Predictions, Synthetic Strategy, and Isolation of a Linear Tetrametallic Triple‐Stranded Lanthanide Helicate

Abstract

Complex twists: Following theoretical thermodynamic predictions, it is seen that the tetrametallic triple‐stranded lanthanide helicate [Ln4L3]12+ (see structure) dominates the speciation in solution at millimolar concentrations, despite its high positive charge. Isolation of the europium complex in the solid state unambiguously establishes its nanometric triple‐helical structure.

Homo‐ and Heterodinuclear Helicates of Lanthanide(III), Zinc(II) and Aluminium(III) Based on 8‐Hydroxyquinoline Ligands

“…Heterodinuclear helicates: [12] Heterodinuclear complexes [K(3) 3 LaAl]Cl, [Rb(4) 3 LaZn] and [K(4) 3 LaAl]Cl were prepared by the treatment of 3 À H 2 or 4 À H 2 (3 equiv), LaCl 3 ·6H 2 O (1 equiv), hydrated AlCl 3 or ZnA C H T U N G T R E N N U N G (OAc) 2 (1 equiv) and potassium or rubidium carbonate (3 equiv) in either methanol/water or methanol (Scheme 2). Positive ESIMS shows the molar peaks of the cations [K(3) 3 LaAl] , J = 15.9 Hz).…”

“…[ 1 equiv) or ZnA C H T U N G T R E N N U N G (OAc) 2 (1.0 equiv) was stirred in MeOH (15 mL) at 55 8C for 8 h, and then at RT for another 12 h. The solvent was evaporated under reduced pressure. The red residue was dissolved in CHCl 3 and filtered to remove insoluble species.…”

“…[Rb (2) (2) 3 ; 1 calcd = 1.461 g cm À3 ; m = 2.369 mm À1 ; empirical absorption correction (0.384 T 0.649); Z = 4; monoclinic; space group P2 1 /c (No. 14); l = 0.71073 ; T = 223(2) K; w and f scans; 63 848 reflections collected (AE h, AE k, AE l); [(sinq)/l] = 0.62 À1 ; 21 051 independent (R int = 0.067) and 12 169 observed reflections [I !…”

“…[2,3] A ligand system based on the bis(benzimidazole)pyridine chelating unit allows the self-assembly of up to tetranuclear triple-stranded helicates with rare-earth-metal ions. [2] In addition, a series of fÀf and fÀd heterodinuclear complexes was obtained and spectroscopically investigated. [3] Recently, we introduced the 2-carbamide-8-hydroxyquinoline moiety [4] …”

Supramolecular Click Assembly of a Fused Double‐Stranded [MnII3] Dihelicate

“…[6][7][8][9] Most multistranded helicates reported feature two metal centres. [10] Examples containing a trinuclear (or higher) array of metal ions are less common, but they are increasingly described. [11] In the course of our investigations on the design and preparation of polynuclear metal complexes with attractive magnetic properties, the potentially tetradentate, rigid N,Oligand 2-methoxy-6-(pyridine-2-ylhydrazonomethyl)phenol [12] (HL) was used to generate metal clusters.…”