Synthesis and Crystal Structure of Novel Mixed-metal Alkoxide Clusters of Ytterbium and Sodium: Yb4O4(OiPr)16Na12

The mixed-metal cluster Yb4O4(OiPr)(16)Na-12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 with a = b = c = 13.9788(3) angstrom, V = 2731.55(10) angstrom(3), Z = 1, D-c = 1.202 g/cm(3), M-r = 1977.42, mu = 3.480 min(-1), F(000) = 972, the final R = 0.0288 and wR = 0.1511 for 1677 observed reflections with I > 2 sigma(I). X-ray analysis reveals that Yb4O4(OiPr)(16)Na-12 is centrosymmetric and the structure contains four ytterbium metals and twelve sodium metals, and each ytterbium atom is coordinated by six oxygen atoms. In addition, an ancillary computational analysis of the optimized molecular unit was provided. The large energy gap (3.31 eV) between HOMO and LUMO indicates that the structure framework is particularly stable.