Synthesis, structural characterization, and electrochemical properties of dinuclear Ni/Mn model complexes for the active site of [NiFe]-hydrogenases.

Four new dinuclear Ni/Mn model complexes RN(PPh2)2Ni(µ-SEt)2(µ-Cl)Mn(CO)3 (7, R = p-MeC6H4CH2; 8, R = EtO2CCH2) and RN(PPh2)2Ni(µ-SEt)2(µ-Br)Mn(CO)3 (9, R = p-MeC6H4CH2; 10, R = EtO2CCH2) have been prepared via the four separated step-reactions involving six new precursors RN(PPh2)2 (1, R = p-MeC6H4CH2; 2, R = EtO2CCH2), RN(PPh2)2NiCl2 (3, R = p-MeC6H4CH2; 4, R = EtO2CCH2), and RN(PPh2)2Ni(SEt)2 (5, R = p-MeC6H4CH2; 6, R = EtO2CCH2). The Et3N-assisted aminolysis of Ph2PCl with p-MeC6H4CH2NH2 or EtO2CCH2NH2·HCl in CH2Cl2 gave the azadiphosphine ligands 1 and 2 in 38% and 53% yields, whereas the coordination reaction of 1 or 2 with NiCl2·6H2O in CH2Cl2/MeOH afforded the mononuclear Ni dichloride complexes 3 and 4 in 59% and 78% yields, respectively. While thiolysis of 3 or 4 with EtSH under the assistance of Et3N in CH2Cl2 produced the mononuclear Ni dithiolate complexes 5 and 6 in 64% and 68% yields, further treatment of 5 and 6 with Mn(CO)5Cl or Mn(CO)5Br resulted in formation of the dinuclear Ni/Mn model complexes 7-10 in 31-73% yields. All the new compounds 1-10 have been structurally characterized, while model complexes 7 and 9 have been found to be catalysts for HOAc proton reduction to hydrogen under CV conditions.

Biomimetic models for the active site of [Fe]hydrogenase featuring an acylmethyl(hydroxymethyl)pyridine ligand.

The first acylmethyl(hydroxymethyl)pyridine ligand-containing [Fe]hydrogenase model complexes 2-4 have been synthesized starting from the nucleophilic substitution reaction of 2-(4-MeC(6)H(4)SO(3)CH(2))-6-HOCH(2)C(5)H(3)N with Na(2)Fe(CO)(4). While the reaction course for producing complex 3 via the highly unstable intermediate complex 1 is monitored by in situ IR spectroscopy, the isolated model complexes 2-4 are fully characterized.

Synthesis and structural characterization of some new porphyrin-fullerene dyads and their application in photoinduced H2 evolution.

The [3 + 2] cycloaddition reaction of C(60) with ethyl isonicotinoylacetate in the presence of piperidine in PhCl at room temperature or in the presence of Mn(OAc)(3) in refluxing PhCl gave the pyridyl-containing dihydrofuran-fused C(60) derivative (4-C(5)H(4)N)C(O)═C(C(60))CO(2)Et (1), whereas the phenyl-containing C(60) derivative PhC(O)═C(C(60))CO(2)Et (2) was similarly prepared by [3 + 2] cycloaddition reaction of C(60) with ethyl benzoylacetate in the presence of piperidine or Mn(OAc)(3). More interestingly, one of the new porphyrin-fullerene dyads, i.e., [4-C(5)H(4)NC(O)═C(C(60))CO(2)Et]·ZnTPPH (3, ZnTPPH = tetraphenylporphyrinozinc), could be prepared by coordination reaction of the pyridyl-containing C(60) derivative 1 with equimolar ZnTPPH in CS(2)/hexane at room temperature. In addition, the ß-keto ester-substituted porphyrin derivative H(2)TPPC(O)CH(2)CO(2)Et (4) was prepared by a sequential reaction of HO(2)CCH(2)CO(2)Et with n-BuLi in 1:2 molar ratio followed by treatment with H(2)TPPC(O)Cl in the presence of Et(3)N and then hydrolysis with diluted HCl, whereas the porphyrinozinc derivative ZnTPPC(O)CH(2)CO(2)Et (5) could be prepared by coordination reaction of 4 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH. Particularly interesting is that the second new porphyrin-fullerene dyad H(2)TPPC(O)═C(C(60))CO(2)Et (6) could be prepared by [3 + 2] cycloaddition reaction of 4 with C(60) in the presence of piperidine in PhCl at room temperature. In addition, treatment of 6 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH afforded the third new dyad ZnTPPC(O)═C(C(60))CO(2)Et (7). All the new compounds 1-7 were characterized by elemental analysis and various spectroscopic methods and particularly for 2, 3, and 5 by X-ray crystallography. The five-component system consisting of an electron donor EDTA, dyad 3, an electron mediator methylviologen (MV(2+)), the catalyst colloidal Pt, and a proton source HOAc was proved to be effective for photoinduced H(2) evolution. A possible pathway for such a type of H(2) evolution was proposed.

