Trinuclear Cluster Research Articles

Two-Periodic MoS2-Type Metal-Organic Frameworks with Intrinsic Intralayer Porosity for High-Capacity Water Sorption.

2D metal-organic frameworks (2D-MOFs) are an important class of functional porous materials. However, the low porosity and surface area of 2D-MOFs have greatly limited their functionalities and applications. Herein, the rational synthesis of a class of mos-MOFs with molybdenum disulfide (mos) net based on the assembly of trinuclear metal clusters and 3-connected tripodal organic ligands is reported. The non-crystallographic (3,6)-connected mos net, different from the 3-connected hcb net of graphene, offers abundant intralayer voids courtesy of the split of one node into two. Indeed, mos-MOFs exhibit high apparent Brunauer-Emmett-Teller surface areas, significantly superior to those of other 2D-MOF analogs. Markedly, hydrolytically stable Cr-mos-MOF-1 displays an impressive water vapor uptake of 0.75 g g-1 at 298 K and P/P0 = 0.9, among the highest in 2D-MOFs. The combined water adsorption and X-ray diffraction study reveal the water adsorption mechanisms, suggesting the importance of intralayer porosities of mos-MOFs for high-performance water capture. This study paves the way for a reliable approach to synthesizing 2D-MOFs with high porosity and surface areas for diverse applications.

Modulator-Directed Counterintuitive Catenation Control for Crafting Highly Porous and Robust Metal-Organic Frameworks with Record High SO2 Uptake Capacity.

Sulfur dioxide (SO2) is an important industrial feedstock that can be directly utilized or catalytically transformed to value-added chemicals such as sulfuric acid. The development of regenerable porous sorbents for the highly efficient storage and energy-minimal release of toxic SO2 operating under ambient conditions has attracted growing interest. Herein, we report the topology-guided construction of highly porous acs-type metal-organic frameworks (MOFs) through a counterintuitive modulator-directed catenation control approach. In contrast to the conventional modulator facilitated coordination competition that favors the thermodynamic catenated phase, we show that the elevation of modulator concentration can promote the formation of the noncatenated phase probably through a sublattice dissolution pathway. The assembly of a custom-designed trigonal prismatic triptycene-quinoxaline linker and trinuclear Fe3O cluster affords either the threefold catenated SJTU-219 or noncatenated SJTU-220 with desired acs net. Impressively, the synthetic approach is applicable to various metal ions, including Al3+, V3+, and even Ti4+. The noncatenated SJTU-220 exhibits an extraordinary SO2 sorption capacity of 29.6 mmol g-1 at 298 K and 1 bar, surpassing all reported solid sorbents. The uptake capacity can be further raised to 35.6 mmol g-1 via the replacement of Fe3+ with kinetically more inert Cr3+, resulting in a staggering ∼329-fold volume reduction compared with free ideal SO2 gas. Computational simulations suggest that unique Fe3+···S(SO2) interactions dominate the SO2 seeding process, facilitating the efficient packing of SO2 molecules in the large channels. Besides, the exceptionally low uptake at the low pressure region implies global weak framework-SO2 interactions, which offer great potential for practically implementing an "easy-on/easy-off" SO2 delivery system.

Trinuclear iron-oxo cocatalyst regulating new electron transfer pathway in Pt loaded bismuth oxychloride for efficient photocatalytic hydrogen production

BiOCl, a traditional p-type semiconductor, finds extensive application in photocatalytic oxidation and degradation, whereas it is less common in photocatalytic water splitting and hydrogen production. Here, the photocatalytic hydrogen production performance of black BiOCl has been examined by the introduction of noble metal platinum and cocatalyst trinuclear iron-oxo cluster. During the 5-h photocatalytic process, the established system significantly augments the hydrogen production efficiency of black BiOCl by an estimated factor of 8.53. Under illumination, trinuclear iron-oxo clusters provide electron recombination with holes in the valence band of the catalyst, thereby increasing the utilization of photogenerated electrons. Additionally, since the specific energy level structure has a significant impact on the cocatalyst function, trinuclear iron-oxo clusters can be suitable in a variety of photocatalytic systems. This new endeavor might present creative design approaches and low-cost cocatalyst alternatives for the photocatalytic hydrogen evolution from the water splitting of conventional p-type semiconductor materials.

