A Rational Approach to the Preparation of Polydipyridyldiacetylenes:  An Exercise in Crystal Design

Abstract

Crystals have been designed for the purpose of carrying out the topochemical polymerization of two isomeric dipyridyldiacetylenes, 1,4-di(pyrdin-3-yl)buta-1,3-diyne (3-pda) and 1,4-di(pyrdin-4-yl)buta-1,3-diyne (4-pda). A successful polymerization depends on achieving a monomer spacing, d m , of 4.90 Å with a close contact R 1,4 , between the reacting atoms, C1−C4‘, of neighboring diacetylenes. A series of five oxalamide dicarboxylic acid host molecules were chosen for the study since they were known to form hydrogen-bond networks with spacings near the required 4.90 Å. Five host molecules and two diacetylene guests should have given 10 cocrystals, but only eight were successfully obtained. The best parameters were found for the cocrystal of the 4-pyridyl isomer, 4-pda, with the oxalamide of glycine, 1-ox. The repeat distance, d m , was 4.93 Å with an R 1,4 contact of 3.62 Å. The 4-pda:1-ox cocrystals were stable to heat, but ultraviolet irradiation polymerized the compound with an isolated yield of 61%.

Structural Aspects and Templation of Photochemistry in Solid‐State Supramolecular Systems

“…In their effort to design a better host -guest system to enable polymerization of diacetylenes, they were able to prepare eight cocrystals with oxalamides 102a , 102b , and 102c as the host molecule and the pyridyldiacetylenes 103 and 104 . 101 The crystals of 102a:104 ( Fig. 7.28 ) were quite sensitive to UV irradiation.…”

Photochemical Reactions in Supramolecular Assemblies of Gels: Dimerizations and Polymerizations via Pericyclic Reactions

“…As the course of the reaction changes the geometry of the molecule significantly, the substituent attached to the diacetylene unit has profound influence on polymerization. [9,20,[45][46][47][48][49] Therefore, the probability of this reaction decreases with an increase in the bulkiness and complexity of the substituents of the diacetylene moiety. Further, it is often difficult to obtain the single crystals of high molecular weight diacetylene derivatives.…”

The first oxalamide‐bridged ferrocene: Facile synthesis, preliminary conformational analysis and biological evaluation

“…Although the oxalamide moieties were not found in biomolecules, they have been applied in bioorganic and medicinal chemistry, in engineering and crystal design, in coordination chemistry and in organogel formation . The dissymmetric and asymmetric N , N ′‐bis(substituted)oxamides were found to exhibit anticancer activities consistent with their DNA binding affinities .…”