查看更多>>摘要：Two crystalline silver alkynyl assemblies, namely, [Ag6(tBuC---C)4 L1]n (1), [Ag10(tBuC---C)6(L2)2]n (2) (H2L1 = 1,8-naphthalene dicarboxylic acid and H2L2 = 1,4-naphthalene dicarboxylic acid) have been obtained by the reaction of polymeric [tBuC---CAg]n with silver salts and dicarboxylic acids under mild solvothermal conditions. Compounds 1 and 2 are coordination polymers of irregular silver alkynyl clusters. 1 is chains of cube-like silver clusters connected with L1 and tBuC---C- ligands. In compound 2, the Ag10 clusters surrounded by six tBuC---Cligands are linked by silver atoms to 1D chains, which are further extended by L2 ligands to a rare 3D framework. From the topological view, the structure of 2 can be regarded as alpha-Po topology. The luminescence properties indicated that the two complexes display more than one peak maxima at 298 K using 335 nm excitation.
Molloy, MatthewKilpatrick, Alexander F. R.Tsoureas, NikolaosCloke, F. Geoffrey N....
7页
查看更多>>摘要：Reaction of the syn-bimetallic complex [Ti-2(mu:eta(5),eta(5)-Pn & DAG;& DAG;)(2)] (1) (Pn & DAG;& DAG; = 1,4-((SiPr3)-Pr-i)(2)-C8H4) with 1,3-trans-buta-diene in toluene results in the clean formation of the 1:1 adduct [Ti-2(mu:eta(5),eta(5)-Pn & DAG;& DAG;)(2)(mu: eta(2),eta(2)-s-trans-C4H6)] (2) featuring an essentially planar butadiene ligand. Complex (2) represents the first example of a bimetallic early transition metal complex where a coordinated butadiene adopts such a conformation. When (1) is reacted with propene an unexpected "tuck-over " alkene pi-complex (3) is formed with co-current loss of propane. Complex (3) features a coordinated eta(2),eta(1) vinylic (H2C = CMe)-(SiPr2)-Pr-i-Pn & DAG; moiety as a result of C-H activation of one of the isopropyl substituents of the (SiPr3)-Pr-i groups on the Pn & DAG;& DAG; supporting ligand. One of the hydrogens of this secondary vinylic moiety is significantly shifted upfield in the H-1 NMR spectrum of (3) and a single crystal XRD study shows an interaction between this hydrogen and one of the Ti centres. Preliminary kinetic studies of the formation of (3) show a slightly negative entropy of activation and 1st order consumption of (1) both of which suggest the involvement of a Ti-H(Pr-i) agostic interaction during the cyclometallation reaction.
查看更多>>摘要：Functionalized abnormal/mesoionic NHC (NHC = N-heterocyclic carbene) complexes have been much less investigated in contrast to their normal NHC counterparts. In this work, a series of [(CcarbeneOcarboxylate)-O-boolean AND]- and [(CcarbeneC)-C-boolean AND'(phenyl)]-type Ru(II) complexes bearing normal and abnormal NHCs have been synthesized. Their spectroscopic features, solid-state structure and aquation reactivity have also been reported. All the assynthesized complexes have served as precatalysts to catalyze intramolecular or intermolecular carboxylic acid-to-alkyne addition reactions. It was found that the catalytic behavior of abnormal NHC complexes is superior to that of the normal NHC analogs. An anti-Markovnikov addition reactivity, leading to the formation of an E-type enol ester as the major product, was observed. A few stoichiometric experiments have also been carried out to provide preliminary insight into the catalytic mechanism.
查看更多>>摘要：Three new copper(II) complexes, [Cu(DPA)(ClO4)(2)(H2O)]MAP 1, [Cu(DPA)(ImH)(ClO4)(2)] 2 and [Cu-2(DPA)(2)(2COO-)(ClO4)(2)]H2O 3 (where, DPA = di-(2-picolyl)amine, MPA = 2-methoxyacetophenone, ImH = Imidazole and 2COO(-) = oxalate anion), have been synthesized and characterized using various physico-chemical techniques. DPA is a tridentate ligand with NNN donors atoms and imidazole is a monodentate ligand whereas, oxalate anion is a bridging ligand. Single crystal X-ray analysis reveals that 1-3 are neutral complexes. The X band Epr spectral study in polycrystalline at RT and in DMSO solution at LNT have been analyzed. To examine the stability of complexes, density functional theory (DFT) calculations were performed. The obtained quantum chemical parameters like electron affinity, ionization potential, electronegativity, electrophilicity and global hardness and softness were discussed within the frame work of electronic structures and principles known as maximum hardness, minimum polarizability and minimum electrophilicity principles. Hirshfeld surface analysis showed that the supramolecular structures of the complexes 1-3 is stabilized mainly by CH center dot center dot center dot pi, lp center dot center dot center dot pi and various hydrogen bonding intermolecular interactions. Complex 3 shows ferromagnetic interaction, with J = +1.5 cm(-1), due to perchlorate bridging anion complex. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) support the electrochemical features of these complexes. The Hirshfeld surface analysis exhibited short-range forces of the hydrogen bonds in all studied complexes. In addition, antioxidant superoxide dismutase activity measurements of these complexes were also performed and discussed. The increased SOD activity of 1 can be assigned due to presence of labile coordinated water molecule. The results of SOD activity reveal that the coordination geometries have significant effect on the SOD catalytic activity.
