＜正＞Many manganese carboxylate clusters have been implicated as an essential part of the active center in a var...
WANG Mei~(a,b) MA Cheng-Bing~a CHEN Chang-Neng~(a,*) LIU Qiu-Tian~a a(State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,The Chinese Academy of Sciences,Fuzhou,Fujian 350002,China) b(Graduate School of the Chinese Academy of Sciences,Beijing 100039,China)
A new three-dimensional coordination polymer [Mn(2,3-pdc)(H2O)]n (2,3-pdc=pyridine-2,3-dicarboxylate) 1 has been hydrothermally synthesized and structurally characterized. The crystal belongs to the monoclinic system,space group P21/c with a=6.4168(5),b=10.7939(9),c=11.1549(10),β=94.733(4)o,V=769.98(11)3,Z=4,Mr=238.06,Dc=2.054 g/cm3,μ(MoKα)=1.707 mm-1,F(000)=476,Rint=0.0326,R=0.0499 and wR=0.1636 for 1564 observed reflections with I > 2σ(I). X-ray diffraction analyses reveal that the title compound is a three-dimensional coordination polymer consisting of one MnII center with a distorted octahedral environment arranged by four 2,3-pdc ligands and one water molecule.
Two new noble-metal-free molecular devices,[{Co(dmgH) 2 Cl}{Zn(PyTPP)}](1,dmgH = dimethyloxime,PyTPP = 5-(4pyridyl)-10,15,20-triphenylporphyrin) and [{Co(dmgH) 2 Cl}{Zn(apPyTPP)}](2,apPyTPP = 5-[4-(isonicotinamidyl)phenyl]10,15,20-triphenylporphyrin),for light-driven hydrogen generation were prepared and spectroscopically characterized.The zinc porphyrin photosensitizer and the Co III-based catalyst unit are linked by axial coordination of a pyridyl group in the periphery of zinc-porphyrin to the cobalt centre of catalyst with different lengths of bridges.The apparent fluorescence quenching and lifetime decays of 1 and 2 were observed in comparison with their reference chromophores,Zn(PyTPP)(3) and Zn(apPyTPP)(4),suggesting a possibility for an intramolecular electron transfer from the singlet excited state of zinc porphyrin unit to the cobalt centre in the molecular devices.Photochemical H2-evolving studies show that complexes 1 and 2 are efficient molecular photocatalysts for visible light-driven H2 generation from water with triethylamine as a sacrificial electron donor in THF/H2 O,with turnover numbers up to 46 and 35 for 1 and 2,respectively.In contrast to these molecular devices,the multicomponent catalyst of zinc porphyrin and [Co(dmgH) 2 PyCl] did not show any fluorescence quenching and as a consequence,no H2 gas was detected by GC analysis in the presence of triethylamine with irradiation of visible light.The plausible mechanism for the photochemical H2 generation with these molecular devices is discussed.
The reaction of a new salicylideneaniline ligand, (Z)-4-(2-hydroxybenzylidenea- mino)-2-hydroxybenzoic acid (HL) with CoCl2·6H2O yields one Co(II) complex, [CoL2(CH3OH)2 (H2O)2]. This complex crystallizes in monoclinic P21/n space group, with a = 5.4992(5), b = 18.2200(15), c = 14.8678(14) , β = 98.64(1)°, V = 1472.8(2) 3, C30H32CoN2O12, Mr = 671.51, Z = 2, Dc = 1.51416 g/cm3, F(000) = 698, μ = 0.652 mm–1, T = 298(2) K, R = 0.0514 and wR = 0.1735 for all 2675 observed reflections (I > 2σ(I)). In this complex, the imine N does not link to Co(II) and a remarkable torsion around C=N bond is observed. Through hydrogen bonds, the monomers aggregate into an interesting 'Z-shape' framework.
＜正＞The only-hydrogenanses have attracted attentions in the scientific communities due to their efficient catal...
ZHANG Yue~(a,b) HU Ming-Qiang~a SI You-Tao~a WEN Hui-Min~a CHEN Chang-Nen~(a,*) LIU Qiu-Tian~a a (State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,The Chinese Academy of Sciences,Fuzhou,Fujian 350002,China) b (Graduate School of the Chinese Academy of Sciences,Beijing 100039,China)
Two mononuclear Mn compounds of Mn III (salen)(L 1) and Mn III (salen)(L 2) (H 2 salen=N,N-ethylenebis-(salicylideneaminato),L 1=4-(2-hydroxybenzylideneamino)benzoic acid and L 2=4-(2-hydroxybenzylideneamino)-2-hydroxybenzoic acid) have been prepared and characterized by X-ray crystallography.Both compounds crystallize in the monoclinic system,space group P2 1 /c with a=14.351(4),b=14.955(3),c=11.869(3) and β=91.529(3)° for 1;and those for 2:a=14.439(9),b=15.217(9),c=11.660(7) and β=91.648(1)°.The compounds have similar structures,in which the Mn III center adopts a distorted square-pyramidal geometry with the basal plane constructed by two N and two O atoms from the salen ligand and the apical position occupied by the carboxylate O atom from L 1 or L 2 ligand.The voltammetric behavior of the compounds is examined,which shows quasi-reversible one-electron reduction of Mn(Ⅲ) to Mn(Ⅱ).The reduction potentials of both compounds fall between-0.33 V [E 0 (O 2 /O 2 ·)] and 0.65 V [E 0 (1 O 2 /O 2 ·)],which suggest that 1 and 2 could be potential mimics of Mn-SOD.
