•MOFs exhibit fascinating properties in terms of chemical and structural flexibility.•Green synthesis chemistry of MOFs help in elimination of hazards associated with conventional MOFs.•Green ...synthesis strategies are based on choice of solvents, metal ions, organic linkers, and the synthesis route.•Green MOFs are highly suitable for environmental and medical applications.•Future outlook for MOF research from laboratory prototype to industrial scale up.
Sustainable methods of synthesizing metal–organic frameworks (MOFs) are of paramount importance to energy conservation efforts and environmental remediation. It can be a significant tool in the global campaign to avoid use of hazardous substances, such as metal ions, organic solvents, and complexes in metal–organic chemistry. MOFs with porosity and crystalline nature offer structural tunability via variation in metal node and organic linker that promote their wide applicability at both scientific and industrial level. Besides fascinating properties of MOFs, their real field applications are still limited due to adverse environmental impact of the conventional synthesis approaches. Considerable research efforts have been devoted to devising clean and sustainable synthesis routes for MOFs to reduce the environmental impact of their preparation. This review covers the design strategies for greener, more energy-efficient, and less-toxic MOF synthesis through application of 12 green chemistry principles. Attention is given to development of green and industrially acceptable MOF chemistry based on (i) safer solvent/or reaction media, (ii) sustainable metal ions, and (iii) biocompatible (i.e., biomolecule/biomass-derived) organic linkers. The versatile functionality, biodegradability, biocompatible nature, and high drug loading capacity of green MOFs are highly promising for environmental and medical applications. In this review, the recent update on applicability of green MOFs in catalysis, adsorption/separation processes, and therapeutics is highlighted. In the last section, outlook and future challenges are illustrated, keeping in view their disposal and health related concerns.
•Surfactant-assisted strategy for synthesis of single crystal MOFs.•Surfactant-assisted strategy for separating the pure single-phase of MOFs.•Surfactant-assisted strategy for the control of MOFs’ ...morphology.
Extensive attention has been paid to metal-organic frameworks (MOFs) due to their interesting structures and plenty of potential applications in catalysis, chemical sensors, magnetism, drug delivery, gas separation and storage. A variety of synthetic methodologies for the synthesis of multifunctional MOFs with complicated structures and attracting properties (such as solvothermal, hydrothermal, urothermal and ionothermal methods), have been developed. Recently, the surfactant-assisted strategy for the synthesis, adjustment and control of multifunctional MOFs has attracted extensive research interest, because surfactants forcefully determine the dimensions, phases, and morphologies of MOFs materials via acting as emulsifiers, detergents, foaming agents, wetting agents or dispersants. This review offers recent developments and prospects in the surfactants as promising templates in the field of growing MOFs, namely, surfactant-assisted strategy for the synthesis of crystalline MOFs, the separation of the pure single-phase of MOFs, the control of the pore’s sizes and morphologies of MOFs (such as core/shell, nanodisks, nanoplates, nanorods, nanosheets) as well as their mechanism.
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•Types of catalysts and ligands.•Homogeneous and heterogeneous catalysis.•Catalysis by metals other than palladium.•Selected synthetic applications and mechanistic consideration.
...Synthetic organic chemistry experienced a significant advance in the last quarter of the 20th century with the advent of the transition-metal catalyzed cross-coupling reactions. The utility of these reactions was universally acknowledged and expressed in the Chemistry Nobel prize awarded to professors Heck, Suzuki and Negishi in 2010. In this scenario, the discovery of the Suzuki-Miyaura reaction was a landmark that occupies a privileged position because of its versatility, compatibility and pivotal contribution to diverse disciplines, including materials science and drug discovery. Despite the substantial progress attained for this reaction until 2010, there is still room for improvement, particularly, if we are concerned about the health of the Earth and aware of the paramount importance to produce substances under the guidelines of sustainable and Green Chemistry. In the present review, we summarize the efforts devoted by a wide and specialized scientific community to upgrade the Suzuki-Miyaura reaction during the post-Nobel prize period. An overview covering new catalytic systems, methods and conditions is provided, together with some applications and updated mechanistic viewpoints.
We report a ruthenium complex containing an N,N′-diimine ligand for the selective decomposition of formic acid to H2 and CO2 in water in the absence of any organic additives. A turnover frequency of ...12 000 h–1 and a turnover number of 350 000 at 90 °C were achieved in the HCOOH/HCOONa aqueous solution. Efficient production of high-pressure H2 and CO2 (24.0 MPa (3480 psi)) was achieved through the decomposition of formic acid with no formation of CO. Mechanistic studies by NMR and DFT calculations indicate that there may be two competitive pathways for the key hydride transfer rate-determining step in the catalytic process.
•Synthesizing π-conjugated BODIPYs for optoelectronic applications.•Potential application of BODIPY derivatives in OLEDs, NLOs, sensing, PSCs, etc.•BODIPY derivatives as hole transporting and ...ultrafast charge transfer materials.•π-conjugated BODIPYs with strong absorption and high fluorescence quantum yield.•Photonic and electronic properties of the meso-, a- and b-functionalized BODIPYs.
