Selenium-Centered, Undecanuclear Silver Cages Surrounded by Iodo and Dialkyldiselenophosphato Ligands. Syntheses, Structures, and Photophysical Properties

Abstract

Three clusters [Ag11(mu9-Se)(mu3-I)3{Se2P(OR)2}6] (R = Et, 1; iPr, 2; 2Bu, 3) were isolated from the reaction of [Ag(CH3CN)4](PF6), NH4[Se2P(OR)2], and Bu4NI in a molar ratio of 4:3:1 in CH2Cl2 in 47-55% yield. Compounds 1 and 2 can also be synthesized with high yield from the reaction of Ag10(Se)[Se2P(OR)2]8 with 8 equiv of Bu4NI. In the positive fast atom bombardment mass spectra of 1-3, two major peaks that correspond to the intact molecule with the loss of an iodide ion, [Ag11(mu9-Se)(mu3-I)(2){Se2P(OR)2}6]+, and a diselenophosphate ligand, [Ag11(mu9-Se)(mu3-I)3{Se2P(OR)2}5]+, were identified. Single-crystal X-ray analyses of 2 and 3 reveal an Ag11Se core stabilized by three iodide anions and six diselenophosphato ligands in a tetrametallic tetraconnective (mu2,mu2) coordination mode. The central core adopts the geometry of a 3,3,4,4,4-pentacapped trigonal prism with a selenium atom in the center. In addition, weak intermolecular Se...I interactions exist in 2 and form a one-dimensional polymeric chain structure. Furthermore, all compounds exhibit orange-red luminescence in both the solid state and solution.