Crystal structures and optical properties of 1-D iodoplumbates templated by in situ synthesized p-phenylenediamine derivatives

Two inorganic–organic hybrids, (MPDA)2n(Pb3I10)n (MPDA = p-Me3NC6H4NMe3) (1) and (H2EPDA)n(Pb2I6)n·2nH2O (H2EPDA = p-Et2NHC6H4NHEt2) (2), have been solvothermally synthesized using p-phenylenediamine (PDA) as a precursor. Their iodoplumbate ions all show 1-D chain structures, but differ in interlinkage modes of [PbI6] octahedra: the former is both face- and edge-sharing, while the latter is face-sharing. The chain-like structure in 1 was reported only once in the literature. The results of optical absorption spectra and theoretical calculations for compounds PbI2 and 1–2 reveal a quantum confinement effect. Photoluminescent analyses show that they all exhibit blue emissions upon UV irradiation, which mainly originate from charge transfer from iodine atoms to ammoniums.