A Solomon Link through an Interwoven Molecular Grid

Abstract

A molecular Solomon link was synthesized through the assembly of an interwoven molecular grid consisting of four bis(benzimidazolepyridyl)benzthiazolo[5,4-d]thiazole ligands and four zinc(II), iron(II), or cobalt(II) cations, followed by ring-closing olefin metathesis. NMR spectroscopy, mass spectrometry, and X-ray crystallography confirmed the doubly interlocked topology, and subsequent demetalation afforded the wholly organic Solomon link. The synthesis, in which each metal ion defines the crossing point of two ligand strands, suggests that interwoven molecular grids should be useful scaffolds for the rational construction of other topologically complex structures.

A Diaminopillar[5]arene‐Based Macrobicyclic Molecule: Synthesis, Characterization and A Lock–Key Story

“…The alkylation of DAP5‐1 formed dialkylated pillar[5]arene DAP5‐2 , followed by removing the Boc groups with trifluoroacetic acid (TFA) to give dienaminopillar[5]arene DAP5‐3 . The cyclization of DAP5‐3 using Grubbs metathesis afforded the macrobicyclic molecule BC‐DAP5 , but the reaction yield was very low (≈9 %), which, we believe, could be due to the instability of the diaminophenyl unit or the poison from the naked amino groups to Grubbs catalyst (Scheme , route 1). Thus, Grubbs metathesis was also carried out on the Boc‐protected DAP5‐2 (Scheme , route 2), and, as expected, the reaction afforded DAP5‐4 in excellent yield (≈93 %).…”

“…The diaminopillar [5]arene-based macrobicyclic molecule (BC-DAP5)w as preparedb ya na lternative multistep synthetic pathway,a sf ully detailed in the Scheme 1. Initially,b yf ollowing ap rocedure previously reported by our group, [25,26] diaminopillar [5]arene DAP5-1 was obtainedi ng ood yield.T he alkylation of DAP5-1 formed dialkylated pillar [5]arene DAP5-2,f ollowed by removing the Bocg roupsw ith trifluoroacetic acid (TFA) to give dienaminopillar [5]arene DAP5-3.T he cyclization of DAP5-3 using Grubbs metathesis [30] afforded the macrobicyclic molecule BC-DAP5,b ut the reactiony ield was very low ( % 9%), which, we believe, could be due to the instability of the diaminophenyl unit or the poison from the naked amino groupst oG rubbs catalyst (Scheme 1, route 1). Thus, Grubbs metathesis was also carried out on the Boc-protected DAP5-2 (Scheme 1, route 2), and,a se xpected, the reactiona fforded DAP5-4 in excellent yield ( % 93 %).…”

A Six‐Crossing Doubly Interlocked [2]Catenane with Twisted Rings, and a Molecular Granny Knot

“…Most of the complex molecular links synthesized to date are derived from metal coordination complexes that assemble ligand strands in spatial arrangements that direct the ring‐closing reactions to generate the required topology . Types of motifs employed include orthogonally positioned ligand complexes, linear and circular metal helicates, and interwoven molecular grids . A 2×2 interwoven grid was previously used to synthesize a Solomon link by connecting the ends of parallel ligand strands .…”

Divergente Koordinationschemie: Parallele Synthese von [2×2]‐Eisen(II)‐Gitterkomplextautokonformeren

“…In diesem Sinne und in dem Wissen, dass Selbstorganisation für die dynamische Erzeugung von molekularer und supramolekularer Diversität und Komplexität in dreidimensionalen (3D) Volumenstrukturen gleichermaßen verantwortlich ist, berichten wir hier über die Komplexierung eines homoditopen Liganden mit zwei dreizähnigen Chelaten mittels Eisen(II)‐Metallionen in Lösung und die dabei beobachtete tautomeriegetriebene Entstehung von Komplexität auf der Grundlage der parallelen Ausbildung von unterschiedlichen Koordinationsmotiven (der obigen Definition folgend gleichbedeutend mit erhöhter Multiplizität). Interessanterweise wird in der Literatur die Koordination von Liganden mit tautomeren Untereinheiten mit Übergangsmetallionen zwar beschrieben, aber das dabei prinzipiell mögliche Auftreten verschiedener Tautokonformere mit der daraus folgenden parallelen Ausbildung isomerer Reaktionsprodukte ist bisher nicht erwähnt worden. Für die vorliegende Arbeit wurde deshalb der Ligand L konzipiert, welcher aus zwei dreizähnigen 2‐(1 H ‐Imidazol‐2‐yl)‐6‐(pyrazol‐1‐yl)pyridin‐Einheiten besteht, die über eine zentrale Benzo[1,2‐ d :4,5‐ d ′]diimidazol‐Brücke (lila, Abbildung a) miteinander verbunden sind.…”