Nanohybrid Comprising Gold Nanoparticles – MoS2 Nanosheets for Electrochemical Sensing of Folic Acid in Serum Samples

Folic acid (FA) deficiency is associated with several clinical conditions such as megaloblastic anemia, neuropsychiatric, and pregnancy-related syndromes, this makes FA an important metabolite to be monitored. We have fabricated an electrochemical biosensor based on gold nanoparticles decorated molybdenum disulfide nanosheets (AuNPs−MoS₂NSs) nanocomposite as a transducer matrix for specific and rapid electrochemical detection of FA. Differential pulse voltammetry (DPV) studies displayed a rapid analytical response of the fabricated AuNPs−MoS₂NSs/GCE sensor probe towards FA in a wide concentration range of 0.001–100 μM with a very low detection limit of 0.72±0.03 nM. The selectivity of the fabricated sensor probe has been examined in the presence of interferents such as dopamine, uric acid, ascorbic acid, glucose, and urea. The clinical potential of the fabricated biosensor was established by monitoring FA in human serum samples. The developed AuNPs−MoS₂NSs/GCE sensor probe showed high reproducibility and stability, indicating its promise for FA detection in clinical settings.     

Cation-Promoted Strain-Release-Driven Access to Functionalized Azetidines from Azabicyclo[1.1.0]butanes

Access to 1,3-functionalized azetidines through a diversity-oriented approach is highly sought-after for finding new applications in drug-discovery. To this goal, strain-release-driven functionalization of azabicyclo[1.1.0]-butane (ABB) has generated significant interest. Through appropriate N-activation, C3-substituted ABBs are shown to render tandem N/C3-fucntionalization/rearrangement, furnishing azetidines; although, modalities of such N-activation vis-à-vis N-functionalization remain limited to selected electrophiles. This work showcases a versatile cation-driven activation strategy of ABBs. And capitalizes on the use of Csp³ precursors amenable to forming reactive (aza)oxyallyl cations in situ. Herein, N-activation leads to formation of a congested C−N bond, and effective C3 activation. The concept was extended to formal [3+2] annulations involving (aza)oxyallyl cations and ABBs, leading to bridged bicyclic azetidines. Besides the fundamental appeal of this new activation paradigm, operational simplicity and remarkable diversity should engender its prompt use in synthetic and medicinal chemistry.     

Pyrazine Derivative as Supramolecular Host for Immobilization of Palladium Nanoparticles for Efficient Suzuki Coupling

Palladium nanoparticles (NPs) have been extensively explored as unique catalyst for carbon-carbon coupling reactions. Nonetheless, because of extreme tendency of nanoparticles to undergo agglomeration, the immobilization of these metal NPs on organic frameworks is an important area of research. The present investigation demonstrates the synthesis of pyrazine derivative PYZ - TA as a supramolecular host for holding co-released Pd NPs derived from the original catalyst (Pd(II)) under standard Suzuki coupling. Unprecedent, physical bars are not required to capture Pd NPs within the pores of supramolecular host. The as obtained catalyst PYZ - TA@Pd exhibits high potential to undergo self-assembly in solid as well as in liquid state. The PYZ - TA@Pd ensemble shows high catalytic activity and recyclability (up to seven cycles) in Suzuki-Miyaura coupling reactions using low palladium loading and provides the corresponding products in excellent yields (up to 98 %). Therefore, this study provides an efficient strategy to develop an easy to synthesize palladium centered solid catalyst through coordination between organic host and Pd NPs.