Ruthenium hydrazone complexes with 1:1 and 1:2 metal–ligand stoichiometry: a comparison of biomolecular interactions and in vitro cytotoxicities

Transition Metal Chemistry - Two ruthenium(II) complexes [RuIICl(PPh3)2(L)] (1) and [RuII(L)2] (2) were synthesized by reacting [RuCl2(PPh3)3] and thiophene-2-carboxylic acid...     

Thermally induced A'-A site exchange in novel layered perovskites Ag2[Ca1.5M3O10] (M = Nb,Ta)

We have synthesized and characterized new layered perovskites Ag2[A1.5M3O10] (A = Ca, M = Nb, Ta), from their lithium analogues, by soft-chemical ion exchange. These oxides show topotactic irreversible thermally induced A'-A site exchange, resulting in Ag1.1Ca0.9[Ca0.6Ag0.9M3O10], conferred from our high-temperature X-ray and ionic conductivity studies. The latter phases are the first compounds where Ag+ ions reside in both A' and A sites in layered perovskites. The absence of similar phase transition for A = Sr suggests that these transitions strongly depend on the size, charge, and the coordination preference of A' and A cations. This result provides a new synthetic tool for modifying the occupation of the 12-coordinate A site of layered perovskites using soft chemical routes.     

Butterfly-Like Triarylamines with High Hole Mobility and On/Off Ratio in Bottom-Gated OFETs

Highly π-extended butterfly-shaped triarylamine dyads with aryleneethynylene spacer were constructed using an efficient synthetic route. These aryleneethynylene-bridged dyads are highly fluorescent and exhibited high HOMO levels, and low bandgaps, which are suitable for high-performance p-type OFETs. The field-effect transistors were fabricated through a solution-processable method and exhibited promising p-type performance with field-effect mobility up to 4.3 cm²/Vs and high I_on/off of 10⁸ under ambient conditions.     

Macrocyclic Complexes Derived from Four cis-L2Pt Corners and Four Butadiynediyl Linkers; Syntheses,Electronic Structures,and Square versus Skew Rhombus Geometries

The dialkyl malonate derived 1,3-diphosphines R₂C(CH₂PPh₂)₂ (R= a , Me; b , Et; c , n-Bu; d , n-Dec; e , Bn; f , p-tolCH₂) are combined with (p-tol₃P)₂PtCl₂ or trans-(p-tol₃P)₂Pt((C≡C)₂H)₂ to give the chelates cis-(R₂C(CH₂PPh₂)₂)PtCl₂ ( 2 a – f , 94–69 %) or cis-(R₂C(CH₂PPh₂)₂)Pt((C≡C)₂H)₂ ( 3 a – f , 97–54 %). Complexes 3 a – d are also available from 2 a – d and excess 1,3-butadiyne in the presence of CuI (cat.) and excess HNEt₂ (87–65 %). Under similar conditions, 2 and 3 react to give the title compounds [(R₂C(CH₂PPh₂)₂)[Pt(C≡C)₂]₄ ( 4 a – f ; 89–14 % (64 % avg)), from which ammonium salts such as the co-product [H₂NEt₂]⁺ Cl⁻ are challenging to remove. Crystal structures of 4 a , b show skew rhombus as opposed to square Pt₄ geometries. The NMR and IR properties of 4 a – f are similar to those of mono- or diplatinum model compounds. However, cyclic voltammetry gives only irreversible oxidations. As compared to mono-platinum or Pt(C≡C)₂Pt species, the UV-visible spectra show much more intense and red-shifted bands. Time dependent DFT calculations define the transitions and principal orbitals involved. Electrostatic potential surface maps reveal strongly negative Pt₄C₁₆ cores that likely facilitate ammonium cation binding. Analogous electronic properties of Pt₃C₁₂ and Pt₅C₂₀ homologs and selected equilibria are explored computationally.     

Solution-Processable Unsymmetrical Triarylamines: Towards High Mobility and ON/OFF Ratio in Bottom-Gated OFETs

Self-assembly of organic small molecules into an ordered thin film has been the key strategy towards efficient charge transport for organic field-effect transistors (OFETs). Solution processing is a feasible and economic way to enhance pi–pi interaction. Herein, nitrile-substituted unsymmetrical triarylamines for OFET applications with high mobility are reported. The compounds were constructed by Suzuki cross-coupling reactions under inert conditions. The HOMO level of about 5.3 eV indicates good hole-transporting ability. OFETs were assembled in bottom-gate, top-contact architecture. Devices fabricated from a binary solvent system exhibited excellent p-channel characteristics, with impressively high charge-carrier mobility of up to 2.58 cm² V⁻¹ s⁻¹ and I_ON/OFF current ratios of 10⁶–10⁷. SEM and AFM analysis showed the efficient molecular self-assembly attained by the simple and effective solvent-engineering method. Theoretical insights obtained by DFT calculations supported by single-crystal structures showed that the crystalline nature and packing modes of these compounds ensure high mobility. The results prove that these compounds have great potential for use in numerous electronic applications, such as sensors and logic switches.     

