Expression of concern: Preparation of polydopamine sulfamic acid-functionalized magnetic Fe3O4 nanoparticles with a core/shell nanostructure as heterogeneous and recyclable nanocatalysts for the acetylation of alcohols, phenols, amines and thiols under solvent-free conditions

Expression of concern for ‘Preparation of polydopamine sulfamic acid-functionalized magnetic Fe 3 O 4 nanoparticles with a core/shell nanostructure as heterogeneous and recyclable nanocatalysts for the acetylation of alcohols, phenols, amines and thiols under solvent-free conditions’ by Hojat Veisi et al. , Green Chem. , 2016, 18 , 6337–6348, https://doi.org/10.1039/C6GC01975G.