Covalent Functionalization of FeCo/Graphitic Shell Nanocrystals via 1, 3‐Dipolar Cycloaddition. Issue 1 (25th October 2017)

• Record Type: Journal Article
• Authors: Kim, Da Jeong; Hong, Yonghoon; Seo, Yu Jeong; Yang, Daehee; Lee, Sung Woo; Gil, Na‐Yeon; Moon, Bongjin; Cha, Hyuk‐Jin; Lee, Gaehang; Seo, Won Seok
• Is Part Of: ChemNanoMat. Volume 4:Issue 1(2018)
• Page Start: 132
• Page End: 139
• Publication Date: 2017-10-25
• Subjects: Cobalt -- covalent functionalization -- 1, 3-dipolar cycloaddition -- graphitic shell -- iron -- magnetic resonance imaging (MRI); Nanochemistry -- Periodicals; Nanostructured materials -- Periodicals; Nanochemistry; Nanostructured materials; Periodicals; 541.2
• DOI: 10.1002/cnma.201700223
• Languages: English
• ISSNs: 2199-692X

Abstract

Abstract: Covalently functionalized water‐soluble FeCo/graphitic shell nanocrystals ( f −FeCo/GC NCs) were synthesized via 1, 3‐dipolar cycloaddition of azomethine ylides generated in situ from sarcosine and glucose. The FeCo core has superparamagnetic properties at room temperature, and the graphitic shell exhibits near‐infrared optical absorbance. Acetylation of the hydroxyl groups on the f −FeCo/GC NCs gives doubly functionalized FeCo/GC ( ff −FeCo/GC) NCs that are soluble only in organic solvents such as ethyl acetate. The f −FeCo/GC NCs were shown to be excellent T 1 or T 2 MRI contrast agents. Especially, due to the hydrophilic and compact surface functionalization, f −FeCo/GC NCs exhibit a doubled r 1 relaxivity and half r 2 / r 1 ratio compared to those of the non‐covalently PL‐PEG‐functionalized FeCo/GC NCs. This work shows not only the first synthesis of covalently functionalized highly water‐soluble metal NCs coated with a single‐layered graphitic shell, but also for the first time the MR enhancing properties of the covalently functionalized magnetic NCs. Abstract : Covalently functionalized FeCo/graphitic shell nanocrystals ( f −FeCo/GC NCs) are synthesized by 1, 3‐dipolar cycloaddition of azomethine ylides generated from sarcosine and glucose. Due to the hydrophilic and compact surface functionalization, the highly water‐soluble f −FeCo/GC NCs exhibit a doubled r 1 relaxivity and half r 2 / r 1 ratio compared to those of the non‐covalently PL‐PEG‐functionalized FeCo/GC NCs.