Polymerization by Insertion of Molecular Oxygen into Crystals of 7,7,8,8‐Tetrakis(ethoxycarbonyl)quinodimethane

Abstract

Gleiten durch das Gitter: Molekularer Sauerstoff reagiert in einem Radikalmechanismus mit Kristallen des Chinodimethans 1 zu einem hochkristallinen alternierenden Copolymer. Die röntgenographische Untersuchung ergab, dass die einzigartige Anordnung von 1 im Kristall für die Copolymerisation entscheidend ist.

Synthesis of Triazole‐linked Homonucleoside Polymers through Topochemical Azide–Alkyne Cycloaddition

“…[6] Topochemical polymerization [7] enables the synthesis of highly ordered, stereoregular and homogeneous polymers. [8] However, owing to the inconvenience of designing crystals that fulfill the strict geometrical prerequisites, topochemical polymerization is limited to a small set of compounds. [6][7][8][9] Because of the possible attractive noncovalent forces such as dipole•••p and p•••p interactions between azide and alkyne motifs, they prefer to a adopt parallel orientation in close proximity in crystals.…”

“…[8] However, owing to the inconvenience of designing crystals that fulfill the strict geometrical prerequisites, topochemical polymerization is limited to a small set of compounds. [6][7][8][9] Because of the possible attractive noncovalent forces such as dipole•••p and p•••p interactions between azide and alkyne motifs, they prefer to a adopt parallel orientation in close proximity in crystals. [10] They can then undergo topochemical azide-alkyne cycloaddition (TAAC) to form either 1,4substituted or 1,5-substituted triazoles regiospecifically, depending on their orientation in the crystal lattice.…”

A Crystal‐to‐Crystal Synthesis of Triazolyl‐Linked Polysaccharide

“…Topochemical polymerization, proximity driven polymerization in a crystal lattice,7 offers a solvent‐free and catalyst‐free method for making crystalline polymers8 of high order, stereocontrol, and homogeneity. However, there are only a limited class of compounds, such as diynes,7b, 8a, 9 triynes,10 dienes,11 trienes,12 dienoic acid derivatives13 and quinodimethane derivatives,8d, 14 known to undergo topochemical polymerization. This limit is due to the difficulty in designing a crystal satisfying the stringent geometrical requirements for the reacting partners in the crystal lattice.…”