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Ruthenafuran and osmafuran monocationic complexes [Ru([14]aneS4)(C ∧ O)] + or [M(bpy) 2 (C ∧ O)] + (C ∧ O = anionic bidentate chelate [C(OR)CHC(Ph)O] − ; [14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane; M = Ru, Os; bpy = 2,2′-bipyridine) have been prepared from reactions between phenylynone HCC(CO)Ph and [Ru ([14]aneS4)Cl 2 ] or [M-(bpy) 2 Cl 2 ] in alcoholic solvents ROH. The formation of metal− vinylidene intermediate, followed by nucleophilic attack by RO − , and carbonyl group coordination to the metal center are believed to be the key steps in the formation of these metallafurans. The nature of the anionic C ∧ O ligand was investigated by electrochemical, spectroscopic, and theoretical means. ■ INTRODUCTIONActivation of alkynes for functional and novel organic products by transition-metal complexes is one of the most important topics in organometallic chemistry. 1 It is well documented that alkynes generally interact with d6-transition-metal centers through the formation of reactive yet sometimes isolable metal−vinylidene intermediates, which can further transform into other carbon-rich organometallic species including metal− acetylide, −acyl, −allenylidene, −alkoxycarbene, and −carbyne complexes, depending on the functionality of the alkynes and the reactants available in the reaction mixture. 2, 3 Our group has been scrutinizing the reactivity between a variety of organic substrates and structurally well-defined d6-transition-metal complexes, and the spectroscopic properties of the derived organometallic complexes. 4 As an extension of this research direction, we now present the reactivity of a specific type of alkyne, phenyl-ynone HCC(CO)Ph, toward [Ru([14]aneS4)Cl 2 ] and [M(bpy) 2 Cl 2 ] (M = Ru and Os; [14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane; bpy = 2,2′-bipyridine) in alcoholic solvents ROH. Our results reveal that the resultant products are metallafuran monocationic complexes [Ru([14]aneS4)(C ∧ O)] + and [M(bpy) 2 (C ∧ O)] + , where C ∧ O represents an anionic bidentate [C(−OR)CHC(−Ph) O] − chelate. It is worth mentioning that metallafuran and other members of metallacycles have received extensive attention in the field of organometallic and theoretical chemistry, 5,6 and the reactivity reported in this work may represent a general synthetic approach for different metallafurans. Moreover, the electronic properties of the ruthenafurans and osmafuran have been probed by electrochemical, spectroscopic, and theoretical studies. ■ RESULTS AND DISCUSSION Synthesis and Characterizations. Ruthenafuran and osmafuran monocationic complexes 1−3 have been prepared in high yield (50−80%) from reactions between phenyl-ynone HCC(CO)Ph and metal precursors [Ru([14]aneS4)Cl 2 ] or [M(bpy) 2 Cl 2 ] (M = Ru, Os) in alcoholic solvents (Scheme 1).These metallafuran complexes are air stable in both solution and solid forms. The alkoxy group attached to the C α is determined by the alcoholic solvent used (cf. synthesis of 1 and 1′). The carbenoid character for the M−C bonds is indicated by the low-field 13 C NMR ...

Luminescent ruthenium(II)-cyanide complex with N-heterocyclic carbene pincer ligand C∧N∧C = 2,6-bis(1-butylimidazol-2-ylidene)pyridine and 2,2′-bipyridine (bpy) shows minimal cytotoxicity to both human breast carcinoma cell (MCF-7) and human retinal pigmented epithelium cell (RPE) in a wide range of concentration (0.1–500 μM), and can be used for the luminescent imaging of endocytosis of the complex in these cells.