Inter‐Network Charge‐Transfer Excited State Formation Within a Two‐fold Catenated Metal–Organic Framework

Abstract

Charge‐transfer excited state (CTES) defines the ability to split photon energy into work producing redox equivalents suitable for photocatalysis. Here, we report inter‐net CTES formation within a two‐fold catenated crystalline metal–organic framework (MOF), constructed with two linkers, N,N′‐di(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide (DPNDI) and 2,6‐dicarboxynaphthalene (NDC). The structural flexibility puts two complementary linkers from two nets in a proximal position to interact strongly. Supported by the electrochemical and steady‐state electronic spectroscopic data, this ground‐state interaction facilitates forming CTES that can be populated by direct excitation. We map the dynamics of the CTES which persists over a few nanoseconds and highlight the utilities of such relatively long‐lived CTES as enhanced conductivity of the MOF under light over that measured in dark and as a proof‐of‐the‐principle test, photo‐reduction of methyl viologen under white light.

Antibactericidal Ir(III) and Ru(II) Complexes with Phosphine‐Alkaloid Conjugate and Their Interactions with Biomolecules: A Case of N‐Methylphenethylamine

“…The authors have cited additional references within the Supporting Information [81–102] . In the ESI the Figures S1–S19 and Tables S1 and S2 – NMR; Figures S20–S31 – ESI(+)MS; Figures S32‐.S34 – TGA; Figures S35‐S38 – absorption and luminescence; Figures S41–S43 and Table S3 – hydrolysis studies; Figures S39, S40, S44–S47 and Tables S4–S7 – DFT calculations; Figures S48–S51 – CV; Figures S52–S55 – interactions with NADH; Figures S56–S67 – interactions with Asc; Figures S68–S75 – interactions with GSH; Figures S76–S81 – interactions with the mixture of NADH, Asc and GSH; Figures S82–S88 – interactions with DNA have been included.…”

Inter-network charge-transfer excited state formation in a catenated metal–organic framework

“…Here, we show the inter-network CTES with a cobalt-based pillarpaddlewheel network consisted of electron-rich naphthalene dicarboxylic acid (NDC) and N, N′-di(4-pyridyl)-1,4,5,8naphthalenetetracarboxydiimide (DPNDI). [6] Within the two-fold intercatenated MOF, we show that one of four possible NDC/DPNDI pairs is in the proximity to exert a strongly coupled system displaying a solvent-dependent, low-energy linker-to-linker charge transfer (LLCT) transition (Figure 1). The 'excess' NDC linkers (those that are not so much coupled with the DPNDI) display a sort of light-harvesting behavior as exciting these NDC linkers in MOF showed a quenched emission quantum yield and shortened lifetime by transferring its energy to the low energy LLCT state.…”

Highly Robust Metal–Organic Framework for Efficiently Catalyzing Knoevenagel Condensation and the Strecker Reaction under Solvent-Free Conditions

“…Among the solid catalysts, the employment of heterogeneous catalysts is more advantageous than the homogeneous catalysts due to having several superiorities such as (i) easier catalyst recovery by filtration from reaction mixtures , (ii) reusable for consecutive runs , and (iii) their excellent adaptability to continuous flow processes . , However, to obtain the maximum efficiency of heterogeneous catalysts, a high surface area is required for more favorable interactions between the active sites of employed insoluble solids and the substrates and reagents. In this regard, metal–organic frameworks (MOFs) are the superior candidate over other solid catalysts, as they possess distinct superior qualities such as a high surface area with well-defined porosity − and innumerable structural diversity with suitable framework tunability. − MOFs exhibit superior catalytic activity due to the presence of several active sites such as (i) open metal sites (OMSs) , (ii) structural defect formations , (iii) bared functional groups’ presence of the employed organic linkers, and so on . Moreover, the synthesis flexibility and various binding modes of the metal centers (which often generate OMSs by mild activation) made MOFs promising candidates for heterogeneous catalysis.…”