Synthesis and characterization of a series of edge-sharing octahedral-tetrahedral-octahedral linear trinuclear complexes [M3(L1O)4]2+, where M = Mn2+, Co2+, Ni2+, Cu2+, and Zn2+ and L1OH is the "heteroscorpionate" ligand (2-hydroxyphenyl)bis(pyrazolyl)methane

The mixed functionality pyrazole/phenol ligand (2-hydroxyphenyl)bis(pyrazolyl)methane, L1OH, has been used to prepare a series of linear trimetallic systems with the general structural motif [M-3(L1O)(4)](2+), where M = Mn2+, Co2+, Ni2+, Cu2+, and Zn2+. Each of these complexes has been structurally characterized by X-ray crystallography giving the following structural parameters: [Zn-3(L1O)(4)][BF4](2) . H2O, C52H44N16B2F8O5Zn3, monoclinic, a = 18.572(4) Angstrom, b = 22.400(5) Angstrom, c = 15.921(3), beta = 112.439(8)degrees, space group C2/c, Z = 4; [Cu-3(L1O)(4)] [BF4](2) . 2MeCN, C56H44N18B2Cu3F8O4, monoclinic, a = 40.574(2) Angstrom, b = 16.701(1) Angstrom, c = 19.841(2) Angstrom, beta = 111.388(5)degrees, space group C2/c, Z = 8; [Ni-3(L1O)(4)][ClO4](2) . MeCN . 0.5H(2)O, C54H44N17Cl2Ni3O12.5, monoclinic, a = 12.324(4) Angstrom, b = 26.537(2) Angstrom, c = 18.829(3) Angstrom, beta = 102.78(1)degrees, space group C2/c, Z = 4; [Co-3(L1O)(4)][BF4](2) . MeCN, C54H44N17B2Co3F8O4, monoclinic, a = 12.395(2) Angstrom, b = 26.483(3) Angstrom, c = 18.703(4) Angstrom, beta = 103.22(2)degrees, space group C2/c, Z = 4; [Mn-3(L1O)(4)(MeCN)][ClO4](2) . 1.4MeCN, C56.68H44N18.34Cl2Mn3O12, orthorhombic, a = 15.471(2) Angstrom, b = 17.364(2) Angstrom, c = 24.216(2) Angstrom, space group Pbcn, Z = 4. For Zn2+, Cu2+, Ni2+, and Co2+ the central metal atom of the linear trimetallic [M-3(L1O)(4)](2+) unit is four coordinate and has a pseudotetrahedral geometry with a dihedral angle, omega, between the two McentralO2Mterminal planes of 79.9 degrees (Zn), 61.2 degrees (Co), 60.4 degrees (Ni), and 46.8 degrees (Cu). The central Mn2+ atom of [Mn-3(L1O)(4)(MeCN)][ClO4](2) . 1.4MeCN is five-coordinate, with a trigonal bipyramidal stereochemistry, the result of an equatorially coordinated MeCN solvent molecule. Variable-temperature magnetic data indicate that the Ni, Cu, and Mn complexes display modest antiferromagnetic coupling between the metal centers, while the Co derivative is strongly ferromagnetically coupled.