Reduced arene complexes of rare-earth metals are of great interest and importance because of their unique reactivity mimicking low-valence rare-earth metal species.Here,we present the synthesis and structural characte...Reduced arene complexes of rare-earth metals are of great interest and importance because of their unique reactivity mimicking low-valence rare-earth metal species.Here,we present the synthesis and structural characterization of a series of reduced naphthalene or anthracene complexes of mononuclear scandium with mixed C_(5)Me_(5)(Cp^(*))and amidinate ligands.Among them,the reduced anthracene complexes of mononuclear scandium have been found for the first time to undergo a rapid inter-ring rearrangement.Significantly,a reduced anthracene complex with a scandium center attached to the terminal six-membered ring of anthracene was synthesized by modulating the substituents on the amidinate ligand.The diversified two-electron redox reactions of the reduced naphthalene complex of mononuclear scandium toward cyclooctatetraene(COT),dibenzo[a,e]cyclooctene,benzophenone,1,4-diazabutadiene(DAD),isothiocyanate,and selenium were examined.The scope of two-electron redox reactions via the trivalent scandium complex with the mixed Cp^(*)/amidinate/arene ligand system is significantly expanded,and thus,these results remedy the shortcomings where it is difficult for rare-earth complexes to undergo the two-electron redox process.展开更多
A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste ele...A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the adsorbed complex were recorded by model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). The experimental conditions of the working procedure were optimized. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.61 V, corresponding to the reduction of the alizarin red S in the mix-polynuclear complex at the electrode. The detection limit of Sc^(3+) is 1.0×10^(-10) mol·L^(-1) for 3 min of accumulation time. The procedure was successfully applied to the determination of trace amount of scandium in the sample ores.展开更多
This paper addresses the problem of the observation of the so-called C-C agostic interactions in cyclopropyl complexes of scandium.Three new cyclopropyl complexes of scandium based on theβ-diketiminato ligand were sy...This paper addresses the problem of the observation of the so-called C-C agostic interactions in cyclopropyl complexes of scandium.Three new cyclopropyl complexes of scandium based on theβ-diketiminato ligand were synthesized including by an intramolecular C-H bond activation reaction in one case.X-ray diffraction analysis revealed distorted cyclopropyl groups in the complexes,and the distortion could be observed in solution as well for one of the complexes thanks to the natural abundance INADEQUATE NMR spectroscopy which showed a markedly reduced J_(C-C)coupling constant.This signature of the C-C agostic interaction was further examined using DFT modelling which,together with NBO calculations,indicated that C-H and C-C agostic interactions are not exclusive but can complement each other,accounting for the distortions.The intramolecular C-H bond activation in the scandium biscyclopropyl complex was investigated by isotopic labeling experiments,which indicated a direct proton abstraction of the isopropyl group in theβ-diketiminato ligand by a cyclopropyl group.展开更多
The title complex, [MnSc (DTPA) (H2O)2]·2H2O (DTPA is diethylenetriaminepentaacetic acid). has been synthesized in aqueous solution. Its crystal structure has been determined by four-circle X-ray diffractometer. ...The title complex, [MnSc (DTPA) (H2O)2]·2H2O (DTPA is diethylenetriaminepentaacetic acid). has been synthesized in aqueous solution. Its crystal structure has been determined by four-circle X-ray diffractometer. The crystal is monoclinic with space group P21/n. The cell parameters are as follows:α=0.7886 (3) nm, b=1.5094 (5) nm. c=1. 8162(6) nm; β=100. 32(2)°, V= 2. 121 (2) nm3 , Z= 4 , Dc =1. 75 g/cm3. In the crystal,Sc3+ ion is coordinated by five oxygen atoms and three nitrogen atoms of DTPA with coordination number eight. taking a trigondodecahedron arrangement. Mn2+ ion is coordinated by four oxygen atoms from different DTPA and two oxygen atoms from H2O molecules with coordination number six, forming an octahedron. Each Sc(DTPA) is further connected with Mn2+ ions through four carboxyl groups of DPTA serving as bridges to form a three dimensional network.展开更多
基金work was supported by the National Key R&D Program of China(No.2021YFF0701600)the National Natural Science Foundation of China(No.21725201,21890721,and 22131001).
