119Sn NMR Research Articles

Self-assembly of a unique triangle-like tungstovanadate containing pentagonal {(WO7)W3(SnR)2} cluster.

In aqueous solution, a novel triangle-like tungstovanadate estertin derivative K10H10.5[(W4O15(H2O)2){(SnCH2CH2COO)2(V0.75W10.75/V0.25O39)}{{(SnCH2CH2COO)2(μ-OH)}2(SnCH2CH2COO)(VW10O37)}2]·31H2O ((SnR)8-V3W35, R = CH2CH2COO) was assembled by a conventional synthetic method. (SnR)8-V3W35 is composed of one [VW11O39]7- ({VW11}) and two [VW10O37]9- ({VW10}) units connected by eight [Sn(CH2)2COO]2+ groups and a {W4O19} cluster. Interestingly, there exists a pentagonal bipyramid WO7 polyhedral center surrounded by two SnCO5 and three WO6 octahedra, forming a pentagonal {(WO7)W3(SnR)2} cluster in this polyoxometalate (POM), which is also the first example of a pentagonal structure formed by transition metals (TMs) and main group organometals in the POM family. Furthermore, the structure of this organic-inorganic hybrid POM also exhibits the largest number of organotin groups introduced into the POM system. It was characterized with various physico-chemical and spectroscopic methods, including X-ray single crystal and powder diffraction analysis, 119Sn and 51V NMR, IR, thermal gravimetric analysis (TGA), etc. In addition, the catalytic activity of (SnR)8-V3W35 as a mimic of peroxidase was evaluated using o-phenylenediamine (OPD) as a peroxidase substrate. The major factors influencing the oxidation reaction such as pH, the dosage of (SnR)8-V3W35, and concentrations of OPD and H2O2 were mainly studied. (SnR)8-V3W35 exhibits good peroxidase-like catalytic activity. From another perspective, the successful acquisition of (SnR)8-V3W35 further proves the instability and easy reassembly characteristics of TM-sandwich-type tungstovanadates, which also provides a new assembly strategy for synthesizing POM-estertin derivatives.

Syntheses and exploration of the catalytic activities of organotin(IV) compounds.

Six organotin(IV) compounds (1-6) have been synthesized by reaction of the polydentate pro-ligands H3L and H2L, respectively, with the corresponding diorganotin chlorides. All of the compounds were characterized by FT-IR spectroscopy, 1H, 13C{1H}, and 119Sn (1H) NMR spectroscopy, HRMS spectrometry, and single-crystal X-ray diffraction. The solid-state structures show that all of the compounds are monomeric (except compound 3) and contain a penta-coordinated tin atom. Compound 3 is a dimer with two hexa-coordinated tin atoms. Compounds 1-3 contain a non-coordinated hydroxymethyl group. All of the compounds have been screened for their catalytic efficacy in the synthesis of 1,2 disubstituted benzimidazoles using o-phenylenediamine and aldehyde derivatives. It has been observed that both the Lewis acidic Sn(IV) centre and the hydroxymethyl group (hydrogen bond donor) catalyse the reactions with a product yield of up to 92%.

A tin analogue of propadiene with cumulated C[double bond, length as m-dash]Sn double bonds.

The synthesis, structure, and properties of a stable, linear 2-stannapropadiene are reported. The identical C[double bond, length as m-dash]Sn bonds in this 2-stannapropadiene are the shortest hitherto reported C-Sn bonds. This 2-stannapropadiene features a 119Sn NMR signal at 507 ppm for the central tin atom, indicative of an unsaturated Sn4+ oxidation state. Due to the inert-pair effect, the tin atom displays a pronounced preference for the +2 oxidation state over the +4 oxidation state. Nevertheless, by employing silyl substituents, it is possible to disrupt the inert-pair effect, leading to the formation of an isolable 2-stannapropadiene with a linear structure centered on a Sn4+ atom. Treatment of this 2-stannapropadiene with SnBr2·dioxane resulted in the formation of a novel four-membered cyclic 1,1-dibromo-1,3-distannetane, which was subsequently reduced to afford the corresponding stable four-membered cyclic bis(stannylene).

Temperature-dependent photoluminescence down to 77 K of organotin molecular rotors: eco-friendly synthesis, photophysical characterization, X-ray structures, and DFT studies.