Customized Heteronuclear Dual Single‐Atom and Cluster Assemblies via D‐Band Orchestration for Oxygen Reduction Reaction

AbstractAdvanced oxygen reduction reaction (ORR) catalysts, integrating with well‐dispersed single atom (SA) and atomic cluster (AC) sites, showcase potential in bolstering catalytic activity. However, the precise structural modulation and in‐depth investigation of their catalytic mechanisms pose ongoing challenges. Herein, a proactive cluster lockdown strategy is introduced, relying on the confinement of trinuclear clusters with metal atom exchange in the covalent organic polymers, enabling the targeted synthesis of a series of multicomponent ensembles featuring FeCo (Fe or Co) dual‐single‐atom (DSA) and atomic cluster (AC) configurations (FeCo‐DSA/AC) via thermal pyrolysis. The designed FeCo‐DSA/AC surpasses Fe‐ and Co‐derived counterparts by 18 mV and 49 mV in ORR half‐wave potential, whilst exhibiting exemplary performance in Zn‐air batteries. Comprehensive analysis and theoretical simulation elucidate the enhanced activity stems from adeptly orchestrating dz2‐dxz and O 2p orbital hybridization proximate to the Fermi level, fine‐tuning the antibonding states to expedite OH* desorption and OOH* formation, thereby augmenting catalytic activity. This work elucidates the synergistic potentiation of active sites in hybrid electrocatalysts, pioneering innovative targeted design strategies for single‐atom‐cluster electrocatalysts.

Dye Induced Luminescence Properties of Gold(I) Complexes with near Unity Quantum Efficiency

AbstractTo study the effect of a dye on the photoluminescence (PL) properties of metal complexes, a series of gold(I) complexes were synthesized, containing a 7‐amino‐4‐methylcoumarin luminophore. The complexes are comprised of a coumarin moiety featuring different ancillary ligands, specifically N‐heterocyclic carbenes, triphenylphosphine, and diphenyl‐2‐pyridylphosphine. The synthesized gold(I) complexes are luminescent both in solution and the solid state at room temperature and 77 K. Complexes of different nuclearity, i.e., mono‐, di‐ and trinuclear compounds were synthesized. A clear trend between the nuclearity and the quantum yields can be seen. The coumarin dye not only improves the PL properties, but also enhances the luminescence of trinuclear clusters, which are otherwise known to be weak emitters in solution. The optical absorption properties were investigated in detail by quantum chemical calculations.

Dye induced luminescence properties of gold(I) complexes with near unity quantum efficiency.

To study the effect of a dye on the photoluminescence (PL) properties of metal complexes, a series of gold(I) complexes were synthesized, containing a 7-amino-4-methylcoumarin luminophore. The complexes are comprised of a coumarin moiety featuring different ancillary ligands, specifically N-heterocyclic carbenes, triphenylphosphine, and diphenyl-2-pyridylphosphine. The synthesized gold(I) complexes are luminescent both in solution and the solid state at room temperature and 77 K. Complexes of different nuclearity, i.e., mono-, di- and trinuclear compounds were synthesized. A clear trend between the nuclearity and the quantum yields can be seen. The coumarin dye not only improves the PL properties, but also enhances the luminescence of trinuclear clusters, which are otherwise known to be weak emitters in solution. The optical absorption properties were investigated in detail by quantum chemical calculations.

