title: A series of new copper iodobismuthates: structural relationships, optical band gaps affected by dimensionality, and distinct thermal stabilities.
abstract: Three new copper iodobismuthates, red tetranuclear [n-Bu(4)N][Cu(2)(CH(3)CN)(2)Bi(2)I(10)] (1), dark-red infinite linear [Et(4)N](2n)[Cu(2)Bi(2)I(10)](n) (2), and black polymeric ladderlike [Cu(CH(3)CN)(4)](2n)[Cu(2)Bi(2)I(10)](n) (3), crystallize from solutions of BiI3 and CuI in the presence of different cations. A regular structural relationship from 0-D (1) to 1-D linear anion chains (2) to 1-D ladderlike anion chains (3) is observed. The self-assembly of the basic building unit Cu(2)Bi(2)I(10) as altered by different cations is proposed to be the driving force for their formation. The optical band gaps exhibit a structure-related decrease from 1 to 2/3, in agreement with their color changes and the density functional theory (DFT) calculation results. The electronic structures and the relationship with corresponding monobismuth analogues and the Ag-Bi isotypes are discussed on the basis of DFT calculations. In spite of their structural similarities, the compounds are distinctive thermally: 2 is stable to 230 degrees C, 1 undergoes a solvent loss at 85 degrees C to form a new phase that is thermally stable to 230 degrees C, and 3 releases a solvent molecule and decomposes at 80 degrees C into BiI(3) and CuI. The essential reasons for these differences are discussed.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China.
authors.forename: Wen-Xiang
authors.initials: WX
authors.lastname: Chai
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Wu
authors.forename: Jun-Qian
authors.initials: JQ
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Chen