X-ray Structure, Magnetic and Catalytic Properties of a Cyclic Trinuclear CoII/CoIII/CoIII Complex with a μ3-Hydroxy Anion

Abstract

The mixed-valent cyclic trinuclear cobalt(II)/cobalt(III)/cobalt(III) complex tris(dibenzoylmethanato-1κ 2 O,OЈ;2κ 2 O,OЈ;3 κ 2 O,OЈ)(µ 3 -hydroxo-1:2κ 2 O;1:3κ 2 O;2:3κ 2 O)tetrakis(µ-pyrazolato-1:2κ 4 N 1 N 2 ;1:3κ 2 N 1 N 2 ;2:3κ 2 N 1 N 2 )-1,2-dicobalt-(III)-3-cobalt(II) with four bridging pyrazolate anions and a µ 3 -hydroxy anion has been synthesized and its molecular structure has been elucidated on the basis of X-ray crystallographic, magnetic, NMR, and EPR studies. The remaining coordination sites of the pentacoordinate cobalt(II) and hexa-

Coordination Versatility of Pyrazole‐Based Ligands towards High‐Nuclearity Transition‐Metal and Rare‐Earth Clusters

“…Compounds X 4 [Fe 3 (µ 3 -O)(L1f) 6 Cl 3 ]Cl 2 (X + = HNEt 3 + , Bu 4 N + , PPh 4 + ) have a structure which resembles the basic carboxylates because of the presence of six pyrazole ligands. [55] Numerous compounds were synthesized with the copper(II) ion. [54] In this case, the pyrazole ligands mediate stronger antiferromagnetic interactions than the analogous carboxylates.…”

Structure, spectroscopic, and magnetic properties of copper(II) dinuclear complex with μ-hydroxo and μ-pyrazolato bridges

“…The same procedure was successfully applied for selective isolation of the unique [Co 3 (pz) 4 (DBM) 3 (l 3 -OH)] complex [24]. 1 was purified by crystallization from tetrahydrofurane/hexane solvent mixture until disappearance of EPR spectrum originate from mononuclear complexes (impurities, mostly Cu(DBM) 2 identified by independent X-ray crystallographic measurement and IR fingerprint spectrum).…”

“…The attempts to obtain mixedmetal species in forcing conditions (addition of polar solvents and pyridine) in the reaction between 1 [Cu 2 (DBM) 2 (l-pz)(l-OH)]) and cyclic trinuclear Co(III)/ Co(III)/Co(II) complex (2, [(Co) 3 (DBM) 3 (l-pz) 4 (l 3 -OH)] [24]) failed, presumably due to higher stability of 1 and 2 in comparison with any cross-exchanged species. Exceptional stability of 1 was also reflected in its electrochemical properties.…”

A tricobalt(II) coordination polymer incorporating in situ generated 5-methyltetrazolate ligands

“…At the center of the [Co 3 (l 3 -OH)] core is sitting one disordered OH À group that works as a triply-bridging ligand to link three Co 2+ ions. Such a core was found in [Co 3 (DBM) 3 (pz) 4 (OH)] Á 2THF (DBM = dibenzoylmethanate; pz = pyrazole) [8]. The mean Co1-O1(OH) distance (2.113(2) Å ) is longer than that of the corresponding ones in [Co 3 (DBM) 3 (pz) 4 (OH)] Á 2THF (2.033(2) Å ).…”