Structural Isomerism Effect in Platinum(II) Acetylide-Based Supramolecular Polymers

Abstract

The self-assembly of π-aromatic organic and organometallic molecules into long-range-ordered supramolecular polymers is dictated by a variety of molecular parameters and external conditions. In this work, structural isomerism, representing one of the potent molecular parameters, has been investigated to modulate the self-assembly behaviors. Two platinum(II) acetylide-based structural isomers, with different N-hexyl substitution positions on the inner benzotriazole core, have been designed. Thanks to the synergistic participation of hydrogen-bonding and π−π-stacking interactions, both platinum(II) acetylide-based compounds are prone to forming supramolecular polymers via a nucleation− elongation cooperative mechanism in apolar media. Thermal hysteresis phenomena are observed for both compounds, suggesting the different supramolecular polymerization pathways upon cooling and heating. Remarkably, in addition to the spectroscopic difference, these two supramolecular polymers display distinct thermostability and rheological moduli, ascribing to different binding enthalpies of the neighboring monomers. Overall, it is evident that a minor variation at the molecular level brings huge differences to the properties of long-range-ordered supramolecular polymers. The current study illustrates the importance of the structural isomerism effect for the rational design of π-functional supramolecular materials.

Acylhydrazone-based supramolecular assemblies undergoing a converse sol-to-gel transition on trans → cis photoisomerization

“…As is well known, hydrocarbon solvents such as decane are the common poor solvents for rodcoil-type monomers to form ordered supramolecular assemblies. [47][48][49] When switching the solvent from DCE to decane, the UV-vis absorption spectra of 1-E showed an emergence of a shoulder band located between 400 and 475 nm (ESI Fig. S6 †).…”

Efficient Solid‐State Emission Control by Positional Isomerism for Platinum(II) Complex with Donor–π–Acceptor Ligand

“…[ 5 ] In particular, the ligand isomer influences the nanoparticle and macromolecular arrays structures of the Pt(II) complex and controls their properties. [ 6 ] Recently, the Pt(II) complexes containing stereoisomer ligands, such as enantiomer, and chiral with circularly polarized luminescence properties from the molecular level to assembled supramolecular architectures have been reported. [ 7 ] Therefore, the ligand molecular structure and its electronic states are the key points to developing highly effective and efficient square‐planar Pt(II) complex materials in various research areas.…”

Investigation of the Amide Linkages on Cooperative Supramolecular Polymerization of Organoplatinum(II) Complexes

“…A plausible approach to attain this objective is to embed amide or urea units on the outside of π-conjugated cores. It facilitates the incorporation of intermolecular hydrogen bonds between the neighboring monomers, and thereby induces electronic cooperativity during the supramolecular polymerization process [ 13 , 14 , 15 , 16 , 17 ]. By adopting this principle, a variety of π-conjugated moieties such as arenes, oligo(phenylene ethynylene)s (OPEs), perylene bisimides (PBIs), porphyrins have been reported to form cooperative supramolecular polymers [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”