Mao-Lin Hu

Supramolecular assemblies of Ru(II) organometallic half-sandwich complexes

A series of new Ru(II) half-sandwich complexes with the general formula [(arene)Ru(L)Cl2], where L is a monodentate amine ligand and arene is a p-cymene or benzene ring, were synthesized and characterized and their supramolecular structures were analyzed. The crystal packing of these compounds was studied using geometrical analysis, Hirshfeld surface analysis and theoretical calculations. Our study reveals the importance of three common hydrogen bonding motifs as the primary factor controlling the supramolecular architecture of this series of complexes. Furthermore, the role of an amine ligand substituent could be different depending on the type of interactions that occurs between functional groups. Interestingly, homomeric self-complementary intermolecular interactions are formed when the ancillary ligand contains benzyl cyanide or alkyl 4-aminobenzoate. These non-conventional interactions could be promising for the design of organometallic supramolecular arrays.

Sonochemical effect on two new Ruthenium(II) complexes with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline precursors for synthesis of RuO2 nanoparticles

Two novel Ru(II) complexes [(η6-p-cymene)RuCl(L2)]PF6 (R2) and [(η6-C6H6)RuCl(L2)]PF6 (R4), with ligand (E)-N-((6-bromopyridin-2-yl)methylene)-4-(methylthio)aniline (L2), were synthesized and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. Based on X-ray crystallography studies, complexes R2 and R4 have coordination environments with formulated (η6-p-cymene)Ru(N2Cl) and (η6-C6H6)Ru(N2Cl), respectively. The thermal stabilities of compounds R2 and R4 were studied by thermal gravimetric (TG) and differential scanning calorimetry (DSC). Thermal decomposition of these complexes was at 280°C and 260°C under air atmosphere respectively. The interaction of these complexes with calf thymus DNA (CT-DNA) was explored through electronic absorption spectra, fluorescence and redox behavior studies. The results showed that the complexes bind to CT-DNA with electrostatic interactions. Nanoparticles of RuO2 were prepared by calcination of R2 and R4. Also the role of the ultrasound waves on the characteristics of the RuO2 nanoparticles was studied. The nanoparticles were characterized by IR spectroscopy and X-ray diffraction (XRD). Also size and morphology of nanoparticles were studied by scanning electron microscopy (SEM).

Zeolite nanofiber assemblies as acid catalysts with high activity for the acetalization of carbonyl compounds with alcohols

Zeolite nanofiber assemblies (HNB-MOR) as efficient heterogeneous catalysts for the formation of a range of acetals in good yields. The mesoporosity of HNB-MOR benefits mass transfer, and the strong acidic sites on HNB-MOR facilitate acetalization activity. The catalyst can be reused 10 times without loss of activity.

Ultrasonic effect on RuO2 nanostructures prepared by direct calcination of two new Ru(II)-organic supramolecular polymers

Two novel Ru(II) complexes [(η6-p-cymene)RuCl(L1)]PF6 (R1) and [(η6-C6H6)RuCl(L1)]PF6 (R3) with ligand (E)-4-(methylthio)-N-((quinolin-2-yl)methylene)benzenamine (L1), were synthesized and investigated using elemental analysis, IR, 1H NMR, 13C NMR spectroscopy and X-ray crystallography. Complexes R1 and R3 have coordination environments with formulated (η6-p-cymene)Ru(N2Cl) and (η6-C6H6)Ru(N2Cl) respectively. The thermal stabilities of compounds R1 and R3 were studied by thermal gravimetric (TG) and differential scanning calorimetry (DSC). The binding of the complexes R1 and R3 to calf thymus DNA (CT DNA) was investigated by using electronic absorption spectra, fluorescence and redox behavior studies. Such experimental data showed that there are interactions between complexes and CT-DNA and the nature of this binding is electrostatic interaction type. Calcination of ultrasonic treated R1 and R3 results in the formation of nanoparticles of RuO2. The nanoparticles were characterized by IR spectroscopy and X-ray diffraction (XRD). Also size and morphology of nanoparticles were investigated by scanning electron microscopy (SEM).

