Special ∞1[OPb2] Chains and ∞1[O2Pb3] Ribbons Based on OPb4 Anion-Centered Tetrahedra in Pb2(O4Pb8)(BO3)3Br3 and Pb2(O8Pb12)(BO3)2Br6

The structures of two new lead-containing oxyborate bromines, Pb2(O4Pb8)­(BO3)3Br3 (1) and Pb2(O8Pb12)­(BO3)2Br6 (2), are determined by single-crystal X-ray diffraction for the first time. Both of them crystallize in the space group C2/c of the monoclinic crystal system. Although the two compounds have the same type of fundmental building units (FBUs), the OPb4 anion-centered tetrahedra and BO3 triangles, they exhibit different connection modes. Compound 1 consists of single ∞1[OPb2] chains, while compound 2 possesses ∞1[O2Pb3] ribbons. Interestingly, large Br atoms profoundly influence the conformation of polyions based on the OPb4 anion-centered tetrahedra, resulting in single ∞1[OPb2] chains linked up by finite zweier chains with four OPb4 tetrahedra via the opposite edges in compound 1 and ∞1[O2Pb3] ribbons with sequential condensation of OPb2 chains in compound 2. A detailed description of the effect of large Br atoms on the conformation of polyions is discussed. IR spectroscopy, UV–vis–NIR diffuse reflectance spectroscopy, and thermal analysis are also performed on the reported materials.