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Reactions of a series of unsymmetrically substituted N-heterocyclic carbene ligands with Ru3(CO)12afforded a variety of mononuclear (1, 2), trinuclear (3, 4, 5, and 5′), and tetranuclear (6, 7) ruthenium complexes via intramolecular ruthenium-mediated sp2and sp3C–H bond activations. Complexes 6and 7include an octahedral cluster skeleton consisting of four ruthenium atoms and two metalated carbon atoms. The formation of this type of ruthenium clusters is proposed to involve the initial C–C double-bond migration and subsequent sp2C–H bond activations. All new complexes were fully characterized, and the molecular structures of 1, 2, 5, 6, and 7were determined by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Thermal treatment of Ru3(CO)12with equimolar amounts of (1H-inden-3-yl)diphenylphosphine and (1H-inden-2-yl)diphenylphosphine in octane gave two isomeric trinuclear ruthenium clusters Ru3(μ2-H)(μ3-3-Ph2PC9H6)(CO)9(1) and Ru3(μ2-H)(μ3-2-Ph2PC9H6)(CO)9(2), respectively, via a C−H bond cleavage. Heating either 1or 2in octane afforded the trinuclear and tetranuclear ruthenium clusters Ru3(μ3-PPh)(μ3-C9H6)(CO)9(3) and Ru4(μ4-PPh)(μ4-C9H6)(CO)11(4) via double C−P bond cleavage. Thermal treatment of Ru3(CO)12with (4,7-dimethyl-1H-inden-3-yl)diphenylphosphine in octane gave trinuclear ruthenium cluster Ru3(μ2-H)(μ3-3-Ph2PC11H10)(CO)9(5) via a C−H bond cleavage. Heating 5in octane afforded a trinuclear ruthenium cluster Ru3(μ3-PPh)(μ3-C11H10)(CO)9(6) and two isomeric tetranuclear ruthenium clusters Ru4(μ3-PPh)(μ2-η5:η1-C11H10)(CO)11(7) and [Ru4(μ4-PPh)(μ4-C11H10)(CO)11] (8) via double C−P bond cleavage. Thermal treatment of Ru3(CO)12with (3,4,7-trimethyl-1H-inden-1-yl)diphenylphosphine in toluene afforded two trinuclear ruthenium clusters Ru3(μ2-H)2(μ3-3-Ph2PC12H11)(CO)8(9) via both sp3and sp2C−H bond cleavage and Ru3(μ2-PPh2)(μ3-η2:η2:η5-C12H13)(CO)6(10) via a C−P bond cleavage. Thermal treatment of Ru3(CO)12with (3-methyl-1H-inden-1-yl)diphenylphosphine in toluene afforded a trinuclear ruthenium cluster Ru3(μ2-H)(μ3-3-Ph2PC10H8)(CO)9] (11) via a C−H bond cleavage. The molecular structures of complexes 1−5and 7−11have been determined by single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Thermal treatment of dihydrooctamethyl-s-indacene with Ru3(CO)12afforded the trinuclear and tetranuclear complexes Ru3(η5:η5:η2-C20H24)(CO)7(1) and Ru4(η5:η4:η1-C20H24)(μ-CO)2(CO)7(2), via intramolecular sp3C−H bond activation, and the mononuclear complex Ru(η5-C20H25)(CO)2Cl (3), which might be formed via chlorination of a terminal hydride complex during column chromatography. Reaction of 1,2,3,4,7-pentamethylindene with Ru3(CO)12also yielded the tetranuclear complex Ru4(η5:η3:η2-C14H16)(CO)9(4) via the same sp3C−H bond activation, together with the dinuclear complex [(η5-C9H2Me5)Ru(CO)]2(μ-CO)2(5). In contrast, reaction of 4,7-dimethylindene with Ru3(CO)12gave only the dinuclear complex [(η5-C9H5Me2)Ru(CO)]2(μ-CO)2(6). The molecular structures of all six complexes have been determined by single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Six cadmium(II) complexes containing the N2O2donor tetradentate asymmetrical Schiff base ligand 2-{[2-(dimethylamino)ethylimino]methyl}-6-methoxyphenol (HL5), namely, [(Cd3L52Cl4)2]·CH3OH·H2O (1), [Cd(L5)Cl]2·CH3OH (2), [Cd2(HL5)Cl4]n(3), {[Cd3(H2L5)2Cl8]·2H2O}n(4), [(H2L5)2]2·[CdCl4]2−·H2O (5), and [(H2L5)2]2·[CdCl4]2−(6), have been synthesized using cadmium(II) chloride and the asymmetrical Schiff base ligand HL5under different pH conditions at room temperature. The diverse structures show the marked sensitivity of the structural chemistry of the tetradentate asymmetrical Schiff base ligand HL5. Complex 1formed at pH = 10 exhibits a rare zero-dimensional structure of trinuclear cadmium(II). At pH = 8−9, a dinuclear cadmium(II) complex 2is formed. The reaction at pH = 5−7 leads to two one-dimensional structures of 3and 4. A further decrease of the pH to 3−5 results in a zero-dimensional structure 5. Owing to the departure of lattice water molecules in the crystal, complex 5at room temperature can gradually undergo single-crystal-to-single-crystal transformation to result in complex 6.The results further show that conversions of complex 1−5can also be achieved by adjusting the pH value of the reaction solution, 1→ 2pH=8→ 5pH=3and 3→ 4pH=5. Comparing these experimental results, it is clear that the pH plays a crucial role in the formation of the resulting structures, which simultaneously provides very effective strategies for constructing the CdIIcompounds with N2O2donor tetradentate asymmetrical Schiff base ligand. The strong fluorescent emissions of the six compounds (1−6) make them potentially useful photoactive materials. Furthermore, six Schiff base cadmium complexes (1−6), with 2,2-dipheny1-1-picrylhydrazy1 (DPPH) as a co-oxidant exhibited the stronger scavenging activity. [ABSTRACT FROM AUTHOR]

Thermal treatment of indenyl-functionalized imidazolium salts and N-heterocyclic carbenes with Ru3(CO)12gave different products. The normal mononuclear metal complexes (2a, 2b) were obtained viadirect reaction of indenyl-functionalized imidazolium salts (1a, 1b) with Ru3(CO)12. Unexpected intramolecular C–H activated products (3a, 3b, 4a, 4b) were obtained viathermal treatment of corresponding indenyl-functionalized N-heterocyclic carbenes. All complexes were determined by 1H NMR, 13C NMR, IR spectra and elemental analysis. The molecular structures of 2b, 3a, 3band 4bwere determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]