Substrate-directed trimeric nucleation and manipulable reconfiguration of 2,8-bis(diphenylphosphoryl)-dibenzothiophene on Au(111) and hBN/Rh(111)

We investigate the real-space nucleation behavior of 2,8-bis(diphenylphosphoryl)-dibenzo[b,d]thiophene (PPT) on Au(111) and hBN/Rh(111) using low-temperature Scanning Tunneling Microscopy (STM). PPT forms a robust nucleation unit, exhibiting emergent left- and right-handed configurations despite its intrinsic achirality. On Au(111), this chiral trimer serves as a robust nucleation unit that remains intact under tip manipulation and directs anisotropic, herringbone-guided growth. In contrast, the hBN nanomesh confines PPT within individual pores, producing isolated trimers and enabling reversible tip-induced reconfiguration between disordered and ordered chiral states. These results reveal how substrate symmetry and confinement stabilize chiral characteristic trimeric clusters and govern molecular assembly, offering new strategies for deterministic control of organic semiconductor ordering.