A nonacoordinated bridging selenide in a tricapped trigonal prismatic geometry identified in undecanuclear copper clusters: Syntheses, structures, and DIFT calculations

作者：Liu CW^*; Hung CM; Santra BK; Chu YH; Wang JC; Lin ZY

来源：Inorganic Chemistry, 2004, 43(14): 4306-4314.

DOI：10.1021/ic049589j

Undecanuclear copper clusters, [Cu-11(mug-Se)(mu(3)-Br)(3){Se2P(OR)(2)}(6)] (R = Et, Pr, Pr-i) (1a-c), were isolated along with closed-shell ion-centered cubes, [Cu-8(mu(8)-Br){Se2P(OR)(2)}(6)] (PF6) (2a-c) and [Cu-8(mu(8)-Se){Se2P(OR)(2)}(6)] (3a-c), from the reaction of [Cu(CH3CN)(4)](PF6), NH4[Se2P(OR)(2)], and Bu4NBr in a molar ratio of 2:3:2 in CH2Br2. The molecular formulations of these clusters were confirmed by elemental analysis, positive FAB mass spectrometry, and multinuclear NMR (H-1, P-31, and Se-77). Se-77 NMR spectra of Cull clusters (1a-c) are of special interest as two inequivalent selenium nuclei of the diselenophosphate (dsep) ligand exhibit different scalar coupling patterns with the adjacent phosphorus nuclei. X-ray analysis of 1c reveals a Cu11Se core stabilized by three bromide and six dsep ligands. The central core adopts the geometry of a 3,3,4,4,4-pentacapped trigonal prism with a selenium atom in the center. The coordination geometry for the nonacoordinate selenium atom is tricapped trigonal prismatic. The X-ray structure 2a or 2c consists of a cationic cluster in which eight copper ions are linked by six diselenophosphate ligands with a central mu(8)-Br ion. The shape of the molecule is a bromide-centered distorted Cu8 cube. Each diselenophosphate ligand occupies square faces of the cube and adopts a tetrametallic tetraconnective coordination pattern. Each copper atom of the cube is coordinated by three selenium atoms with a strong interaction with the central bromide ion. Molecular orbital calculations at the B3LYP level of the density functional theory have been carried out to study the Cu-mu(9)-Se interactions for clusters [Cu-11(mu(9)-Se)(mu(3)-X)(3){Se2P(OR)(2)}(6)] (X = Br, I). Calculations show that the formal bond order of each Cu-mu(9)-Se bond is slightly smaller than half of those calculated for the terminal Cu-mu(2)-Se bonds.

• 出版日期2004-7-12
• 单位苏州大学