Authors:	Liu, Yi
Title:	From cyclic oligophenylenes to graphenes
Online publication date:	9-Jun-2017
Year of first publication:	2017
Language:	english
Abstract:	With the advent of graphene at 2004, carbon materials have attracted numerous interests as a consequence of their unique structures and extraordinary electronic properties. And the variable hybridization states of carbon atoms have rendered lots of possibilities to construct diverse carbon networks by modulating periodical binding networks as well as the composition of sp3-, sp2- and sp-hybridized carbon atoms in the backbone. In this dissertation, the research ranges from the synthesis of new carbon networks and their substructures to construction of functional nano-sized segments of graphene via controllable chemical modification. The first two chapters are dedicated to the proposal of new carbon networks (two-dimensional or double-helical), and synthesis of cyclic oligophenylenes with novel topology (like shape-persistent spoked-wheel, “figure eight” and Möbius strip) as their substructures. The synthesis was carried out through nickel-catalyzed intramolecular Yamamoto coupling of a specific polyphenylene precursor. Characterizations by NMR spectroscopy, MALDI-TOF mass spectrometry, and STM microscopy provided an unambiguous structural proof for these molecules. In the last two chapters, the work was aimed at controllable chemical modification of graphene sheets and nanographenes to tune their electronic properties. With the aid of oxidation on sulfur atoms, the HOMO/LUMO level of nanographene molecules could be efficiently modulated by controlling the valence state of the sulfur atoms, which were embedded in the edge region of nanographenes. In addition, the band gap of graphene could also be engineered via spatially-controlled chemical functionalization on the basal planes of graphene sheets.
DDC:	540 Chemie 540 Chemistry and allied sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-859
URN:	urn:nbn:de:hebis:77-diss-1000013484
Version:	Original work
Publication type:	Dissertation
License:	In Copyright
Information on rights of use:	https://rightsstatements.org/vocab/InC/1.0/
Extent:	232 Seiten
Appears in collections:	JGU-Publikationen