查看更多>>摘要：Heteroleptic homo dinuclear complexes, [Pr(fod)(3)(mu-bpp)Pr(fod)(3)] and [Tb(fod)(3)(mu-bpp)Tb(fod)(3)] (fod is the anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod) and bpp is 2,3-bis(2-pyridyl)pyrazine) have been synthesized and thoroughly characterized. The H-1 NMR spectra of the complexes are consistent with the dinuclear complex formation. In the absorption spectra, the P-3(2) <- H-3(4), P-3(1) + I-1(6) <- H-3(4) and D-1(2) <- H-3(4) transitions of Pr(III) complex show considerable sensitivity towards the host medium and prominent stark splitting of these transitions is observed in chloroform and dichloromethane. The effect of phase change on photophysical properties of Pr(III) and Tb(III) complexes is investigated by observing the steady state and time resolved fluorescence spectra of the solid complexes, their solutions and PMMA doped thin hybrid films. Intense emission is observed for the PMMA doped hybrid materials of the complexes. In the case of [Pr(fod)(3)(mu-bpp)Pr (fod)(3)] complex doped PMMA, additional emission peaks are observed from the high energy excited states (P-3(2), I-1(6), P-3(1) and P-3(0)), indicating that the PMMA facilitates emission from the higher emitting levels. The emitting colour of Pr(III) complex shows phase dependence with the emission of blue and purple light in the solutions, orange in solid state and in the case of PMMA doped hybrid films at a doping concentration of 5 % and 10 %, the Commission Internationale de l'Eclairage (CIE) colour coordinates are in the white region x = 0.351, y = 0.377 and light blue region x = 0.313, y = 0.319, respectively. Intense green light emission is observed for the terbium complex in all media. The semiempirical theoretical tool of Sparkle/PM7 has been used for obtaining the geometry of the complexes.
Ghasemzadeh, Mohammad AliMirhosseini-Eshkevari, BoshraSanaei-Rad, Saleheh
10页
查看更多>>摘要：An efficient and stable MgFe2O4 nanoparticles incorporated in zeolitic imidazolate framework-8 supported on graphene oxide (GO) was synthesized. Using the achieved heterogeneous catalyst including ZIF-8@GO@MgFe2O4, various pyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine-dione derivatives were synthesized through the onepot five-component reaction of hydrazine hydrate, ethyl acetoacetate, 1,3-dimethyl barbituric acid, ammonium acetate, and aryl aldehydes in the absence of any solvent. Furthermore, it was found that such a new heterogeneous catalyst was simply recyclable and separable. This research introduces a green and suitable versatile to synthesize a class of organic compounds by simple work-up, facile recycling system, excellent yields, utilizing non-toxic materials, as well as short reaction times. X-ray diffraction spectroscopy (XRD), Furrier transforms infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX/Mapping), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis were used to characterization and structure elucidation of the catalyst.
Bubnov, Michael P.Teplova, Irina A.Baranov, EvgenyFukin, Georgy...
7页
查看更多>>摘要：Ditopic ligand - 4,7-di(tert-butyl)-5,6-dihydro-1,3-benzodithiole-2,5,6-trione (o-quinone having fused 1,3-dithiolene-2-one cycle (-S-(C = O)-S-) in back position) interacts with Mn-2(CO)(10) in toluene forming 2D-coordination polymer which layers are subdivided by the solvent molecules. Each manganese atom has six coordination environment which consists of square planar bis-dioxolene fragment and additional axial coordination is provided by two oxygen atoms of C = O group of -S-(C = O)-S- five-membered cycle from adjacent bis-dioxolene manganese fragment. Four bis-dioxolene manganese fragments form cycle which is the unit cell of 2D-polymer. Weak coordination of C = O group with manganese atom can be simply destroyed. Re-crystallization of complex from tetrahydrofuran leads to the decomposition of the 2D structure and results in octahedral mononuclear (THF)(2)Mn(semiquinone)(catecholate) complex.
