Search

Metal–organic frameworks (MOFs) have emerged as ideal multifunctional platforms for renewable hydrogen (H2) energy applications owing to their tunable chemical compositions and structures and high porosity. Their advanced component species and porous structure contribute greatly to the enhanced activity, electrical conductivity, photo response, charge‐hole separation efficiency, and structural stability of MOF materials, which are promising for practical H2 economy. In this review, we mainly introduce design strategies for the enhancement of electro‐/photochemical behaviors or adsorption performance of porous MOF materials for H2 production, storage, and utilization from compositional perspective. Following these engineering strategies, the correlation between composition and property‐structure‐performance of pristine MOFs and their composite with advanced components is illustrated. Finally, challenges and directions of future development of related MOFs and MOF composites for H2 economy are provided. [ABSTRACT FROM AUTHOR]

Syntheses and characterization of mono- (1) and binuclear (2) heteroleptic Ni(II) complexes having redox active dipyrrins ligands have been described and their electrochemical hydrogen generation ability explored. Molecular structures of the complexes have been authenticated by X-ray-single crystal analyses. The electrocatalytic properties and stability of the complexes toward hydrogen evolution reactions have been investigated by cyclic voltammetric and bulk electrolysis studies at a fixed potential (−1.8 V) in an organic medium in presence of the acetic acid as a weak proton source. The probable mechanism of the electrocatalytic proton reduction reaction has also been supported by theoretical studies. [Display omitted] • The design of two new homogenous molecular catalysts for proton reduction reaction based on dipyrrin ligands. • The stability and H 2 production capability of these complexes has also been investigated by bulk electrolysis study. • We have also supported the tentative mechanism of proton reduction based on theoretical calculation. The effect of nuclearity on electrochemical hydrogen generation using new heteroleptic Ni(II) complexes containing redox-active dipyrrin and dithiocarbamate ligands has been described. Complexes 1 – 2 have been meticulously characterized by spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV–vis) and their structures unambiguously confirmed by X-ray single crystal analyses. Electrocatalytic properties of the complexes toward hydrogen evolution reaction have been investigated by cyclic voltammetric studies in an organic medium in the presence of acetic acid as a weak proton source. Notably, complexes 1 and 2 produce H 2 via doubly reduced Ni(II) species i.e. Ni(0) in the presence of acetic acid. Further, these complexes exhibited significant electrocatalytic activity (TOF: 264 (1) and 650 s−1 (2). Controlled potential electrolysis established a minimum Faradaic efficiency of 92 (1) and 96 % (2). Complex 2 exhibited higher turnover frequency relative to 1 , while 1 showed lower overpotential (0.35 V) in comparison to 2 (0.45 V). The stability of the complexes and the amount of produced H 2 has been investigated by bulk electrolysis study. A tentative mechanism (ECEC; E, electrons and C, chemical steps) and involved intermediate species for the proton reduction reaction for 1 has been established by theoretical studies. [ABSTRACT FROM AUTHOR]

Synthesis of an entirely new series of arene ruthenium complexes [Ru(η6-C6H6)(L1)Cl]PF6, (1), [Ru(η6-C10H14)(L1)Cl]PF6 (2), [Ru(η6-C6H6)(L2)Cl]PF6 (3) and [Ru(η6-C10H14)(L2)Cl]PF6 (4) involving 5-[2-(1H-pyrazol-1-yl)quinoline]-BODIPY (L1) and 5-[6-methoxy-2-(1H-pyrazol-1-yl)quinoline]-BODIPY (L2) was described. The ligands and complexes were thoroughly characterized by various physicochemical techniques and the structures of L1, 1 and 4 were determined by X-ray single crystal analyses. Photo-/ and electrochemical property, DNA binding, cytotoxicity, cellular uptake and apoptotic studies on 1–4 were performed by various methods, while singlet oxygen-mediated cytotoxicity via photo-irradiation by visible light was supported by 1,3-diphenylisobenzofuran titration studies. Binding of the complexes in the minor groove of CT-DNA via van der Waals forces and electrostatic interactions was affirmed by molecular docking studies. In vitro antiproliferative activity and photocytotoxicity of 1–4 were examined against the human cervical cancer cell line (HeLa) which clearly showed that these are extremely photocytotoxic under visible light (400–700 nm, 10 J cm−2; IC50 49.15, 1; 25.18, 2; 15.85, 3; 12.87, 4), less toxic in the dark (IC50 ＞ 100 μM) and preferentially accumulate in the lysosome of the HeLa cells. Further, these complexes behave as a potential theranostic agent and their ability to kill cancer cells under visible light lies in the order 4 ＞ 3 ＞ 2 ＞ 1. [ABSTRACT FROM AUTHOR]

