Synthetic analog approach to metallobleomycins. 4. New halobridged dimeric and polymeric (infinite zigzag chain) complexes of copper(II) with peptide ligands related to bleomycins

Abstract

ChemInform Abstract The reaction of the Cu halides (II) with the peptide ligands (I) which resemble part of the metal-chelating portion of the antitumor drug bleomycin affords the new title complexes (III) and (IV). (IIIa) crystallizes in P21/n with Z=4, (IVb) in P21/c with Z=4. In solution the compounds (III) dissociate into monomeric tetragonal Cu(II) complexes. Some magnetic properties of (III) and (IV) are discussed.

Halide-bridged polymers of divalent metals with donor ligands – structures and properties

“…Scheme 1b). Several examples of square-pyramidal Cu complexes have been described in which a bridging chloride [30][31][32][33] or bromide [34] represents a ligand in the base plane of one cation and in the apical position of a neighbouring cation. Sharing of a common vertex between adjacent polyhedra has also been encountered in copper complexes with coordination geometry in-between trigonal-bipyramidal and square-pyramidal, again both for chloro [35,36] and bromo bridges [37].…”

“…Cases of ferromagnetic [34,37] as well as of antiferromagnetic interactions [35,36] have been described.…”

Monomeric and Dimeric Copper(II) Complexes of a Pyrrole‐Containing Tridentate Schiff‐Base Ligand

“…[12] The Cu-N(1) (pyrrole nitrogen) is very similar to that reported for related copper(II) complexes. [2,[11][12][13][14] Cu-N (pyridine nitrogen) bonds are usually 2.00-2.05 Å long, [15] so the Cu-N(3) (pyridine nitrogen) distance in this complex [2.021(2) 2 ] were obtained by the slow diffusion of diethyl ether vapour into a dichloromethane solution of the complex and the X-ray crystal structure determined ( Figure 3, Table 2). The asymmetric unit contains half of the neutral dimeric molecule and the other half is generated by a centre of inversion.…”

Mechanistic Insights into Stereoselective Catalysis—The Effects of Counterions in a CuII–Bissulfoximine‐Catalyzed Diels–Alder Reaction

“…Spin-spin interactions between copper ions can be mediated by halide bridging and give rise either to dimeric or to polymeric Cu II ···halogenide arrangements in crystallized complexes. In such crystals, bis-halide dimers have a Cu-Cu distance in the order of 340-440 pm, [29][30][31] in polymeric chains these distances become larger depending on the type of bridging. For bisbridged halide copper compounds this value is around 450 pm, [32] for monobridged halide chains it is larger than 470 pm.…”