Graphene Decorated With Mo3S7 Clusters for Sensing CO2

AbstractThis paper reports for the first time a gas‐sensitive nanohybrid based on trinuclear molybdenum sulfido clusters ((Bu4N)2[Mo3(μ3‐S)(μ‐S2)3Cl6] (Mo3S7)) supported on graphene flakes (Mo3S7@Graphene). The nanomaterial, once implemented in a chemoresistive device, changes its electrical resistivity when exposed, at room temperature (RT), to toxic and harmful gases, such as hydrogen (H2), carbon dioxide (CO2), carbon monoxide (CO), and benzene. Particularly, the Mo3S7@Graphene hybrid shows an outstanding sensing performance toward CO2. Theoretical calculations provide a better understanding of the plausible gas sensing mechanisms. These findings open the door for a new generation of molybdenum sulfido cluster‐based sensors in which electronic interrogation can be implemented, advancing toward the realization of highly sensitive gas sensing.

Reactions of Ru3(CO)12 with 1,5-bis(diphenylphosphino)pentane: Synthesis, characterization, crystal structure, Hirshfeld surface and QTAIM Analysis of Ru3(CO)10(µ-dpppe)

Reactions of Ru3(CO)12 with 1,5-bis(diphenylphosphino)pentane (dpppe) in THF induced by sodium benzophenone ketyl radical anion, resulted in the expected metal cluster [Ru3(CO)11]2(µ-dpppe) (1) and Ru3(CO)10(µ-dpppe) (2) as the main products. Clusters 1 and 2 were characterized by spectroscopic methods, including Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H and 31P{1H} NMR).The structural features were determined using single crystal X-ray diffraction analysis. In cluster 1 and 2, the (dpppe) links two trinuclear cluster units via phosphine moieties and bridges to Ru–Ru bond, respectively. Both clusters were stabilized by the presence of C–H⋯O interactions and were further analyzed by Hirshfeld surface analysis. The bonding interactions within cluster 2 were studied using the Quantum Theory of Atoms in Molecules (QTAIM). Various local and integral topological properties of the electron density were calculated, along with the source function (SF) calculations and electron localization function (ELF) analysis.

Controlling the Size of Molecular Copper Clusters Supported by a Multinucleating Macrocycle.

The use of a nonrigid, pyridyldialdimine-derived macrocyclic ligand (3PDAI2) enabled the synthesis of well-defined mono-, di-, tri-, and tetra-nuclear Cu(I) complexes in good yields through rational synthetic means. Starting from mono- and diargentous 3PDAI2 complexes, transmetalation to Cu(I) proceeded smoothly with formation of AgX (X = Cl, I) salts to generate mono-, di-, and trinuclear copper complexes. Monodentate supporting ligands (MeCN, xylNC, PMe3, PPh3) were found to either transmetallate with or bind various di- and trinuclear clusters. The solution-phase dynamic behaviors of these species were studied through NMR spectroscopic investigations, and an in-depth study of the trinuclear systems revealed a rate dependence on the identity of the supporting ligand, indicating that ligand dissociation reactions were involved in the dynamic exchange processes. Synthetic investigations further found methods for the purposeful interconversion between the di- and trinuclear systems as well as the synthesis of a pseudotetrahedral tetracopper complex with two μ-Ph supporting ligands.

Customized Heteronuclear Dual Single-Atom and Cluster Assemblies via D-Band Orchestration for Oxygen Reduction Reaction.