文摘Reduced arene complexes of rare-earth metals are of great interest and importance because of their unique reactivity mimicking low-valence rare-earth metal species.Here,we present the synthesis and structural characterization of a series of reduced naphthalene or anthracene complexes of mononuclear scandium with mixed C_(5)Me_(5)(Cp^(*))and amidinate ligands.Among them,the reduced anthracene complexes of mononuclear scandium have been found for the first time to undergo a rapid inter-ring rearrangement.Significantly,a reduced anthracene complex with a scandium center attached to the terminal six-membered ring of anthracene was synthesized by modulating the substituents on the amidinate ligand.The diversified two-electron redox reactions of the reduced naphthalene complex of mononuclear scandium toward cyclooctatetraene(COT),dibenzo[a,e]cyclooctene,benzophenone,1,4-diazabutadiene(DAD),isothiocyanate,and selenium were examined.The scope of two-electron redox reactions via the trivalent scandium complex with the mixed Cp^(*)/amidinate/arene ligand system is significantly expanded,and thus,these results remedy the shortcomings where it is difficult for rare-earth complexes to undergo the two-electron redox process.
文摘A novel method was described for the determination of ultra trace amount of scandium based on the cathodic adsorptive voltammetry of the mix-polynuclear complex of scandium-calcium-alizarin red S at a carbon paste electrode (CPE). The 2nd-order derivative linear scan voltammograms of the adsorbed complex were recorded by model JP-303 polarographic analyzer from 0.0 to -1.0 V (vs. SCE). The experimental conditions of the working procedure were optimized. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at -0.61 V, corresponding to the reduction of the alizarin red S in the mix-polynuclear complex at the electrode. The detection limit of Sc^(3+) is 1.0×10^(-10) mol·L^(-1) for 3 min of accumulation time. The procedure was successfully applied to the determination of trace amount of scandium in the sample ores.
基金National Natural Science Foundation of China(No.21732007,21890721,21821002)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB20000000)Program of Shanghai Academic Research Leader。
文摘This paper addresses the problem of the observation of the so-called C-C agostic interactions in cyclopropyl complexes of scandium.Three new cyclopropyl complexes of scandium based on theβ-diketiminato ligand were synthesized including by an intramolecular C-H bond activation reaction in one case.X-ray diffraction analysis revealed distorted cyclopropyl groups in the complexes,and the distortion could be observed in solution as well for one of the complexes thanks to the natural abundance INADEQUATE NMR spectroscopy which showed a markedly reduced J_(C-C)coupling constant.This signature of the C-C agostic interaction was further examined using DFT modelling which,together with NBO calculations,indicated that C-H and C-C agostic interactions are not exclusive but can complement each other,accounting for the distortions.The intramolecular C-H bond activation in the scandium biscyclopropyl complex was investigated by isotopic labeling experiments,which indicated a direct proton abstraction of the isopropyl group in theβ-diketiminato ligand by a cyclopropyl group.
文摘The title complex, [MnSc (DTPA) (H2O)2]·2H2O (DTPA is diethylenetriaminepentaacetic acid). has been synthesized in aqueous solution. Its crystal structure has been determined by four-circle X-ray diffractometer. The crystal is monoclinic with space group P21/n. The cell parameters are as follows:α=0.7886 (3) nm, b=1.5094 (5) nm. c=1. 8162(6) nm; β=100. 32(2)°, V= 2. 121 (2) nm3 , Z= 4 , Dc =1. 75 g/cm3. In the crystal,Sc3+ ion is coordinated by five oxygen atoms and three nitrogen atoms of DTPA with coordination number eight. taking a trigondodecahedron arrangement. Mn2+ ion is coordinated by four oxygen atoms from different DTPA and two oxygen atoms from H2O molecules with coordination number six, forming an octahedron. Each Sc(DTPA) is further connected with Mn2+ ions through four carboxyl groups of DPTA serving as bridges to form a three dimensional network.
