Thermal transformation of 1D-Pb(en)2Cl2 to 3D-PbCl2via 2D-Pb(en)Cl2 and their substantial modification of the coordination environment on Pb(II)

The solvothermal synthesis and crystal structures of two new lead(II) compounds, bis(ethylenediamine)lead(II) chloride, Pb(en)2Cl21 and mono(ethylenediamine)lead(II) chloride, Pb(en)Cl22, are reported. A detailed comparison of the two structures is given. In 1, the Pb(II) center is coordinated by two chlorine atoms and four nitrogen atoms from three en ligands, which act as either chelating or bridging ligands, allowing links to other Pb(II) centers. This creates an infinite linear chain of Pb(en)2Cl2. In 2, the Pb(II) center is chelated by one en ligand and is coordinated by six chlorine atoms, including two unusually weak Pb–Cl bonds (>3.5 Å) connected through μ2- and μ4-Cl to build a neutral layer of Pb(en)Cl2 units. Complex 1 contains a hemidirected Pb(II), while complex 2 has a (pseudo-)hemidirected Pb(II). TGA and high-temperature controlled powder-XRD studies show that compound 1 decomposes to compound 2 near 150 °C, and finally to PbCl2 above 320 °C.

Two new lead(II) compounds, 1D-Pb(en)2Cl21 and 2D-Pb(en)Cl22, where en is ethylenediamine, are solvothermally prepared and characterized. Complex 1 possessing a hemidirected Pb(II) coordination sphere thermally transforms to 3D-PbCl2 (holodirected) via an intermediate 2 ((pseudo-)hemidirected) by substantial removal of each en molecule.Figure optionsDownload as PowerPoint slide