Advanced oxygen reduction reaction (ORR) catalysts, integrating with well-dispersed single atom (SA) and atomic cluster (AC) sites, showcase potential in bolstering catalytic activity. However, the precise structural modulation and in-depth investigation of their catalytic mechanisms pose ongoing challenges. Herein, a proactive cluster lockdown strategy is introduced, relying on the confinement of trinuclear clusters with metal atom exchange in the covalent organic polymers, enabling the targeted synthesis of a series of multicomponent ensembles featuring FeCo (Fe or Co) dual-single-atom (DSA) and atomic cluster (AC) configurations (FeCo-DSA/AC) via thermal pyrolysis. The designed FeCo-DSA/AC surpasses Fe- and Co-derived counterparts by 18 mV and 49 mV in ORR half-wave potential, whilst exhibiting exemplary performance in Zn-air batteries. Comprehensive analysis and theoretical simulation elucidate the enhanced activity stems from adeptly orchestrating dz 2-dxz and O 2p orbital hybridization proximate to the Fermi level, fine-tuning the antibonding states to expedite OH* desorption and OOH* formation, thereby augmenting catalytic activity. This work elucidates the synergistic potentiation of active sites in hybrid electrocatalysts, pioneering innovative targeted design strategies for single-atom-cluster electrocatalysts.

Solvent Effect for the Structural Control of Molecular Architectures Consisting of Trinuclear Ruthenium Clusters and Ligands at the HOPG Surface.

The molecular architecture of a triruthenium complex and 1,4-di(4-pyridyl)benzene on highly oriented pyrolytic graphite was investigated by drop-casting mixed tetrahydrofuran and methanol solutions. Atomic force microscopy revealed the formation of one-dimensional molecular wires on highly oriented pyrolytic graphite after heating the mixed tetrahydrofuran solution, whereas large ring structures were formed in the methanolic solution. It was found that the molecular architectures composed of triruthenium complexes and 1,4-di(4-pyridyl)benzene strongly depend not only on the temperature of the solution but also on the organic solvents. The formation of the molecular architecture was supported by the ultraviolet-visible absorption spectra of the mixed solution and the electrochemical responses of the deposited film.

Modifying Parallel Excitations into One Framework for C(sp3)─H Bond Activation with Energy Combined More Than Two Photons.

Natural photosynthesis enzymesutilize energies of several photons for challenging oxidation of water, whereas artificial photo-catalysis typically involves only single-photon excitation. Herein, a multiphoton excitation strategy is reported that combines parallel photo-excitations with a photoinduced electron transfer process for the activation of C(sp3)─H bonds, including methane. The metal-organic framework Fe3-MOF is designed to consolidate 4,4',4″-nitrilotrisbenzoic units for the photoactivation of dioxygen and trinuclear iron clusters as the HAT precursor for photoactivating alkanes. Under visible light irradiation, the dyes and iron clusters absorbed parallel photons simultaneously to reach their excited states, respectively, generating 1O2 via energy transfer and chlorine radical via ligand-to-metal charge transfer. The further excitation of organic dyes leads to the reduction of 1O2 into O2 •- through a photoinduced electron transfer, guaranteeing an extra multiphoton oxygen activation manner. The chlorine radical abstracts a hydrogen atom from alkanes, generating the carbon radical for further oxidation transformation. Accordingly, the total oxidation conversion of alkane utilizing three photoexcitation processes combines the energies of more than two photons. This new platform synergistically combines a consecutive excited photoredox organic dye and a HAT catalyst to combine the energies of more than two photons, providing a promising multiphoton catalysis strategy under energy saving, and high efficiency.

Cd-Ln (Ln = Pr, Sm, Yb and Nd) heteronuclear complexes based on the linear chain ether Schiff base: Structural regulation and fluorescence properties

