Cu4I4 Clusters Supported by PN-type Ligands: New Structures with Tunable Emission Colors

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• 作者：Zhiwei Liu ; Peter I. Djurovich ; Matthew T. Whited ; Mark E. Thompson
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：January 2, 2012
• 年：2012
• 卷：51
• 期：1
• 页码：230-236
• 全文大小：462K
• 年卷期：v.51,no.1(January 2, 2012)
• ISSN：1520-510X

文摘

A series of Cu₄I₄ clusters (1鈥?b>5) supported by two PN-type ligands 2-[(diRphosphino)methyl]pyridine (1, R = phenyl; 2, R = cyclohexyl; 3, R = tert-butyl; 4, R = iso-propyl; 5, R = ethyl) have been synthesized. Single crystal X-ray analyses show that all five clusters adopt a rare 鈥渙ctahedral鈥?geometry. The central core of the cluster consists of the copper atoms arranged in a parallelogram with 渭⁴-iodides above and below the copper plane. The copper atoms on the two short edges of the parallelogram (Cu鈥揅u = 2.525(2)鈥?.630(1) 脜) are bridged with 渭²-iodides, whereas the long edges (Cu鈥揅u = 2.839(3)鈥?.035(2) 脜) are bridged in an antiparallel fashion by the PN ligands. This Cu₄I₄ geometry differs significantly from the 鈥渃ubane鈥?and 鈥渟tairstep鈥?geometries reported for other Cu₄I₄L₄ clusters. Luminescence spectra of clusters 3 and 4 display a single emission around 460 nm at room temperature that is assigned to emission from a triplet halide-to-ligand charge-transfer (³XLCT) excited state, whereas clusters 1, 2, and 5 also have a second band around 570 nm that is assigned to a Cu₄I₄ cluster-centered (³CC) excited state. The structural and photophysical properties of a dinuclear Cu₂I₂(PN)₂ complex obtained during the sublimation of cluster 3 is also provided.