Deposition of silver nanoparticles on polyester fiber under ultrasound irradiations

The polyester fiber containing Ag nanoparticles was prepared through the chemical reduction under ultrasound irradiation. Influences of reduction reagents on the morphological properties of Ag nanoparticles@polyester fiber were studied. The sizes of metallic nanoparticles vary significantly with the types of reduction reagents used in the synthesis. A strong reduction reaction promotes a fast reaction rate and favors the formation of smaller nanoparticle. A weak reduction reagent induces a slow reaction rate and favors relatively larger particles. The products were investigated by means of scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD).

CuCl/air-mediated oxidative coupling reaction of imidazoheterocycles with N-aryl glycine esters

A copper/air mediated oxidative coupling reaction of imidazoheterocycles with N-aryl glycine esters is here described. The reaction proceeded effectively under an air atmosphere without the use of peroxide agents. This simple protocol allows for the preparation of a wide range of imidazoheterocycles with a glycine ester motif, which are of great interest in the field of medicinal chemistry. Interestingly, the coupling of imidazo[1,2-a]pyridine with secondary or tertiary α-amino phenylethanone selectively affords the imidazo[1,2-a]pyridin-3-yl imine or imidazo[1,2-a]pyridin-3-yl diketone in the presence of CuCl and TBHP (tertbutyl hydroperoxide).

A diaryl Schiff base as a photo- and pH-responsive bifunctional molecule

A diaryl Schiff base was explored as a new type of photo- and pH-responsive bifunctional molecule. Its regulation mechanism is probably related to an irreversible photo-cyclization and a reversible pH-promoted bond cleavage.

The synthesis and anticancer activities of peptide 5-fluorouracil derivatives

A new series of peptide 5-fluorouracil derivatives was designed and synthesised in order to test in vitro anticancer activities. The results indicated that peptide 5-fluorouracil derivatives possessed anticancer activities against human HL-60 and Bel-7402 cell lines. The structures of the compounds were determined by means of 1H NMR, 13C NMR, IR, mass spectra and elemental analyses.

Hydrothermal synthesis and characterizations of a novel modular europium(III) coordination polymer bridged by biphenyl-2,2′-dicarboxylate dianions and 1,10-phenanthroline

A novel europium(III) coordination polymer, [Eu2(bpdc)3(phen)2(H2O)2] n ·nH2O (1) (bpdc = biphenyl-2,2′-dicarboxylate; phen = 1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction methods. Complex 1 is monoclinic, space group C2/c, with a = 24.3862(6), b = 12.0792(3), c = 22.9120(5) Å, α = 90.00, β = 115.160(1), γ = 90.00°, V = 6108.8(3) Å3, Z = 4, final R 1 = 0.0605 and wR 2 = 0.1760. Each Eu(III) ion is coordinated by six oxygen atoms from three carboxylate groups of three different bpdc anions, an oxygen atom from one coordinated water molecule and two nitrogen atoms from one phen ligand to complete a deformed monocapped square antiprism. Each pair of bpdc anions acts as a tetradentate ligand to connect two adjacent Eu(III) ions through chelating carboxylate groups, resulting in a centrosymmetric binuclear unit. Each binuclear unit links two adjacent binuclear units through two terminal bpdc anions to produce a one-directional zigzag chain. Two different kinds of hydrogen-bonding interactions link the chains and the lattice water molecules to form a hydrogen-bonding network.

Sonochemical synthesis and characterization of new nanostructures cobalt(II) metal-organic complexes derived from the azo-coupling reaction of 4-amino benzoic acid with anthranilic acid, salicylaldehyde and 2-naphtol

Nanostructures of three new cobalt(II) complexes, (CoL1)·0.5DMF·1.5MeOH (1), [H2L1=5-(4-Carboxy phenyl azo) anthranilic acid], (Co(L2)2)·1.5MeOH (2), [HL2=5-(4-Carboxy phenyl azo) salicylaldehyde] and (Co(L3)2)·0.5DMF·0.5MeOH (3), [HL3=1-(4-Carboxy phenyl azo) 2-naphtol], have been synthesized by the reaction of H2L1, HL2 and HL3 with Co(OAc)2·4H2O through sonochemical process. Calcination of the nano-sized compounds 1-3 yield Co3O4 nanoparticles at 450°C under air atmosphere. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1-3 was studied by thermogravimetric (TG) and differential thermal analyses (DTA).