Fluorescent azo-phenol BODIPYs (1–3) have been obtained by the substituent (–OCH3/–CH3) directed synthesis of ortho (L1) and para (L2–L3) azo-phenol aldehydes. These display aggregation caused quenching (ACQ, 1) and aggregation induced emission enhancement (AIEE, 2 and 3) depending on the position of azo relative to the phenolic hydroxyl group. An intriguing time dependent morphological transition from nanospheres to ordered nanorods and subsequent emission changes in AIEE active azo-phenol BODIPYs have been successfully realized by time dependent fluorescence, scanning electron (SEM), transmission electron (TEM) and fluorescence optical microscopy (FOM) studies. The existence of one-dimensional (1D) nanorods as ultimate species in these compounds (2–3) has been supported by crystal packing patterns. Diverse aggregated forms and hierarchical nanostructures have been related to variable extents of fluorescence enhancement. The plausible charge transfer process and its role in AIEE have been supported by DFT studies. [ABSTRACT FROM AUTHOR]

A series of copper(ii) complexes (1–9 and 3′) derived from bis-dipyrrin ligands (L1–L9 and L3′) with diverse spacer lengths [–(CH2)n–] have been described. Structural diversities in these complexes have been explicitly established by spectral and structural studies on these and a closely related nickel(ii) complex (3′′). All the ligands and complexes have been thoroughly characterized by spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV/vis) and structures of 2, 3′, 3′′, 6, 8 and 9 were determined by X-ray single crystal analyses. It has been unambiguously established that ligands with n≤ 6 gave heteroleptic binuclear (1–5), while those with n≥ 7 yielded homoleptic mononuclear (6–9) bis-dipyrrinato complexes. Spectral and structural studies revealed distorted square planar (1–5) and distorted tetrahedral geometries (6–9) about the copper(ii) centre in these complexes which has further been evidenced by EPR and electrochemical studies. Structural differences based on the odd and even number of methylene spacers in these complexes have been supported by DFT studies. A line between the syn- and anti-conformations of the complexes has been drawn on the basis of a limiting spacer length. [ABSTRACT FROM AUTHOR]

Synthesis of four new arene ruthenium(II) complexes [(η 6 -C 10 H 14 )RuCl(MFPdpm)] ( 1 ); [(η 6 -C 12 H 18 )Ru-Cl(MFPdpm)] ( 2 ); [(η 6 -C 10 H 14 )RuCl(PFPdpm)] ( 3 ) and [(η 6 -C 12 H 18 )RuCl(PFPdpm)] ( 4 ) containing dipyrrin ligands 5-(4-fluoro)phenyldipyrromethene (MFPdpm) and 5-(penta-fluoro)phenyldipyrromethene (PFPdpm) have been described. The ligands and complexes have been thoroughly characterized by elemental analyses, spectroscopic studies (ESI-MS, IR, 1 H, 13 C NMR, UV–Vis) and structure of the representative complex 4 determined by X-ray single crystal analyses. DNA binding activities of 1 – 4 have been investigated by UV–Vis and fluorescence spectroscopy and their binding through the minor groove of DNA has been established by molecular docking studies. The complexes 1 – 4 exhibit significant cytotoxicity toward human lung cancer cell line (A549). Cytotoxicity, morphological changes, and apoptosis studies have been evaluated through MTT assay, Hoechst 33342/PI staining, and cell cycle analysis by fluorescence activated cell sorting (FACS). In vitro antitumor activity and cytotoxicity of the complexes lie in the order 4 > 3 > 2 > 1 . [ABSTRACT FROM AUTHOR]

Efficacy of the ferrocene appended piano-stool dipyrrinato complexes [(η6-C6H6)RuCl(fcdpm)] (1), [(η6-C10H14)RuCl(fcdpm)] (2), [(η6-C12H18)RuCl(fcdpm)] (3) [(η5-C5Me5)RhCl(fcdpm)] (4) and [(η5-C5Me5)IrCl(fcdpm)] (5) [fcdpm = 5-ferrocenyldipyrromethene] toward anticancer activity have been described. Binding of the complexes with calf thymus DNA (CT-DNA) and BSA (bovine serum albumin) have been thoroughly investigated by UV-Vis and fluorescence spectroscopy. Binding constants for 1-5 (range, 104-105 M-1) validated their efficient binding with CT-DNA. Molecular docking studies revealed interaction through minor groove of the DNA, on the other hand these also interact through hydrophobic residues of the protein, particularly cavity in the subdomain IIA. In vitro anticancer activity have been scrutinized by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder (fragmentation) assay against Dalton's Lymphoma (DL) cells. Present study revealed that rhodium complex (4) is more effective relative to ruthenium (1-3) and iridium (5) complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Three push-pull type terpyridine ligands (L1 – L3) based Zn(II) complexes (C1 – C3) have been synthesized and their photophysical properties thoroughly examined. The role of substituents (–H, C1 ; –CH3, C2 and –OCH3, C3) and solvent on photophysical behaviour and morphology of aggregate (C3) have been established with the help of various spectroscopic studies (UV/Vis, fluorescence and SEM). Abstract Synthesis of the terpyridine based novel Zn(II) complexes (C1 – C3) have been described. Characterization of these complexes has been achieved by spectroscopic studies (IR, 1H, 13C, 19F, HRMS, UV/Vis and fluorescence) and structure of C1 determined by X-ray single crystal analyses. Cautious tuning by incorporating appropriate substituents (–H; C1 , –CH 3 ; C2 and –OCH 3 ; C3) enabled the complexes to exhibit solvent dependent emission indicative of more polarized excited state probably due to enhanced intramolecular charge transfer (ICT). Occurrence of aggregation induced emission (AIE) in C3 has been validated by solid state emission and vital role of RIR in inducing AIE upon aggregation by fluorescence lifetime experiments. The role of solvent and substituents on photophysical behaviour and morphology of the complexes has been investigated by UV/Vis, emission and scanning electron microscopy (SEM). As well, lowering of the energy gap between HOMO and LUMO by electron donating substituents –CH 3 (C2) and –OCH 3 (C3) has been supported by DFT studies. [ABSTRACT FROM AUTHOR]

