Ru(II)- and Os(II)-Induced Cycloisomerization of Phenol-Tethered Alkyne for Functional Chromene and Chromone Complexes

Abstract

Diphosphine-containing Ru­(II)/Os­(II)–chromene and −chromone complexes were synthesized from reactions between phenol ynone HCC­(CO)­(o-C6H4OH) and cis-[Ru/Os­(dppm)2Cl2] (dppm = 1,1-bis­(diphenylphosphino)­methane). The structures of these complexes in the solid state along with their pH-dependent chromene/chromone equilibrium behavior in aqueous medium were investigated. The cis–trans equilibration in solution demonstrated by chloride-ligated Ru–chromene and −chromone series represents a rare example for Ru complexes bearing dppm auxiliary ligands. More importantly, these metalated chromene and chromone complexes exhibit moderate to strong cytotoxicity against several human cancer cell lines and stronger antioxidative activities in comparison with their organic counterpart. Overall, these findings highlight the potential applications of metalated chromenes and chromones as anticancer agents and antioxidants.

Ruthenafuran Complexes Supported by the Bipyridine-Bis(diphenylphosphino)methane Ligand Set: Synthesis and Cytotoxicity Studies

“…Although the formation of metal–vinylidene species via alkyne–vinylidene rearrangement has been regarded as a key step in Ru(II)-induced alkyne transformations, a number of our synthetic studies revealed that Ru(II) can also activate alkynes via “non-vinylidene” pathways [ 31 , 32 ]. With the aim to gain control on the modes of alkyne activation, we initiated research activities on probing and isolating intermediates and products from the reactions between functionalized alkynes and a variety of Fe(II), Ru(II) and Os(II) complexes [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. In 2015, we reported the synthesis of metallafuran complexes in the form of [M(bpy) 2 (C^O)] + from the reactions between cis -[M(bpy) 2 Cl 2 ] (M = Ru, Os; bpy = 2,2′-bipyridine) and ynone HC≡C(C=O)Ph in MeOH ( Scheme 1 a; C^O represents an anionic bidentate [ C (OMe)CHC(Ph) O ] − chelate, coordinating atoms in italics) [ 38 ].…”

A multi-functional chromone-modified polyethylene obtained by metal-free C–H activation

“…Besides, being a privileged scaffold for drug development due to their biological and pharmacological activities (e.g., anti-inflammatory, antitumor, antimicrobial, and antioxidative properties), [24][25][26][27][28][29][30] the optical properties of chromones offer them new potential applications in fluorescent probes, light-emitting devices, and photochromic materials. [31][32][33] Recently, Han and coworkers reported a metal-free oxidative C-H functionalization of small alkane molecules to prepare 2-alkylchromanones. 34 In view of the mild conditions and high efficiency of this reaction as well as the unique properties of chromones, we adopted this chemistry in the macromolecular realm for polyolefin modification in this report.…”

A New Tetradentate Mixed Aza-Thioether Macrocycle and Its Complexation Behavior towards Fe(II), Ni(II) and Cu(II) Ions

“…Our group has recently initiated a paradigm in scrutinizing the reactivity between low-valent transition metal precursors and heteroatom-functionalized alkynes [16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Gratifyingly, several Ru-and Os-heterocyclic complexes reported by our group exhibit interesting biological applications.…”