Polymeric copper(ii) and dimeric oxovanadium(v) complexes of amide-imine conjugate: bilirubin recognition and green catalysis.

An exceptionally simple amide-imine conjugate, ()-'-(4-(diethylamino)-2-hydroxybenzylidene)-4-methylbenzohydrazide (L), derived by the condensation of 4-methyl-benzoic acid hydrazide (PTA) with 4-(diethylamino)-2-hydroxybenzaldehyde was utilized to prepare a dimeric oxo-vanadium (V1) and a one-dimensional (1D) copper(ii) coordination polymer (C1). The structures of L, V1 and C1 were confirmed by single crystal X-ray diffraction analysis. The experimental results indicate that V1 is a promising green catalyst for the oxidation of sulfide, whereas C1 has potential for a C-S cross-coupling reaction in a greener way.

Mo(vi) complexes of amide-imine conjugates for tuning the selectivity of fluorescence recognition of Y(iii) Pb(ii).

Two amide-imine conjugates, 3-methyl-benzoic acid (4-diethylamino-2-hydroxy-benzylidene)-hydrazide (L1) and 3-methyl-benzoic acid (2-hydroxy-naphthalen-1-ylmethylene)-hydrazide (L2), have been prepared and used for a further synthesis of Mo(vi) complexes (M1 and M2, respectively). Single crystal X-ray diffraction analysis confirmed their structures. Interestingly, M1 selectively recognizes Y and Pb at two different wavelengths, whereas M2 selectively interacts with Y with a significantly high binding constant, 1.

One pot tandem dehydrogenative cross-coupling of primary and secondary alcohols by ruthenium amido-functionalized 1,2,4-triazole derived N-heterocyclic carbene complexes.

One-pot tandem dehydrogenative cross-coupling of primary and secondary alcohols was catalyzed by three ruthenium complexes [1-()-4--(furan-2-ylmethyl)acetamido-1,2,4-triazol-5-ylidene]Ru(-cymene)Cl [R = Et (1b), i-Pr (2b), Bn (3b)], of amido-functionalized 1,2,4-triazole derived N-heterocyclic carbene (NHC) ligands. Density Functional Theory (DFT) calculations were employed for the ruthenium (1b) precatalyst to understand this reaction mechanism completely, and the mechanisms adapted are divided categorically into three steps (i) nucleophilic substitution of chloride ions by alcohols, (ii) dehydrogenation of primary and secondary alcohols, and (iii) olefin and ketone hydrogenation. Our mechanistic study reveals that the formation of a deprotonated Ru-alcoholate (A) or (E) intermediate is favorable compared to the protonated form (A') or (E') from (1b) by associative nucleophilic substitution.

One pot tandem dual CC and CO bond reductions in the β-alkylation of secondary alcohols with primary alcohols by ruthenium complexes of amido and picolyl functionalized N-heterocyclic carbenes.

Two different classes of ruthenium complexes, namely, [1-mesityl-3-(2,6-Me-phenylacetamido)-imidazol-2-ylidene]Ru(-cymene)Cl (1c) and {[1-(pyridin-2-ylmethyl)-3-(2,6-Me-phenyl)-imidazol-2-ylidene]Ru(-cymene)Cl}Cl (2c), successfully catalyzed the one-pot tandem alcohol-alcohol coupling reactions of a variety of secondary and primary alcohols, in moderate to good yields of . 63-89%. The mechanistic investigation performed on two representative catalytic substrates, 1-phenylethanol and benzyl alcohol using the neutral ruthenium (1c) complex showed that the catalysis proceeded a partially reduced CC hydrogenated carbonyl species, [PhCOCHCHPh] (3'), to the fully reduced CO and CC hydrogenated secondary alcohol, [PhCH(OH)CHCHPh] (3).

Exploring a new dinuclear Fe(iii) complex for the fixation of atmospheric CO and optical recognition of nano-molar levels of Zn ions.