查看更多>>摘要：The interaction with red blood cells (RBC) of vanadium(V) complexes formed by 3,5-difluoropicolinic acid (HpicFF), 3-hydroxypicolinic acid (H(2)hypic) and pyrazinecarboxylic acid (Hprz) has been examined. Electron Paramagnetic Resonance (EPR) spectroscopy results suggest that V(V) is reduced in all cases to V(IV) inside the erythrocytes. The thermodynamic stability of V(V) and corresponding V(IV) complexes has been related with the species detected in the cellular environment; when the ligands form unstable complexes with both (VO2+)-O-V and (VO2+)-O-IV ions (picFF and prz), the species formed inside RBC are similar to those observed when starting with vanadate(V) alone, that is (VO2+)-O-IV - formed upon V(V) reduction - which distributes among the cellular bioligands forming different types of complexes. When in the ligand molecule other groups able to form chelated complexes are present (H(2)hypic), more stable species are formed inside the RBC. The amount of complex able to enter the RBC depends on the ligand structure which could influence the metal uptake. The interaction of different (VO2+)-O-IV complexes formed by picolinate (picFF, pic = picolinate, picCN = 5-cyanopicolinate) and pyrazinecarboxylate (prz and przNH(2) = 3-aminopyrazine-2-carboxylate) derivatives with hemoglobin (Hb), which is the main candidate to bind the (VO2+)-O-IV ion in the cytosol, was also investigated to rationalize the results. The ligands which form at physiological pH relatively stable complexes with (VO2+)-O-IV (przNH(2) and pic) can give inside the erythrocytes mixed species after the replacement of an equatorial water molecule by an imidazole nitrogen of a histidine residue of the protein, while the ligands which form with (VO2+)-O-IV unstable complexes (picCN, picFF, prz) yield the same species observed in the binary system (VO2+)-O-IV-Hb.
查看更多>>摘要：Three hetero-tri-spin complexes, namely [Ln(2)Cu(hfac)(8)(1-Me-3-NIT-Pyz)(2)]center dot CH2Cl2 (Ln = Gd (1), Tb (2), Dy (3); hfac = hexafluoroacetylacetone; 1-Me-3-NIT-Pyz = 2-{3-(1-methyl)-pyrazolyl]}-4,4,5,5-tetramethylimidazoline1-oxyl-3-oxide), have been successfully obtained through the reaction of Cu(hfac)(2) and the pre-synthesized compounds [Ln(hfac)(3)(1-Me-3-NIT-Pyz)]. These 2p-3d-4f complexes are isomorphic three-nuclear clusters with the structure sequence of [Ln-Rad-Cu-Rad-Ln], in which each 1-Me-3-NIT-Pyz ligand exists as a tridentate bridging ligand by chelating to one Ln(hfac)(3) unit through one NO group and one pyrazole nitrogen atom, the other NO group is coordinated to the Cu(hfac)(2) unit. The static magnetic properties of all the three complexes were measured. For complex 1, with the help of a spin Hamiltonian calculation and the MAGPACK program, it was concluded that there exist ferromagnetic couplings not only between the Gd-III ion and the NIT radical but also between the Cu-II ion and the NIT radical, with J(1) = 4.2(1) and J(2) = 23.6(1) cm(-1), respectively. The fitted antiferromagnetic constant (J(3)) between radical and radical is -6.7(1) cm(-1). The dynamic magnetic results indicate that the Tb and Dy complexes show no distinct out-of-phase signals.
查看更多>>摘要：Bi surface plasmon resonance (SPR)-promoted BiPO4/BiOI-BiOCl (Bi/BPCI) ternary heterostructure as plasmonic blue-light-driven photocatalyst was prepared by one-pot UV-photoreduction process assisted hydrothermal method with to require any additives. As-prepared photocatalyst was characterized by PL, DRS, FESEM, XRD, EDS and EIS methods and its hierarchical heterostructured exhibits excellent photocatalytic activity toward Auramine O (AO) as typical cationic organic dyes under blue light irradiation. The band structures of the Bi/BiPO4, BiOI and BiOCl are determined combined with the flat potential (V-fb) and bandgap energy (Eg) evaluated by UV-Vis diffuse reflectance spectra. The founding illustrate that the as-synthesized composite of the three Bibased semiconductors facilitates the photosensitized degradation of AO under blue light as well as we described the optical absorption originated from the SPR influence and direct band gap transition in an individual Bi and transportation of photogenerated carriers at the interface of Bi/BPCI. The photocatalytic mechanism is further proposed by identifying the photogenerated reactive species and intermediates by scavenger test. The OH radical generation confirmed that the OH and h(+) were the key species in the present system, which lead to the elimination and part mineralization of the AO.
NSTL
Elsevier