Structure, Dynamics, and Photophysics in the Copper(I) Iodide–Tetrahydrothiophene System

Abstract

Combination of CuI and tetrahydrothiophene (THT) in MeCN or neat THT produces various phases depending upon experimental conditions. Green luminescent product (CuI)4(THT)2 (1) consists of Cu4I4 cubane units knit into a 3-D network by 2-THT ligands. Yellow luminescent (CuI)10(THT)7(MeCN) (2) contains {[Cu4I4(THT)](2-THT)2(Cu2I2)(2-THT)2[Cu4I4(NCMe)]} "rungs" linked into 1-D ladders by pairs of 2-THT ligands. Two molecular (CuI)4(THT)4 phases were found: 2 orange luminescent 3a and dull yellow luminescent 3b. Triclinic 3b is the more stable phase at 25 °C, but undergoes endothermic transformation to monoclinic 3a at 38 °C. 3a transforms to a triclinic phase (3a') that retains orange emission at −60 °C. Non-emissive (CuI)3(THT)3•MeCN (4) is a 2-D sheet structure in which Cu3(THT)3 rings are linked in trigonal directions by rhomboid Cu2I2 dimer units. The previously reported (CuI)2(THT)4 (5) is a molecular dimer. Temperature and mixing ratio domains for the formation of the CuI-THT phases from MeCN are presented. Luminescence in 1, 2, 3a, and 3b is rationalized based on varying degrees of halide-to-metal charge transfer (XMCT) and metal-centered (MC) behavior. Low temperature spectra reveal reversible changes, including modest red shifts for 1 and 2, and splitting into two excitation/emission band pairs for 3a and 3b.

Synthesis, structure, and luminescence of the “octahedral” cluster Cu4I4(rac-IsMePCH2PMeIs)2 (Is=2,4,6-(i-Pr)3C6H2)

“…The HE emission bands for 1 (598 and 619 nm at 298 and 77 K) were within the range of energies reported for the analogous complexes in Table 3, while the LE emission energy (525 nm) showed a small red shift. This red shift and the dependence of the LE emission on excitation wavelength [12] are consistent with a mixed 3 XLCT/ 3 MLCT excited state [13], and it is also possible that the two diastereomers of 1 have different temperature-dependent luminescence. More generally, these observations suggest that the steric and electronic properties of the bis(phosphine) and bis(phosphite) ligands B and C affect both excited states, as they do with phosphino-pyridines D. The Cu-Cu distances in Cu 4 I 4 clusters have been correlated to their photophysical properties, especially for the 3 CC transition [2,7,8,14].…”

Cu(I) hybrid inorganic–organic materials with intriguing stimuli responsive and optoelectronic properties

“…A wide range of luminescence behavior was observed, with emission wavelength varying from blue (447 nm in the case of 3-BrPy) to orange (620 nm for tetrahydrothiophene, THT displaying also a green 530 nm emission) and was often distinctive even for chemically similar VOCs, demonstrating the potential selectivity of CuI detection ( Figure 12). On the basis of the observed multiple emission of CuI-THT, suggesting the presence of various phases, the same group further investigated this derivative [65]. According to the stoichiometry and the temperature six different phases were recognized and isolated from the reaction of CuI with THT in MeCN.…”

Designs of 3-Dimensional Networks and MOFs Using Mono- and Polymetallic Copper(I) Secondary Building Units and Mono- and Polythioethers: Materials Based on the Cu–S Coordination Bond

“…It forms a 3D coordination polymer of the composition [(Cu 4 I 4 )(l 2 -THT) 2 ] n (CSD FIZUE) when reacted with CuI in MeCN at relatively high temperatures and high CuI contents (Fig. 14) [50]. The presence of closed cubane cluster makes the materials luminescent at both 293 and 77 K with the following characteristics: 293 K: k emi = 519 nm (k exc = 350 nm), Stokes shift = 9700 cm -1 , s e = 12.1 ls; 77 K: k emi = 528 nm (k exc = 339 nm), Stokes shift = 16,000 cm -1 , s e = 10.4 ls.…”