A dinuclear Fe(iii) complex (F1) of an imine derivative (L1) derived from 3-ethoxy-2-hydroxy-benzaldehyde and hydrazine, structurally characterised single crystal X-ray studies, is employed for the catalytic conversion of epoxides to cyclic carbonates utilizing carbon dioxide. In addition, F1 is employed for the selective optical recognition of nano-molar levels of Zn (42.23 nM) a metal displacement approach.

A polynuclear Cu(ii) complex for real time monitoring of mitochondrial cytochrome C release during cellular apoptosis.

A new amide-imine conjugate, 2-hydroxybenzoic acid-(2-hydroxybenzylidene)-hydrazide (L), is employed to prepare a single crystal X-ray structurally characterized poly-nuclear Cu(ii) complex (M1). M1 selectively and spatially interacts with cytochrome C (Cyt C) to allow fluorescence imaging of intracellular translocation events in living cells. Thus, direct visualization of a Cyt C translocation event during an apoptotic process is achieved for the first time.

Oxovanadium(V) and Dioxomolybdenum(VI) Complexes of Amide-Imine Conjugates: Structures, Catalytic and Antitumor Activities.

Three new amide-imine conjugates, namely [(E)-2-hydroxy-'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide] (SALNP), [(E)-'-(4-(diethylamino)-2-hydroxybenzylidene)-2-hydroxybenzohydrazide] (SALSD), and [(E)-'-(3-ethoxy-4-hydroxybenzylidene)-2-hydroxybenzohydrazide] (SALVN), derived by reacting 2-hydroxybenzohydrazide (SAL) with three different aldehyde, 2-hydroxynapthaldehyde, 4-(diethylamino)-2-hydroxybenzaldehyde, and 3-ethoxy-4-hydroxybenzaldehyde, respectively. Three mononuclear oxovanadium(V) and two μ-bridged dinuclear molybdenum(VI) complexes have been synthesized using SALNP and SALSD. Besides, SALVN is used to prepare oxovanadium(V) and dioxomolybdenum(VI) complexes.

Sequential Fluorescence Recognition of Molybdenum(VI), Arsenite, and Phosphate Ions in a Ratiometric Manner: A Facile Approach for Discrimination of AsO and HPO.

An amide-based smart probe (L) is explored for nanomolar detection of Mo(VI) ion in a ratiometric manner, involving hydrogen-bond-assisted chelation-enhanced fluorescence process through inhibition of photoinduced electron transfer process. The recognition of Mo(VI) is associated with a 17-fold fluorescence enhancement and confirmed by single-crystal X-ray diffraction of the resulting Mo(VI) complex (M1). Further, M1 selectively recognizes arsenite through green emission of their adduct (C1) with an 81-fold fluorescence enhancement.

Metal-Ion Displacement Approach for Optical Recognition of Thorium: Application of a Molybdenum(VI) Complex for Nanomolar Determination and Enrichment of Th(IV).

An azine-based molybdenum (Mo(VI)) complex (M1) is exploited for selective detection of thorium (Th(IV)) ions through a metal-ion displacement protocol. Th(IV) displaces Mo(VI) from M1 instantly leading to the formation of the Th(IV) complex, having orange-red emission. Consequently, a red shift of the emission wavelength along with 41-fold fluorescence enhancement is observed.

Exploring Anticancer and (Bio)catalytic Activities of New Oxovanadium(V), Dioxomolybdenum(VI), and Copper(II) Complexes of Amide-Imine Conjugates.

An amide-imine conjugate, ()-'-((2-hydroxynaphthalen-1-yl) methylene)-4-methylbenzohydrazide (PTANAP), derived from 4-methyl-benzoic acid hydrazide (PTA) and 2-hydroxynapthaldehyde, is explored to prepare dinuclear oxovanadium(V), mononuclear dioxomolydenum(VI), and Cu(II) complexes. Single crystal X-ray structurally characterized complexes have been exploited as catalyst for oxidation of ethylbenzene, catechol, and -aminophenol. The anticancer properties of the oxo-vanadium complex have been explored against human leukemia cell (K-562) and mouse lymphoma cells (2PK3).

