Flexible cofacial binuclear metal complexes derived from α,α-bis(salicylimino)-m-xylene

Abstract

The tetradentate Schiff-base ligand SIXH2 (alpha,alpha-bis(salicylimino)-m-xylene), prepared from salicylaldehyde and m-xylylenediamine, forms cofacial binuclear complexes with Pd and Cu. Of the two isomers possible (trans-syn and trans-anti) for M2(SIX)2, these complexes crystallize exclusively as the trans-anti isomer. In ansolvous Pd2(SIX)2, the metal-containing planes are approximately parallel, with PdPd 4.416(1) A. Pd2(SIX)2 also forms a crystalline solvate, in which the molecules adopt a more open conformation with longer metal-metal distances (5.109(1) and 5.112(1) A). The M...M distance is significantly longer in Cu2(SIX)2 (6.653(1) A), because of conformational changes in the m-xylylene moieties and substantial tetrahedral distortion about Cu.

Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex

“…5.24 Å for the approximately parallel conformation (dihedral angle of 67.6 and 39.7°) and are perpendicular to one another in the second rotational isomer. On the other hand, a weak π-π interaction is present in the helical structure of the Cu 2 [N,NЈ-bis(salicylidene)-1,3-phenylenedimethanamine] 2 (4.44 Å), [57] and a double π-π interaction (3.5-3.9 Å) is realized in the Cu complexes containing the longer ligands bis(salicylidene-4,4Ј-diaminodiphenylmethane) [54] and bis-(salicylidene)-4,4Ј-diaminodiphenylether. [50] Crystal Structure of 2…”

Uranyl(VI) binding by bis(2-hydroxyaryl)diimine and bis(2-hydroxyaryl)diamine ligand derivatives. Synthetic, X-ray, DFT and solvent extraction studies

“…UV data were collected using a Perkin Elmer type Lambda 25 spectrophotometer in the range 200-1200 nm. The syntheses of H 2 L 1 (from m-xylylenediamine and salicylaldehyde) [32,33], H 2 L 5 (from o-aminophenol and isophthalaldehyde) [34], H 2 L 6 (from 1,2-phenylenediamine and salicylaldehyde) [33,35] and (H 2 L 7 ) (from (±)-trans-1,2-diaminocyclohexane and salicylaldehyde) [36,37] were carried out by the respective literature procedures.…”

Diastereoselective Self‐Assembly of a Neutral Dinuclear Double‐Stranded Zinc(II) Helicate via Narcissistic Self‐Sorting

“…Despite the fact that bis(salicylimine) ligands like the famous salene ligands have been widely used in coordination chemistry for a very long time, there have been surprisingly few reports on oligonuclear coordination compounds that contain more than one ligand strand bearing the salicylimine coordination motif so far, and in all cases except for only two examples, the metal ions exist in a square‐planar coordination sphere . Such ions, however, are not applicable for ligands with rather rigid V‐shaped backbones such as Tröger's base.…”