Heterogeneous Cu-Mn mixed oxides can mediate TEMPO-catalyzed selective oxidation of benzyl alcohol by molecular oxygen under neutral condition, and is recyclable. In the case of the molar ratio of Cu and Mn over 1, th...Heterogeneous Cu-Mn mixed oxides can mediate TEMPO-catalyzed selective oxidation of benzyl alcohol by molecular oxygen under neutral condition, and is recyclable. In the case of the molar ratio of Cu and Mn over 1, the highly-dispersed CuO inside the Cu-Mn mixed oxides is responsible for the good performances in catalytic oxidation.展开更多
An atomic O radical anion bound to a metal ion(metal-oxyl)is a key intermediate in a variety of oxidative reactions.Understanding its structure-reactivity relationship is highly desirable for the rational design of ch...An atomic O radical anion bound to a metal ion(metal-oxyl)is a key intermediate in a variety of oxidative reactions.Understanding its structure-reactivity relationship is highly desirable for the rational design of challenging oxidative transformation processes.However,due to the diffculty of analysis,even the identification of an oxyl is a challenging subject especially in the researchfield of heterogeneous catalysts.Here,we report for thefirst time a low-temperature oxyl transfer to CO from the Zn^(Ⅱ)-oxyl bond isolated in a zeolite catalyst.Zeolite matrix isolation of this novel Zn^(Ⅱ)-oxyl bond allows us to observe the unique spectroscopic probes of the oxyl:a vibronically-resolved spectrum and ESR signatures.Using the oxyl selective spectroscopic probes,we successfully demonstrated that the Zn^(Ⅱ)-oxyl bond has the capability of transferring the oxyl to CO even at 150 K with the generation of a single ZnI•species.The super hyperfine interaction of the ZnI•species with the framework Al atom,observed during the oxyl-transfer reaction,provided direct experimental evidence that the oxyl-functionality emerged at the framework Al site.DFT calculations showed that the Zn^(Ⅱ)-oxyl bond,which is constrained by the zeolite lattice ligation,acts as a superior electron donor toward CO at the rate-determining step of the oxyl-transfer reaction and effectively reduces the barrier to be<5 kJ mol^(−1).Based on the results obtained in the present study as well as the previous work,we further deepen the understanding of why the abnormal Zn^(Ⅱ)-oxyl bond having exceptional reactivities is formed by the zeolite lattice ligation.展开更多
Terminal oxo compounds of high-valent late transition metals attracted attention because of their peculiar metal–oxygen bond in which the oxo ligand exhibits an electrophilic and distinct radical oxyl(O^(˙−))rather ...Terminal oxo compounds of high-valent late transition metals attracted attention because of their peculiar metal–oxygen bond in which the oxo ligand exhibits an electrophilic and distinct radical oxyl(O^(˙−))rather than the commonly expected nucleophilic(O^(2−))character.These properties confer the late transition metal oxo compounds their promising high reactivity in oxidation reactions,as well as H-atom transfer(HAT)and O-atom transfer(OAT)reactions.On the other hand,because of their highly reactive nature,direct spectroscopic evidence especially for high-valent nickel oxo compounds is rare.In this work,we report on linear oxo monofluorides OMF(C∞v)and difluorides OMF_(2)(C_(2v))of the group 10 metal atoms M=Ni,Pd and Pt,as well as on the hypofluorite FOPdF(Cs)and the oxo trifluoride OPtF_(3)(C_(2v)).These molecules were prepared by the reaction of the metal atoms with gaseous OF2 and isolated in solid Ne and Ar matrices.They have been investigated by a joint analysis of IR matrix isolation spectroscopy and electronic structure calculations at the DFT,CCSD(T),as well as CASPT2 and MRCI levels of theory.The linear OMF molecules have ^(4)Σ−ground states and bear a terminal oxyl radical ligand.The oxo difluorides have planar T-shaped structures in the 3A2 electronic states.The terminal oxo ligand in these difluorides also carries large spin densities of≥1.0.A contradiction about the electronic ground state for the recently reported ONiF_(2)[Wei et al.,Inorg.Chem.,2019,58,9796–9810]could be solved experimentally by the observation of a more complete vibrational spectrum.The relationship between the electron and spin population on the oxo ligand in the group 10 transition metal oxofluorides and related compounds will be discussed.Remarkable differences were found for the metal–oxygen bonds in ONiF_(2) and OCuF_(2).The continuous transition from a predominantly ionic to an inverted ligand field is shown by comparing the linear oxo monofluorides of group 10(O[10]F),with the difluorides of group 9(F[9]F)and the isoelectronic dioxides of group 11(O[11]O).展开更多
PhCH2)3Sn·(O2CC5H4N)·(H2O)]n was synthesized by the reaction of 4-pyridine car-boxylic acid with the tribenzyltin o xide and was characterized by IR,1 H NMR and MS.Its crystal structure was determined by X-r...PhCH2)3Sn·(O2CC5H4N)·(H2O)]n was synthesized by the reaction of 4-pyridine car-boxylic acid with the tribenzyltin o xide and was characterized by IR,1 H NMR and MS.Its crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to monoclinic.The space group P21 /c with unit cell parameters a=1.2241(8)nm,b=0.9660(6)nm,c=2.3708(15)nm,β=102.722(12)°,V=2.734(3)nm3,Z =4,Dc=1.298g·cm-3 .In crystal,the tin atom rendered five-coordinate in a trigo nal bipyramidal structure which is b ridged by 4-pyridine carboxy-late into one-dimensional chain polymers.展开更多
基金the National Natural Science Foundation of China (No.20572102)
文摘Heterogeneous Cu-Mn mixed oxides can mediate TEMPO-catalyzed selective oxidation of benzyl alcohol by molecular oxygen under neutral condition, and is recyclable. In the case of the molar ratio of Cu and Mn over 1, the highly-dispersed CuO inside the Cu-Mn mixed oxides is responsible for the good performances in catalytic oxidation.