4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based-π-conjugated derivatives are endowed with extraordinary photonic and electronic properties. The BODIPYs possess unique features, including easy functionalization, simple synthetic modification, highly conjugated structure, strong absorption with high fluorescence quantum yield. In the last few decades, research has been devoted for developing BODIPY based materials with a wide range of applications in the field of both optoelectronic and biomedical applications. The incorporation of a variety of π-conjugated substituents at the meso position as well as at the pyrrolic position of BODIPY perturbs the photophysical and electrochemical properties to a greater extend. This perturbation leads to redshifted absorption with high molar extinction coefficient, excellent luminescent properties, good ion sensing properties and balanced hole and electron transport of BODIPY based materials. In this review, we have discussed the photophysical properties of a wide range of π-conjugated BODIPY based materials which are having potential applications in organic light-emitting diodes (OLEDs), nonlinear optics (NLOs), sensing, hole-transporting materials (HTMs) and electron-transporting materials (ETMs) for perovskite solar cells (PSCs) as well as materials for ultrafast charge transfer. We have also addressed the photophysical and electrochemical properties of the meso-, α- and β-functionalized BODIPYs which depend on the substitution pattern on the BODIPY core.
•We describe the numerous postfunctionalization methodologies of the BODIPY core.•The BODIPY nucleus can be postfunctionalized at all possible positions.•Comparison is made with prefunctionalization ...methodology.•Important properties and applications of BODIPYs made by the methods described in this review.
Fluorophores based on the 4-bora-3a,4a-diaza-s-indacene (aka boron dipyrromethene, boron dipyrrin, or BODIPY) platform have found diverse applications in different fields of modern science, medicine and (bio)technology. In this review we describe the numerous postfunctionalization methodologies of the boron dipyrromethene core designed and realized by research groups around the globe. In the postfunctionalization approach, boron dipyrromethenes with reactive functionalities attached directly to the core (halogen or hydrogen atoms, methyl, formyl, or alkylthio groups) are used as starting materials for further derivatization. The various synthetic methods towards these starting compounds and their postmodification are reviewed. We discuss the different strategies devised for postderivatization of the BODIPY nucleus at all possible positions (the pyrrole carbons, the meso-carbon, and the boron atom) and compare them concisely with the standard prefunctionalization methodology. Important properties and applications of a number of substituted BODIPYs made by the methods described in this review are also presented.
•Transition metal complexes are promising photosensitisers in photodynamic therapy.•The first transition metal photosensitiser entered clinical trials in 2017.•Transition metal complexes are ...efficient two-photon absorbers of the NIR light.•TMC could enable a potentially revolutionary two-photon activated PDT to be developed.•Photoindices as high as >150 (per J/cm2) have been reported.
Photodynamic therapy (PDT) exploits light-activated compounds for therapeutic use. It relies on a photosensitiser (PS) that is inactive in the absence of light. When irradiated, the PS absorbs light and is promoted to a higher energy, “excited” state (PS∗), which is either toxic to cells in itself or triggers formation of other species which are toxic to cells, and hence particular wavelengths of light can be used to induce light-dependent cell killing. In PDT occurring via the so-called type I and type II mechanisms, the PS∗ engages in energy transfer to dioxygen present in cells and tissues. This process generates highly reactive singlet oxygen (1O2) and/or other reactive oxygen species (ROS), which in turn cause damage in the immediate vicinity of the irradiation and ultimately can lead to cell death. Whilst the main focus of research for the last 50 years has been on organic molecules or porphyrins as sensitisers, there is now emerging interest in extending the use to transition metal (TM) complexes, which can display intense absorptions in the visible region, and many also possess high two-photon absorption cross-sections, enabling two-photon excitation with NIR light. As with any other type of photosensitiser, the issues to consider whilst designing a TM complex as a photosensitiser include cell permeability, efficient absorption of NIR light for deeper penetration, preferential affinity to cancer cells over healthy cells, targeted intracellular localisation and lack of side effects. This review summarises recent developments involving photosensitisers containing Ru(II), Os(II), Pt, Ir(III), and Re(I) ions, and the approaches used to address the above requirements. Several remarkable recent advances made in this area, including the first clinical trial of a metal complex as a photosensitiser, indicate the bright future of this class of compounds in PDT.
Although oxidation was deemed as the main factor responsible for the instability of MXenes in aqueous colloids, here we put forward and test a hypothesis about the central role of water as the ...primary factor. We show that water and related processes of MXene hydrolysis play the main role in the phenomena leading to complete transformations of 2D titanium carbide MXenes into titania in aqueous environments. To demonstrate the role of water, the stability of two MXenes, Ti3C2T x and Ti2CT x , has been systematically studied in aqueous and nonaqueous colloids exposed to oxygen and inert gas atmospheres. The calculated time constant for degradation of Ti3C2T x dispersed in anhydrous iso-propanol saturated with pure oxygen exceeds 5 years, in striking contrast to the same MXene dispersed in water, where more than a half of it would transform into titania even in an oxygen-less atmosphere over ∼41 days. A thinner Ti2CT x MXene showed similar behavior, albeit with shorter time constants in both solvents, correspondingly. UV–vis and Raman spectroscopy were used to analyze the oxidation kinetics and composition of fresh and aged MXenes. An intense anatase peak was observed in MXenes stored in aqueous solutions under Ar atmosphere, while no signs of oxidation could be found in iso-propanol solutions of the MXenes stored under O2 atmosphere over a similar period of time.
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