Fixation of carbon dioxide to aryl/aromatic carboxylic acids

Visible-light-driven photocatalytic carboxylation to aromatic carboxylic acids with CO2

(Hetero)aromatic carboxylic acids and their derivatives attract attention due to their role in the synthesis of several biologically active molecules, active pharmaceutical ingredients, polymers, etc. Carbon dioxide (CO2) is a prime C1 source for the synthesis of aromatic carboxylic acids because of its nontoxicity, nonflammability, abundance and renewability. Owing to the thermodynamic and chemical inertness of CO2, traditional carboxylation to aromatic carboxylic acids with CO2 is always performed under harsh reaction conditions or using stoichiometric metallic reductants. Visible-light-driven carboxylation with CO2 provides an environmentally benign, mild, and high-efficiency route for the production of aromatic carboxylic acids. This review comprehensively introduces the visible-light-driven preparation of aromatic carboxylic acids through a visible-light-driven oxidative addition and reductive elimination mechanism, binding of aryl (radical) anions which are produced by photoinduced electron transfer (PET) to CO2, binding of carbon dioxide anion radicals (CO2˙-) which are formed by PET to aryl compounds, radical coupling between CO2˙- and aryl radicals, and other mechanisms. Finally, this review provides a summary and the future work direction. This article offers a theoretical guidance for efficient synthesis of aromatic carboxylic acids via photocatalysis.

Pairing Electrocarboxylation of Unsaturated Bonds with Oxidative Transformation of Alcohol and Amine

A parallel paired electrosynthetic method, coupling electrocarboxylation incorporating CO2 into ketone, imine, and alkene with alcohol oxidation or oxidative cyanation of amine, was developed for the first time. Various carboxylic acids as well as aldehyde/ketone or α-nitrile amine were prepared at the cathode and anode respectively in a divided cell. Its utility and merits on simultaneously achieving high atom-economic CO2 utilization, elevated faradaic efficiency (FE, total FE of up to 166 %), and broad substrate scope were demonstrated. The preparation of pharmaceutical intermediates for Naproxen and Ibuprofen via this approach proved its potential application in green organic electrosynthesis.

Thermocatalytic Conversion of CO2 to Valuable Products Activated by Noble-Metal-Free Metal-Organic Frameworks

Thermocatalysis of CO2 into high valuable products is an efficient and green method for mitigating global warming and other environmental problems, of which Noble-metal-free metal-organic frameworks (MOFs) are one of the most promising heterogeneous catalysts for CO2 thermocatalysis, and many excellent researches have been published. Hence, this review focuses on the valuable products obtained from various CO2 conversion reactions catalyzed by noble-metal-free MOFs, such as cyclic carbonates, oxazolidinones, carboxylic acids, N-phenylformamide, methanol, ethanol, and methane. We classified these published references according to the types of products, and analyzed the methods for improving the catalytic efficiency of MOFs in CO2 reaction. The advantages of using noble-metal-free MOF catalysts for CO2 conversion were also discussed along the text. This review concludes with future perspectives on the challenges to be addressed and potential research directions. We believe that this review will be helpful to readers and attract more scientists to join the topic of CO2 conversion.

Engineering of metal-organic frameworks (MOFs) for thermometry

Metal-organic frameworks (MOFs ) are excellent candidates for use in chemistry, material sciences and engineering thanks to their interesting qualitative features and potential applications. Quite interestingly, the luminescence of MOFs can be engineered by regulation of the ligand design, metal ion selection and encapsulation of guest molecules within the MOF cavity. Temperature is a very crucial physical parameter and the market share of temperature sensors is rapidly expanding with technology and medicinal advancement. Among the wide variety of available temperature sensors, recently MOFs have emerged as potential temperature sensors with the capacity to precisely measure the temperature. Lanthanide-based thermometry has advantages because of its ratiometric response ability, high quantum yield and photostability, and therefore lanthanide-based MOFs were initially focused on to construct MOF thermometers. As science and technology have gradually changed, it has been observed that with the inclusion of dye, quantum dots, etc. within the MOF cavity, it is possible to develop MOF-based thermometry. This review consolidates the recent advances of MOF-based ratiometric thermometers and their mechanism of energy transfer for determining the temperature (thermal sensitivity and temperature uncertainty). In addition, some fundamental points are also discussed, such as concepts for guiding the design of MOF ratiometric thermometers, thermometric performance and tuning the properties of MOF thermometers.

Highly Luminescent MOF and Its In Situ Fabricated Sustainable Corn Starch Gel Composite as a Fluoro-Switchable Reversible Sensor Triggered by Antibiotics and Oxo-Anions

Frequent use of antibiotics and the growth of industry lead to the pollution of several natural resources which is one of the major consequences for fatality to human health. Exploration of smart sensing materials is highly anticipated for ultrasensitive detection of those hazardous organics. The robust porous hydrogen bonded network encompassing a free-NH₂ moiety, Zn(II)-based metal-organic framework (MOF) (1), is used for the selective detection of antibiotics and toxic oxo-anions at the ppb level. The framework is able to detect the electronically dissimilar antibiotic sulfadiazine and nitrofurazone via fluorescence "turn-on" and "turn-off" processes, respectively. The antibiotic-triggered reversible fluoro-switching phenomena (fluorescence "on-off-on") are also observed by using the fluorimetric method. An extensive theoretical investigation was performed to establish the fluoro-switching response of 1, triggered by a class of antibiotics and also the sensing of oxo-anions. This investigation reveals that the interchange of the HOMO-LUMO energy levels of fluorophore and analytes is responsible for such a fluoro-switchable sensing activity. Sensor 1 showed the versatile detection ability which is reflected by the detection of a carcinogenic nitro-group-containing drug "roxarsone". In view of the sustainable environment along with quick-responsive merit of 1, an in situ MOF gel composite (1@CS; CS = corn starch) is prepared using 1 and CS due to its useful potential features such as biocompatibility, toxicologically innocuous, good flexibility, and low commercial price. The MOF composite exhibited visual detection of the above analytes as well as antibiotic-triggered reversible fluoro-switchable colorimetric "on-off-on" response. Therefore, 1@CS represents a promising smart sensing material for monitoring of the antibiotics and oxo-anions, particularly appropriate for the real-field analysis of carcinogenic drug molecule "roxarsone" in food specimens.

Recent advancements in visible-light-driven carboxylation with carbon dioxide

Carbon dioxide as a classic C1 source has long been investigated in organic synthetic chemistry. Diverse catalytic methods for CO2 activation were reported in the past several decades. In this...

Challenges and recent advancements in the transformation of CO2 into carboxylic acids: straightforward assembly with homogeneous 3d metals

Transformation of carbon dioxide (CO2) into valuable organic carboxylic acids is essential for maintaining sustainability. In this review, such CO2 thermo-, photo- and electrochemical transformations under 3d-transition metal catalysis are described from 2017 until 2022.