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Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe 2 O 4 Nanoparticles
Author(s) -
Georgiadou Violetta,
DendrinouSamara Catherine
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201402323
Subject(s) - chemistry , thermogravimetric analysis , magnetic nanoparticles , nuclear chemistry , bromide , fourier transform infrared spectroscopy , nanoparticle , crystallinity , nuclear magnetic resonance spectroscopy , inorganic chemistry , chemical engineering , organic chemistry , crystallography , engineering
CoFe 2 O 4 magnetic nanoparticles (MNPs) were synthesized in a new synthetic system from metal acetylacetonates in the presence of octadecylamine (ODA) in autoclaves with subcritical water. By altering the water extent and ratio of the precursors, four samples were isolated. High crystallinity MNPs of various sizes (26, 15, 18, 9 nm) and saturation magnetization (71, 87, 93, 64 emu g –1 ) were formed. The organic coating was characterized by FTIR spectroscopy, 1 H NMR and 13 C NMR spectroscopy, and thermogravimetric analysis (TGA), and the free amine groups were detected by a ninhydrin assay. Under the present conditions, the CoFe 2 O 4 MNPs were covered by a bilayer consisting of N ‐octadecylamide and ODA. The MNPs were converted into fluorescence probes through the formation of a sulfonamide bond between ODA and sulforhodamine B (SRB). NMR relaxometric measurements were performed for MNPs modified with SRB, cetyltrimethylammonium bromide, and by 2,3‐dimercaptosuccinic acid. The bimodal magnetic fluorescent MNPs showed relaxivity values of up to r 2 = 219.5 m M –1 s –1 , which renders them promising as dual agents.