Synthesis of terpyridyl based ligands 3-([2,2′:6′,2′′-terpyridin]-4′-yl)-7-methoxy-2-(methylthio)-quinolone, (L1); 3-([2,2′:6′,2′′-terpyridin]-4′-yl)-6-methoxyquinolin-2(1H)-one, (L2); 3-([2,2′-:6′,2′′-terpyridin]-4′-yl)-6-methylquinolin-2(1H)-one (L3) and cyclometalated iridium(iii) complexes [[Ir(ppy)2L1]+PF6− (1), [Ir(ppy)2L2]+PF6− (2), [Ir(ppy)2L3]+PF6− (3) (2-phenylpyridine = Hppy)] involving these ligands has been described. The ligands L1–L3 and complexes 1–3 have been thoroughly characterized by elemental analyses, spectral studies (IR, 1H, 13C NMR, UV/vis and fluorescence) ESI-MS, and the structure of 3 has been unambiguously authenticated by single crystal X-ray analyses. UV/vis, fluorescence and circular dichroism spectroscopic studies showed rather efficient binding of 1 with CT-DNA (calf thymus DNA) and BSA (bovine serum albumin) relative to 2 and 3. Molecular docking studies unveiled binding of 1–3 with minor groove of CT-DNA via van der Waal's forces and electrostatically with the hydrophobic moiety of HSA (human serum albumin). The ligands and complexes exhibited moderate cytotoxicity towards MDA-MB-231 (breast cancer cell line) and significant influence on HeLa (cervical cancer cell line) cells. Cytotoxicity, morphological changes, and apoptosis have been followed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide) assay, Hoechst 33342/PI (PI = propidium iodide) staining, cell cycle analysis by FACS (fluorescence activated cell sorting), and ROS (reactive oxygen species) generation by DCFH-DA (dichlorodihydrofluorescein diacetate) dye. Confocal microscopy images revealed that the drug efficiently initiates apoptosis in the cell cytosol. The IC50 values showed superior cytotoxicity of 1–3 against the HeLa cell line relative to cisplatin, and their ability to induce apoptosis is in the order 1 ＞ 2 ＞ 3. [ABSTRACT FROM AUTHOR]

Synthesis of 2-chloro-3-(di(1H-pyrrol-2-yl)methyl)quinoline (L) and their Ru(II) complexes (R1-R2) have been described. Characterization of the ligands and complexes have been achieved by spectral studies (IR, 1H, 13C, ESI–MS, electronic absorption,) and crystal structures of R1 determined crystallographically. Interaction of the complexes with calf thymus DNA (CT DNA) has been supported by absorption titration studies and ethidium bromide experiments. [Display omitted] • Ru(II)-arene complexes. • DNA/protein interactions. • Anticancer activity. • DFT calculations. Arene ruthenium complexes [(η 6–arene)Ru(L)Cl] (η 6–arene = benzene, R1 ; p -cymene, R2) containing the chelating ligand (2–chloro–3–(di(1H–pyrrol–2–yl)methyl)quinoline) (L) have been synthesized and carefully characterized by various studies (1H and 13C NMR, IR, ESI–MS, UV–vis). The structure of R1 has been verified by X-ray single crystal analyses. Binding of the complexes with calf thymus DNA (CT–DNA) has been investigated by absorption titration, ethidium bromide (EB) displacement and viscosity measurements. Experimental binding constants (5.1 × 104 M−1, R1 ; 5.7 × 104 M−1, R2) suggested appreciable bonding of the complexes with CT–DNA. Fluorescence, synchronous and 3D fluorescence spectroscopic studies showed that complexes strongly bind with bovine serum albumin. Intercalative interaction of the complexes with DNA has been further supported by DFT studies. Our studies have shown potential anticancer activity of both the complexes R1 and R2 against T cell lymphoma. Among these complexes R2 showed better anticancer activity relative to R1 (IC 50 , R1, 30 μM and R2, 20 μM). [ABSTRACT FROM AUTHOR]

