Novel Viologen Derivative Based Uranyl Coordination Polymers Featuring Photochromic Behaviors

Abstract

A series of novel uranyl coordination polymers have been synthesized by hydrothermal reactions. Both complexes 1 and 2 prosess two ipbp ligands (H ipbpCl=1-(3,5-dicarboxyphenyl)-4,4'-bipyridinium chloride), one uranyl cation, and two coordination water molecules, which can further extend to 2D networks through hydrogen bonding. In complex 1, two sets of equivalent nets are entangled together, resulting in a 2D + 2D → 3D polycatenated framework. In complex 2, the neighbouring equivalent nets interpenetrate each other, forming a twofold interpenetrated network. Complexes 3 and 4 are isomers, and both of them are constructed from (UO ) (OH) dinuclear units, which are connected with four ipbp ligands. The 3D structures of complexes 3 and 4 are similar along the b axis. Similar to other viologen-based coordination polymers, complexes 3 and 4 exhibit photochromic and thermochromic properties, which are rarely observed in actinide coordination polymers. Unlike the monotonous coordination mode in complexes 1-4, the ipbp ligands feature a μ -bridge through two kinds of coordination modes in complex 5. Notably, complex 5 presents a unique example in which terminal pyridine nitrogen atom is involved in the coordination.

Construction of Hybrid Bimetallic Uranyl Compounds Based on a Preassembled Terpyridine Metalloligand

“…The large aperture allows two sets of 2D composite planar nets to be entangled together with a dihedral angle of 49.53° (Figure 4 c), resulting in a 2D+2D→3D polycatenated framework (Figure 4 d). Interpenetrating structures are relatively uncommon for planar graphene‐like cellular networks compared with 3D frameworks, and improve the topological diversity of uranyl–organic compounds to a certain extent [6b, 19–20] …”

2,5-Thiophenedicarboxylate: An Interpenetration-Inducing Ligand in Uranyl Chemistry

“…Considering the extent to which the structures involving tdc 2-are sensitive to such effects, it appeared worthwhile to further investigate the influence of different counterions or structure-directing species displaying varying characteristics in terms of bulkiness and possible weak interactions. In particular, the significant number of interpenetrated structures which have been found in this family was an incentive to further search for the structure-directing species able to promote this phenomenon, of which several examples have lately been given in uranyl chemistry [13][14][15][16][17][18][19][20][21][22][23][24][25][26] (an overview of the cases reported prior to 2017 has previously been given 13 ).…”

3D Uranyl Organic Frameworks Supported by Rigid Octadentate Carboxylate Ligand: Synthesis, Structure Diversity, and Luminescence Properties

“…The so‐called uranyl cation, [UO 2 ] 2+ , features a special linear triatomic topology with two terminal O located in the axis, exhibiting a special chemical ability to coordinate with 4–6 additional O/N‐donors in the equatorial plane. Until now, with the use of multidentate carboxylates, phosphates and sulfonate ligands, a huge amount of the uranyl‐organic frameworks (UOFs) have been characterized in the lab [15–21] . Among these structures, 3D structures are relatively lacking but highly desirable, and it generally exhibits excellent thermal stability and outstanding properties with respect to low‐dimensional structures.…”

“…Until now, with the use of multidentate carboxylates, phosphates and sulfonate ligands, a huge amount of the uranyl-organic frameworks (UOFs) have been characterized in the lab. [15][16][17][18][19][20][21] Among these structures, 3D structures are relatively lacking but highly desirable, and it generally exhibits excellent thermal stability and outstanding properties with respect to low-dimensional structures.…”