2D and 3D Anilato-Based Heterometallic M(I)M(III) Lattices: The Missing Link
dataset
posted on 2015-06-01, 00:00 authored by Samia Benmansour, Cristina Vallés-García, Patricia Gómez-Claramunt, Guillermo Mínguez Espallargas, Carlos J. Gómez-GarcíaThe
similar bis-bidentate coordination mode of oxalato and anilato-based
ligands is exploited here to create the first examples of 2D and 3D
heterometallic lattices based on anilato ligands combining M(I) and
a M(III) ions, phases already observed with oxalato but unknown with
anilato-type ligands. These lattices are prepared with alkaline metal
ions and magnetic chiral tris(anilato)metalate molecular building
blocks: [M<sup>III</sup>(C<sub>6</sub>O<sub>4</sub>X<sub>2</sub>)<sub>3</sub>]<sup>3–</sup> (M<sup>III</sup> = Fe and Cr; X = Cl
and Br; (C<sub>6</sub>O<sub>4</sub>X<sub>2</sub>)<sup>2–</sup> = dianion of the 3,6-disubstituted derivatives of 2,5-dihydroxy-1,4-benzoquinone,
H<sub>4</sub>C<sub>6</sub>O<sub>4</sub>). The new compounds include
two very similar 2D lattices formulated as (PBu<sub>3</sub>Me)<sub>2</sub>[NaCr(C<sub>6</sub>O<sub>4</sub>Br<sub>2</sub>)<sub>3</sub>] (<b>1</b>) and (PPh<sub>3</sub>Et)<sub>2</sub>[KFe(C<sub>6</sub>O<sub>4</sub>Cl<sub>2</sub>)<sub>3</sub>](dmf)<sub>2</sub> (<b>2</b>), both presenting hexagonal [M<sup>I</sup>M<sup>III</sup>(C<sub>6</sub>O<sub>4</sub>X<sub>2</sub>)<sub>3</sub>]<sup>2–</sup> honeycomb layers with (PBu<sub>3</sub>Me)<sup>+</sup> in <b>1</b> or (PPh<sub>3</sub>Et)<sup>+</sup> and dmf in <b>2</b> inserted between them. Minor modifications in the synthetic
conditions yield the novel 3D lattice (NEt<sub>3</sub>Me)[Na(dmf)][NaFe(C<sub>6</sub>O<sub>4</sub>Cl<sub>2</sub>)<sub>3</sub>] (<b>3</b>),
in which hexagonal layers analogous to <b>1</b> and <b>2</b> are interconnected through Na<sup>+</sup> cations, and (NBu<sub>3</sub>Me)<sub>2</sub>[NaCr(C<sub>6</sub>O<sub>4</sub>Br<sub>2</sub>)<sub>3</sub>] (<b>4</b>), the first heterometallic 3D lattice
based on anilato ligands. This compound presents two interlocked chiral
3D (10,3) lattices with opposite chiralities. Attempts to prepare <b>4</b> in larger quantities result in the 2D polymorph of compound <b>4</b> (<b>4</b>′). Magnetic properties of compounds <b>1</b>, <b>3</b>, and <b>4</b>′ are reported,
and in all cases we observe, as expected, paramagnetic behaviors that
can be satisfactorily reproduced with simple monomer models including
a zero field splitting (ZFS) of the corresponding S = 3/2 for Cr(III)
in <b>1</b> and <b>4</b>′ or S = 5/2 for Fe(III)
in <b>3</b>.
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