Effect of phosphorus flame retardants on thermo-oxidative decomposition of cotton

The effect of six organophosphorus compounds, including Pyrovatex CP (PCP), diammonium phosphate (DAP), phosphoric acid (PA), tributyl phosphate (TBP), triallyl phosphate (TAP) and triallyl phosphoric triamide (TPT) on the flame retardancy of cotton cellulose was studied. PCP, PA, and DAP are more efficient compared with the other three compounds in improving the limiting oxygen index (LOI) of cotton. The effectiveness of these compounds was investigated using scanning electron microscope (SEM) images of char formed after LOI tests, char content, activation energy of decomposition and heat of combustion data. SEM images showed that DAP, PCP and PA chars maintain the surface morphology during the burning process, which might be due to the formation of a protective layer or crosslinking effect. PA, PCP, and DAP treated fabrics have a higher activation energy of decomposition, higher char content and lower heat of combustion.     

Efficacious and sustained release of an anticancer drug mitoxantrone from new covalent organic frameworks using protein corona

Solid porous and crystalline covalent organic frameworks (COFs) are characterized by their higher specific BET surface areas and functional pore walls, which allow the adsorption of various bioactive molecules inside the porous lattices. We have introduced a perylene-based COF, PER@PDA-COF-1, which acts as an effective porous volumetric reservoir for an anticancer drug, mitoxantrone (MXT). The drug-loaded COF (MXT–PER@PDA-COF-1) exhibited zero cellular release of MXT towards cancer cells, which can be attributed to the strong intercalation between the anthracene-dione motif of the drug and the perylene-based COF backbone. Here, we have introduced a strategy involving the serum-albumin-triggered intracellular release of mitoxantrone from MXT–PER@PDA-COF-1. The serum albumin acts as an exfoliating agent and as a colloidal stabilizer in PBS medium (pH = 7.4), rapidly forming a protein corona around the exfoliated COF crystallites and inducing the sustained release of MXT from the COF into tumorigenic cells.

Solid porous and crystalline covalent organic frameworks (COFs) are characterized by their higher specific BET surface areas and functional pore walls, which allow the adsorption of various bioactive molecules inside the porous lattices.     

Tridentate Schiff base and 4,4′-bipyridine coordinated di/polynuclear Cu (II) complexes: Synthesis,crystal structure,DNA/protein binding and catecholase activity

4,4′-bipyridine bridged two Cu (II) complexes, [Cu₂L¹₂(4,4′-bipy)(H₂O)₂](ClO₄)₂ ( 1 ) and [Cu₂L²₂(4,4′-bipy)]_n·(2H₂O)_n ( 2 ) (where, HL¹ = 2-[(3-methylamino-propylimino)-methyl]-phenol, H₂L² = 3-[(2-hydroxy-3-methoxy-benzylidene)-amino]-propionic acid, and 4,4′-bipy = 4,4′-bipyridine) have been synthesized and characterized by single crystal structure determination, mass spectrometry, FT-IR, electronic absorption, and emission spectroscopy. Complex 1 is dinuclear cationic compound and counter balanced by perchlorate anion, whereas complex 2 possesses 1D poly-nuclear structure. Both the complexes crystallize in monoclinic system with P2₁/c space group and the copper centers possess square pyramidal geometry. H-bonding, C-H···π, π···π interactions results the formation of two dimentional supramolecular structure for both the complexes. Interactions of complexes with bovine serum albumins (BSA) and human serum albumins (HSA) have been studied by using electronic absorption and emission spectroscopic technique. The calculated values of binding constants (K_b) are (9.22 ± 0.26) × 10⁵ L mol⁻¹ ( 1 -BSA), (7.19 ± 0.16) × 10⁵ L mol⁻¹ ( 1 -HSA), (5.05 ± 0.20) × 10⁵ L mol⁻¹ ( 2 -BSA) and (3.56 ± 0.25) × 10⁵ L mol⁻¹ ( 2 -HSA). The mechanism of serum albumins-complex interactions have been investigated by fluorescence lifetime measurement. Fluorescence spectroscopic studies indicate that both the complexes interact with calf thymas-DNA. Catecholase activity of the complexes has been studied in methanol using 3,5-di-tert-butylcatechol (3,5-DTBC) as substrate and the result show that both the complexes are active for catalytic oxidation of 3,5-DTBC to 3,5-di-tert-butylquinone (3,5-DTBQ) in presence of molecular oxygen. Calculated values of turnover numbers are 71.81 ± 1.04 h⁻¹ and 69.45 ± 0.74 h⁻¹ for 1 and 2 , respectively.     

TRANSITION METAL,NON-METAL CARBONYL CLUSTRS AS SUPPORTS FOR UNUSUAL ACETYLIDE REACTIVITY

Group 16 elements serve as useful bridging and stabilising single atom ligands in mixed-metal carbonyl complexes and impart unusual reactivity on coordinated acetylenic moieties. Reactions of [Fe ₃ (CO) ₉ (μ ₃ -E) ₂ ] (E = S, or Se) with mononuclear acetylide complexes, [CpM(CO)_3-x(CCR)] (M = Mo or W, x = 0, R = Ph; M = Fe, x = 1, R = Ph or ferrocenyl) under facile conditions yield complexes featuring acetylide coupling, acetylide-flip and formation of oxo and acetylide-bridged complexes. In presence of free acetylenes, unusual ligand systems arising from C─S bond formation are observed and under certain conditions, formation of quinones by coupling of acetylenes with carbon monoxide is facilitated.     

Pharmacophore modelling,molecular docking and virtual screening for EGFR (HER 1) tyrosine kinase inhibitors

A pharmacophore model has been developed using diverse classes of epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitors useful in the treatment of human tumours. Among the top 10 generated hypotheses, the second hypothesis, with one hydrogen bond acceptor, one ring aromatic and three hydrophobic features, was found to be the best on the basis of Cat Scramble validation as well as test set prediction (r _training?=?0.89, r _test?=?0.82). The model also maps well to the external test set molecules as well as clinically active molecules and corroborates the docking studies. Finally, 10 hits were identified as potential leads after virtual screening of ZINC database for EGFR TK inhibition. The study may facilitate the designing and discovery of novel EGFR TK inhibitors.