title: The unusual thermochromic NIR luminescence of Cu(I) clusters: tuned by Cu-Cu interactions and packing modes.
abstract: Two hexanuclear Cu(I) clusters [Cu(I)(3)(4-ptt)(3)](2)·3DMF·3H(2)O (1) and [Cu(I)(4-ptt)](6)·8DMF·7H(2)O (2) (4-Hptt = 5-(pyridin-4-yl)-1H-1,2,4-triazole-3-thiol, DMF = N,N-dimethylformamide), were synthesized and characterized. Compounds 1 and 2 with similar coordination environments are isomers, but their detailed structures are different due to the reaction temperature tuning effect. Both 1 and 2 extend from monomers to 3D supramolecules with the help of hydrogen bonding between the triazole and pyridine from the 4-ptt ligands. The Cu(6)S(6) units of 1 pack in a polydirectional array, while the Cu(6)S(6) units in 2 extend in one direction and link the planes of adjacent ligands to enhance the delocalization of π electrons. Their varied Cu-Cu interactions and individual packing modes cause differences in luminescent and thermostable behaviors. Compound 1 exhibits an unusually long wavelength at about 900 nm and a higher thermal stability; while the emission of 2 splits into two bands (high-energy and low-energy emission bands) as the temperature decreases. Therefore, the emissions of 1 originate from a (3)CC transition, and those of 2 are from a mixture of (3)CC and MLCT.
authors: State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
authors: Xiao-Chen
authors: XC
authors: Shan
authors: Fei-Long
authors: FL
authors: Jiang
authors: Da-Qiang
authors: DQ
authors: Yuan
authors: Ming-Yan
authors: MY
authors: Wu
authors: Shu-Quan
authors: SQ
authors: Zhang
authors: Mao-Chun
authors: MC
authors: Hong
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D049449:Luminescence; D033362:Powder Diffraction; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D056831:Coordination Complexes; D003300:Copper