Syntheses And Properties Of Coordination Polymers Constructed From Tetraphenylethylene Building Block

Coordination polymers?CPs?,as an emerging class of organic-inorganic hybrid materials,have developed rapidly in many potential applications over the past decade.The use of tetraphenylethylene?TPE?derivatives as ligands to synthesize coordination polymers and explore their new functions has attracted wide attention from scientists.In this paper,by using TPE as a building block,tetrapyridine and bis-pyridine and dicarboxyl-containing nitrogen or carboxyl ligands are synthesized through post-modification of TPE.Then,a series of novel coordination polymers have been successfully synthesized with these TPE ligands and different metal clusters or metal ions under solvothermal conditions.The mechanochromic,thermochromism and adsorption of iodine of these compounds were investigated.In addition,the post-modification synthesis method is also used to introduce tetraphenylethylene derivatives into bio-MOF-101,and their properties as a white light-emitting diode?WLED?device were also explored.1.By introduction of four pyridine groups in tetraphenylethylene building block,tetrapyridyltetrastyrene ligands:1,1,2,2-tetrakis?4-?pyridin-4-yl?phenyl?ethane?tppe?were synthesized.Then,two new coordination polymers[Cd?tppe?Cl₂]·14H₂O?1?and[Cd?tppe?Cl₂]·10H₂O?2?have been prepared by using tppe ligands and Cd²⁺ions under solvothermal conditions.Compound 1 possesses a classical 2D framework with an ABAB stacking sequence.For compound 2,it shows a doubly interpenetrated 3D framework.Remarkably,both samples 1 and 2 exhibit interesting mechanochromic behaviour with color changes visible to the naked-eye from blue to green-yellow under UV irradiation,and the emission wavelength red shift by 49 and 62 nm for 1 and 2,respectively.Moreover,these fluorescence recoveries are reversible by soaking in DMF,showing that these CPs can be used as chemical sensors.2.By using tetraphenylethylene as a building block,cis-and trans-bipyridyl TPE ligands:cis-1,2-bis?4-?pyridin-2-yl?phenyl?-ethane and trans-1,2-bis?4-?pyridin-2-yl?phenyl?ethane?cis-bpype and trans-bpype?were synthesized.Then,two Cu?I?cluster based coordinationpolymers,[CuI?cis-bpype?]·CH₃CN?3?and[Cu₄I₄?cis-bpype?₃?trans-bpype?]·3DMF?4?have been synthesized from cis-and trans-bpype ligands and{Cu₄I₄?PPh₃?₄}as starting materials.In compound 3,adjacent rhomboid-type{Cu₂I₂}units from the decomposition of{Cu₄I₄?PPh₃?₄}starting material connect by cis-bpype ligands to form a 1D framework.Compound 4 also has a 1D structure,but it has a{M₂L₃}-type coordinated cage constructed by three cis-bpype ligands and two{Cu₄I₄}secondary building units?SBU?,and these coordination cages further link by trans-bpype to form the final frameworks.Upon cooling from 300 to 80 K,these Cu?I?cluster based coordination polymers exhibit interesting thermochromic behavior.In particular,compound 4gives a chromic process from green luminescence at room temperature to red luminescence at80 K and its corresponding CIE coordinates shift from green?0.34,0.43?at 300 K to red?0.46,0.42?at 80 K,respectively.This red shift of 124 nm?516 to 640 nm?is large enough to ensure a color change visible to the naked eye,which can be potentially utilized as a temperature sensor with a wide range.3.By introduction of two benzoic acid groups in tetraphenylethylene building block,1,2-Bis?4-?4-carboxyphenyl??-1,2-diphenylethene?H₂BCPPE?ligand were synthesized.Then,H₂BCPPE has been successfully introduced into bio-MOF-101 archetype structure usage via solvent-assisted ligand exchange?SALE?.After ligand exchange,the crystallinity and topological structure of as-synthesized bio-MOF-101-BCPPE is well retained.The exchange ratio of BCPPE ligands within bio-MOF-101-BCPPE reaches to 18.3 mol%,determined by¹H NMR spectra of dissolved samples.Additionally,bio-MOF-101-BCPPE also exhibits a broadband white emission with the CIE coordinates of?0.35,0.36?under the excitation wavelength at 375 nm and 3 V applied bias.This work can be easily expanded to other luminescent MOFs for the design and development of new light devices.4.By using tetraphenylethylene as a building block,tetrapyridyltetrastyrene?tppe?ligand was synthesized.Then,three new supramolecular isomers[Cu₂I₂?tppe?]·4DMF?5??[Cu₂I₂?tppe?]·2DMF?6??[Cu₂I₂?tppe?]·PEG200?7?have been prepared by tuning the poly?ethylene glycol??PEG?content in the feed.These supramolecular isomers have the same framework formula of[Cu₂I₂?tppe?]and different architectures from the classical 2D stacking framework to a 3D entangled system with the coexistence of interpenetration and polycatenation,and a 3D topological framework.Interestingly,these CPs could be utilized for capturing iodine molecules.According to multiple complementary experiments and crystallographic analyses,iodine capture is mainly based on halogen-bond interactions in the inorganic{Cu₂I₂}building blocks of the framework.The present study describes a structure-property relationship in supramolecular isomerism with distinct topological structures.