Coordination-induced emission enhancement in copper(I) iodide coordination polymers supported by 2-(alkylsulfanyl)pyrimidines

First examples of copper(i) complexes with 2-(alkylsulfanyl)pyrimidine ligands have been synthesized. Reactions of copper(i) iodide with 2-(methylsulfanyl)pyrimidine (L1) in various metal-to-ligand molar ratios in MeCN afford a ladder-type coordination polymer [Cu2L1I2]n with polymeric chains built from double-stranded (Cu2I2)n ribbons supported on both sides by μ2-N,S-L1 molecules. Although the second ligand, 2-(ethylsulfanyl)pyrimidine (L2), differs from L1 only by a methylene group, its reactions with copper(i) iodide in MeCN yield not only a congenerous coordination polymer, [Cu2L2I2]n, but also [CuL2I]n, in which a similar (Cu2I2)n ribbon is decorated by N-monodentate L2 molecules. Absorption spectra of all compounds represent an interplay of metal + iodine-to-ligand charge transfer (XMLCT) and ligand-centered (LC) and cluster-centered (CC) transitions, while the emission occurs from the excited states of XMLCT nature. The luminescence of [Cu2L1I2]n and [Cu2L2I2]n is blue-shifted and greatly enhanced in comparison with that of [CuL2I]n (quantum yields: 89% and 68% for [Cu2L1I2]n and [Cu2L2I2]nvs. 23% for [CuL2I]n at 77 K), which can be associated with a more rigid μ2-N,S coordination of 2-(alkylsulfanyl)pyrimidine ligands in [Cu2L1I2]n and [Cu2L2I2]n leading to a less distorted T1 state.

Highly efficient and very robust blue-excitable yellow phosphors built on multiple-stranded one-dimensional inorganic-organic hybrid chains

Inorganic-organic hybrid semiconductors are promising candidates for energy-related applications. Here, we have developed a unique class of multiple-stranded one-dimensional (1D) structures as very robust and efficient lighting phosphors. Following a systematic ligand design strategy, these structures are constructed by forming multiple coordination bonds between adjacent copper iodide inorganic building units Cu m I m (m = 2, 4, 6) (e.g. dimer, tetramer and hexamer clusters) and strong-binding bidentate organic ligands with low LUMO energies which give rise to infinite 1D chains of high stability and low bandgaps. The significantly enhanced thermal/photostability of these multiple-stranded chain structures is largely attributed to the multi-dentate nature and enhanced Cu-N bonding, and their excellent blue excitability is a result of using benzotriazole based ligands with low-lying LUMO energies. These facts are confirmed by Density Functional Theory (DFT) calculations. The luminescence mechanism of these compounds is studied by temperature dependent photoluminescence experiments. High internal quantum yields (IQYs) are achieved under blue excitation, marking the highest value reported so far for crystalline inorganic-organic hybrid yellow phosphors. Excellent thermal- and photo-stability, coupled with high luminescence efficiency, make this class of materials promising candidates for use as rare-earth element (REE) free phosphors in energy efficient general lighting devices.

1,3-Dithianes as Assembling Ligands for the Construction of Copper(I) Coordination Polymers. Investigation of the Impact of the RC(H)S2C3H6 Substituent and Reaction Conditions on the Architecture of the 0D-3D Networks

The parent compound 1,3-dithiane (L1) was reacted with CuI providing the 1D coordination polymer [{Cu(μ₂-I)₂Cu}(μ₂-L1)₂] _n (CP1), an isostructural compound [{Cu(μ₂-Br)₂Cu}(μ₂-L1)₂] _n (CP2) was isolated upon treatment of CuBr with L1. In contrast, treatment of L1 with CuCl results in the formation of 2D polymeric [{Cu(μ₂-Cl)₂Cu}(μ₂-L1)] _n (CP3), in which each sulfur atom acts as a 4-electron donor. The 1D compounds [{Cu(μ₂-X)₂Cu}(μ₂-L2)₂] _n (CP7, X = Br, and CP8, X = Cl) resulting from treatment of 2-methyl-1,3 dithiane (L2) with CuBr and CuCl are isostructural with their CuI homologue [{Cu(μ₂-I)₂Cu}(μ₂-L2)₂] _n (CP5), reported previously. Using CuCN, a 2D CP of composition [{Cu(μ₂-CN)₂Cu}(μ₂-L2)₂] _n (CP9) has been isolated. Complexation of 2-isobutyl-1,3-dithiane (L3) on CuI generates a 2D material [{Cu₃(μ₃-I)(μ₂-I)₂(μ₂-L3)₂}] _n (CP10), incorporating the usual trinuclear μ₃-I-capped Cu clusters as SBUs, whereas 2D-polymeric compounds [{Cu(μ₂-Br)₂Cu}(μ₂-L3)₂] _n (CP11) and [{Cu(μ₂-Cl)₂Cu}(μ₂-L3)₂] _n (CP12) were obtained with CuBr and CuCl. Treatment of 2-Me₃Si-1,3-dithiane (L4) with CuX yields the series [{Cu₂(μ₄-X)(μ₂-X)}(μ₂-L4)] _n (CP13-CP15). With 2-phenyl-1,3-dithiane (L5), the outcome of the reaction with CuI depends on the reaction conditions. Reaction with CuI in MeCN provides a 1D ribbon [{Cu(μ₂-I)₂Cu}(MeCN)₂(μ₂-L5)₂] _n (CP16), whereas treatment of CuI with L5 in hot EtCN yields 2D-polymeric[{Cu₃(μ₃-I)(μ₂-I)₂(μ₂-L5)₂}] _n (CP17). A reversible phase transition from triclinic P1̅ to monoclinic P2₁/ m is observed when recording the structure of CP16 at five different temperatures in the 100-300 K range. Ligand L6 containing a ferrocenyl function at the 2-position was also probed as organometallic dithioether ligand. Reaction of L6 with 1 equiv of CuI produces the 0D dinuclear complex [{Cu(μ₂-I)₂Cu}(η¹-L6)₂(MeCN)₂] (D1), whereas treatment with 2 equiv of CuI affords the novel 1D CP [{Cu(μ₃-I)₂Cu}(μ-L6)] _n (CP18), in which both S atoms of one L6 molecule span two copper centers of the infinite (CuI) _n ribbon. Some selected results of thermal analyses and luminescence measurements are also presented.

