Metal organic frameworks and their composites as effective tools for sensing environmental hazards: An up to date tale of mechanism, current trends and future prospects

Fortification of the environment is domineering in order not to compromise our safety. Therefore, developing advanced detection methods and effective sensory materials is required to detect toxic substances. Coordination chemistry has always been the tool for understanding the material perspective of metal-organic chemistry. The metal-organic chemistry has evolved due to its stability and non-destructive properties. Metal-organic Frameworks (MOFs), also known as inorganic-organic hybrid materials, are of great interest to scientists due to their functional tunability and prompted by their various potential applications. In the last few decades, MOFs are emerging as fluorescent sensor materials owning to the presence of well-defined chromophores in the crystalline environment. In this review article, the current trend of metal-organic frameworks, their chemical nature, their structural tunability, and sensing of hazardous substances related to tuning the MOF structure are discussed in detail. The nitro aromatic compounds are the main constituent of explosives, and their detection is very important for homeland security. Similarly, hazardous metal ions and anions are dangerous to human life and other living organisms. Thus, detecting these substances is a challenging task for any inorganic-material chemist. Therefore, this review article deals with various MOF materials, their stability and composite and how they have been tuned for functional application, specifically in the fluorescence sensing method. This comprehensive review has elaborated on various classical examples of detecting these NACs, metal cations and anions using the fluorescence sensing method. Detailed composite material detecting the poisonous substance from water and other organic solvent has also been discussed. The review also suggests various mechanisms associated with sensing these dangerous substances using MOF and MOF-based composite. The tuning of MOF into other materials improves its sensing ability, durability, and recyclability. Thus, this article will benefit the researchers working in inorganic materials and inspire them to explore the metal-organic chemistry for better sensitive and selective detection of various fatal substances for a better surrounding in future actions.