Synthesis of a series of novel binucleating ligands based on 1,4,7-triazacyclononane and o-, m- and p-xylene: crystal structure of the μ-hydroxy-bridged dicopper(II) complex [Cu2Lm(OH)2][BPh4 ]2 [Lm = α,α′-bis (N-1,4,7-triazacyclononane)-m-xylene]

Copper(II) Complexes of N‐Methylated Derivatives of ortho‐ and meta‐Xylyl‐Bridged Bis(1,4,7‐triazacyclononane) Ligands: Synthesis, X‐ray Structure and Reactivity as Artificial Nucleases

“…Indeed, the intramolecular dihydroxobridged dinuclear copper(II) complex of L mx has been isolated by Farrugia et al, [21] and we have structurally characterised several copper(II) complexes of ligands featuring pairs of dihydroxo-bridged Cu II -tacn units attached to the meta positions of an aromatic ring. [44] Thus, at pH 7.4, significant proportions of the dinuclear Cu II complexes of L mx and L memx could be present as intramolecular hydroxobridged dimers, substantially lowering the effective concentration of hydrolytically active species in solution.…”

“…2.9 Å found for structures featuring dihydroxo-bridged copper(II) centres. [21,29] A least-squares plane analysis shows that the angle between the planes of the acetate groups and the basal coordination plane of Cu (1) are 61.29 (2) o and Table 1. Selected bond lengths and angles for C m .…”

“…The methylated ligands (L memx and L meox ) were prepared by modifications to the route first described by Farrugia et al [21] to prepare the two parent bis(macrocycles), L mx and L ox , as their hydrobromide salts. Two equivalents of 1,4,7-triazatricyclo[5.2.0 4.10 ]decane were treated with one equivalent of 1,3-bis(bromomethyl)benzene or 1,2-bis(bromomethyl)benzene to yield bis(amidimium) salt intermediates (see Scheme 1).…”

“…It was envisaged that this simple modification would sterically hinder the formation of hydroxo-bridged dinuclear complexes and/or mononuclear sandwich-type structures, thus leading to higher effective concentrations of hydrolytically active species in solution. Methylated derivatives of two bis(tacn) ligands, 1,3-and 1,2-bis[(1,4,7-triazacyclononan-1-yl)-methyl]benzene (L mx and L ox ), [21] have been synthesised (L memx and L meox ) and used in the preparation of two new…”

Bi-Nuclear Metal Complexes of 2,6-Bis(1,4,7-triazacyclonon-1-yl-methylene)pyridine with Zinc(II), Copper(II), and Nickel(II)

“…[1,2] The wide variety of available linkers between the two [9]aneN 3 groups, such as alkanes, [3][4][5][6][7][8] xylenes, [9,10] napthalenes [10][11][12] alcohols, [13] and phenols, [14] offers an array of tuneable coordination modes for metal complexation that are dependent on the functionality and structure of the linker. We have recently reported the synthesis and structures of copper(II) complexes of some xylene-bridged bis(tacn) ligands bearing phenyl, carboxylic acid, or nitro substituents on the aromatic ring.…”