Porphyrin-Based Metal-Organic Frameworks as Heterogeneous Catalysts in Oxidation Reactions

Porphyrin-based Metal-Organic Frameworks (Por-MOFs) constitute a special branch of the wide MOF family that has proven its own value and high potential in different applications. In this mini-review the application of these materials as catalysts in oxidation reactions is highlighted

Experimental particle formation rates spanning tropospheric sulfuric acid and ammonia abundances, ion production rates, and temperatures

Binary nucleation of sulfuric acid and water as well as ternary nucleation involving ammonia are thought to be the dominant processes responsible for new particle formation (NPF) in the cold temperatures of the middle and upper troposphere. Ions are also thought to be important for particle nucleation in these regions. However, global models presently lack experimentally measured NPF rates under controlled laboratory conditions and so at present must rely on theoretical or empirical parameterizations. Here with data obtained in the European Organization for Nuclear Research CLOUD (Cosmics Leaving OUtdoor Droplets) chamber, we present the first experimental survey of NPF rates spanning free tropospheric conditions. The conditions during nucleation cover a temperature range from 208 to 298K, sulfuric acid concentrations between 5x10(5) and 1x10(9)cm(-3), and ammonia mixing ratios from zero added ammonia, i.e., nominally pure binary, to a maximum of -1400 parts per trillion by volume (pptv). We performed nucleation studies under pure neutral conditions with zero ions being present in the chamber and at ionization rates of up to 75ion pairs cm(-3)s(-1) to study neutral and ion-induced nucleation. We found that the contribution from ion-induced nucleation is small at temperatures between 208 and 248K when ammonia is present at several pptv or higher. However, the presence of charges significantly enhances the nucleation rates, especially at 248K with zero added ammonia, and for higher temperatures independent of NH3 levels. We compare these experimental data with calculated cluster formation rates from the Atmospheric Cluster Dynamics Code with cluster evaporation rates obtained from quantum chemistry.Peer reviewe

Neutral molecular cluster formation of sulfuric acid-dimethylamine observed in real time under atmospheric conditions

Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Layered Metal-Organic Frameworks Based on Octahedral Lanthanides and a Phosphonate Linker: Control of Crystal Size

The hydrothermal reaction between lanthanide salts and residues of (benzene-1,3,5-triyltris(methylene))triphosphonic acid (H(6)bmt) promotes the formation of a new series of isotypical layered lanthanideorganic frameworks (LnOFs), [Ln(2)(H(3)bmt)(2)]center dot H2O [where Ln(3+) = Eu3+ (1), Gd3+ (2), Tb3+ (3), Dy3+ (4), Ho3+ (5), Er3+ (6), Tm3+ (7), and Yb3+ (8)]. The crystal structure was unveiled from powder X-ray diffraction data (both laboratory and synchrotron) in tandem with other characterization techniques (namely thermogravimetry, thermodiffractometry, vibrational spectroscopy, and elemental analysis). It is shown that the lanthanide contraction leads, on average, to a reduction of the average crystallite size, up to the nanometer scale in the case of compound 8. The unique structural features of the (2)(infinity)[Ln(2)(H(3)bmt)(2)] layers are discussed in detail, in particular, the six-coordination environment of the lanthanide cations and its topological relationship with the formation of the first 5,5L4 binodal network based on chelating phosphonate groups

Synthesis and photophysical characterization of dimethylamine-derived Zn(II)phthalocyanines: exploring their potential as selective chemosensors for trinitrophenol

We report a novel synthetic approach, with good yields, for the synthesis of selective dimethylamine-substituted phthalonitriles (1-3) in the presence of triethyl phosphite and dimethylformamide at 160 degrees C. The peripherally modified dimethylamine substituted Zn(II) phthalocyanines (ZnPc1-3) with varied numbers and positions of dimethylamine groups were prepared for a systematic investigation of the effect of the substituents on their electronic and spectroscopic properties. Compounds show strong aggregation behaviour in methanol and this behaviour decreases with the increase of the alkyl chain length of the alcohol solvents (i.e., from methanol to octanol). The fluorescence quantum yields of ZnPc1-3 showed an excellent correlation with the extent of the molecular aggregation. The versatility of the ZnPc1-5 compounds possessing both electron donating and electron withdrawing substituents at their periphery is investigated towards the detection of nitroaromatic compounds (NACs) in solution and in the vapour phase. It was found that ZnPc1-5 exhibit high selectivity towards trinitrophenol (TNP). A good linearity of fluorescence detection using ZnPc3 as the fluorescent probe was observed in the concentration range of 50 x 10(-6) to 450 x 10(-6) M in chloroform, with a detection limit (LOD) of 11 +/- 2 ppm. Stern-Volmer (SV) and DFT studies reveal that the fluorescence quenching behaviour occurs through photo-induced electron transfer from the excited state of ZnPcs to TNP with static quenching behaviour occurring in a predominant fashion. The formation of a porous morphology of ZnPc3 thin films promotes high selectivity and accessibility to TNP vapours (7.7 x 10(-3) ppb)