[Investigation on a seasonal influenza accompanying with the first locale novel A/H1N1 influenza outbreak in China].

OBJECTIVE: To timely summarize past experience and to provide more pertinent reference for control and prevention in A/H1N1 cases in influenza season. METHODS: During May 25 to 31, 2009, 2 secondary community cases caused by a influenza A/H1N1 imported case. In the close contacts of 3 A/H1N1 cases, 14 had some aspirator symptoms onset, such as fever (> or = 37.5 degrees C), cough, sore throat and etc. Laboratory tests excluded the infection of A/H1N1 influenza. For throat swab test for the 14 cases, 7 were tested for seasonal influenza virus. A face-to-face or telephone interview was conducted by CDC staff to collect information of 62 close contacts. RESULTS: Of 14 fever cases, there was no significant by differences by age[15-age group: 19.2% (5/26), over 25-age group: 25.0% (9/36); chi(2) = 0.287, P = 0.592]; by sex group [24.0% (6/25) for male and 21.6% (8/37) for female; chi(2) = 0.048, P = 0.826], by working units [dressing and design, photograph, saleroom and others, consumer group: 42.1% (8/19), 27.3% (3/11), 12.5% (2/16) and 6.3% (1/16); chi(2) = 7.653, P = 0.054], by dormitory style [dormitory style = 33.3% (4/12), non-dormitory style = 29.4% (10/34); chi(2) = 0.699, P = 0.403]. All the cases had fever (37.5 - 37.9 degrees C), no case had diarrhea. One in 3 A/H1N1 cases had diarrhea. All the 14 cases were negative result for A/H1N1 RNA. Six from 7 cases were positive for seasonal influenza test. CONCLUSION: This was a seasonal influenza outbreak happened in the close contacts of first confirmed A/H1N1 cases in community in mainland China. It showed that we should exclude the seasonal influenza in the investigation of A/H1N1 cases in the seasonal influenza period in some time. It is necessary to take effective measure to strengthen the control and prevention of seasonal influenza.

The First Example of Hetero-Triple-Walled Metal-Organic Frameworks with High Chemical Stability Constructed via Flexible Integration of Mixed Molecular Building Blocks.

An unprecedented 3D hetero-triple-walled metal-organic framework is obtained by straightforward elaboration of the mixed molecular building block (MBB) strategy. In this approach, multiple individual flexible and rigid MBBs are integrated into one composite building block as separate layers, which are of the same shape but different sizes. This MOF shows exceptional water stability and the application of Li-ion battery electrodes.

Synthesis, structural characterization, and some properties of 2-acylmethyl-6-ester group-difunctionalized pyridine-containing iron complexes related to the active site of [Fe]-hydrogenase.

As biomimetic models for [Fe]-hydrogenase, the 2-acylmethyl-6-ester group-difunctionalized pyridine-containing iron(II) complexes 1-4 have been successfully prepared via the following three separate steps. In the first step, the acylation or esterification of difunctionalized pyridine 2-(p-MeC6H4SO3CH2)-6-HOCH2C5H3N with acetyl chloride or benzoic acid gives the corresponding pyridine derivatives 2-(p-MeC6H4SO3CH2)-6-RCO2CH2C5H3N (A, R = Me; B, R = Ph). The second step involves reaction of A or B with Na2Fe(CO)4 followed by treatment of the intermediate Fe(0) complexes [Na(2-CH2-6-RCO2CH2C5H3N)Fe(CO)4] (M1, R = Me; M2, R = Ph) with iodine to afford 2-acylmethyl-6-acetoxymethyl or 6-benzoyloxymethyl-difunctionalized pyridine-containing Fe(II) iodide complexes [2-C(O)CH2-6-RCO2CH2C5H3N]Fe(CO)2I (1, R = Me; 3, R = Ph). Finally, when 1 or 3 is treated with sodium 2-mercaptopyridinate, the corresponding difunctionalized pyridine-containing Fe(ii) mercaptopyridinate complexes [2-C(O)CH2-6-RCO2C5H3N]Fe(CO)2(2-SC5H4N) (2, R = Me; 4, R = Ph) are produced. While the structures of model complexes 1-4 are confirmed by X-ray crystallography, the electrochemical properties of 2 and 4 are compared with those of the two previously reported models. In addition, complexes 2 and 4 have been found to be catalysts for H2 production in the presence of TFA under CV conditions.

