Grinding of an organometallic crystalline material leads to quantitative formation of a hydrated polymorph

Abstract

The hydrated crystalline material [(η⁵-C₅H₅)₂Co]⁺[(η⁵-C₅H₄CO₂H)(η⁵-C₅H₄CO₂)Fe]^–·H₂O 3 is prepared by simply grinding either the crystalline powder 1 that precipitates from thf on reacting [(η⁵-C₅H₅)₂Co] with [(η⁵-C₅H₄CO₂H)₂Fe] or single crystals of [(η⁵-C₅H₅)₂Co]⁺[(η⁵-C₅H₄CO₂H)(η⁵-C₅H₄CO₂)Fe]^– 2 obtained by recrystallization of 1 from nitromethane; on heating at 373K 3 loses water and reverts to the starting material 1.