Fluorescent organotin compounds are useful in sensing, optoelectronic devices, and in vitro bioimaging. Although in vitro fluorescence bioimaging shows low resolution at room temperature, a better resolution is possible at cryotemperatures. Therefore, the search for new cryoluminescent materials with potential application in high-resolution fluorescence bioimaging remains a great challenge. Herein, we report the cryoluminescence properties of two fluorescent bis-organotin compounds, namely, BisNTHySnBu2 (5) and BisNTHySnPh2 (6), synthesized via microwave irradiation. All compounds were fully characterized using 1H, 13C, and 119Sn NMR spectroscopy, Raman spectroscopy, IR spectroscopy, and HR-MS. The 119Sn δ and 3J(1H,119Sn) of 5 and 6 indicate that two Sn-ligands are chemically and electronically equivalent, as confirmed by cyclic voltammetry. The crystal structure of 6 showed pentacoordinate tin atoms with skeleton ligands. The study of self-assembled monolayers of both Sn-complexes via STM microscopy revealed a similar supramolecular packing in lamella-like patterns, adopting a face-on arrangement, where molecules stay flat lying on HOPG in accordance with the height profile of closely packed monolayers on graphite of about 0.33 nm thickness. However, only the Sn complex 6, which bears phenyls, covers large surface areas. The photophysical properties of bis-organotin compounds were also investigated in solution (room and low temperatures) and in the solid state. Good luminescence properties in solutions with fluorescence quantum yields (Φ) of approximately 35% and 50% were found. Despite this, Φ is quenched in the solid state because of aggregation, as supported by solvent/non solvent fluorescence studies, which is in agreement with STM and AFM investigation.

Advanced Characterization Development for Metal Anodes in Aqueous Batteries

Renewable penetration of the electric grid necessitates inexpensive and safe energy storage solutions. With these priorities, aqueous batteries with metal anodes (Zn, Al, Mg, Sn, etc.) are an exciting area of development as they have low material costs, inherent safety, and high theoretical energy density. Understanding and quantifying the faradaic and chemical reactions occurring in aqueous alkaline batteries with metal anodes necessitates probing the solid, liquid, and gaseous phases that evolve during cycling. The interplay of plating, stripping, precipitation, disproportionation, and parasitic gases generation complicates our understanding of metal anode cycling behavior and often muddle the real failure mechanisms in aqueous batteries.In our work, we have developed a robust toolbox of direct characterization tools to investigate metal anodes in aqueous batteries. Our investigation focuses on tin (Sn) as a largely unexplored metal anode and characterizes its performance and speciation during cycling. We will present a variety of methods to probe the charge/discharge speciation and efficiency losses to parasitic side reactions, including operando XRD, in-situ gas detection, RRDE, EQCM, and liquid 119Sn NMR. These techniques have allowed us to develop a mechanistic understanding of the Sn metal anode system and construct a high coulombic-efficiency, high utilization, and long cycle-life aqueous battery.

Synthesis, crystal structure and antitumor activity of trialkyltin (IV) 9,10-anthraquinone-2-carboxylate

Two new anthraquinone-organotin complexes [Ph3Sn(O2CC14H7O2)·MeOH]·MeOH (AQS01) and Cy3Sn(O2CC14H7O2) (AQS02) were synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR, 119 Sn NMR, X-ray crystallography and thermo-gravimetric analysis. Incorporation of 9,10-anthraquinone with organotin successfully enhanced its anticancer activity. Interestingly, the anti-proliferative activity of AQS01 against CAL-27 cells in vitro was almost 10-fold that of mitoxantrone and 40-fold that of cisplatin. Flow cytometry showed that AQS01 could induce apoptosis and arrest cell cycle in S phase. UV–visible absorption spectrometry and molecular docking showed that AQS01 can be well embedded in the double helix of DNA. Moreover, AQS01 induced cell death by upregulating the expression level of the DNA damage protein γ-H2AX and activating the mitochondrial apoptotic signaling pathway (Bax/Bcl-2). Therefore, AQS01 can be used as a potential anticancer drug and has potential for further research.

