Recent progress of poly (N-isopropylacrylamide) hybrid hydrogels: synthesis,fundamentals and applications – review

Hydrogels, having nanomaterials (e.g. nanoparticles and nanorods) incorporated inside their polymeric meshes, are generally called hybrid gels/hydrogels. These assemblies combine the properties of both hydrogels and nanomaterials in one system. These responsive hybrid hydrogels, particularly polymerized N-isopropylacrylamide (PoNip) polymeric gels, have been extensively exploited for various multi-disciplinary applications in the literature over the past two decades because of their unique and exquisite particulars. Next generation assemblies have been prepared by using the smart nature of these gels toward the general incentives (e.g. temperature, ionic strength, and pH) in the fields of nanocatalysis, water purification, drug delivery, photonics, and optics. This review presents an overview of the PoNip hybrid assemblies engineered over the past 7 years i.e. 2010–2016 and extensively discusses the interaction of the incorporated nanomaterial with the polymeric chains of the hydrogels as it is the most significant factor which makes these assemblies attractive for all the associated applications. Moreover, this article also describes the preparative routes, properties, classification, and applications of these hybrid hydrogels in the fields of medicine, environment, catalysis, and nanotechnology.     

DNA‐Templated Copper Nanoprobes: Overview,Feature, Application,and Current Development in Detection Technologies

Metal nanoprobes have recently attracted board research interestinr their application in establishing sensing systems due to their unique optical, electrical, physical, and chemical properties. In comparison to gold and silver nanoprobes, analytical platform based on copper nanoprobes (Cu‐NPs) is still in the early stages of development. In this review, we focus on single‐stranded, and double‐stranded DNA capped Cu‐NPs sensing systems which have been designed for various analytes, including metal ions, anions, small molecules, biomolecules (DNA, RNA, and protein, etc.). In addition, the application of Cu‐NPs in biological labeling or bio‐imaging platforms has also been introduced and summarized.     

Urease inhibition and anti-leishmanial assay of substituted benzoylguanidines and their copper(II) complexes

A series of N,N',N'-trisubstituted guanidines (1-6) and their copper(II) complexes, [κ(2)(O,N)-C(6)H(5)CONHC(NHC(6)H(4)Cl)NR](2)Cu(ii) (R = iso-propyl (1a), n-butyl (2a), sec-butyl (3a), tert-butyl (4a), benzyl (5a), and para-tolyl (6a)) were synthesized and characterized using elemental analysis, FTIR and NMR spectroscopy. DFT studies were used to assess the location of the protons in the free ligands. However, calculations have shown that, in all cases, hydrogen bonding from either N-H group gives conformations that are very similar in energy. Single crystal XRD studies were used to characterize ligands 1 and 4 and the related complexes 1a and 4a. The structures reveal that these complexes are mononuclear in the solid state and that copper adopts a regular square planar geometry. In both metallic species, the N, N', N'-trisubstituted guanidine ligands chelate the Cu(II) atom using the oxygen and one nitrogen. The synthesized compounds were investigated for urease inhibition using thiourea as a standard drug. Most complexes exhibit a better activity than the respective guanidines and compound 1a was found to be the most active with IC(50) = 9.83 ± 0.07 μM (the IC(50) for thiourea is 21.0 ± 0.1 μM). The species were also screened for their anti-leishmanial activity. However, all of the compounds were devoid of any significant activity.     

Regioselective Synthesis of Trichloromethyl‐Substituted Salicylates and Cyclohexenones by One‐Pot Cyclizations of 1,3‐Bis(trimethylsilyloxy)buta‐1,3‐dienes

A variety of 6‐(trichloromethyl)salicylates (=2‐hydroxy‐6‐(trichloromethyl)benzoates) were prepared by TiCl₄‐mediated cyclization of 1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes with 1,1,1‐trichloro‐4,4‐dimethoxybut‐3‐en‐2‐one. The employment of trimethylsilyl trifluoromethanesulfonate (Me₃SiOTf) as Lewis acid resulted in the formation of trichloromethyl‐substituted cyclohexenones. The cyclizations proceeded with good‐to‐very‐good regioselectivities.     