Fast detection of nitroaromatics using phosphonate pyrene motifs as dual chemosensors

A new class of dual fluorescent chemosensors for nitroaromatic compounds (NACs) based on phosphonated pyrene derivatives is reported, showing high selectivity towards trinitrotoluene (TNT). The strong intermolecular interactions (pi-pi stacking and hydrogen bonding) allow high fluorescence quenching with visual detection in short response times

Synthesis of hexaphyrins and N-fused pentaphyrins bearing pyridin-4-ylsulfanyl groups

In recent years much attention has been devoted to expanded macrocyclic chemistry. Nevertheless, while several advancements were achieved in the synthesis of novel expanded porphyrin architectures, not much has been developed in the functionalization of these macrocycles. This report shows the selective replacement of the p-fluorine atoms of meso-pentakis(pentafluorophenyl) N-fused [22]pentaphyrin and meso-hexakis(pentafluorophenyl) [26]hexaphyrin with 4-mercaptopyridine moieties, thus increasing their potential as ligands for coordination chemistry and catalysis or electronic transfer applications striving new synthetic methodologies and a new set of specific applications for this type of compounds

Multifunctional metal-organic frameworks: from academia to industrial applications

After three decades of intense and fundamental research on metal-organic frameworks (MOFs), is there anything left to say or to explain? The synthesis and properties of MOFs have already been comprehensively described elsewhere. It is time, however, to prove the nature of their true usability: technological applications based on these extended materials require development and implementation as a natural consequence of the up-to-known intensive research focused on their design and preparation. The current large number of reviews on MOFs emphasizes practical strategies to develop novel networks with varied crystal size, shape and topology, being mainly devoted to academic concerns. The present survey intends to push the boundaries and summarise the state-of-the-art on the preparation of promising (multi) functional MOFs in worldwide laboratories and their use as materials for industrial implementation. This review starts, on the one hand, to describe several tools and striking examples of remarkable and recent (multi) functional MOFs exhibiting outstanding properties (e.g., in gas adsorption and separation, selective sorption of harmful compounds, heterogeneous catalysis, luminescent and corrosion protectants). On the other hand, and in a second part, it intends to use these examples of MOFs to incite scientists to move towards the transference of knowledge from the laboratories to the industry. Within this context, we exhaustively review the many efforts of several worldwide commercial companies to bring functional MOFs towards the daily use, analysing the various patents and applications reported to date. Overall, this review goes from the very basic concepts of functional MOF engineering and preparation ending up in their industrial production on a large scale and direct applications in society

Facile synthesis of highly stable BF3-induced meso-tetrakis (4-sulfonato phenyl) porphyrin (TPPS4)-J-aggregates: structure, photophysical and electrochemical properties

We report herein, a novel method for the formation of highly stable BF3-induced J-aggregates by interaction between meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS4) and BF3O(C2H5)(2). The aggregates were characterized by NMR (H-1, B-11 and F-19), optical absorption, cyclic voltammetry, FT-IR and fluorescence spectroscopic techniques. TPPS4 readily forms a 1 : 2 adduct with BF3 which further converts into BF3-induced TPPS4 aggregates whose spectroscopic properties strongly depend on the concentration of BF3. The optical absorption spectrum shows the formation of J-type aggregates with an apparent association constant (logK(app)) of 4.2 +/- 0.1. The steady state emission shows formation of 1 : 2 (TPPS4-BF3) adducts at similar to 685 nm and J-aggregates exhibit emission at 732 nm with a red shift of similar to 17 nm in comparison to J-aggregates of TPPS4 with TFA. The fluorescence lifetime of TPPS4 : BF3 (1 : 2) adducts exhibits similar to 3.68 ns and aggregates show a lifetime of 4.32 +/- 0.2 ns with major abundance. NMR study reveals that proton transfer occurs from pyrrole N-H to the SO3- groups and J-aggregates were stabilized by strong intermolecular hydrogen bonding interaction between N-2-BF2 and SO3H. Cyclic voltammetry shows a decrease in the reduction peak current along with a change in the peak potentials for the aggregates. The PXRD pattern of the aggregates exhibits orthorhombic structure with interplanar distance of 4.87 angstrom. The variations in unusual stability, photophysical, electrochemical properties and nature of the aggregates were rationalized with aggregates of TPPS4 dication