Crystal structure, Hirshfeld analysis and computational study on tin (IV) complex: Insights from synthesis, spectroscopic, anticancer activity and molecular docking studies

A new class of tin (IV) complex (M1) was synthesized from 1,10-phenenthroline and di(o-chlorobenzyl) tin dichloride in good yield. The synthesized complex was assigned by 1H NMR, 13C NMR, 119Sn NMR, and single crystal X-ray diffraction analyses. The tin complex M1 was compared theoretically and agreed well with experimental results. From the single crystal analysis, the synthesized complex containing two nitrogen and two chlorine atoms located in equatorial position, the benzene ring attached to two CH2 has an axial position and Sn is in a central position. This proves that the Sn-Cl and Sn-N bonds have a considerable binding interaction with the distances are 2.5004 A° and 2.5111 A° for Sn-Cl and 2.349 A° and 2.332 A° for Sn-N. The theoretical FT-IR and FT-Raman spectroscopic investigation agree well with the experimental one. In the FMO analysis, the calculated HOMO and LUMO bond gap value is 1.35 eV. The electrophilic and nucleophilic attack sites are confirmed by the MEP study. The synthesized tin complex was assayed for its in vitro anticancer activity against MCF7 and PC3 cell lines. Among them, compound displayed effective anticancer activity against PC3 cell lines which comparable activity to the reference standard drug, Cisplatin. In the docking study, a good binding affinity score was observed in the PC3(6XXO) cell line which correlates well with in vitro findings.

Synthesis, structural characterization, and DNA binding/cleavage studies of diorganotin(IV) carboxylates and their complexes with 1,10-phenanthroline: X-ray structures of [Me8Sn4(p-FC6H4CO2)4O2], [Bu2Sn(p-NO2C6H4CO2)2.phen], and DFT studies

The present study is focused on the mode of DNA-interactions with diorganotin(IV) carboxylates and their 1,10-phenanthroline (phen) complexes, and revealed that the planarity and extended π system of phen may increase the probability of DNA intercalation. Diorganotin(IV) derivatives of p-fluoro-/p-hydroxy-/p-nitro benzoic acid, viz. Bu2Sn(p-XC6H4CO2)2: X = F (1), OH (2), NO2 (3), Oct2Sn(p-NO2C6H4CO2)2 (4), and Me8Sn4(p-FC6H4CO2)4O2 (5), and their complexes with phen viz. Bu2Sn(p-XC6H4CO2)2.phen: X = F (6), OH (7), NO2 (8), Oct2Sn(p-NO2C6H4CO2)2.phen (9), and Me2Sn(p-FC6H4CO2)2.phen (10) have been synthesized and characterized by using various techniques including single crystal X-ray diffraction studies, nuclear magnetic resonance (1H, 13C, and 119Sn NMR), electrospray ionization mass spectrometry (ESI-MS), infrared (FT-IR), and elemental analysis. Based on crystal data, complexes (5) and (8) have a P-1 space group with a triclinic crystal system. In the octahedral geometry of complex (5), Sn atom has a tetranuclear Sn4O2 core, whereas complex (8) has a pentagonal bipyramidal geometry around Sn atom. The LanL2Z basis set has been employed for optimized gas-phase geometries, and the calculated ∠C-Sn-C bond angles agree with those obtained from NMR/X-ray studies. UV-visible, fluorescence and circular dichroism (CD) titrations showed interaction with Calf Thymus DNA (CT-DNA), and Kb and KSV values in the order of 103–105 M−1 indicate intercalation within the base pairs or in minor groove. Further, gel electrophoreses studies indicate that all of the complexes have efficiently cleaved plasmid pBR322 DNA into three bands; supercoiled, nicked/circular along with linear structure. The intriguing biophysical results suggest that these complexes may have anticancer potential.

Novel diphenyltin(IV) complexes with carboxylato N-functionalized 2-quinolone ligands: Synthesis, characterization and in vitro anticancer studies

Three new diphenyltin(IV) complexes, bis(3-(4-methyl-2-oxoquinolinyl-1(2H)-yl)propanoato)diphenyltin(IV) (1), bis(2-(4-methyl-2-oxoquinolin-1(2H)-yl)ethanoato)diphenyltin(IV) (2), and bis(2-(4-hydroxy-2-oxoquinolin-1(2H)-yl)ethanoato)diphenyltin(IV) (3), were synthesized and characterized by elemental microanalysis, FT-IR spectroscopy, and multinuclear (1H, 13C and 119Sn) NMR spectroscopy. Crystal structure of ligand precursor, 2-(4-methyl-2-oxoquinolinyl-1-(2H)-yl)acetic acid (HL2), has been determined by X-ray diffraction studies. Asymmetric bidentate coordination of the carboxylato ligands and skew trapezoidal structures are assumed for the synthesized complexes. In vitro anticancer activity of the synthesized diphenyltin(IV) complexes was evaluated against three human: MCF-7 (breast adenocarcinoma), A375 (melanoma), HCT116 (colorectal carcinoma), and three mouse tumor cell lines: 4T1 (breast carcinoma), B16 (melanoma), CT26 (colon carcinoma) using MTT and CV assays. The IC50 values fall in the range from 0.1 to 3.7 μM. Flow cytometric analysis and fluorescent microscopy suggest that complex 1 induces caspase-dependent apoptosis followed with strong blockade of cell division in HCT116 cells. Since complex 1 showed ROS/RNS scavenging potential mentioned cytotoxicity was not connected with oxidative stress.