小麦秸秆发酵产生的真菌Pleurotus ostreatus IBL-02锰过氧化物酶的溶胶-凝胶固定化及其催化污水脱色(英文)

Solid state bio-processing of wheat straw was carried out through an indigenous fungal strain Pleurotus ostreatus IBL-02 under pre-optimized fermentation conditions. The maximum activity, 692±12 U/mL, of the industrially important manganese peroxidase (MnP) enzyme was recorded after five days of still culture incubation. The crude MnP was 2.1-fold purified with a specific activity of 860 U/mg after purification on a Sephadex-G-100 gel column. On native and SDS-PAGE electrophoresis gels, the purified MnP fraction was a single homogenous band of 45 kDa. An active fraction of MnP was immobilized using hydrophobic sol-gel entrapment comprising tetramethoxysilane (T) and propyltrimethoxysilane (P) at different T:P molar ratios. Characterization revealed that after 24 h incubation at varying pH and temperatures, the MnP fraction immobilized at a T:P ratio of 1:2 in the sol-gel retained 82% and 75% of its original activity at pH4 and 70 ℃, respectively. The optimally active fraction at a 1:2 T:P ratio was tested against MnSO4 as a substrate to determine the kinetic catalytic constants KM and Vmax . To explore the industrial applicability of P. ostreatus IBL-02 MnP, both the free and immobilized MnP were used for the decolorization of four different textile industrial effluents. A maximum of 100% decolorization was achieved for the different textile effluents within the shortest time period. A lower KM , higher Vmax , hyper-activation, and enhanced acidic and thermal resistance up to 70 ℃ were the novel catalytic features of the sol-gel immobilized MnP, suggesting that it may be a potential candidate for biotechnological applications particularly for textile bioremediation purposes.     

Total synthesis of (+)-xyloketal D, a secondary metabolite from the mangrove fungus Xylaria sp.

(+)-Xyloketal D was prepared in a one-pot multistep domino reaction by heating optically active 5-hydroxy-4-methyl-3-methylenepentan-2-one (R) in toluene with 2,4-dihydroxyacetophenone. The absolute configuration of the natural product was confirmed by preparation of the starting enone from a lactone of established absolute configuration.     

The role of C-H and C-C stretching modes in the intrinsic non-radiative decay of triplet states in a Pt-containing conjugated phenylene ethynylene

The intrinsic non-radiative decay (internal conversion) from the triplet excited state in phosphorescent dyes can be described by a multi-phonon emission process. Since non-radiative decay of triplet excitons can be a significant process in organic light-emitting diodes, a detailed understanding of this decay mechanism is important if the overall device efficiency is to be controlled. We compare a deuterated Pt(II)-containing phenylene ethynylene with its non-deuterated counterpart in order to investigate which phonon modes control to the non-radiative decay path. We observe that deuteration does not decrease the non-radiative decay rate. A Franck-Condon analysis of the phosphorescence spectra shows that the electronic excitation is coupled strongly to the breathing mode of the phenyl ring and the C≡C carbon stretching modes, while high-energy C-H or C-D stretching modes play an insignificant role. We, therefore, associate the internal conversion process with the carbon-carbon stretching vibrations.     

Facile Synthesis and Properties of 2‐λ5‐Phosphaquinolines and 2‐λ5‐Phosphaquinolin‐2‐ones

Treatment of 2‐ethynylanilines with P(OPh)₃ gives either 2,2‐diphenoxy‐2‐λ⁵‐phosphaquinolines or 2‐phenoxy‐2‐λ⁵‐phosphaquinolin‐2‐ones under transition‐metal‐free conditions. This reaction offers access to an underexplored heterocycle, which opens up the study of the fundamental nature of the N?P^V double bond and its potential for delocalization within a cyclic π‐electron system. This heterocycle can serve as a carbostyril mimic, with application as a bioisostere for pharmaceuticals based on the 2‐quinolinone scaffold. It also holds promise as a new fluorophore, since initial screening reveals quantum yields upwards of 40 %, Stokes shifts of 50–150 nm, and emission wavelengths of 380–540 nm. The phosphaquinolin‐2‐ones possess one of the strongest solution‐state dimerization constants for a D–A system (130 M ^?1) owing to the close proximity of a strong acceptor (P?O) and a strong donor (phosphonamidate N? H), which suggests that they might hold promise as new hydrogen‐bonding hosts for optoelectronic sensing.     

Diorganotin(IV) Complexes with Monohydrate Disodium Salt of Iminodiacetic Acid: Synthesis,Characterization, Crystal Structure and Biological Activities

Diorganotin(IV) derivatives have been synthesized by the reaction of R₂SnL₂ (R=n‐Bu 1 , Ph 2 ) with monohydrate disodium salt of iminodiacetic acid ( Na₂L ) in 1 : 1 M/L ratio under reflux conditions. The compounds have been characterized by FT‐IR, NMR (¹H and ¹³C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono‐dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra‐coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative ( 2 ) was found slightly higher than that of the free ligand ( Na₂L ). Single crystal X‐ray analysis of the complex 1 have shown a hexa‐coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand.