Qian- Li

Novel μ2-oxo-bridged dinuclear aryltelluronic triorganotin(IV) esters: syntheses, structural characterizations, and in vitro cytotoxicity

Four new μ2-oxo-bridged dinuclear aryltelluronic triorganotin esters [ArTe(μ-O)(OH)(OSnR3)2]2 (Ar = n-propyl-Ph, R = Me: 1, R = Ph: 2; Ar = i-propyl-Ph, R = Me: 3, R = Ph: 4) were synthesized by reaction of μ2-oxo-bridged dinuclear aryltelluronic acids and the corresponding R3SnCl (R = Me, Ph) with potassium hydroxide in methanol. The complexes were characterized by X-ray crystallography, elemental analysis, FT-IR, and NMR (1H, 13C, 119Sn) spectroscopy. The structural analysis indicates that these complexes are isostructural and crystallized as Sn4Te2 molecules, in which the asymmetric four-membered Te2(μ2-O)2 units are situated in the center. The geometry of tellurium is described as a distorted octahedron and each tin is described as a distorted tetrahedron. Complex 2 has a 2-D network structure connected by intermolecular C–H⋯π interactions. Complexes 1–4 were tested for in vitro cytotoxicity against human lung cancer cells (A549) and human hepatocellular carcinoma cells (HepG2). Graphical Abstract

Novel organotin complexes derived from 2,2′-selenodiacetic acid: synthesis and biological evaluation

The reactions of 2,2′-selenodiacetic acid and the corresponding organotin(IV) chloride with sodium ethoxide in ethanol, or via a solvothermal synthetic route, have afforded four organotin polymers, namely, [(Me3Sn)2Se(CH2COO)2]n (1), [(Me2Sn)2Se(CH2COO)2(μ3-O)]n (2), [(Bu3Sn)2Se(CH2COO)2]n (3), and [(Bu2Sn)Se(CH2COO)2]n (4). All the complexes were fully characterized by elemental analysis, FT-IR, NMR (1H, 13C, and 119Sn) spectroscopy and single crystal X-ray diffraction analysis. The structural analysis reveals that complex 1 is a 2D-polymer containing interconnected 24-membered (Sn4O8C10Se2) macrocyclic rings. Unlike complex 1, the 2D polymer structure of complex 2 is made up of the typical ladder tetraorganodistannoxane unit containing 32-membered (Sn4O8C16Se4) macrocyclic rings. Complex 3 is a 3D corrugated polymeric structure in which the deprotonated dicarboxylic acid acts as a tetradentate ligand by four oxygen atoms. Complex 4 is a 1D zigzag coordination polymer and the tin coordination geometry is described as skewed-trapezoidal bipyramidal. In particular, preliminary cytotoxic assessments of the involvement of complex 4 in the apoptotic death of MDA cells were conducted, and the results revealed that the antiproliferative and proapoptotic effect of complex 4 in MDA cells prominently contributed to the overload of intracellular ROS levels and the dysfunctional depolarization of mitochondrial membranes.

Syntheses and structural characterization of organotin complexes derived from 2-(trifluoromethyl)benzeneseleninic acid: tetranuclear macrocycle, 1-D polymeric chain, helical double-chain

Abstract Four organotin(IV) complexes based on 2-(trifluoromethyl)benzeneseleninic acid, [Me3Sn(O2SeC6H4-2-CF3)]4 (1), [Ph3Sn(O2SeC6H4-2-CF3)]n (2), [R2Sn(O2SeC6H4-2-CF3)2]n (R = Me 3; n-Bu 4), have been synthesized and characterized by X-ray diffraction, elemental analysis, infrared spectroscopy, and NMR (1H, 13C and 119Sn) spectroscopy. Single-crystal X-ray analyses show that 1 has a centrosymmetric tetranuclear triorganotin selenite with a tetranuclear 16-membered macrocycle formed by trimethyltin and ligand alternately linking; 2 exhibits a 1-D neutral infinite chain structure in which the [O2SeC6H4-2-CF3]− is a μ2-bridging ligand; 3 and 4 are polymeric chain structures containing Sn2O4Se2 eight-membered rings where the areneseleninate groups are double bridges between the tin ions. Examination of the intermolecular contacts of 1 reveals the existence of the C–H⋯O hydrogen bonding interactions and C–H⋯π interactions. Weak C–H⋯O interactions were also found to be important for the formation of the 3-D structure for 3.

