An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomole...An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomolecule,has been credibly functioning as the chiral precursor imparting the chirality to the aforementioned complex.The highly symmetric new-fangled M_(4)Cu_(8)coordination-core,comprising of four square-symmetrically coordinated Dy/Y-vertex sharing M_(2)Cu_(2)cubane units,has been synthesized as an unprecedented discrete coordination complex,which has been analysed by magnetic measurements.展开更多
The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,...The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,we designed one OH-containing Schiff base ligand of 1-[[(2-hydroxyethyl)imino]methyl]-2-naphthalenol(H_(2)L)with coordination pockets facile for selective coordination with CoII/NiII and 4f metal ions.Its reactions with the corresponding metal ions gave two new isostructural dodecanuclear complexes[Dy_(4)Co_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3EtOH·3CH_(3)CN·H_(2)O(1)and[Dy_(4)Ni_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3.5EtOH·0.5CH_(3)CN·5H_(2)O(2),which feature a vertex-sharing tetracubane cyclic skeleton with the four DyIII ions wrapped by the eight 3d metal ions.High-resolution electrospray mass spectrometry(HRESI-MS)tests showed that the skeletons of clusters 1 and 2 have high stability even under gradually increasing energy of the ion source.Most notably,the intermediates formed in the reaction courses for clusters 1 and 2 were tracked using time-dependent HRESI-MS,which gave different proposed assembly mechanisms for 1(H_(2)L→DyL→DyCoL→Dy_(2)CoL→Dy_(3)CoL→Dy_(4)CoL_(2)→Dy_(4)Co_(2)L_(3)→Dy_(4)Co_(4)L_(4)→Dy_(4)Co_(8)L_(8))and 2(H_(2)L→NiL→Dy_(2)NiL_(2)→Dy_(3)NiL_(2)→Dy_(4)NiL_(2)→Dy_(4)Ni_(2)L_(3)→Dy_(4)Ni_(4)L_(3)→Dy_(4)Ni_(6)L_(4)→Dy_(4)Ni_(8)L_(8)),respectively.This is the first time that different assembly mechanisms for isostructural heterometallic complexes are shown.Detailed magnetic studies revealed the absence of slow magnetic relaxation for 1 and the presence of slow magnetic relaxation for 2 with an energy barrier of 7.66 K and a pre-exponential factor of 1.45×10^(-6) s.The different magnetic performances of the two title complexes might be caused by the different metal ions of Co_((II))and Ni_((II)).展开更多
基金DST(project no.GAP/DST/CHE-12-0083)is acknowledged for the financial supportDST-FIST(SR/FST/CSII-023/2012)is acknowledged for micro-focus SC-XRD facility.
文摘An isostructural family of three dodecanuclear chiral M_(4)Cu_(8)(M=Dy,Y)complexes has been synthesized by adopting a mixed-ligand strategy,wherein one of the constituent linkers,pyroglutamic acid,a recognized biomolecule,has been credibly functioning as the chiral precursor imparting the chirality to the aforementioned complex.The highly symmetric new-fangled M_(4)Cu_(8)coordination-core,comprising of four square-symmetrically coordinated Dy/Y-vertex sharing M_(2)Cu_(2)cubane units,has been synthesized as an unprecedented discrete coordination complex,which has been analysed by magnetic measurements.
基金supported by the National Natural Science Foundation of China(grant no.12064002,22061004 and 21901050)the Guangxi Natural Science Foundation of China(grant no.2018GXNSFBA050031 and 2020GXNSFAA159132)+1 种基金the Guangxi Technology Base and Talent Subject(grant no.GUIKE AD19245002)the Key Project of Guangxi Normal University(grant no.2018ZD003).
文摘The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters.Thus the tracking of their assembly mechanism is challenging.To achieve this task,we designed one OH-containing Schiff base ligand of 1-[[(2-hydroxyethyl)imino]methyl]-2-naphthalenol(H_(2)L)with coordination pockets facile for selective coordination with CoII/NiII and 4f metal ions.Its reactions with the corresponding metal ions gave two new isostructural dodecanuclear complexes[Dy_(4)Co_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3EtOH·3CH_(3)CN·H_(2)O(1)and[Dy_(4)Ni_(8)(μ_(3)-OH)_(8)(L)_(8)(OAc)_(4)(H_(2)O)_(4)]·3.5EtOH·0.5CH_(3)CN·5H_(2)O(2),which feature a vertex-sharing tetracubane cyclic skeleton with the four DyIII ions wrapped by the eight 3d metal ions.High-resolution electrospray mass spectrometry(HRESI-MS)tests showed that the skeletons of clusters 1 and 2 have high stability even under gradually increasing energy of the ion source.Most notably,the intermediates formed in the reaction courses for clusters 1 and 2 were tracked using time-dependent HRESI-MS,which gave different proposed assembly mechanisms for 1(H_(2)L→DyL→DyCoL→Dy_(2)CoL→Dy_(3)CoL→Dy_(4)CoL_(2)→Dy_(4)Co_(2)L_(3)→Dy_(4)Co_(4)L_(4)→Dy_(4)Co_(8)L_(8))and 2(H_(2)L→NiL→Dy_(2)NiL_(2)→Dy_(3)NiL_(2)→Dy_(4)NiL_(2)→Dy_(4)Ni_(2)L_(3)→Dy_(4)Ni_(4)L_(3)→Dy_(4)Ni_(6)L_(4)→Dy_(4)Ni_(8)L_(8)),respectively.This is the first time that different assembly mechanisms for isostructural heterometallic complexes are shown.Detailed magnetic studies revealed the absence of slow magnetic relaxation for 1 and the presence of slow magnetic relaxation for 2 with an energy barrier of 7.66 K and a pre-exponential factor of 1.45×10^(-6) s.The different magnetic performances of the two title complexes might be caused by the different metal ions of Co_((II))and Ni_((II)).
