Title

Antiferromagnetically and Ferromagnetically Coupled Nickel(II) Dimers with and Without Interdimer Coupling

Alternative Title

Solvent effects in the preparation of nickel(II) dimers

Abstract

The structural and magnetic properties are reported for a group of chemically similar nickel(II) dimers with salicylaldimine ligands. Three general categories of compounds may be prepared for a variety of bidentate Schiff base (sb) nickel(II) complexes that have the same general formula [Ni(sb)(NO3)L]2 and differ only in structural details and the type of Lewis acid solvent molecule (L) that is present during crystallization. Antiferromagnetic interactions are observed when the central Ni2O2 bridging group is approximately coplanar with the principal sb ligand plane. Ferromagnetic interactions are observed when these planes are approximately orthogonal. When L = C2H5OH, hydrogen bonding between L and the NO3 groups of neighboring molecules forms an antiferromagnetic pathway along infinite chains of ferromagnetic dimers. The three categories are represented by the following complexes. [Ni(ps)(NO3)(2-pic)]2·CH2Cl2 (ps = phenylsalicylaldimine): crystal data space group P1, Z = 1, a = 9.424 (2) Å, b = 11.327 (3) Å, c = 11.468 (3) Å, α = 117.96 (2)°, β = 90.29 (3)°, γ = 91.62 (2)°, V = 1081 Å3, R = 4.5% for 2342 reflections; magnetic data g = 2.12, J = 8.7 cm-1, D ≈ 13 cm-1 (zJ′ = 0.07). [Ni2(ips)2(NO3)2(EtOH) 2]∞ (ips = isopropylsalicylaldimine): crystal data space group P1, Z = 1, a = 9.161 (5) Å, b = 9.183 (2) Å, c= 13.353 (7) Å, α = 128.25 (3)°, β = 93.72 (4)°, γ = 110.44 (3)°, V = 764 Å3, R = 3.1% for 1851 reflections; magnetic data g = 2.15, J = 16.0 cm-1, D ≈ 15 cm-1 (zJ′, = 0.14). [Ni(ips)(NO3)DMF]2: crystal data space group P1, Z = 1, a = 9.506 (2) Å, b = 10.095 (4) Å, c = 10.588 (3) Å, α = 94.80 (2)°, β = 126.59 (2)°, γ = 92.70 (2)°, V = 807 Å3, R = 5.5% for 2039 reflections; magnetic data g = 2.32, J = -9.2 cm-1, D ≈ 12 cm-1. The magnetic behavior is correlated with differences in exchange pathways as obtained from the crystal structures. Although it is demonstrated that D and zJ′ cannot be estimated accurately from the magnetic data, the values of the intradimer interaction, J, are reliable. © 1981 American Chemical Society.

Department(s)

Chemistry

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1981 American Chemical Society (ACS), All rights reserved.


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