Thermally reversible single-crystal to single-crystal transformation of mononuclear to dinuclear Zn(ii) complexes by [2+2] cycloaddition reaction

Abstract

Two Zn(II) complexes of trans-4-styrylpyridine ligands undergo [2+2] cycloaddition reaction forming Zn(II) complex dimers in a single-crystal to single-crystal (SCSC) manner which were thermally reversible. The dimers are presumed to be the stable intermediates in the formation of 1D coordination polymers upon prolonged exposure to UV light.

Fabrication of Large Single Crystals for Platinum‐Based Linear Polymers with Controlled‐Release and Photoactuator Performance

“…In addition, this photo-polymerization process can be tracked with sample color change from yellow to light yellow.UV/Vis spectroscopy revealed the absorption band at 445 nm in the visible region, ascribed to p-p*t ransition of anthracene,g radually disappear due to the loss of the conjugation after polymerization (Figure S3). [14] Solid-state 13 CNMR and FT-IR was used to further monitor the polymerization process.F or the monomer,t he primary peaks of aromatic anthracene (ranging 123.9 to 129.0 ppm), with partial overlap,c an be attributed to the similar electronic environments within anthracene (Figure S4). Additionally,t he carbon peak at 172.5 ppm assigned to -C=N-and the peak at 62.6 ppm assigned to the -CH 2 -o ft he ethanediamine linker can be identified by their standard chemical shifts.A fter irradiation, ac haracteristic signal at d = 66.2 ppm assigned to the bridgehead of dianthracene appeared.…”

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

“…Notably, very recently the solid state [2 + 2] single crystal to single crystal (SCSC) photopolymerizations in organic and metal-organic materials have been re-ported. [28,[66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] The extension of these strategies of solid state to gel state may result in novel functional polymers in future.…”

Features of styryl dye crystal packings and their influence on [2 + 2] photocycloaddition reaction with single crystal retention

“…The PCA reaction is also challenging for creation of information optical recording systems. [3][4][5][6][7]9,[17][18][19][20]22,28,29,38,43,45,46 In studies of PCA reactions it is important to a priori achieve the formation of a "pre-organized" dimeric pair which shows the stacking interaction of the two molecules. 49 However, these reactions are thermal and they proceed in solution.…”

“…8,16 Many reactions of cycloaddition are known in organic chemistry, for instance -[2 + 3] cyloaddition, 47 [3 + 4] cycloaddition, 48 [4 + 2] cycloaddition. Many examples of pre-organized dimeric pairs are described in the literature via the coordination of the initial ethylene systems with metal cations 11,30,32,34,38,40,43,50 or the formation of hydrogen bonds between the components, 7,9,10,12,14,15,17,20,21,[23][24][25]29,30,40,41,46,50 as well as entering two structural units in cavitand cavitycyclodextrins, calixarenes, cucurbit [8]uril, nanocages. Whereas, PCA represents a temperature independent process.…”