Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·...Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·_(16)H_(2)O(3)have been synthesized using the tris(oxalato)oxoniobate(V)complex anion as the oxalate source,and their structures have been determined by single crystal X-ray diffraction.X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V)complex anion.The structures of 1-4 all contain oxalate-bridged dimetal(Ⅱ)units with didentate dmphen molecules acting as end-cap ligands;electroneutrality is achieved by perchlorate(1-4)and oxotris(oxalato)niobate(V)(3)anions.Each divalent metal ion in 1-4 is tris-chelated in a six-coordinate distorted octahedral environment.The niobium(V)ion in 3 is seven-coordinate in a distorted pentagonal bipyramidal geometry built from one oxo group and six oxygen atoms from three didentate oxalate ligands.The values of the metal-metal separation across the bis-chelating oxalate are 5.626(1)(1),5.575(1)(2),5.434(1)to 5.447(1)(3)and 5.603(1)Å(4).The cryomagnetic measurements in the temperature range of 2.0 to 300 K for compounds 1-3 show the occurrence of antiferromagnetic interactions between the divalent metal ions across the oxalate bridge.The nature and amplitude of these magnetic interactions are rationalized by simple symmetry considerations and compared with those previously reported for related oxalate-bridged systems.展开更多
Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the s...Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the same extent and modulate microbial communities in a similar way.To investigate that,different microbial enrichments with and without activated carbon(AC),magnetite(Mag),and zeolites(Zeo)(at 0.5 g/L)were developed.MP profiles and microbial composition changes were compared among enrichments.The behavior of all enrichments was different,although the initial inoculum sludge was the same.Lag phase duration was lower in AC enrichment,while the complete conversion of butyrate to methane was faster in Mag enrichment.Syntrophomonas was the most abundant bacterial genus in all enrichments,but changes in the methanogenic community were evident.Acetoclastic methanogens were more diverse in Mag enrichment,with microorganisms assigned to Methanosarcina and Methanothrix gener1,but Methanothrix was the only acetoclastic methanogen in the other enrichments.On the other hand,different species of hydrogenotrophic methanogens prevailed in distinct enrichments.The metatranscriptomics results revealed that the dominant mechanism of interspecies electron transfer in the AC enrichment utilized hydrogen as the electron carrier,and no evidences of direct interspecies electron transfer(DIET)could be found.These results showed how different CM modulate microbial communities and affect MP efficiency through mechanisms that do not necessarily involve DIET or mediation via CM.展开更多
The well-known El Nio event, the abnormal increase of Equatorial sea surface temperature of the east Pacific Ocean exerts significant influence on the global-scale atmospheric circulation and climatical anomaly in var...The well-known El Nio event, the abnormal increase of Equatorial sea surface temperature of the east Pacific Ocean exerts significant influence on the global-scale atmospheric circulation and climatical anomaly in various areas. The El Nio events have been reported to result from an earlier-stage warm water accumulation in the west Pacific and the eastward transmission of Kelvin waves caused by the collapse of the SE trades, or rolated to the weakening of the trades led by decrease of SE Pacific high.展开更多
基金supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),Fundação de AmparoàPesquisa do Estado de Minas Gerais(Project PPM 00508-16)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior(CAPES)Ministerio Español de Economía y Competitividad(MINECO)(Project CTQ2016-75068P and Unidad de Excelencia María de Maetzu MDM-2015-0538).
文摘Four compounds with the formula[M_(2)(dmphen)4(μ-C_(2)O_(4))](ClO_(4))_(2)·2dmso[M=Fe(1),Co(2)and Zn(4);dmphen=2,9-dimethyl-1,10-phenanthroline]and[Ni2(dmphen)_(4)(μ-C_(2)O_(4))]_(3)[NbO(C_(2)O_(4))_(3)]2·_(16)H_(2)O(3)have been synthesized using the tris(oxalato)oxoniobate(V)complex anion as the oxalate source,and their structures have been determined by single crystal X-ray diffraction.X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V)complex anion.The structures of 1-4 all contain oxalate-bridged dimetal(Ⅱ)units with didentate dmphen molecules acting as end-cap ligands;electroneutrality is achieved by perchlorate(1-4)and oxotris(oxalato)niobate(V)(3)anions.Each divalent metal ion in 1-4 is tris-chelated in a six-coordinate distorted octahedral environment.The niobium(V)ion in 3 is seven-coordinate in a distorted pentagonal bipyramidal geometry built from one oxo group and six oxygen atoms from three didentate oxalate ligands.The values of the metal-metal separation across the bis-chelating oxalate are 5.626(1)(1),5.575(1)(2),5.434(1)to 5.447(1)(3)and 5.603(1)Å(4).The cryomagnetic measurements in the temperature range of 2.0 to 300 K for compounds 1-3 show the occurrence of antiferromagnetic interactions between the divalent metal ions across the oxalate bridge.The nature and amplitude of these magnetic interactions are rationalized by simple symmetry considerations and compared with those previously reported for related oxalate-bridged systems.
基金supported by the Portuguese Foundation for Science and Technology(FCT)under the scope of the strategic funding of UIDB/04469/2020 unit and by the CM4Methane project(Ref:PTDC/BTA-BTA/2249/2021,DOI 10.54499/PTDC/BTABTA/2249/2021)FCT and European Union(EU),through the Portuguese State Budget and the European Social Fund under the scope of Norte2020-Programa Operacional Regional do Norte,also funded the SFRH/BD/132003/2017 and COVID/BD/152431/2022 grants held by Cátia S.N.Braga.,and the SFRH/BD/147271/2019 grant held by João C.Sequeira.M.SaloméDuarte acknowledges FCT for the Junior Research contract obtained under the scope of the Scientific Stimulus Employment 2022(ref:2022.06569.CEECIND/CP1718/CT0004,doi:https://doi.org/10.54499/2022.06569.CEECIND/CP1718/CT0004)PhD M.Fernando R.Pereira and PhD O.SaloméG.Soares from the Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials,Faculty of Engineering(University of Porto),for providing the AC used in this study.
文摘Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the same extent and modulate microbial communities in a similar way.To investigate that,different microbial enrichments with and without activated carbon(AC),magnetite(Mag),and zeolites(Zeo)(at 0.5 g/L)were developed.MP profiles and microbial composition changes were compared among enrichments.The behavior of all enrichments was different,although the initial inoculum sludge was the same.Lag phase duration was lower in AC enrichment,while the complete conversion of butyrate to methane was faster in Mag enrichment.Syntrophomonas was the most abundant bacterial genus in all enrichments,but changes in the methanogenic community were evident.Acetoclastic methanogens were more diverse in Mag enrichment,with microorganisms assigned to Methanosarcina and Methanothrix gener1,but Methanothrix was the only acetoclastic methanogen in the other enrichments.On the other hand,different species of hydrogenotrophic methanogens prevailed in distinct enrichments.The metatranscriptomics results revealed that the dominant mechanism of interspecies electron transfer in the AC enrichment utilized hydrogen as the electron carrier,and no evidences of direct interspecies electron transfer(DIET)could be found.These results showed how different CM modulate microbial communities and affect MP efficiency through mechanisms that do not necessarily involve DIET or mediation via CM.
文摘The well-known El Nio event, the abnormal increase of Equatorial sea surface temperature of the east Pacific Ocean exerts significant influence on the global-scale atmospheric circulation and climatical anomaly in various areas. The El Nio events have been reported to result from an earlier-stage warm water accumulation in the west Pacific and the eastward transmission of Kelvin waves caused by the collapse of the SE trades, or rolated to the weakening of the trades led by decrease of SE Pacific high.