Mullite‐type EMBO4: synthesis, structural, optical, and vibrational properties of rare tin(II) borates with M = Al and Ga

AbstractMetal tin‐(II)‐borates are rarely studied mainly due to the susceptibility of either oxidation into tin(IV) or disproportionation into elemental tin(0) and tin(IV). We report mullite‐type SnAlBO4 and SnGaBO4 ceramics produced by conventional solid‐state synthesis in sealed quartz tubes at low pressure of 10–7 MPa. Both compounds are isostructural to PbAlBO4 as confirmed by Rietveld refinements of powder X‐ray data. The crystal structures are highly influenced by the stereochemical activity of the 5s2 lone electron pair of the Sn2+ cation measured by the Wang–Liebau eccentricity parameter. To further consolidate the structural features 119Sn Mössbauer, solid state NMR, Raman, IR and UV/vis spectroscopic measurements are performed. The 119Sn Mössbauer isomer shifts and the quadrupole splitting values confirm the SnO4 coordination and Sn(II) valence states. Solid state 11B, 27Al and 119Sn NMR spectra provided insights into the local crystal‐chemical environment. The vibrational properties are discussed from group theoretical analysis to mode assignments. SnAlBO4 and SnGaBO4, respectively, possess an electronic band gap of 3.73(9) and 3.21(4) eV calculated from the diffuse reflectance UV/Vis spectra.

Exploring the antimalarial, antioxidant and antimicrobial properties of newly synthesized diorganotin(IV) complexes with ONO-donor hydrazone ligands

Inspired by the role of organotin(IV) compounds as potential pharmaceutical agents, we have synthesized a series of new diorganotin(IV) complexes (5–20) of hydrazone ligands (1–4) derived from 2-chlorophenoxyacetic hydrazide and salicylaldehyde derivatives. Numerous techniques such as FT-IR, UV–Vis, (1H, 13C, 119Sn) NMR, mass spectrometry, powder XRD, SEM, EDAX, TGA and molar conductance were used to elucidate the structure of the synthesized compounds. These techniques ascertain that the hydrazone ligands coupled with diorganotin(IV) in a tridentate manner via imine nitrogen, phenolic oxygen atom and deprotonated hydroxyl group generating pentacoordinated geometry of the complexes. The low molar conductance values of synthesized compounds indicated their non-electrolytic nature. SnO2 was the final product formed as a result of the thermal breakdown of complexes which suggested the thermal stability of the complexes up to about 176°C. In vitro antimalarial (P.falciparum) activity was performed using microassay protocol which advocated for the higher potency of complexes 16,20 (IC50 = 0.62–0.67 µM). The antioxidant activity also supported the results of antimalarial data suggesting 16,20 complexes as active compounds. In vitro, the antimicrobial potential of the compounds has been tested against six pathogens including four bacterial and two fungal strains by serial dilution assay taking ciprofloxacin and fluconazole as reference drugs. Among the synthesized compounds, complexes 8 and 12 (MIC value = 0.0048, 0.0045 µmol/mL) exhibited superior activity. Additionally, the compounds were subjected to in silico ADME analysis suggesting that the compounds can be employed as orally active drugs.

From Sn(II) to Sn(IV): Enhancing Lewis Acidity Via Oxidation.

We demonstrate the increased Lewis acidity on going from Sn(II) to Sn(IV) by oxidizing TpMe2SnOTf (OTf = SO3CF3) to TpMe2SnF(OTf)2. Replacement of the fluoride ion in TpMe2SnF(OTf)2 by a triflate, resulting in TpMe2Sn(OTf)3 further enhances the Lewis acidity at tin. 119Sn NMR spectroscopy, modified Gutmann-Beckett test, computational analysis, and catalytic phosphine oxide deoxygenation support the claims.

