# Recoverable and Sensitive Pressure-Induced Mechanochromic Photoluminescence of a Au-P Complex

## TL;DR

A gold-phosphorus complex shows reversible color changes under pressure and can be used for encrypted information transfer.

## Contribution

The paper introduces a recoverable mechanochromic photoluminescent Au-P complex with potential for encrypted information transfer.

## Key findings

- The Au-P complex emits yellow phosphorescence that shifts to green under 5 MPa pressure.
- The color change is recoverable with exposure to CH2Cl2 vapor or grinding.
- The complex enables recyclable write/erase functionality on filter paper for encrypted information.

## Abstract

A binuclear Au-P complex [Au2(2-bdppmapy)2](PF6)2 (1) was synthesised by the reaction of 2-bdppmapy (N,N′-bis-(diphenylphosphanylmethyl-2-aminopyridine) with AuCN and [Cu(MeCN)4]PF6. The solid phase of 1 emitted bright yellow phosphorescence at λmax = 580 nm under UV excitation (QY = 4.41%, τ = 1.88 μs), which shifted to green (λmax = 551 nm, QY = 5.73%) after being pressurised under 5 MPa. This colour change was recoverable upon exposure to CH2Cl2 vapor. Similar mechanochromic photoluminescence behaviour was observed after grinding the crystals of 1. A filter paper impregnated with 1 demonstrated recyclable write/erase functionality for encrypted information transfer.