Molecules Molecules, Vol 26, Iss 6690, p 6690 (2021) Molecules 26(21), 6690-(2021). doi:10.3390/molecules26216690 Volume 26 Issue 21 Molecules : a journal of synthetic chemistry and natural product chemistry 26(21), 6690 (2021). doi:10.3390/molecules26216690 special issue: "Special Issue "Advances in NMR and MRI of Materials" / Special Issue Editor: Prof. Dr. Igor Serša, Guest Editor"