Diverse Architectures and Luminescence Properties of Group 11 Complexes Containing Pyrimidine-Based Phosphine, N-((Diphenylphosphine)methyl)pyrimidin-2-amine

In this article, the synthesis, structural studies, and luminescence properties of Cu^I, Ag^I, and Au^I complexes of pyrimidine-based phosphine [C₄H₃N₂-2-NH(CH₂PPh₂)] (1) are described. The reactions of 1 with CuX led to the isolation of one-dimensional (1D) chain, tetranuclear ladder, or cyclic derivatives. The structural features of these complexes are greatly influenced by the metal-to-ligand ratio, reaction conditions, and CuX (X = Cl, Br or I) employed. In the case of CuCl and CuBr, one-dimensional coordination polymers [{CuCl}{C₄H₃N₂-2-NH(CH₂PPh₂)}]_∞ (2) and [{CuBr}{C₄H₃N₂-2-NH(CH₂PPh₂)}]_∞ (3) were obtained, whereas CuI afforded tetracopper complex [{CuI}₄{C₄H₃N₂-2-NH(CH₂PPh₂)}₂(NCCH₃)₂] (4) having Cu₄ ladder structure supported by P∩N-bridging coordination of 1. The reaction of 1 with AgOTf yielded unprecedented one-dimensional chain structure [{AgOTf}{C₄H₃N₂-2-NH(CH₂PPh₂)}]_∞ (5), whereas the reaction with AgBF₄ produced a 12-membered dinuclear complex, [{Ag}{C₄H₃N₂-2-NH(CH₂PPh₂)}]₂[BF₄]₂ (6), with each silver atom having a linear geometry. Gold complex [{AuCl}{C₄H₃N₂-2-NH(CH₂PPh₂)}]₂ (7) was synthesized by reacting 1 with [AuCl(SMe₂)]. Compounds 2-4 were also prepared using a pestle and mortar by grinding method in almost quantitative yield. Complex 4 with a Cu···Cu distance of 2.828(5) Å shows high luminescence due to the nonbonded metal···metal interactions.

Synthesis, Crystal Structure, and Photoluminescent Properties of a Series of LnIII–CuI Heterometallic Coordination Polymers Based on Cu4I3 Clusters and Ln–ina Rod Units

A novel series of LnIII–CuI heterometallic coordination polymers (HCPs) {[Ln2Cu4I3(ina)7(DMA)2]n·nDMA, Ln = La (1), Ce (2), Pr (3) Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9) Ho (10), Er (11), Yb (12), Hina = isonicotinic acid, DMA = N,N-dimethylacetamide} were synthesised by a solvothermal reaction. The structures of compounds 1–12 were characterised by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. Single crystal X-ray diffraction studies revealed that 1–12 are isomorphous and are 3D heterometallic coordination polymers based on inorganic Cu4I3 clusters and Ln2(ina)7(DMA) rod units. In addition, the luminescent properties of compounds 5–9 have been investigated in detail. All of them exhibited green light emission due to the synergistic effects of characteristic emissions of lanthanide ions and iodide-to-copper charge transfer.

Copper(i) 5-phenylpyrimidine-2-thiolate complexes showing unique optical properties and high visible light-directed catalytic performance

Copper(i) 5-phenylpyrimidine-2-thiolate complexes exhibit intriguing luminescence properties and excellent visible light-directed catalytic activity towards aerobic oxidative hydroxylation of arylboronic acids.

Luminescent [Cu4I4] aggregates and [Cu3I3]-cyclic coordination polymers supported by quinolyl-triazoles

A series of quinolyl-1,2,3-triazole supported luminescent [Cu₄I₄] aggregates and six-membered [Cu₃I₃]-cyclic coordination polymers.

Polymeric one- and two-dimensional copper(i) iodide complexes showing photoluminescence tunable by azaaromatic ligands

Photoluminescent properties of four low-dimensional [(CuI)_xL]_n complexes were investigated in the solid state at ambient temperature. A photoluminescence quantum yield of 73% was recorded for [(CuI)₂(46dmpm)]_n.