Exploring aggregation-induced emission through tuning of ligand structure for picomolar detection of pyrene.

Tuning of ligand structures through controlled variation of ring number in fused-ring aromatic moiety appended to antipyrine allows detection of 7.8 × 10  M pyrene via aggregation-induced emission (AIE) associated with 101-fold fluorescence enhancement. In one case, antipyrine unit is replaced by pyridine to derive bis-methylanthracenyl picolyl amine.

A unique benzimidazole-naphthalene hybrid molecule for independent detection of Zn and N ions: Experimental and theoretical investigations.

Single crystal X-ray structurally characterized benzimidazole-naphthalene hybrid (NABI) functions as a unique dual analyte sensor that can detect Zn cation and N anion independently. The NABI forms chelate with Zn to inhibit internal charge transfer (ICT) and CHN isomerisation resulting chelation enhanced fluorescence (CHEF). On the other hand, the sensing of N is based on formation of supramolecular H-bonded rigid assembly.

Azine based smart probe for optical recognition and enrichment of Mo(vi ).

Single crystal X-ray structure-characterized azine derivative (L) was explored for the selective detection of molybdenum (Mo(vi)) cations through green fluorescence emission. The Mo(vi) cation assisted inhibition of photo-induced electron transfer (PET) resulted in a 37-fold fluorescence enhancement via chelation enhanced fluorescence (CHEF) that allows detection of Mo(vi) with concentration as low as 2 × 10-9 M. The chelation of Mo(vi) cations by L has been confirmed by the single crystal X-ray structure of the resulting complex.

Exploring the Scope of Photo-Induced Electron Transfer-Chelation-Enhanced Fluorescence-Fluorescence Resonance Energy Transfer Processes for Recognition and Discrimination of Zn, Cd, Hg, and Al in a Ratiometric Manner: Application to Sea Fish Analysis.

A rhodamine-based smart probe () has been developed for trace-level detection and discrimination of multiple cations, viz. Al, Zn, Cd, and Hg in a ratiometric manner involving photo-induced electron transfer-chelation-enhanced fluorescence-fluorescence resonance energy transfer processes. The method being very fast and highly selective allows their bare eye visualization at a physiological pH.

Tuning of azine derivatives for selective recognition of Ag with the in vitro tracking of endophytic bacteria in rice root tissue.

Several azine derivatives have been prepared and structurally characterized by spectroscopic and single-crystal X-ray diffraction analysis. Two of them, viz. naphthalene based (A10) and anthracene based (A11) show fluorescence enhancement in the presence of Ag in aqueous-methanol.

Pyridine-antipyrine appended indole derivative for selective recognition of Fe: Concentration dependent coloration.

Combination of pyridine, antipyrine and indole in a single molecule (L2) allows selective recognition of Fe colorimetrically in CHCN. The structure of L2 is confirmed from single crystal X-ray diffraction analysis. The probe displays two different visible bands at 541nm and 715nm in the presence of Fe, associated with two different colors, viz.

Dual mode ratiometric recognition of zinc acetate: nanomolar detection with in vitro tracking of endophytic bacteria in rice root tissue.

Several naphthalene-based aldazine derivatives were developed as efficient colorimetric and fluorescence probes for selective ratiometric recognition of traces of zinc acetate. The derivative structures were characterized by single-crystal X-ray diffraction. The probes were used for in vitro tracking of zinc acetate in endophytic bacteria within rice root tissue and to image zinc acetate in human breast cancer cells (MCF7) by normal and fluorescence microscopy.

Structurally Characterized Zn2+ Selective Ratiometric Fluorescence Probe in 100 % Water for HeLa Cell Imaging: Experimental and Computational Studies.

Fluorescence recognition of Zn2+ in 100% aqueous medium using 2-((1, 3 dihydroxy-2-(hydroxymethyl)propan-2 ylimino) methyl) phenol (SALTM) as ratiometric probe is reported. Moreover, SALTM can discriminate Zn2+ from Cd2+very effectively. The binding constant and detection limit of the probe for Zn2+ is 2.