Four structurally different Cd-Ln heteronuclear complexes based on the linear chain ether Schiff base ligand (bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine (H2L) and the co-ligands 4,4′-bipyridine (bipy) or isonicotinate (IN), with composition [PrCd2L2(CH3COO)2](NO3)·CH2Cl2 (1), {[SmCdL(bipy)(NO3)3]·CH2Cl2·CH3CH2OH}n (2), [YbCdL(IN)(NO3)(CH3COO)]n (3) and {[Nd2Cd2L2(IN)2(NO3)2(CH3OH)2(CH3COO)](NO3)}n (4), have been synthesized by interfacial diffusion methods. Structural regulation is achieved by changes in the co-ligands or Ln(III) ions of different radii: Single crystal X-ray analysis determined that 1 is a trinuclear cluster with the Pr(III) ion as a joint bridging of two CdL coordination units; 2 and 3 are both infinite one-dimensional zigzag coordination polymers consisting of CdLnL secondary units through coordination bridging bipy or IN; 4 is a two-dimensional graphene laminate structure formed by two types of CdNdL secondary units bridged by both IN and acetate simultaneously. In the solid state, the complexes 1–4 all exhibit fluorescence peaks based on H2L with blue shift and enhancement. The order of fluorescence peaks intensity of the complexes in N,N-dimethylformamide (DMF) solution is consistent with that in the solid state. Moreover, the corresponding characteristic emissions of Sm(III) ion in complex 2 can be observed in the fluorescence spectra in either solid state and DMF solution, indicating that [CdL] unit is suitable for the sensitization of Sm(III) ion.

Micropollutants (ciprofloxacin and norfloxacin) remediation from wastewater through laccase derived from spent mushroom waste: Fate, toxicity, and degradation

Fluoroquinolone antibiotics frequently found in environmental matrices (wastewater treatment plants, hospital wastewater, industrial wastewater and surface wastewater) causes potential threat to the environment. Enzymatic treatment for degradation of antibiotics from environmental matrices is a green and sustainable approach. Focusing on this, this study aimed to degrade two frequently found fluroquinolone emergent pollutants, ciprofloxacin and norfloxacin from wastewater. The trinuclear cluster of copper ions present in laccase has the ability to effectively remove organic micropollutants (OMPs). The uniqueness of this study is that it utilizes laccase enzyme extracted from spent mushroom waste (SMW) of P. florida for degradation of ciprofloxacin and norfloxacin and to achieve highest degradation efficiency various parameters were tweaked such as pH (3–6), temperature (30 °C and 50 °C), and ABTS (0.05, 0.6, and 1 mM) concentration. The results showed that the most effective degradation of ciprofloxacin (86.12–75.94%) and norfloxacin (83.27–65.94%) was achieved in 3 h at pH 4.5, temperature 30 °C, and 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 0.05 mM concentration. Nevertheless, achieving degradation at 50 °C for both antibiotics, indicates thermostability nature of laccase (P. florida). Further, the fate of transformed products obtained from laccase mediated degradation was confirmed by liquid chromatography (LC-MS). Both the antibiotics undergo decarboxylation, depiperylyzation, dealkylation and defluorination as a result of laccase-mediated bond breakage. Anti-microbial activity of the biodegraded products was monitored by residual anti-bacterial toxicity test (E. coli and Staphylococcus aureus). The biodegraded products were found to be non-toxic and resulted in the growth of E. coli and Staphylococcus aureus, as determined by the agar-diffusion method. Moreover, the storage stability of laccase was determined for 28-day duration at varying pH (3–10) and temperature (4–50 °C). The maximum storage stability was obtained at pH 4.5 and temperature 30 °C. Therefore, utilizing SMW for the degradation of OMPs from wastewater not only benefits in degradation but also reuses SMW agro waste, shedding light on agro waste management. Thus, SMW is a one-pot solution for both OMPs biodegradation and circularity in the economy.

An overview on copper based heterometallic complexes in combination with d10 metal ions derived from N2O2 donor di-Schiff base ligands

