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The reactions of the diruthenium carbonyl complexes [Ru2(μ-dppm)2(CO)4(μ,η2-O2CMe)]X (X=BF4− (1a) or PF6− (1b)) with neutral or anionic bidentate ligands (L,L) afford a series of the diruthenium bridging carbonyl complexes [Ru2(μ-dppm)2(μ-CO)2(η2-(L,L))2]Xn ((L,L)=acetate (O2CMe), 2,2′-bipyridine (bpy), acetylacetonate (acac), 8-quinolinolate (quin); n=0, 1, 2). Apparently with coordination of the bidentate ligands, the bound acetate ligand of [Ru2(μ-dppm)2(CO)4(μ,η2-O2CMe)]+ either migrates within the same complex or into a different one, or is simply replaced. The reaction of [Ru2(μ-dppm)2(CO)4(μ,η2-O2CMe)]+ (1) with 2,2′-bipyridine produces [Ru2(μ-dppm)2(μ-CO)2(η2-O2CMe)2] (2), [Ru2(μ-dppm)2(μ-CO)2(η2-O2CMe)(η2-bpy)]+ (3), and [Ru2(μ-dppm)2(μ-CO)2(η2-bpy)2]2+ (4). Alternatively compound 2 can be prepared from the reaction of 1a with MeCO2H–Et3N, while compound 4 can be obtained from the reaction of 3 with bpy. The reaction of 1b with acetylacetone–Et3N produces [Ru2(μ-dppm)2(μ-CO)2(η2-O2CMe)(η2-acac)] (5) and [Ru2(μ-dppm)2(μ-CO)2(η2-acac)2] (6). Compound 2 can also react with acetylacetone–Et3N to produce 6. Surprisingly [Ru2(μ-dppm)2(μ-CO)2(η2-quin)2] (7) was obtained stereospecifically as the only one product from the reaction of 1b with 8-quinolinol–Et3N. The structure of 7 has been established by X-ray crystallography and found to adopt a cis geometry. Further, the stereospecific reaction is probably caused by the second-sphere π–π face-to-face stacking interactions between the phenyl rings of dppm and the electron-deficient six-membered ring moiety of the bound quinolinate (i.e. the N-included six-membered ring) in 7. The presence of such interactions is indeed supported by an observed charge-transfer band in a UV–vis spectrum. [Copyright &y& Elsevier]

The organic salts 1-(2-pyridylmethyl)-3-alkylbenzimidazolium halide (pm- RbH+X−) and 1-(2-pyridylmethyl)-3-alkylimidazolium halide (pm-R′ iH+X′−) were prepared (where R = 4-, 3-, 2-fluorobenzyl ( 4f, 3f, and 2f, respectively), 4-, 3-, 2-chlorobenzyl ( 4c, 3c, and 2c, respectively); 4-methoxybenzyl (4mo); 2,3,4,5,6-pentafluorobenzyl (f5); benzyl (b); and methyl (m)); X = Cl and Br; R′ = benzyl (b) and methyl (m); and X′ = Cl and I. From these salts, heteroleptic Ir( III) complexes containing one N-heterocyclic carbene ( NHC) ligand [Ir(κ2-ppy)2(κ2-(pm-Rb))] PF6 (R = 4f, 1( PF6); 3f, 2( PF6); 2f, 3( PF6); f5b, 4( PF6); 4c, 5( PF6); 3c, 6( PF6); 2c, 7( PF6); 4mo, 8( PF6); b, 9( PF6); m, 10( PF6)) and [Ir(κ2-ppy)2(κ2-(pm-R′i))] PF6 (R = b, 11( PF6); m, 12( PF6)), were synthesized, and the crystal structures of 1( PF6), 2( PF6), 3( PF6), 5( PF6), 6( PF6), 7( PF6), 9( PF6), 10( PF6), and 12( PF6) were determined by X-ray diffraction. The neutral NHC ligands 1-(2-pyridylmethyl)-3-alkylbenzimidazolin-2-ylidene (pm-Rb) and 1-(2-pyridylmethyl)-3-alkylimidazolin-2-ylidene (pm-R′i) of all cations were found to be involved in the intermolecular π−π stacking interactions with the surrounding cations in the solid state, thereby probably influencing the photophysical behavior in the solid state and in solution. The absorption and emission properties of all the complexes show only small variations. [ABSTRACT FROM AUTHOR]

Currently, main-group metal cations are totally neglected as the structure-building blocks for the self-assembly of supramolecular coordination metallocages due to the lack of directional bonding. However, here we show that a common Arrhenius acid-base neutralization allows the alkaline-earth metal cations to act as charged binders, easily connecting two or more highly directional anionic transition-metal-based metalloligands to coordination polymers. With a metal salt such as K(+) PF6 (-) added during the neutralization, the main-group metal-connected skeleton can be templated by the largest yet reported ionic-aggregate anion, K2 (PF6 )3 (-) , formed from KPF6 in solution, into molecular metallocages, encapsulating the ion. Crystal-structure details, DFT-calculation results, and controlled-release behavior support the presence of K2 (PF6 )3 (-) as a guest in the cage. Upon removal of PF6 (-) ions, the cage stays intact. Other ions like BF4 (-) can be put back in., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)