基金supported by the JSPS Grant-in-Aid for Young Scientists(No.20K15297)the JSPS Grants-in-Aid for Scientific Research(B)(No.16H04118)+1 种基金the JSPS Grants-in-Aid for Challenging Exploratory(No.21655021)the JST PRESTO.
文摘An atomic O radical anion bound to a metal ion(metal-oxyl)is a key intermediate in a variety of oxidative reactions.Understanding its structure-reactivity relationship is highly desirable for the rational design of challenging oxidative transformation processes.However,due to the diffculty of analysis,even the identification of an oxyl is a challenging subject especially in the researchfield of heterogeneous catalysts.Here,we report for thefirst time a low-temperature oxyl transfer to CO from the Zn^(Ⅱ)-oxyl bond isolated in a zeolite catalyst.Zeolite matrix isolation of this novel Zn^(Ⅱ)-oxyl bond allows us to observe the unique spectroscopic probes of the oxyl:a vibronically-resolved spectrum and ESR signatures.Using the oxyl selective spectroscopic probes,we successfully demonstrated that the Zn^(Ⅱ)-oxyl bond has the capability of transferring the oxyl to CO even at 150 K with the generation of a single ZnI•species.The super hyperfine interaction of the ZnI•species with the framework Al atom,observed during the oxyl-transfer reaction,provided direct experimental evidence that the oxyl-functionality emerged at the framework Al site.DFT calculations showed that the Zn^(Ⅱ)-oxyl bond,which is constrained by the zeolite lattice ligation,acts as a superior electron donor toward CO at the rate-determining step of the oxyl-transfer reaction and effectively reduces the barrier to be<5 kJ mol^(−1).Based on the results obtained in the present study as well as the previous work,we further deepen the understanding of why the abnormal Zn^(Ⅱ)-oxyl bond having exceptional reactivities is formed by the zeolite lattice ligation.
基金the Zentraleinrichtung für Datenverarbeitung(ZEDAT)of the Freie Universität Berlin for the allocation of computer time.We thank the DFG(HA 5639/10)for financial supportFunded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-Project-ID 387284271-SFB 1349.
文摘Terminal oxo compounds of high-valent late transition metals attracted attention because of their peculiar metal–oxygen bond in which the oxo ligand exhibits an electrophilic and distinct radical oxyl(O^(˙−))rather than the commonly expected nucleophilic(O^(2−))character.These properties confer the late transition metal oxo compounds their promising high reactivity in oxidation reactions,as well as H-atom transfer(HAT)and O-atom transfer(OAT)reactions.On the other hand,because of their highly reactive nature,direct spectroscopic evidence especially for high-valent nickel oxo compounds is rare.In this work,we report on linear oxo monofluorides OMF(C∞v)and difluorides OMF_(2)(C_(2v))of the group 10 metal atoms M=Ni,Pd and Pt,as well as on the hypofluorite FOPdF(Cs)and the oxo trifluoride OPtF_(3)(C_(2v)).These molecules were prepared by the reaction of the metal atoms with gaseous OF2 and isolated in solid Ne and Ar matrices.They have been investigated by a joint analysis of IR matrix isolation spectroscopy and electronic structure calculations at the DFT,CCSD(T),as well as CASPT2 and MRCI levels of theory.The linear OMF molecules have ^(4)Σ−ground states and bear a terminal oxyl radical ligand.The oxo difluorides have planar T-shaped structures in the 3A2 electronic states.The terminal oxo ligand in these difluorides also carries large spin densities of≥1.0.A contradiction about the electronic ground state for the recently reported ONiF_(2)[Wei et al.,Inorg.Chem.,2019,58,9796–9810]could be solved experimentally by the observation of a more complete vibrational spectrum.The relationship between the electron and spin population on the oxo ligand in the group 10 transition metal oxofluorides and related compounds will be discussed.Remarkable differences were found for the metal–oxygen bonds in ONiF_(2) and OCuF_(2).The continuous transition from a predominantly ionic to an inverted ligand field is shown by comparing the linear oxo monofluorides of group 10(O[10]F),with the difluorides of group 9(F[9]F)and the isoelectronic dioxides of group 11(O[11]O).
文摘PhCH2)3Sn·(O2CC5H4N)·(H2O)]n was synthesized by the reaction of 4-pyridine car-boxylic acid with the tribenzyltin o xide and was characterized by IR,1 H NMR and MS.Its crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to monoclinic.The space group P21 /c with unit cell parameters a=1.2241(8)nm,b=0.9660(6)nm,c=2.3708(15)nm,β=102.722(12)°,V=2.734(3)nm3,Z =4,Dc=1.298g·cm-3 .In crystal,the tin atom rendered five-coordinate in a trigo nal bipyramidal structure which is b ridged by 4-pyridine carboxy-late into one-dimensional chain polymers.