Four organometallic complexes [(η6-C6H6)RuCl(pmpzdpm)], 1; [(η6-C6H6)RuCl(pypzdpm)], 2; [(η6-C10H14)RuCl(pmpzdpm)], 3 and [(η6-C10H14)RuCl(pypzdpm)], 4 containing 5-(2-pyrimidyl-piperazine)phenyldipyrromethene (pmpzdpm) and 5-(2-pyridylpiperazine)phenyldipyrromethene (pypzdpm) have been designed and synthesized. The complexes 1–4 have been fully characterized by elemental analyses and spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV–vis). Their electrostatic/intercalative interaction with CT DNA has been investigated by UV–vis and competitive ethidium bromide displacement studies while their protein binding affinity toward bovine serum albumin (BSA) was realized by UV–vis, fluorescence, synchronous and three dimensional (3D) fluorescence studies. The interaction with DNA and protein has further been validated by in silico studies. Cellular uptake, in vitro cytotoxicity and flow cytometric analyses have been performed to determine the mode of cell death against the kidney cancer cell line ACHN. Cell cycle analysis suggested that the complexes cause cell cycle arrest in the subG1 phase and overall results indicated that the in vitro antitumor activity of 1–4 lies in the order of 3 ＞ 4 ＞ 1 ＞ 2 (IC50, 7.0 1; 8.0 2; 2.0 3; 4.0 μM, 4). [ABSTRACT FROM AUTHOR]

With intent to fine tune the morphological and photophysical properties, three novel AIE luminogens (BQ1–BQ3) based on quinoline–BODIPY have been synthesized. A judicious choice of substituents (–H, –CH3, –OCH3) in these systems led to nanoballs in BQ1 and BQ2, while in BQ3 it led to reticulated nanofibers with diverse photophysical behaviours. [ABSTRACT FROM AUTHOR]

An expeditious synthesis of new click reaction-based BODIPY–piperazine conjugates separated by alkyl spacers (4–7) has been described. The compounds under investigation have been thoroughly characterized by various physicochemical techniques viz., elemental analyses, IR, HRMS, NMR (1H, 13C, 11B and 19F), electronic absorption, emission and theoretical studies. The comparative sensing abilities of 4–7 toward a range of metal ions have been investigated by various methods. Among these compounds, only 7 exhibited appreciable selectivity towards Hg2+, while the others remained inactive in the presence of various metal ions. Binding constant and Job's plot analysis indicated 1 : 1 stoichiometry between 7 and Hg2+. HRMS data and theoretical studies undoubtedly indicated the formation of a 7·Hg2+ complex and interaction of Hg2+ with the probe via nitrogen atoms in the piperazine and triazole units. [ABSTRACT FROM AUTHOR]

Synthesis, characterization, DNA and protein binding as well as anticancer activity of the organometallic complexes [(η 6 -C 6 H 6 )RuCl(APBI)]Cl ( 1 ), [(η 6 - p -MeC 6 H 4 Pr i )RuCl(APBI)]Cl ( 2 ), [(η 6 -C 6 Me 6 )RuCl(APBI)]Cl ( 3 ), [(η 5 -C 5 Me 5 )RhCl(APBI)]Cl·H 2 O ( 4 ) and [(η 5 -C 5 Me 5 )IrCl(APBI)]Cl·H 2 O ( 5 ) containing 2-aminophenyl benzimidazole (APBI) have been described. The complexes 1 – 5 exhibited strong DNA, protein binding and anticancer activity against cervical cancer (SiHa) cell line. Their binding with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) have been examined by absorption and emission spectral studies. Strong interactions between complexes and CT-DNA have been affirmed by absorption spectral and EthBr displacement studies, while interaction with BSA via static quenching explored by fluorescence titration, synchronous and 3D fluorescence spectroscopy. The interactions between 1 – 5 and DNA has also been scrutinized by 1 H NMR spectral studies using guanosine as a model for DNA. These results have been supported by DFT calculations and molecular docking studies. Cytotoxicity, apoptosis and in vitro anticancer activity of 1 – 5 toward SiHa cell line have been investigated by MTT assay and acridine (AO)/ethidium bromide (EthBr) fluorescence staining. Overall results revealed that DNA and protein binding, as well as anticancer activity of 1 – 5 follows the order as 5 > 3 > 2 > 1 > 4 . [ABSTRACT FROM AUTHOR]