Novel Aggregation-Induced Emission Fluorescent Molecule for Platinum(IV) Ion-Selective Recognition and Imaging of Controlled Release in Cells

The loading, delivery, and release of Pt(IV) precursors in living organisms are important aspects of exploring the development of platinum drugs. In recent years, the biological application of the fluorescent sensors to platinum drugs has been insufficient to meet the study of Pt(IV) precursors. It is urgent to design and develop a biocompatible, multifunctional fluorescent sensor for the study of loading, transport, and release of Pt(IV) ions. Herein, we report a fluorescent molecule (E)-6-(diethylamino)-N'-(4-(diphenylamino) benzylidene)-2-oxo-2H-chromene-3 carbohydrazide (CHTPA). CHTPA has good sensitivity and selectivity to Pt(IV) when the water content is 5%, and significant increase of the fluorescence emission intensity of CHTPA is observed with Pt(IV) concentration. The sensing mechanism is attributed to photo-induced electron transfer, which is verified by X-ray absorption near edge spectroscopy spectra, UV-vis absorption spectroscopy, ¹H NMR spectra, and Fourier transform infrared spectra. Furthermore, the CHTPA-Pt(IV) complex is able to release Pt(IV) in aqueous solution, and the green fluorescence of CHTPA based on the aggregation-induced emission effect can be observed. Inspired by these, the amphiphilic block copolymer poly(ethyloxide)-block-polystyrene (PEO-b-PS) is used to prepare the nonconjugated polymer dots (Pdots). The experimental results show that Pdots can effectively slow down the release speed of Pt(IV) in aqueous solution and it has a great monodispersity in aqueous solution. Meanwhile, Pdots show low cytotoxicity, and this is favorable for intracellular applications. The investigation of cellular imaging indicates that these Pdots can act as a carrier to deliver Pt(IV) into MCF-7 cells for visualized delivery and sustained release of platinum(IV) ions. Therefore, this study provides a new avenue to design and develop a biocompatible multifunctional fluorescent sensor for studying the loading, delivery, and release of Pt(IV) in cells.

Crystal structure of di-aqua-tris-(benzohydrazide-κ2 N,O)(isophthalato-κO)samarium(III) nitrate

The first benzohydrazide complex of a lanthanide is reported. In the title compound, [Sm(C8H4O4)(C7H8N2O)3(H2O)2]NO3, systematic name di-aqua-tris-(benzohydrazide-κ2 N,O)(isophthalato-κO)samarium(III) nitrate, the SmIII ion is nine-coordinated in a distorted tricapped trigonal-prismatic geometry by three oxygen atoms and three nitro-gen atoms from three benzhydrazide (bzz) ligands, one oxygen atom from the isophthalate (itp2-) ligand, and two oxygen atoms from coordinated water mol-ecules. The nitrate group is disordered over two sets of sites with occupancy factors of 0.310 (17) and 0.690 (17). In the crystal, adjacent mol-ecules are linked into chains via pairs of O-H⋯O and N-H⋯O hydrogen bonds between the carboxyl-ate acceptor and the coordinated water and amine NH2 donors. Mol-ecules are further stacked by π-π inter-actions involving the benzene ring of the itp2- ligands, forming double chains that extend in the b-axis direction. These double chains are further linked into a three-dimensional supra-molecular network via hydrogen bonds (O-H⋯O, N-H⋯O and C-H⋯O) between the complex mol-ecule and the nitrate groups along with C-H⋯π and π-π inter-actions involving the benzene rings of the bzz and itp2- ligands.

Pd-catalyzed oxidative annulation of hydrazides with isocyanides: synthesis of 2-amino-1,3,4-oxadiazoles

An efficient palladium-catalyzed oxidative annulation reaction was developed through sequential isocyanide insertions into N-H and O-H bonds of hydrazides, which provides an efficient access to valuable 2-amino-1,3,4-oxadiazoles and their derivatives.

Synthesis, spectroscopic and radical scavenging studies of palladium(II)-hydrazide complexes

In present study, a series of palladium(II) complexes with biologically active hydrazide ligands have been synthesized, characterized and screened for their antioxidant (superoxide and DPPH radical scavenging) properties. Spectral studies (FT-IR, EI-mass, (13)C and (1)H NMR spectroscopy) and physico-chemical measurements including elemental analysis, magnetic susceptibility and conductivity measurements represented square planar structure for all complexes. Substituted and unsubstituted benzohydrazides (1-4) have shown monodentate behavior forming complexes of general formula [PdL2Cl2]. However, pyridinecarbohydrazides (5 and 6) were coordinated in bidentate fashion of [PdLCl2] general formula producing stable five-membered chelate ring. All palladium complexes were found to be considerably more potent inhibitors of DPPH free radical compared to free hydrazides. These complexes are even stronger DPPH scavengers than standard antioxidant propyl gallate. The complexes have also shown good superoxide scavenging ability compared to inactive free hydrazides, however complexes are weaker superoxide scavengers than ascorbic acid, a standard superoxide inhibitor. An interesting structure activity relationship has been evaluated.