Flexibility Control of Two‐Dimensional Coordination Polymers by Crystal Morphology: Water Adsorption and Thermal Expansion

Abstract

Layer flexibility in two‐dimensional coordination polymers (2D‐CPs) contributes to several functional materials as it results in anisotropic structural response to external stimuli. Chemical modification is a common technique for modifying layer structures. This study demonstrates that crystal morphology of a cyanide‐bridged 2D‐CP of type [Mn(salen)]2[ReN(CN)4] (1) consisting of flexible undulating layers significantly impacts the layer configuration and assembly. Nanoplates of 1 showed an in‐plane contraction of layers with a longer interlayer distance compared to the micrometer‐sized rod‐type particles. These effects by crystal morphology on the structure of the 2D‐CP impacted the structural flexibility, resulting in dual‐functional changes: the enhancement of the sensitivity of structural transformation to water adsorption and modification of anisotropic thermal expansion of 1. Moreover, the nanoplates incorporated new adsorption sites within the layers, resulting in the uptake of an additional water molecule compared to the micrometer‐sized rods.

Colloidal and Thermal Stability of Three‐Component Hybrid Materials Containing Clay Mineral, Polysaccharide and Surfactant

“…In the case of AA and HEC samples they both contain significant contents of carbon and hydrogen but a small amount of nitrogen (less than 0.25 %) due to impurities. In the polymer/N−H two components hybrid martials the amounts of carbon and hydrogen are larger than in native N−H which is the evidence of the polysaccharides adsorption on the N−H surface [59,60] . When it comes to comparing the adsorption amounts of individual polymers on the N−H surface, the presented results clearly indicate that AA adsorption is the smallest, HEC adsorption is the highest, and in the case of CC, the adsorption amount is intermediate.…”

“…In the polymer/NÀ H two components hybrid martials the amounts of carbon and hydrogen are larger than in native NÀ H which is the evidence of the polysaccharides adsorption on the NÀ H surface. [59,60] When it comes to comparing the adsorption amounts of individual polymers on the NÀ H surface, the presented results clearly indicate that AA adsorption is the smallest, HEC adsorption is the highest, and in the case of CC, the adsorption amount is intermediate. This tendency is the result of interactions between the adsorbent surface and polymer macromolecules.…”

Mechanical Properties of Modulative Undulating Layers in Two-Dimensional Metal–Organic Frameworks

“…Related to this crystal morphology effect, a similar effect has been demonstrated by the analog of 1 and 2, [Mn(salen)] 2 [ReN(CN) 4 ], on anisotropic thermal expansion behavior. 47 Thus, controlling the crystal growth of 2D-MOFs causes changes to not only intrinsic thermal but also pressure responses associated with layer flexibilities. Note that the powder synthesis of 2 via mixing solutions yielded [Mn(salen)] 2 [Pt II 0.09 Pt IV (I 2 ) 0.91 (CN) 4 ]•H 2 O with a slightly incomplete proportion of iodine.…”

Janus-Type Mixed-Valent Copper–Cyanido Honeycomb Layers

“…2D coordination polymers (CPs) are a class of materials exhibiting various functionalities, such as adsorption, electronic, magnetic, and structural properties. − They exhibit several layer motifs, proving designability based on the selection of molecular components for layer construction, whereas Janus-type structures have rarely been reported. , Our group has been investigating cyanido-bridged 2D CPs consisting of undulating grid-type [M­(salen)] 2 [M′(CN) 4 (solvent)] (M = Mn and Fe; M′ = MnN, ReN, Pt, and Pt­(I 2 ) x ; x = 0.18, 0.45, 0.85, and 1.0; solvent = H 2 O, MeOH, and MeCN) − and flat honeycomb-type [Cu I 2 (CN) 3 ] − layers . The composition- and layer size-dependent anisotropic thermal expansion (TE) behaviors based on structural distortion relaxation phenomena of these layers have been demonstrated.…”