Pathway selection as a tool for crystal defect engineering: A case study with a functional coordination polymer

New synthetic routes capable of achieving defect engineering of functional crystals through well- controlled pathway selection will spark new breakthroughs and advances towards unprecedented and unique functional materials and devices. In nature, the interplay of chemical reactions with the diffusion of reagents in space and time is already used to favor such pathway selection and trigger the formation of materials with bespoke properties and functions, even when the material composition is preserved. Following this approach, herein we show that a controlled interplay of a coordination reaction with mass transport (i.e. the diffusion of reagents) is essential to favor the generation of charge imbalance defects (i.e. protonation defects) in a final crystal structure (thermodynamic product). We show that this syn- thetic pathway is achieved with the isolation of a kinetic product (i.e. a metastable state), which can be only accomplished when a controlled interplay of the reaction with mass transport is satisfied. Account- ing for the relevance of controlling, tuning and understanding structure-properties correlations, we have studied the spin transition evolution of a well-defined spin-crossover complex as a model system

Pathway selection as a tool for crystal defect engineering: A case study with a functional coordination polymer

New synthetic routes capable of achieving defect engineering of functional crystals through well-controlled pathway selection will spark new breakthroughs and advances towards unprecedented and unique functional materials and devices. In nature, the interplay of chemical reactions with the diffusion of reagents in space and time is already used to favor such pathway selection and trigger the formation of materials with bespoke properties and functions, even when the material composition is preserved. Following this approach, herein we show that a controlled interplay of a coordination reaction with mass transport (i.e. the diffusion of reagents) is essential to favor the generation of charge imbalance defects (i.e. protonation defects) in a final crystal structure (thermodynamic product). We show that this synthetic pathway is achieved with the isolation of a kinetic product (i.e. a metastable state), which can be only accomplished when a controlled interplay of the reaction with mass transport is satisfied. Accounting for the relevance of controlling, tuning and understanding structure-properties correlations, we have studied the spin transition evolution of a well-defined spin-crossover complex as a model system.This work was partially supported by the European Union (ERC-2015-STG microCrysFact 677020), the Swiss National Science Foundation (Projects no. 200021_160174 and 200021 181988), MAT 2015–70615-R and MINECOCTQ2017-88948-P and RTI2018-098027-B-C21 from the Spanish Government funds, and by the European Regional Development Fund (ERDF). J.P.L. and S.P. acknowledge networking support by the COST Action CM1407 “e-minds”. The ICN2 is funded by the CERCA programme / Generalitat de Catalunya. The ICN2 is supported by the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant no. SEV-2017-0706). S.S-G. acknowledges the support from MINECO BES-2015-071492 grant. A.R. acknowledges the European Commission through the SPINSWITCH project (H2020-MSCA-RISE-2016, Grant Agreement No. 734322). Additionally, all authors acknowledge Jaume Caelles for SAXS/WAXS measurements performed at IQACCSIC. G.A. thanks support by the Generalitat de Catalunya through the ICREA Academia Prize 2018 Authors A. Abrishamkar, S. Suárez–García and S. Sevim contributed equally to this work.Peer reviewe