Steric control of the formation of dinuclear double helicate and dinuclear meso-helicate assemblies

Abstract

We describe a ligand system that forms either a dinuclear double helicate or a dinuclear double mesocate dependent upon the size of the metal ion or the steric bulk of the ligand strand.

Steric and Electronic Factors Affecting the Conformation of Bimetallic CuI Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands

“…The complex [Cu I (L 2 )] 2 (ClO 4 ) 2 was obtained in ad ark-red colored solution and its rotoevaporation produced ad ark-brown solid. Residual solvents were eliminated by Soxhlet extraction with diethyl ether.E lemental analysis calcd (%) for C 28 2 2 + (FW = 602.10 gmol À1 )a nd 703.04 corresponding to [Cu(L 2 )] 2 (ClO 4 ) + (FW = 703.13 gmol À1 ); FTIR (KBr): ñ = 2933 (ÀCH 2 À), 2860 (ÀCH 2 À), 1593 (C=N), 1084 (ClO 4 À ), 774 cm À1 (aromatic CÀH); bimetallic 1…”

“…In addition, controlled formationo fmeso or helicate structures has been allocated to the coordination preferences of the metal centers. [28,29] In helicates of Cu I ,n ot only is the tetrahedral coordination geometry of the metal an element to consider,b ut also the d 10electronic configuration adds coordinativel abilityt ot he system. [30] To understand how the whole sum of variablesc ontribute to ad efined conformation is au seful tool for the designo fn ew supramolecular materials.…”

Ruthenium‐Containing Linear Helicates and Mesocates with Tuneable p53‐Selective Cytotoxicity in Colorectal Cancer Cells

“…However, reactions of divalent metal ions with L 3 , which contains a methoxy substituent on the central aryl unit, produce dinuclear double mesocates, for example, [M 2 ( L 3 ) 2 ] 4+ . The difference in structures is attributed to intraligand steric interactions, which govern the formation of either helicate or mesocate …”

Control of metallo-supramolecular assemblies via steric, hydrogen bonding and argentophilic interactions; formation of a 3-dimensional polymer of circular helicates

“…The ability to undergo π-stacking is a useful tool in the formation of self-assembled species and can control the self-assembly of helicates. 18,35 Reaction of L 3 with Ag(BF 4 ) in MeCN gave a colourless solution from which crystals were obtained either by slow diffusion of diisopropyl ethyl ether or slow evaporation. Analysis by X-ray crystallography shows that the asymmetric unit cell contains one ligand coordinated to one Ag(I) metal ion via a bidentate pyridyl-thiazole domain (Fig.…”

“…∆Λ) and in such situations a mesocate, the achiral analogue, is formed. 18 Even though the first structure of a mesocate was reported some time ago, 19 in comparison to the helicate, the conditions required for their formation are much less understood. 5,20 Using much the same methodology of helicate assembly larger species can be produced which contain three or more metal ions in a circular arrangement.…”