A series of ferriostannylenes with differing terphenyl substituents

A series of ferriostannylenes of formula ArMe6SnFeCp(CO)2 (ArMe6 = −C6H3-(C6H2–2,4,6-Me3)2, Cp = η5-C5H5) (1), ArMe6SnFeCp*(CO)2 (Cp* = η5-C5Me5) (2), and ArMe6SnFeCp(CO)(PMe3) (3) with differing iron and/or tin substituents was synthesized. Their structures and spectroscopic properties were examined by X-ray crystallography, NMR, IR, and UV–vis spectroscopy and compared with data for related species. The structural data showed that, as the size of the terphenyl substituent increases, the C-Sn-Fe angle decreases slightly which is contrary to steric expectations. The 1H and 119Sn NMR chemical shifts of the least crowded species 1 is similar to, but slightly upfield of those of its more hindered ferriostannylene analogs. Unexpectedly, 3 displayed a 119Sn NMR chemical shift that is ca. 800 ppm downfield of 1 as a result of the substitution of one of the iron carbonyl groups with a PMe3 ligand. This unusual finding is probably a reflection of a decreased paramagnetic shielding of the 119Sn nucleus by the more electron releasing character of the PMe3 ligand which decreases the n→p energy gap. The infrared spectrum of 1 also displayed slightly higher νCO frequencies, and its electronic spectrum indicated a small hypsochromic shift in the energy of its n→p transition whereas both 2 and 3 displayed much greater hypsochromic shifts than 1 consistent with the more electron donating character of the iron phosphine substituent. The results were interpreted in terms of the electronic/steric properties of the various substituents and their effects on metal electron density.

119Sn NMR characterization, X-ray structural studies, and Hirshfeld surface analysis of organotin(IV) macroheterocycles synthesized by a Barbier approach via ultrasound activation

119Sn NMR characterization, X-ray structural studies, and Hirshfeld surface analysis of organotin(IV) macroheterocycles synthesized by a Barbier approach via ultrasound activation

Anthracene appended organotin (IV) compounds: Synthesis, structure elucidation and their cytotoxicity against A549 and RBL cancer cell lines

Two new anthracene Schiff base triorganotin (IV) compounds trimethylstannyl(E)‐4‐((anthracen‐9‐ylmethylene)amino)benzoate (1) and triphenylstannyl(E)‐4‐((anthracen‐9‐ylmethylene)amino)benzoate (2) were synthesized by mixing trimethylstannyl (or triphenylstannyl) 4‐aminobenzoate and 9‐anthraldehyde in anhydrous toluene under refluxing conditions. Elemental analysis, FT‐IR, 1H‐NMR, 119Sn NMR and ESI‐MS were used to determine the composition of the compounds. X‐ray diffraction analyses revealed the structural details of the compounds. The in vitro cytotoxicity assessment of these compunds was screened against human A‐549 (lung carcinoma) and rat RBL (leukemia) cancer cell lines. Both compounds displayed a pronounced in vitro cytotoxic effect on the subjected cancer cell lines. Notably, the proliferation of A‐549 cells experienced substantial inhibition in the presence of compound 2. The mode of interaction with Hsp90 and NF‐κB p65 proteins responsible for cancer propagation was also assessed by molecular docking. Compounds 1 and 2 bind to the Hsp90 protein with binding energies of −307.65 and −373.45 kcal/mol, respectively, while to NF‐κB p65 protein the binding energies are of −329.35 and −395.35 kcal/mol, in the same order. Compound 2 exhibited a significantly high binding affinity to NF‐κB p65 and Hsp90 proteins validating our experimental findings from the in vitro experiments.

Insighting the inhibitory potential of new diorganotin(IV) complexes derived from tridentate ligands: Synthesis, structural elucidation and biological evaluation

In the present study, a series of diorganotin(IV) complexes (1-20) with the general formula R2SnL1-4 were synthesized by the reaction of R2SnCl2 (R = Me, Et, Bu, and Ph) with the hydrazone ligands (H2L1-4). Spectral and physico-analytical techniques such as multinuclear (1H, 13C, 119Sn) NMR, HRMS, FTIR, XRD and SEM studies collectively with elemental analyses were utilized to structurally elucidate the synthesized compounds. Based on the structural investigations, it can be concluded that hydrazone ligands coordinated to the central tin metal in a tridentate manner (ONO) through nitrogen atom of the azomethine group, oxygen atoms of the enolic and phenolic groups. The synthesized compounds have been screened for their in vitro antimicrobial potential against four bacterial (two Gram positive; two Gram negative) and two fungal strains. Antimicrobial activity results concluded that metal complexes exhibited better activity than free ligands towards the tested strains. Among the tested compounds, complexes 8, 12 and 20 were found to be the most active. Furthermore, the in vitro anticancer evaluation of synthesized compounds (1-20) was done against a panel of three cell lines viz; A549, MCF7 and HCT-116 using MTT assay. Complexes 5, 6 and 8 were found to be most active against the three cancer cell lines with lowest IC50 values.

