STIMULI RESPONSIVE COORDINATION POLYMERS

Ph.DDOCTOR OF PHILOSOPHY (FOS

Mechanical Bending and Modulation of Photoactuation Properties in a One-Dimensional Pb(II) Coordination Polymer

With emergent research on stimuli responsive materials, dynamic crystals are at the forefront of investigation. However, research on the mechanical properties of coordination polymers (CPs) is still in its infancy. Elastic deformation induced by pressure and photoactuation are rare occurrences in CPs, let alone their combination in a single CP. Here, we report a one-dimensional (1D) CP comprising PbBr2 chains with 3-fluoro-4’-styrylpyridine arms showing excellent elasticity and photomechanical properties. A slender crystal can be bent to make a circle and write different shapes with restoration of original shape upon removal of the applied force. In addition, photomechanical properties triggered by [2+2] cycloaddition of the olefinic ligand can be modulated easily by variation of the crystal sizes. Crystals with bigger width show destructive photosalient effects while the smaller ones show plastic deformation like bending, twisting, curling etc. upon UV irradiation. This example provides avenue for designing CPs for multi-stimuli responsive actuating properties

Mechanical Bending and Modulation of Photoactuation Properties in a One-Dimensional Pb(II) Coordination Polymer

10.1021/acs.chemmater.1c01124CHEMISTRY OF MATERIALS33124621-462

Photoreactive Crystals Exhibiting [2+2] Photocycloaddition Reaction and Dynamic Effects

10.1021/acs.accounts.2c00107ACCOUNTS OF CHEMICAL RESEARCH55101445-145

Dynamic effects in crystalline coordination polymers

10.1039/d1ce00441gCRYSTENGCOMM23345738-575

Multistimuli-Responsive Dynamic Effects in a One-Dimensional Coordination Polymer

10.1021/acs.chemmater.1c03012CHEMISTRY OF MATERIALS341178-18

Multistimuli Responsive Dynamic Effects in a One-Dimensional Coordination Polymer

The development of multistimuli receptive actuators demands rational combination of suitable functionalities. Achieving such actuating properties in a single crystalline material is a challenge. In spite of several investigation on photo-, thermo- and mechano- responsive crystals, single crystalline material displaying all these effects is unknown. By a judicious combination of photoreactive 2-fluoro-4’-styrylpyridine units and flexible Pb(SCN)2 units, multistimuli responsive 1D CP showing all these dynamic effects has been fabricated. Single crystals of the CP display rapid ballistic events upon UV irradiation triggered by [2+2] cycloaddition of the photoreactive ligands. In addition, macroscopic jumping, bending, splitting of the crystals were observed during both heating and cooling cycles, because of the reversible phase transition. In addition, slander crystals of the CP exhibt elastic deformation upon the application of mechanical force. With handful examples CPs showing macroscopic dynamic effects, this CP paves the way for designing multistimuli responsive multi-salient actuating materials

Enhancement in Two-Photon Absorption and Photoluminescence in Single Crystals of Cd(II) Metal Organic Frameworks.

10.1021/acsami.3c00531ACS Appl Mater Interface

Reversible Thermosalience in a One-Dimensional Coordination Polymer Preceded by Anisotropic Thermal Expansion and the Shape Memory Effect

10.1021/jacs.0c12363JOURNAL OF THE AMERICAN CHEMICAL SOCIETY14342088-209

Rotation of a helical coordination polymer by mechanical grinding

Anisotropic cell volume expansion by mechanical grinding of the solid facilitates the concerted rotation of the photo-inert helical coordination polymer, which causes the misaligned arms containing olefin functional groups in the neighbouring strands to align to undergo [2+2] cycloaddition reaction in 83% yield.Ministry of Education (MOE)This work was financially supported by the Ministry of Education, Singapore (Grant No. Tier 1 WBS R-143-000-A12-114 and R-143-000-B13-114)