Novel organotin(IV) complexes derived from 4-fluorophenyl-selenoacetic acid: synthesis, characterization and in vitro cytostatic activity evaluation

A cluster of novel organotin(IV) complexes with the formulas [Me3Sn(O2CCH2SeC6H4F-p)]n (1), [(Me2Sn)4(μ3-O)2(O2CCH2SeC6H4F-p)4] (2), [n-Bu3Sn(O2CCH2SeC6H4F-p)]n (3) and [n-Bu2Sn(O2CCH2SeC6H4F-p)2] (4) were designed, synthesized, and characterized by elemental analysis, FT-IR, and NMR (1H, 13C, and 119Sn) spectroscopy as well as single-crystal X-ray diffraction. Complexes 1 and 3 represent one-dimensional (1D) coordination polymers composed of alternate [Sn–O]2. The molecular spatial structure of 2 revealed it to be tetranuclear possessing a ladder-like structure and containing four carboxylate ligands. The 1D chain was formed by C–H⋯F interaction. Complex 4 was a monomer connected into a 1D coordination polymer through the intermolecular interaction C–H⋯O. Meanwhile, four novel corresponding organosulfurtin complexes (5–8) were also prepared. Furthermore, complexes 1–4 and 5–8 were evaluated for their in vitro cytostatic activity against human breast cancer cell lines (MDA-MB-231). The preliminary screening showed that the organotin derivatives with an n-butyl group (3, 4 and 7, 8) exhibited significantly higher cytostatic activity than those with a methyl group (1, 2 and 5, 6). Mechanically, further cytotoxic assessments of complex 4 in mediated MDA-MB-231 cells were conducted, and the results revealed that the anti-proliferative and pro-apoptotic effect of complex 4 in MDA-MB-231 cells prominently contributed to the boosted ROS, collapsed mitochondrial membrane potential and the release of cytochrome c from the outer membrane of the mitochondria, which sequently activated caspase-3, the executioner, which was responsible for complex 4s chemotherapeutic potential against MDA-MB-231 cells.

A novel 4-fluorobenzenetelluronic trimethyltin ester: synthesis, characterization and in vitro cytotoxicity assessment

A novel 4-fluorobenzenetelluronic trimethyltin ester (Me3Sn)4[p-F-PhTe(μ-O)(OH)O2]2 (1) has been prepared and fully characterized using elemental analysis, FT-IR, NMR (1H, 13C, 119Sn) spectroscopy, XRD and X-ray crystallography. Structural analysis shows that the complex is crystallized as a Sn4Te2 molecule, in which an asymmetric four-membered Te2(μ2-O)2 unit is situated in the center. The geometry of tellurium is described as a distorted octahedron and for each tin it is described as a distorted tetrahedron. Underlying cytotoxic mechanisms involved in the apoptotic death of A549 cells upon exposure to the complex have been investigated and the results reveal that the anti-proliferative and proapoptotic effects of the complex in A549 cells prominently contributed to the accumulation of ROS, dysfunctional depolarization of the mitochondrial membrane and activation of caspase-3.

Syntheses, characterizations and crystal structures of triorganotin(IV) complexes with amine derivatives of 6-amino-1,3,5-triazine-2,4-dithiol

Four new triorganotin(IV) complexes: Me3SnL1SnMe3 (1), Ph3SnL1SnPh3 (2), [Me3SnL2] n (3), Ph3SnL2SnPh3 (4) have been synthesized from 6-anilino-1,3,5-triazine-2,4-dithiol (L1H2) and 6-(dibutylamino)-1,3,5-triazine-2,4-dithiol (L2H2). All were characterized by elemental analyses, IR and NMR spectra and X-ray diffraction analyses. Crystal structures show that 1, 2 and 4 are monomers with one ligand coordinated to two triorganotin moieties; complex 3 is a helical chain. Significant C–H ··· π, N–H ··· π interactions and intermolecular hydrogen bonds stabilize these structures.

