some nutrient intakes. It can also be concluded that physically active adolescents are not always inclined to eat healthier diets than their less active peers.The HELENA study took place with the financial support of the European Community Sixth RTD Framework Programme (Contract FOOD-CT: 2005-007034). This work was also partially supported by the European Union, in the framework of the Public Health Programme (ALPHA project, Ref: 2006120), the Swedish Council for Working Life and Social Research (FAS), the Spanish Ministry of Education (EX-2007-1124, and EX-2008-0641), and the Spanish Ministry of Health, Maternal, Child Health and Development Network (number RD08/0072) (JPRL, LAM)

Ideal cardiovascular health and inflammation in European adolescents: The HELENA study

Background and aims Inflammation plays a key role in atherosclerosis and this process seems to appear in childhood. The ideal cardiovascular health index (ICHI) has been inversely related to atherosclerotic plaque in adults. However, evidence regarding inflammation and ICHI in adolescents is scarce. The aim is to assess the association between ICHI and inflammation in European adolescents. Methods and results As many as 543 adolescents (251 boys and 292 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, a cross-sectional multi-center study including 9 European countries, were measured. C-reactive protein (CRP), complement factors C3 and C4, leptin and white blood cell counts were used to compute an inflammatory score. Multilevel linear models and multilevel logistic regression were used to assess the association between ICHI and inflammation controlling by covariates. Higher ICHI was associated with a lower inflammatory score, as well as with several individual components, both in boys and girls (p < 0.01). In addition, adolescents with at least 4 ideal components of the ICHI had significantly lower inflammatory score and lower levels of the study biomarkers, except CRP. Finally, the multilevel logistic regression showed that for every unit increase in the ICHI, the probability of having an inflammatory profile decreased by 28.1% in girls. Conclusion Results from this study suggest that a better ICHI is associated with a lower inflammatory profile already in adolescence. Improving these health behaviors, and health factors included in the ICHI, could play an important role in CVD prevention

Evaluation of iron status in European adolescents through biochemical iron indicators: the HELENA Study

BACKGROUND/OBJECTIVES: To assess the iron status among European adolescents through selected biochemical parameters in a cross-sectional study performed in 10 European cities. SUBJECTS/METHODS: Iron status was defined utilising biochemical indicators. Iron depletion was defined as low serum ferritin (SF8.5 mg/l) plus iron depletion. Iron deficiency anaemia (IDA) was defined as ID with haemoglobin (Hb) below the WHO cutoff for age and sex: 12.0 g/dl for girls and for boys aged 12.5-14.99 years and 13.0 g/dl for boys aged ≥15 years. Enzyme linked immunosorbent assay was used as analytical method for SF, sTfR and C-reactive protein (CRP). Subjects with indication of inflammation (CRP >5 mg/l) were excluded from the analyses. A total of 940 adolescents aged 12.5-17.49 years (438 boys and 502 girls) were involved. RESULTS: The percentage of iron depletion was 17.6%, significantly higher in girls (21.0%) compared with boys (13.8%). The overall percentage of ID and IDA was 4.7 and 1.3%, respectively, with no significant differences between boys and girls. A correlation was observed between log (SF) and Hb (r = 0.36, P < 0.01), and between log (sTfR) and mean corpuscular haemoglobin (r = -0.30, P < 0.01). Iron body stores were estimated on the basis of log (sTfR/SF). A higher percentage of negative values of body iron was recorded in girls (16.5%) with respect to boys (8.3%), and body iron values tended to increase with age in boys, whereas the values remained stable in girls. CONCLUSIONS: To ensure adequate iron stores, specific attention should be given to girls at European level to ensure that their dietary intake of iron is adequate.status: publishe

Dietary animal and plant protein intakes and their associations with obesity and cardio-metabolic indicators in European adolescents: The HELENA cross-sectional study

Background: Previous studies suggest that dietary protein might play a beneficial role in combating obesity and its related chronic diseases. Total, animal and plant protein intakes and their associations with anthropometry and serum biomarkers in European adolescents using one standardised methodology across European countries are not well documented. Objectives: To evaluate total, animal and plant protein intakes in European adolescents stratified by gender and age, and to investigate their associations with cardio-metabolic indicators (anthropometry and biomarkers). Methods: The current analysis included 1804 randomly selected adolescents participating in the HELENA study (conducted in 2006-2007) aged 12.5-17.5 y (47% males) who completed two non-consecutive computerised 24-h dietary recalls. Associations between animal and plant protein intakes, and anthropometry and serum biomarkers were examined with General linear Model multivariate analysis. Results: Average total protein intake exceeded the recommendations of World Health Organization and European Food Safety Authority. Mean total protein intake was 96 g/d (59% derived from animal protein). Total, animal and plant protein intakes (g/d) were significantly lower in females than in males and total and plant protein intakes were lower in younger participants (12.5-14.9 y). Protein intake was significantly lower in underweight subjects and higher in obese ones; the direction of the relationship was reversed after adjustments for body weight (g/(kg.d)). The inverse association of plant protein intakes was stronger with BMI z-score and body fat percentage (BF%) compared to animal protein intakes. Additionally, BMI and BF% were positively associated with energy percentage of animal protein. Conclusions: This sample of European adolescents appeared to have adequate total protein intake. Our findings suggest that plant protein intakes may play a role in preventing obesity among European adolescents. Further longitudinal studies are needed to investigate the potential beneficial effects observed in this study in the prevention of obesity and related chronic diseases