Quantifying the Covalent Functionalization of Black Phosphorus

• Published in: Angewandte Chemie International Edition 2020-11, Vol.59 (45), p.20230-20234
• Main Authors: Wild, Stefan, Dinh, Xuan Thong, Maid, Harald, Hauke, Frank, Abellán, Gonzalo, Hirsch, Andreas
• Format: Article
• Language: English
• Subjects: 31P-MAS NMR spectroscopy; black phosphorus; Covalence; covalent functionalization; Graphene; Immunoglobulins; Intercalation compounds; Magnetic resonance spectroscopy; Methylation; NMR; NMR spectroscopy; Nuclear magnetic resonance; Phosphorus; Raman spectra; Raman spectroscopy; reduction; Spectroscopy; Spectrum analysis
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202008646

A straightforward quantification method to consistently determine the overall functionalization degree of covalently modified two‐dimensional (2D) black phosphorus (BP) by Raman spectroscopy has been carried out. Indeed, the successful reductive methylation of the BP lattice using sodium intercalation compounds and exhibiting different functionalization degrees has been demonstrated by 31P‐magic angle spinning (MAS) NMR spectroscopy. Furthermore, the correlation of 31P‐MAS NMR spectroscopy and statistical Raman spectroscopy (SRS) revealed the first method to determine the functionalization degree of BP solely by evaluating the intensities of distinct peaks in the Raman spectra of the covalently modified material, in a similar way to the widely employed ID/IG ratio of graphene research. The covalent functionalization of black phosphorus intercalation compounds (BPICs) with iodomethane has been developed. Starting from BPICs with different amounts of alkali metal the methylation can be achieved in varying functionalization degrees, which can be determined directly by Raman spectroscopy.