Lewis Acid Catalyzed Tandem 1,4-Conjugate Addition/Cyclization of in Situ Generated Alkynyl o-Quinone Methides and Electron-Rich Phenols: Synthesis of Dioxabicyclo[3.3.1]nonane Skeletons

A versatile Lewis acid catalyzed tandem cyclization of in situ generated alkynyl o-quinone methides ( o-AQMs) with electron-rich phenols has been developed on the basis of the mode involving an intermolecular 1,4-conjugate addition/6-endo cyclization/1,3-aryl shift/intramolecular 1,4-conjugate addition cascade. This reaction provides a new method for expeditious assembly of synthetically and biologically interesting tetracyclic bridged dioxabicyclo[3.3.1]nonane skeletons featuring a congested bridgehead oxa-quaternary stereocenter.

Synthesis, structures and magnetic properties of heterobimetallic RuIII–3d (3d = Mn, Ni) compounds based on the chiral RuIII building block

Two pairs of chiral cyano-bridged heterobimetallic compounds, [Mn(salen)Ru((R,R)-(5-Br-salcy))(CN)2]n (1), [Mn(salen)Ru((S,S)-(5-Br-salcy))(CN)2]n (2), [Ni(tren)][Ru((R,R)-(5-Cl-salcy))(CN)2]2 (3), and [Ni(tren)][Ru((S,S)-(5-Cl-salcy))(CN)2]2 (4) [salcy2− = N,N′-(1,2-cyclohexanediylethylene) bis(salicylideneiminato) dianion, tren = tri(2-aminoethyl)amine], have been synthesized and characterized by elemental analysis, IR spectroscopy, X-ray diffraction analyses, and circular dichroism (CD) and vibrational circular dichroism (VCD) spectra. Single X-ray diffraction analysis reveals that complexes 1 and 2 possess a chiral 1D zigzag chain structure that consists of alternating (R,R/S,S)-trans-[Ru(5-Br-salcy)(CN)2]− and [MnIII(salen)]+ units. Complexes 3 and 4 are trinuclear complexes in which the central Ni(II) ion is coordinated with two terminal (R,R/S,S)-trans-[Ru(5-Cl-salcy)(CN)2]− units through cyanide bridges. Investigation of magnetic susceptibilities indicates that antiferromagnetic coupling exists between the cyano-bridged RuIII and MnIII ions for complexes 1 and 2. An estimation of the barrier size (Ea) for 1 reveals a value of 19.1 K, with a characteristic time (τ0) of 1.95 × 10−8. Moreover, complexes 3 and 4 exhibit ferromagnetic coupling between RuIII and NiII through the cyanide bridges with J = 2.73 cm−1.

Syntheses, structures and anti-tumor activity of four organotin(IV) dicarboxylates based on (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid

Four novel organotin complexes, [(Me3Sn)2(O2CCH2S)2C2N2S]n (1), [(Me2Sn)2(O2CCH2S)2C2N2S(μ3-O)]n (2), [(n-Bu3Sn)2(O2CCH2S)2C2N2S]n (3) and [(n-Bu2Sn)(O2CCH2S)2C2N2S]n (4), derived from flexible (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid (H2tzda), have been synthesized and characterized by elemental analysis, FT-IR, NMR and X-ray crystallography. The structural analysis reveals that complexes 1 and 2 display a 1D pipeline-like and 1D ladder chain structure, respectively. Complex 1 contains interconnected 26-membered macrocycles, while complex 2 is made up of the typical ladder tetraorganodistannoxane unit containing 26-membered macrocycles. In addition, the molecules of complexes 1 and 2 are further linked through intermolecular C–H⋯O interactions into a 3D and 2D infinite supramolecular structure, respectively. Complex 3 shows a 2D corrugated polymeric structure constructed by 34-membered macrocycles. Complex 4 adopts a 1D infinite chain structure. Furthermore, in vitro cytotoxicity investigations of complexes 1, 3 and 4 were conducted. Importantly, further cytotoxic assessments of complex 3 against human hepatocellular carcinoma cells (HepG-2) demonstrate that complex 3 could induce an apoptotic retardation effect on proliferation via possible mitochondrial-dependent cross-talk between various signaling proteins and the intracellular p53-Bax-caspases approach should be the major pathway of apoptosis.