Microwave-assisted silylation of graphite oxide and iron(III) porphyrin intercalation

The hybrid material graphite oxide (GO) intercalated with an iron(III) porphyrin was obtained upon a silylation reaction of GO with 3-bromotrimethoxypropylsilane (BrTMS) followed by metalloporphyrin immobilization. Diverse reaction conditions and microwave versus conventional heating were tested. The materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry (TGA) and temperature programmed desorption (TPD). Microwave-assisted synthesis allowed functionalization reactions of 1 h instead of 24 h (conventional heating) with equivalent or improved yields on both silylation and metalloporphyrin immobilization reactions. The immobilizations performed in anhydrous solvent and absence of other exfoliation agents led to an increase on the GO interlayer distance of 0.14 nm, in a total space of 7 Å that match the metalloporphyrin thickness.
The authors thank the Fundação para a Ciência e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE, for funding REQUIMTE through projects PEst-C/EQB/LA0006/2013, NORTE-07-0124-FEDER-000067-nanochemistry and PTDC/EQU-ERQ/110825/2009. Authors acknowledge the MICINN of Spain (Projects CTQ-2011-29272-C04-01 and -03) for financial support. Thanks are also due to Joint Project “Acções Luso-Espanholas” E20/11 Acciones Integradas AIB2010PT-00104. Monika E. Lipińka also thanks FCT for a PhD grant SFRH/BD/66297/2009.