TY - JOUR
T1 - Combining azide, carboxylate, and 2-pyridyloximate ligands in transition-metal chemistry
T2 - Ferromagnetic NiII 5clusters with a bowtie skeleton
AU - Papatriantafyllopoulou, Constantina
AU - Stamatatos, Theocharis C.
AU - Wernsdorfer, Wolfgang
AU - Teat, Simon J.
AU - Tasiopoulos, Anastasios J.
AU - Escuer, Albert
AU - Perlepes, Spyros P.
PY - 2010/11/15
Y1 - 2010/11/15
N2 - The combined use of the anion of phenyl(2-pyridyl)ketone oxime (ppko-) and azides (N3 -) in nickel(II) carboxylate chemistry has afforded two new NiII 5clusters, [Ni5(O2CR′)2(N3)4(ppko)4(MeOH)4] [R′ = H (1), Me (2)]. The structurally unprecedented {Ni5(μ-N3)2(μ3-N3)2}6+cores of the two clusters are almost identical and contain the five NiIIatoms in a bowtie topology. Two N3 -ions are end-on doubly bridging and the other two ions end-on triply bridging. The end-on μ3-N3 -groups link the central NiIIatoms with the two peripheral metal ions on either side of the molecule, while the Ni···Ni bases of the triangles are each bridged by one end-on μ-N3 -group. Variable- temperature, solid-state direct-(dc) and alternating-current (ac) magnetic susceptibility, and magnetization studies at 2.0 K were carried out on both complexes. The data indicate an overall ferromagnetic behavior and an S = 5 ground state for both compounds. The ac susceptibility studies on 1 reveal nonzero, frequency-dependent out-of-phase (ΧM″) signals at temperatures below ∼3.5 K; complex 2 reveals no ΧM″ signals. However, single-crystal magnetization versus dc field scans at variable temperatures and variable sweep rates down to 0.04 K on 1 reveal no noticeable hysteresis loops, except very minor ones at 0.04 K assignable to weak intermolecular interactions propagated by nonclassical hydrogen bonds.
AB - The combined use of the anion of phenyl(2-pyridyl)ketone oxime (ppko-) and azides (N3 -) in nickel(II) carboxylate chemistry has afforded two new NiII 5clusters, [Ni5(O2CR′)2(N3)4(ppko)4(MeOH)4] [R′ = H (1), Me (2)]. The structurally unprecedented {Ni5(μ-N3)2(μ3-N3)2}6+cores of the two clusters are almost identical and contain the five NiIIatoms in a bowtie topology. Two N3 -ions are end-on doubly bridging and the other two ions end-on triply bridging. The end-on μ3-N3 -groups link the central NiIIatoms with the two peripheral metal ions on either side of the molecule, while the Ni···Ni bases of the triangles are each bridged by one end-on μ-N3 -group. Variable- temperature, solid-state direct-(dc) and alternating-current (ac) magnetic susceptibility, and magnetization studies at 2.0 K were carried out on both complexes. The data indicate an overall ferromagnetic behavior and an S = 5 ground state for both compounds. The ac susceptibility studies on 1 reveal nonzero, frequency-dependent out-of-phase (ΧM″) signals at temperatures below ∼3.5 K; complex 2 reveals no ΧM″ signals. However, single-crystal magnetization versus dc field scans at variable temperatures and variable sweep rates down to 0.04 K on 1 reveal no noticeable hysteresis loops, except very minor ones at 0.04 K assignable to weak intermolecular interactions propagated by nonclassical hydrogen bonds.
UR - https://www.scopus.com/pages/publications/78149304676
U2 - 10.1021/ic1014829
DO - 10.1021/ic1014829
M3 - Article
SN - 0020-1669
VL - 49
SP - 10486
EP - 10496
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 22
ER -