Preparation, structure and optical properties of [CH3SC(NH2)NH2]3PbI5, [CH3SC(NH2)NH2]4Pb2Br8and [CH3SC(NH2)NH2]3PbCl5·CH3SC(NH2)NH2Cl
The preparation, crystal structures and optical absorption spectra of [CH3SC(NH2)NH2 ]3PbI51, [CH3SC(NH2)NH2 ]4Pb2Br82 and [CH3SC(NH2)NH2 ]3PbCl5·CH3SC(NH2)NH2Cl 3 are reported. Compounds 1 and 3 consist of deformed PbX6 octahedra, which share opposite corners to form quasi-zero-dimensional or one-dimensional infinite chains along the a-axis. Compound 2 consists of Pb2Br9 units which are connected with two neighbouring units by non-opposite Br atoms; in this way, infinite zigzag chains are formed. A blue shift of the excitonic absorption bands, in comparison to those of systems with higher dimensionality, is observed.