  Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are emerging
as a unique class of 2D electronic materials. However, intrinsically
semiconducting 2D c-MOFs with gaps in the Vis-NIR and high charge carrier
mobility have been rare. Most of the reported semiconducting 2D c-MOFs are
metallic (i.e. gapless), which limits their use in applications where larger
band gaps are needed for logic devices. Herein, we design a new D2h-geometric
ligand, 2,3,6,7,11,12,15,16-octahydroxyphenanthro(9,10b)triphenylene (OHPTP),
and synthesize the first example of a 2D c-MOF single crystal (OHPTP-Cu) with a
rhombohedral pore geometry after coordination with copper. The continuous
rotation electron diffraction (cRED) analysis unveils the orthorhombic crystal
structure at the atomic level with a unique AB layer stacking. The resultant
Cu2(OHPTP) is a p-type semiconductor with an indirect band gap of about 0.50 eV
and exhibits high electrical conductivity of 0.10 S cm-1 and high charge
carrier mobility of 10.0 cm2V-1s-1. Density-functional theory calculations
underline the predominant role of the out-of-plane charge transport in this
semiquinone-based 2D c-MOFs.