Organoruthenium (II) complexes featuring pyrazole‐linked Schiff base ligands: Crystal structure,DNA/BSA interactions,cytotoxicity and molecular docking

Half‐sandwiched ruthenium (II) arene complexes with piano stool‐like geometry with the general formula [(p‐cymene)RuClL¹] and [(p‐cymene)RuClL²] [where L¹ = (Z)‐N′‐((1,3‐diphenyl‐1H‐pyrazol‐4‐yl)methylene)furan‐2‐carbohydrazide and L² = (Z)‐N′‐((1,3‐diphenyl‐1H‐pyrazol‐4‐yl)methylene)thiophene‐2‐carbohydrazide] were synthesized and characterized. The single crystal X‐ray data revealed that the complexes belong to the same crystal system (monoclinic) with octahedral geometry, where the ruthenium atom is surrounded by hydrazone ligand coordinated through ON atoms, one chloride labile co‐ligand and the remaining three coordination sites covered by an electron cloud of p‐cymene moiety. The interaction between the complexes and DNA/bovine serum albumin (BSA) was evaluated using absorption and emission titration methods showing intercalative modes of interaction. The DNA cleavage ability of the complexes was checked by agarose gel electrophoresis method exhibiting the destruction of DNA duplex arrangement. To understand the interaction between ruthenium complex and DNA/BSA molecule, molecular docking studies were performed. In vitro cytotoxicity of the complexes was examined by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay on human lung cancer cell line, A549, and found that at lower IC₅₀, cell growth inhibition has occurred. Similarly, the IC₅₀ values of the complexes treated with cancerous cell lines have produced a significant amount of lactase dehydrogenase and nitrite content in the culture medium, which were evaluated as apoptosis‐inducing factors, suggesting that the ruthenium (II) arene hydrazone complexes with pyrazole ligands have promising anticancer activities.     

Syntheses,Structures, and Spectroscopic Properties of 1,10-Phenanthroline-Based Macrocycles Threaded by PtC8Pt,PtC12Pt,and PtC16Pt Axles: Metal-Capped Rotaxanes as Insulated Molecular Wires

The platinum polyynyl complexes trans-(C₆F₅)(p-tol₃P)₂Pt(C≡C)_n/2H undergo oxidative homocoupling (O₂, CuCl/TMEDA) to diplatinum polyynediyl complexes trans, trans-(C₆F₅)(p-tol₃P)₂Pt(C≡C)_nPt(Pp-tol₃)₂(C₆F₅) (n=4, 2 ; 6, 5 ; 8, 8 ; 92–97 %) as reported previously. When related reactions are conducted in the presence of CuI adducts of the 1,10-phenanthroline-based macrocycles 2,9-(1,10-phenanthrolinediyl)(p-C₆H₄O(CH₂)₆O)₂(1,3-C₆H₄) ( 10 , 33-membered) or 2,9-(1,10-phenanthrolinediyl)(p-C₆H₄O(CH₂)₆O)₂(2,7-naphthalenediyl) ( 11 , 35-membered), excess K₂CO₃, and I₂ (oxidant), rotaxanes are isolated that feature a Pt(C≡C)_nPt axle that has been threaded through the macrocycle ( 2⋅10 , 9 %; 5⋅10 , 41 %; 5⋅11 , 28 %; 8⋅10 , 12 %; 8⋅11 , 9 %). Their crystal structures are determined and analyzed in detail, particularly with respect to geometric perturbations and the degree of steric sp carbon chain insulation. NMR spectra show a number of shielding effects. UV/Vis spectra do not indicate significant electronic interactions between the Pt(C≡C)_nPt axles and macrocycles, although cyclic voltammetry data suggest rapid reactions following oxidation.     

An Atomic View of Cation Diffusion Pathways from Single-Crystal Topochemical Transformations

The diffusion pathways of Li-ions as they traverse cathode structures in the course of insertion reactions underpin many questions fundamental to the functionality of Li-ion batteries. Much current knowledge derives from computational models or the imaging of lithiation behavior at larger length scales; however, it remains difficult to experimentally image Li-ion diffusion at the atomistic level. Here, by using topochemical Li-ion insertion and extraction to induce single-crystal-to-single-crystal transformations in a tunnel-structured V₂O₅ polymorph, coupled with operando powder X-ray diffraction, we leverage single-crystal X-ray diffraction to identify the sequence of lattice interstitial sites preferred by Li-ions to high depths of discharge, and use electron density maps to create a snapshot of ion diffusion in a metastable phase. Our methods enable the atomistic imaging of Li-ions in this cathode material in kinetic states and provide an experimentally validated angstrom-level 3D picture of atomic pathways thus far only conjectured through DFT calculations.     

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

The newfangled chiral aroylthiourea ligands (L1‐L6) were produced from unprotected D/L‐alanine and their water soluble Ru (II) organometallic catalysts ( 1 – 6 ) were designed from their reaction with [RuCl₂(η⁶‐p‐cymene)]₂. The analytical and spectral methods were used to confirm the structure of the ligands and complexes. The solid state structure of L1, 5 and 6 was confirmed by single crystal XRD. The organometallic compounds ( 1 – 6 ) catalyzed the asymmetric transfer hydrogenation of aromatic, heteroaromatic and bulky ketones to yield respective enantiopure secondary alcohols with admirable conversions (up to 99%) and attractive enantiomeric excesses (ee up to 98%), in presence of formic acid and triethylamine in water medium under non‐inert atmospheric conditions.