First Tribo‐Excited Chemical Reaction of a Stacked Lanthanide Coordination Polymer with an in Situ Reaction Monitor

Abstract

A tribo‐excited chemical reaction using a stacked lanthanide coordination polymer is demonstrated for the first time. The polymer is composed of a EuIII ion, hexafluoroacetylacetonato ligands, and an anthracene‐based phosphine oxide bridge. The tightly stacked structure with hydrogen bonding was characterized by X‐ray crystal structure analysis. The mechanical stimulus leads to tribo‐excited oxidation in the EuIII coordination polymer. Electron ionization mass spectroscopy and photo‐spectroscopic analysis reveal that the chemical product afforded by tribo‐oxidation is different from that obtained by photo‐oxidation.

Tribo‐Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework

“…The Eu III complex formed a dinuclear structure with stacked anthracene frameworks. Shape measurement calculations revealed that Eu adopted a square antiprism coordination geometry [7] ( S =0.676), similar to the previously reported triboluminescent lanthanide complexes [4a–c] . The distance between the anthracene frameworks is 3.9 Å; this distance is sufficient for effective dimerization reactions [6] …”

“…The previous study indicate a high priority of 4 f–4 f excited state formation by tribo‐excitation [4a–b] . Recently, we were able to successfully use tribo‐excitation energy to demonstrate chemical oxidation in Eu III polynuclear complexes with hexafluoroacetylacetonato (hfa) and phosphine oxide bridges (Figure 1a) [4c] . The oxidation originated from the energy transfer from the excited Eu III ( 5 D 0 ) induced by tribo‐excitation to the lowest excited triplet state (T 1 ) in the anthracene monomer unit.…”

“…Drastic changes in the luminescence color were observed upon the conversion of Eu to Eu‐UV or Eu‐Tribo . The red Eu III luminescence indicates the progress of the chemical reaction [4c] . Their electronic absorption, emission spectra, and emission lifetimes are given in Figures S3 and S4 and Table S2.…”

Highly photo- and triboluminescent lanthanide(iii) coordination polymers based on diphosphine dioxides containing azaheterocyclic linkers

“…[31][32][33] Recently, diphosphine dioxides have been increasingly used for the construction of coordination compounds with outstanding luminescence properties. 13,22,25,30,[34][35][36][37][38][39][40][41][42][43] Most diphosphine dioxides used for preparing lanthanide complexes contain linkers that are not involved in coordination to the Ln 3+ ion. The introduction of a donor linker moiety into diphosphine dioxide is a promising approach for the preparation of potentially multidentate ligands for the formation of a saturated and rigid coordination sphere around the Ln 3+ ion (Scheme 1).…”

Bright red emission with high color purity from Eu(iii) complexes with π-conjugated polycyclic aromatic ligands and their sensing applications

“…[134][135][136][137][138][139] We focused on the role of Eu(III) excitation energy in excited state chemical reactions to achieve tribo-excitation. 140 Based on this concept, we prepared a Eu(III) coordination polymer with hfa and phosphine oxide ligands containing a reactive anthracene unit (bpa: 2,6-bis(diphenylphosphine oxide)anthracene). The stacked structure between single polymer chains was formed in the coordination polymer via hydrogen bonding.…”