TY - JOUR
T1 - A Ni11 coordination cluster from the use of the Di-2-pyridyl ketone/acetate ligand combination
T2 - Synthetic, structural and magnetic studies
AU - Efthymiou, Constantinos G.
AU - Mylonas-Margaritis, Ioannis
AU - Raptopoulou, Catherine P.
AU - Psycharis, Vassilis
AU - Escuer, Albert
AU - Papatriantafyllopoulou, Constantina
AU - Perlepes, Spyros P.
N1 - Publisher Copyright:
© 2016 by the authors; licensee MDPI, Basel, Switzerland.
PY - 2016/9
Y1 - 2016/9
N2 - The combined use of di-2-pyridyl ketone, (py)2CO, and acetates (MeCO2´) in nickel(II) chemistry in H2O-MeCN under basic conditions (Et3N) afforded the coordination cluster [Ni11(OH)6(O2CMe)12{(py)2C(OH)(O)}4(H2O)2] (1) in 80% yield, where (py)2C(OH)(O)´ is the monoanion of the gem-diol form of (py)2CO. The complex contains a novel core topology. The core of 1 comprises a central non-linear {Ni3(µ2-OH)4}2+ subunit which is connected to two cubane {Ni4(OH)(µ3-OR)2(µ3-OR1)}4+ subunits [RO´ = (py)2C(OH)(O)´ and R1O´ = MeCO2´] via the OH´ groups of the former which become µ3. The linkage of the Ni3 subunit to each Ni4 subunit is completed by two η1:η1:µ2 and one η1:η3:µ4 MeCO2´ groups. Peripheral ligation is provided by two terminal monodentate MeCO2´ and two terminal aqua ligands. The (py)2C(OH)(O)´ ligands adopt the η1:η1:η3:µ3 coordination mode. From the twelve MeCO2´ ligands, two are η1, two η1:η3:µ4 and eight adopt the syn, syn η1:η1:µ2 coordination mode; four of the latter bridge NiII centers at opposite faces of the cubane subunits. Complex 1 is the largest nickel(II)/(py)2CO-based ligand coordination cluster discovered to date and has an extremely rare nuclearity (Ni11) in the cluster chemistry of nickel(II). Variable-temperature, solid state dc susceptibility, and variable-field magnetization studies at low temperatures were carried out on complex 1. The study of the data reveals an S = 3 ground state, which has been well rationalized in terms of known magnetostructural correlations and the structural features of 1. An attempt has also been made to interpret the magnetic properties of the undecanuclear cluster in a quantitative manner using four exchange interaction parameters and the obtained J values are discussed. The role of H2O in the solvent medium that led to 1, and the high nickel(II) and acetate to di-2-pyridyl ketone reaction ratio employed for its preparation, on the nuclearity and identity of the cluster are critically analyzed.
AB - The combined use of di-2-pyridyl ketone, (py)2CO, and acetates (MeCO2´) in nickel(II) chemistry in H2O-MeCN under basic conditions (Et3N) afforded the coordination cluster [Ni11(OH)6(O2CMe)12{(py)2C(OH)(O)}4(H2O)2] (1) in 80% yield, where (py)2C(OH)(O)´ is the monoanion of the gem-diol form of (py)2CO. The complex contains a novel core topology. The core of 1 comprises a central non-linear {Ni3(µ2-OH)4}2+ subunit which is connected to two cubane {Ni4(OH)(µ3-OR)2(µ3-OR1)}4+ subunits [RO´ = (py)2C(OH)(O)´ and R1O´ = MeCO2´] via the OH´ groups of the former which become µ3. The linkage of the Ni3 subunit to each Ni4 subunit is completed by two η1:η1:µ2 and one η1:η3:µ4 MeCO2´ groups. Peripheral ligation is provided by two terminal monodentate MeCO2´ and two terminal aqua ligands. The (py)2C(OH)(O)´ ligands adopt the η1:η1:η3:µ3 coordination mode. From the twelve MeCO2´ ligands, two are η1, two η1:η3:µ4 and eight adopt the syn, syn η1:η1:µ2 coordination mode; four of the latter bridge NiII centers at opposite faces of the cubane subunits. Complex 1 is the largest nickel(II)/(py)2CO-based ligand coordination cluster discovered to date and has an extremely rare nuclearity (Ni11) in the cluster chemistry of nickel(II). Variable-temperature, solid state dc susceptibility, and variable-field magnetization studies at low temperatures were carried out on complex 1. The study of the data reveals an S = 3 ground state, which has been well rationalized in terms of known magnetostructural correlations and the structural features of 1. An attempt has also been made to interpret the magnetic properties of the undecanuclear cluster in a quantitative manner using four exchange interaction parameters and the obtained J values are discussed. The role of H2O in the solvent medium that led to 1, and the high nickel(II) and acetate to di-2-pyridyl ketone reaction ratio employed for its preparation, on the nuclearity and identity of the cluster are critically analyzed.
KW - Ancillary carboxylate ligands
KW - Coordination clusters
KW - Di-2-pyridyl ketone-based ligands
KW - Magnetic properties
KW - Nickel(II)
KW - Undecanuclearity in nickel(II) chemistry
UR - http://www.scopus.com/inward/record.url?scp=85006965757&partnerID=8YFLogxK
U2 - 10.3390/magnetochemistry2030030
DO - 10.3390/magnetochemistry2030030
M3 - Article
SN - 2312-7481
VL - 2
JO - Magnetochemistry
JF - Magnetochemistry
IS - 3
M1 - 30
ER -