Helical Nanographenes Embedded with Contiguous Azulene Units

The
azulene moiety, composed of contiguous pentagonal and heptagonal
rings, is a structural defect that alters the electronic, magnetic,
and structural properties of graphenes and graphene nanoribbons. However,
nanographenes embedded with an azulene cluster have not been widely
investigated because these compounds are difficult to synthesize in
their pure form. Herein, azulene-embedded nanographenes bearing a
unique cove-type edge were synthesized by a novel synthetic protocol.
Experimental and theoretical investigations revealed that this cove
edge imparts stable helical chirality, unlike normal cove edges. The
in-solution self-association behavior and the structural, electronic,
and electrochemical properties were also described in detail.

由相邻五元和七元环构成的薁（azulene）片段，是一类可改变石墨烯及石墨烯纳米带电子、磁学与结构性质的结构缺陷。然而，内嵌薁簇的纳米石墨烯尚未得到广泛研究，这是因为这类化合物难以以纯相形式合成。本研究中，我们通过全新合成方案制备了带有独特凹型边缘（cove-type edge）的内嵌薁纳米石墨烯。实验与理论研究表明，与普通凹边不同，该凹型边缘可赋予其稳定的螺旋手性。本文还详细阐述了其溶液中的自缔合行为，以及结构、电子与电化学性质。