Copper(I) Complexes Based on Pentamethylene Sulfide: Luminescence Thermochromism of Cu 4 I 4 (C 5 H 10 S) 4

Three copper(I) complexes, [Cu 8 I 8 (PMS) 4 (MeCN) 2 ] n ( 1 ), Cu 4 I 4 (PMS) 4 ( 2 ), and Cu 2 I 2 (PMS) 4 ( 3 ) were prepared by the self‐assembly reaction of mole ratio‐controlled CuI and pentamethylene sulfide (PMS). Single crystal X‐ray diffraction analyses displayed crystal structures of three complexes based on new S‐shaped Cu 8 I 8 , cubane Cu 4 I 4 , and rhomboid Cu 2 I 2 cluster units for 1 – 3 , respectively. Crystal transformations between 1 , 2 , and 3 were controlled by the addition of PMS or CuI/acetonitrile. Luminescence properties of 1 and 2 were investigated. Complex 1 showed two very weak emission bands, which were assigned to HE band for λ max  = 415 nm and LE band for λ max  = 575 nm under ultraviolet irradiation (λ ex  = 355 nm). Complex 2 displayed luminescence thermochromism with a slightly hypsochromic shift from 572 to 565 nm (λ ex  = 355 nm).