Synthesis, characterization, and electrochemical properties of diiron propaneditellurolate (PDTe) complexes as active site models of [FeFe]-hydrogenases.

Parent complex (µ-PDTe)Fe(2)(CO)(6) (1, PDTe = µ-TeCH(2)CH(2)CH(2)Te-µ) is prepared via a new synthetic route involving the reaction of (µ-Te(2))Fe(2)(CO)(6) with Et(3)BHLi, followed by treatment of (µ-LiTe)(2)Fe(2)(CO)(6) with Br(CH(2))(3)Br in a 43% yield. Further reactions of 1 with 1 equiv of monophosphines in the presence of the decarbonylating agent Me(3)NO afford the corresponding monophosphine-substituted complexes (µ-PDTe)Fe(2)(CO)(5)(L) (2, L = PPh(3); 3, PPh(2)H; 4, PMe(3)) in 37%-47% yields, whereas the N-heterocyclic carbene I(Mes)-monosubstituted complex (µ-PDTe)Fe(2)(CO)(5)(I(Mes)) (5) can be prepared in a 26% yield by treatment of 1 with the in situ generated I(Mes) from the 1,3-bis(mesityl)imidazolium salt I(Mes)·HCl and n-BuLi. While the diphosphine-bridged single-butterfly complexes (µ-PDTe)Fe(2)(CO)(4)(dppm) (6) and (µ-PDTe)Fe(2)(CO)(4)(dppn) (7) can be prepared in 28% and 21% yields by treatment of 1 with 1 equiv of the corresponding diphosphines in refluxing xylene, treatment of 1 with 0.5 equiv of diphosphines in the presence of Me(3)NO results in the formation of the corresponding diphosphine-bridged double-butterfly complexes [(µ-PDTe)Fe(2)(CO)(5)](2)(dppp) (8), [(µ-PDTe)Fe(2)(CO)(5)](2)(dppb) (9), and [(µ-PDTe)Fe(2)(CO)(5)](2)(dppf) (10) in 25-37% yields. All the new substituted model complexes 2-10 are characterized by combustion analysis and spectroscopy, and particularly for 2, 3, 5, and 7-10, by X-ray crystallography. In addition, a comparative study on the electrochemical and electrocatalytic properties of the PDTe-type model complexes 1 and 7 with their corresponding selenium and sulfur analogs are reported.

Synthetic and structural studies on new diiron azadithiolate (ADT)-type model compounds for active site of [FeFe]hydrogenases.

A series of new diiron azadithiolate (ADT) complexes (1-8), which could be regarded as the active site models of [FeFe]hydrogenases, have been synthesized starting from parent complex [(µ-SCH(2))(2)NCH(2)CH(2)OH]Fe(2)(CO)(6) (A). Treatment of A with ethyl malonyl chloride or malonyl dichloride in the presence of pyridine afforded the malonyl-containing complexes [(µ-SCH(2))(2)NCH(2)CH(2)O(2)CCH(2)CO(2)Et]Fe(2)(CO)(6) (1) and [Fe(2)(CO)(6)(µ-SCH(2))(2)NCH(2)CH(2)O(2)C](2)CH(2) (2). Further treatment of 1 and 2 with PPh(3) under different conditions produced the PPh(3)-substituted complexes [(µ-SCH(2))(2)NCH(2)CH(2)O(2)CCH(2)CO(2)Et]Fe(2)(CO)(5)(PPh(3)) (3), [(µ-SCH(2))(2)NCH(2)CH(2)O(2)CCH(2)CO(2)Et]Fe(2)(CO)(4)(PPh(3))(2) (4), and [Fe(2)(CO)(5)(PPh(3))(µ-SCH(2))(2)NCH(2)CH(2)O(2)C](2)CH(2) (5). More interestingly, complexes 1-3 could react with C(60) in the presence of CBr(4) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) via Bingel-Hirsch reaction to give the C(60)-containing complexes [(µ-SCH(2))(2)NCH(2)CH(2)O(2)CC(C(60))CO(2)Et]Fe(2)(CO)(6) (6), [Fe(2)(CO)(6)(µ-SCH(2))(2)NCH(2)CH(2)O(2)C](2)C(C(60)) (7), and [(µ-SCH(2))(2)NCH(2)CH(2)O(2)CC(C(60))CO(2)Et]Fe(2)(CO)(5)(PPh(3)) (8). The new ADT-type models 1-8 were characterized by elemental analysis and spectroscopy, whereas 2-4 were further studied by X-ray crystallography and 6-8 investigated in detail by DFT methods.