Multi-dimensional iodocuprates of 4-cyanopyridinium and N,N′-dialkyl-4,4′-bipyridinium: syntheses, structures and dielectric properties

Abstract

Solvothermal reactions of CuI with 4-cyanopyridine (4-cypy) or 4,4 0 -bipyridine (4,4 0 -bipy) and alcohols (methanol, ethanol, propanol, isopropanol) in the presence of I 2 and a trace amount of water in acetonitrile gave rise to a family of multi-dimensional iodocuprate complexes of 4-cyanopyridinium and 5). The resulting 4-cyanopyridinium and viologen cations were generated in situ via the cleavage of the C-O bond of alcohols followed by alkylation of 4-cypy or 4,4 0 -bipy. X-ray analysis revealed that compound 1 consists of a unique three-dimensional anionic [Cu 4 I 6 ] n 2nÀ framework while compounds 2-5 contain one-dimensional anionic [Cu 2 I 4 ] n 2nÀ chains that are enclosed into different cationic channels formed by either 4-cyanopyridinium or N,N 0 -dialkyl-4,4 0 -bipyridinium. The dielectric properties of 1-5 were investigated. Experimental Materials and physical measurementsAll starting materials were purchased from commercial sources and used without further purification. Solvents were purchased as reagent grade and distilled prior to use. The elemental analyses for C, H, and N were performed on a Carlo-Erba CHNO-S

Halogen‐ and Counterion‐Modulated Photochromic and Photoluminescence Properties of Haloargentate Hybrids

“…As shown in Figure a–c, the absorption bands of colorless 1–3 are located in UV region (312 nm for 1 , 350 nm for 2 and 368 nm for 3 ), which can be ascribed to the intramolecular electronic transition of [Ag 2 X 3 ] n n– anions . In contrast, obvious red‐shift for 4 (434 nm) and 5 (453 nm) (Figure d‐e) indicates the existence of intermolecular CT between [Ag 2 X 3 ] n n– and unsaturated MCP + /ECP + cations . Furthermore, halogen‐dependent absorption edge can also be observed for 1–3 as well as 4–5 due to the higher polarizability of iodide than bromide.…”

Halocuprate(i) zigzag chain structures with N-methylated DABCO cations – bright metal-centered luminescence and thermally activated color shifts

“…[22][23][24][25] The influence of the c The degeneracy of the deactivating state(s) is not known and therefore, it is set to 1 in this rough estimate. The use of methanol as a high pressure methylation agent yields twofold N-methylated DABCO cations formed in an in-situ S N 2-reaction similar to reactions under extreme conditions reported in literature.…”

“…6 A quite common structural motif in catena-cuprates(I) is a chain of trans edge-sharing tetrahedra. In-situ N-alkylation of DABCO or other amines by methanol has been observed in high pressure experiments 22 and hydrothermal syntheses [23][24][25] , respectively. [7][8][9][10][11][12][13][14][15] Typical cations are alkali metals, ammonium, or even copper(II) which is coordinated by four ammine 7 or two bidental ethylenediamine ligands [8][9][10] .…”

“…In situ N-alkylation of DABCO or other amines by methanol has been observed in high pressure experiments 22 and hydrothermal syntheses, [23][24][25] respectively. The use of DABCO and its protonated forms in halocuprate(I) syntheses has yielded a Cu 4 I 6 2− cluster with an in situ mono-methylated DABCO molecule, 25 and a 3D inorganic framework structure.…”

Crystal structures of the hexafluoridophosphate salts of the isomeric 2-, 3- and 4-cyano-1-methylpyridinium cations and determination of solid-state interaction energies

“…In 4-CMP[{HB(3,5-dimethylpyrazolyl) 3 }Mo(CO) 3 ], the cations form dimers as in 4-CMP[Co(CO) 4 ] and are associated with the anions through C ring -HÁ Á ÁO hydrogen bonds as well as a stacking interaction with one of the pyrazolyl rings (Bockman & Kochi, 1992). An entirely different structure is seen in {(4-CMP) 2 [Cu 4 ( 3 -I)(-I) 2 ]} n where zigzag chains of cations formed by C ring -HÁ Á ÁN hydrogen bonds are arranged at right angles to one another between chains of anions and link the latter through C methyl -HÁ Á ÁI interactions (Chan et al, 2012). Similar zigzag chains of cations are found in {(3-CMP)[Ag 4 ( 4 -I) 2 (-I) 2 (-I)]} n but here they are all coplanar in a layer structure where cation and anion layers alternate (Yu et al, 2014).…”