A good number of heterometallic complexes based on various Cu(II) bound “metalloligands” of N2O2 donor di-Schiff bases and some of their reduced counterpart along with group 12 metal ions have been synthesized and characterized by different research groups in the literature. This review focuses on an overview of the synthetic strategies, X-ray crystallographic structures and a few important properties of these complexes. These have been discussed in three major sub-classes: Cu(II)-Zn(II), Cu(II)-Cd(II) and Cu(II)-Hg(II) heterometallic complexes. Judicious combinations of carbonyls and di-amines in an easy and effective manner gives 14 selected di-Schiff base ligands (symmetrical and unsymmetrical) with particular shape, geometry and denticity that direct the synthesis of these metal complexes totally or preferentially towards di-, tri- or poly-nuclear entities. Moreover, owing to their ability to assemble three metal ions in close proximity, these resulting oxido-bridged flexible coordination clusters adapted to various other ligand functionalities with particular shape and sometimes unusual coordination modes with certain degree of control. Such unique structural aspect of this system is immensely important in inorganic synthesis. The inherent flexibility of the di-oxido bridged trinuclear coordination cluster led to produce isomeric linear and bent structures that usually depend upon various factors e.g. the nature of the Schiff base, anionic co-ligands, temperature, solvent etc. The structural aspects of resulting discrete and polymeric self-assemblies have enriched the coordination library that extended to develop numerous heterometallic systems with significant applications and new scopes

Two new High-Connectivity topological networks constructed from tricarboxylic acids and 1,2,4,5-tetra(4-pyridyl)benzene

Two new coordination polymers [Co3(pta)2(bztpy)(H2O)2]·2H2O (1) and [Co3(bta)2(bztpy)1.5(H2O)2]·4H2O (2) (H3pta = 1,2,3-propanetricarboxylic acid, H3bta = 1,2,3-benzenetricarboxylic acid, bztpy = 1,2,4,5-tetra(4-pyridyl)benzene) have been hydrothermally synthesized and structurally characterized. In 1, pta connects with a trinuclear cobalt cluster to form a (4,4) net, while bztpy also connects with the trinuclear cobalt cluster to form a (4,4) net, thereby creating a very rare (4,8)-connected mixed-node topological network that exhibits ferrimagnetic behavior. 2 is a rare (4,4,12)-connected topological network formed by hexanuclear cobalt rings connected through 12 bztpy ligands, showing antiferromagnetic properties. Both compounds demonstrate the potential of the large tetradentate pyridyl ligand bztpy in constructing high-connectivity topological networks.

Crystal structure and stimulus-responsive properties of three functional compounds containing 1-carboxyethyl-4,4′-bipyridine

Herein, three compounds containing the neutral viologen derivative, 1-carboxyethyl-4,4′-bipyridine (CEbpy) have been synthesized, (CEbpy)·(H2TPDC)·2H2O (1) [Co(CEbpy)(TPDC)(H2O)4]·3H2O (2) and [Cd3(CEbpy)2(TPDC)3·7H2O]n (3) (H2TPDC = thiophene-2,5-dicarboxylic acid). Compound 1 is a supramolecular assembly, linked by non-covalent interactions to constitute the donor-acceptor (D-A) system. Compound 2 owns a zero-dimensional (0D) isolated structure in which metal ions are coordinated with CEbpy and fully deprotonated (TPDC)2- ligands. Compound 3 exhibits a three-dimensional (3D) framework of trinuclear metal clusters, where each metal atom forms its own distinct linear one-dimensional (1D) chain along a specific axis. Although the three compounds comprise the same bipyridinium moiety and aromatic acid, their chromic behaviors are different. Compounds 1 and 3 exhibit reversible photochromism, while 2 reveals hydrochromism upon heating. Additionally, photo-modulated fluorescence as well as their potential applications in inkless erasable printing have been studied.

Two In-MOFs containing pyridine dicarboxylic acids with different functional sites: Sensing of Fe3+ ion in water and selective gas capture

A major goal of MOF research is to design its structure and function for specific applications. In this study, we have successfully synthesized two In-MOFs (In-MOF1 and In-MOF2). The structures of the two kinds of MOFs were characterized, both MOFs contain 9-connected trinuclear indium cluster units, which is rare in the reported In-MOF structures. In-MOF1 demonstrated a three-dimensional network configuration based on the [In3(μ3–O)(CO2)6N2O] SBUs, In-MOF2 demonstrated a three-dimensional network framework based on the [In3(μ3–O)(CO2)6N3] SBUs. Both In-MOF1 and In-MOF2 showed high selective and sensitive for fluorescence detection toward Fe3+ ion in water. In addition, the gas adsorption experiments show that In-MOF1 has the ability to selectively adsorb C2H2 and CO2 over CH4.

