Solvent-Mediated Crystal-to-Crystal Interconversion between Discrete Lanthanide Complexes and One-Dimensional Coordination Polymers and Selective Sensing for Small Molecules

Abstract

Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF.

s‐Triazine pincer ligands: Synthesis of their metal complexes, coordination behavior, and applications

“…[183-186,215a] In presence of ZnCl 2 , the BPT ligand undergone hydrolysis as indicated by the formation of [Zn(pz) 2 Cl 2 ] complex. [186] The same research group reported the Cu(II)mediated hydrolysis of the BPT ligand [215b] followed by complexation giving the followed by complexation Giri et al [134] [Ru(dmdptz)(phen)Cl](ClO Wu et al [136] [ Safin et al [143] [Cd( Frost et al [147] [Cd 2 (TpymT)( Safin et al [148] [Pb 2 (TPymT)(NO Wang et al [176] [ Soliman et al [185] [Cd(BPT) Carranza et al [169] [Ag(bdpdt) Berdiell et al [182] [ [Cu(TPTZ) 2 ](PF 6 ) 2 Breast cancer (MCF-7) Abdi et al [51] [Cu(TPTZ)(Ph 3 P) 2 ](PF 6 ) Cosensitized solar cells Báez-Castro et al [52,53] (Continues)…”

“…Design and modification of the dipyridyl-based s-triazine ligands as a rigid multidentate ligands by insertion of a hydroxyl group, sulfhydryl, or amino group at the third carbon of the s-triazine core were explored by the research group of Cao and Ye in 2013. [136] This modification on the ligand structure offered numerous coordination sites due to the six potential binding sites exist in 4,6-bis(2-pyridyl)-striazin-2-ol (HOBPT; 185) as an example. Subsequently, they synthesized two 1D Ln(III) coordination polymers including Eu(III) and Tb(III) with HOBPT ligand.…”

“…[211] On other hand, the reaction of HOBPT with hardmetal ions such as Na + , Ca 2+ , and Ba 2+ or rare-earth ions such as Eu 3+ or Tb 3+ afforded 1D coordination polymers or discrete complexes in which the ligand is a bridge in mode B coordination behavior. [136,212] Using hydrothermal conditions, the nanocage cation [Co(H 2 O) 6 & Co 8 (OBPT) 12 ] 6+ has been assembled from the reaction of HOBPT with Co (NO 3 ) 2 .6H 2 O under hydrothermal conditions. In this case, the OBPT ligand adopted a mode C with the capability of bridging two cobalt (II) ions in a chelating manner [213] (Figure 19).…”

Lanthanide coordination polymers based on designed bifunctional 2-(2,2′:6′,2″-terpyridin-4′-yl)benzenesulfonate ligand: syntheses, structural diversity and highly tunable emission

“…The versatility and tailorability of physicochemical properties of lanthanide ions make them key to an extremely wide range of techniques and devices (Jones, 2011;Pyykkö, 2015;Samson et al, 2011;Maurin et al, 2017;Guillou et al, 2016). During the past two decades, the design and synthesis of lanthanide coordination polymers (LnCPs) have received great attention due to their powerful attributes, originating from specific functional applications, such as photocatalysis (Qiao & Schelter, 2018), gas storage and separation (Banerjee et al, 2015;Roy et al, 2014;Alezi et al, 2015), magnetism (Liu et al, 2014;Zhang et al, 2015;Mohapatra et al, 2013;Cai et al, 2013;Zou et al, 2010), sensing (Wu et al, 2019(Wu et al, , 2013Chen et al, 2010;Dou et al, 2014;Chen et al, 2017;Zhou et al, 2018;Xu et al, 2017) and tunable luminescence (Cui et al, 2014;SeethaLekshmi et al, 2017;Bü nzli & Piguet, 2005;Xiao et al, 2016;Wu et al, 2011aWu et al, , 2017). These applications are made possible by the characteristic luminescent behaviour of ISSN 2052-5206 # 2019 International Union of Crystallography lanthanide elements, which stem from the shielding of their 4f core-like electrons and the large numbers of unpaired electrons of each Ln 3+ metal centre (Bü nzli & Piguet, 2005;Heffern et al, 2014;Woodruff et al, 2013;.…”

P–C Bond Cleavage-Assisted Lanthanide Phosphate Coordination Polymers

“…Such crystal-crystal transformations have been recently reported. 49 The molecular structure of compound 3 is given in Scheme 1 and in the SI. The molecular structure of compound 3 contains one gadolinium center in the asymmetric unit.…”