Substitution reactivity of [Mo3(µ3-O)(µ3-CCH3)(µ-O2CCHCl2)6(CH3OH)3]O2CCHCl2 (Mo3) and the crystallization of a deca-molybdenum cluster [Mo10O10(μ3-O)8(μ-O)8(py)8](py)2 from Mo3 in pyridine

By heating the trinuclear acetate-bridged molybdenum cluster, [Mo3(µ3-O)(µ3-CCH3)(µ-O2CCH3)6(H2O)3]+ in neat dichloroacetic acid for 4 h (T = 115 °C), a new trinuclear molybdenum cluster with chemical formula [Mo3(µ3-O)(µ3-CCH3)(µ-O2CCHCl2)6(CH3OH)3]+ (abbreviated as Mo3) was synthesized. After precipitation from solution with DI water and redissolution in methanol, red crystals formed after one week at 10 °C. To quantify the rate of substitution of the terminal methanol ligands, crystals of the trinuclear cluster were dissolved in 0.1 M pyridine‑d5 and monitored over time using 1H NMR (T = 297–310 K). The rate constant for substitution was found to be kobs298K = 1.87 × 10−4 s−1 and activation parameters equal toΔHobs‡ = 116 (±7) kJ/mol andΔSobs‡ = 74 (±23) J mol−1K−1. In an attempt to substitute the terminal methanol ligands using concentrated pyridine, a deca-molybdenum cluster with a cube-like polyoxomolybdate core was discovered ([Mo10O10(μ3-O)8(μ-O)8(py)8](py)2) (abbreviated as Mo10). Herein, we describe the synthesis, crystallographic data, and substitution reactivity of [Mo3(µ3-O)(µ3-CCH3)(µ-O2CCH2Cl2)6(CH3OH)3]O2CCHCl2 and report on the unexpected formation of [Mo10O10(μ3-O)8(μ-O)8(py)8](py)2 from neat pyridine.

Design, synthesis and mechanistic studies of novel arylformylhydrazone butylphenyltin complexes as potential anticancer agents

Many diorganotin complexes with various alkyl groups exhibit excellent in vitro anticancer activity. However, most diorganotin is the same alkyl group, and the asymmetric alkyl R group has been rarely reported. Hence, in this paper, twenty butylphenyl mixed dialkyltin arylformylhydrazone complexes have been synthesized by microwave “one-pot” reaction with arylformylhydrazine, substituted α-keto acid or its sodium salt and butylphenyltin dichloride. The crystal structures of nine complexes were determined, indicating that the complexes C1, C2, C11, C12, and C16 ∼ C19 possessed a central symmetric structure of a dinuclear Sn2O2 tetrahedral ring; while the complex C9 is a trinuclear tin-oxygen cluster with a 6-membered ring encased in a 12-membered macrocyclic structure. The inhibiting activity of complexes was tested against the human cell lines NCI-H460, MCF-7, HepG2, Huh-7 and HL-7702. Complex C2 demonstrated the optimal inhibitory effect on HepG2 cells, with an IC50 value of 0.82 ± 0.03 μM. Cellular biology experiments revealed that complex C2 could induce apoptosis and G2/M phase cell cycle arrest in HepG2 and Huh-7 cells. The complex also caused the collapse of the mitochondrial membrane potential and increased intracellular reactive oxygen species in HepG2 and Huh-7 cells. Western blot analysis further clarified that complex C2 could induce cell apoptosis through the mitochondrial pathway along with the release of reactive oxygen species.