Synthesis and structural elucidation of a unique turn-off fluorescent sensor based on oxo-bridged tin (IV) cluster for selective detection of dopamine in biological fluids

An oxo-bridged Sn (IV) Cluster, (TOC) was synthesized and fully characterized by FT-IR, UV–vis, 1H NMR, 119Sn NMR, Mass spectrometry and single crystal X-ray diffraction studies. The single-crystal X-ray analysis revealed that the crystal crystallizes in the monoclinic crystal system possessing the P 21/c space group and exhibited a distorted trigonal bipyramidal geometry. The TOC exhibited a unique turn-off fluorescence response for the selective detection of dopamine (DA) over other analytes. The stoichiometry between the TOC and DA was calculated using Job’s plot. The value of the detection limit was found to be 1.33 µM. The Hirshfeld surface analysis was carried out on the crystal structure to investigate the H-H, Cl-H, Cl-Cl, Sn-Cl and Cl-C interaction studies in the molecule. Density Functional Theory (DFT) studies further supported the sensing mechanism, which closely agreed with the experimental results. Furthermore, the TOC chemosensor was used to detect DA in human blood plasma, and molecular docking studies validated the interaction between the chemosensor and protein. Confocal fluorescence imaging studies were carried out and validated TOC sensing ability for DA in human blood plasma.

Chemical Behavior and Local Structure of the Ruddlesden-Popper and Dion-Jacobson Alloyed Pb/Sn Bromide 2D Perovskites.

The alloyed lead/tin (Pb/Sn) halide perovskites have gained significant attention in the development of tandem solar cells and other optoelectronic devices due to their widely tunable absorption edge. To gain a better understanding of the intriguing properties of Pb/Sn perovskites, such as their anomalous bandgap's dependence on stoichiometry, it is important to deepen the understanding of their chemical behavior and local structure. Herein, we investigate a series of two-dimensional Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) phase alloyed Pb/Sn bromide perovskites using butylammonium (BA) and 3-(aminomethyl)pyridinium (3AMPY) as the spacer cations: (BA)2(MA)n-1PbxSnn-xBr3n+1 (n = 1-3) and (3AMPY)(MA)n-1PbxSnn-xBr3n+1 (n = 1-3) through a solution-based approach. Our results show that the ratio and site preference of Pb/Sn atoms are influenced by the layer thickness (n) and spacer cations (A'), as determined by single-crystal X-ray diffraction. Solid-state 1H, 119Sn, and 207Pb NMR spectroscopy analysis shows that the Pb atoms prefer the outer layers in n = 3 members: (BA)2(MA)PbxSnn-xBr10 and (3AMPY)(MA)PbxSnn-xBr10. Layered 2D DJ alloyed Pb/Sn bromide perovskites (3AMPY)(MA)n-1PbxSnn-xBr3n+1 (n = 1-3) demonstrate much narrower optical band gaps, lower energy PL emission peaks, and longer carrier lifetimes compared to those of RP analogs. Density functional theory calculations suggest that Pb-rich alloys (Pb:Sn ∼4:1) for n = 1 compounds are thermodynamically favored over 50:50 (Pb:Sn ∼1:1) compositions. From grazing-incidence wide-angle X-ray scattering (GIWAXS), we see that films in the RP phase orient parallel to the substrate, whereas for DJ cases, random orientations are observed relative to the substrate.

Synthesis, Structure, and Spectroscopy of the Biscarboranyl Stannylenes (bc)Sn·THF and K2[(bc)Sn]2 (bc = 1,1'(ortho-Biscarborane)) and Dibiscarboranyl Ethene (bc)CH=CH(bc).

Two compounds containing a Sn(II) atom supported by a bidentate biscarborane ligand have been synthesized via salt metathesis. The synthetic procedures for (bc)Sn·THF (bc = 1,1' (ortho-carborane) (1) and K2[(bc)Sn]2 (2) involved the reaction of K2[bc] with SnCl2 in either a THF solution (1) or in a benzene/dichloromethane solvent mixture (2). Using the same solvent conditions as those used for 2 but using a shorter reaction time gave a dibiscarboranyl ethene (3). The products were characterized by 1H, 13C, 11B, 119Sn NMR, UV-vis, and IR spectroscopy, and by X-ray crystallography. The diffraction data for 1 and 2 show that the Sn atom has a trigonal pyramid environment and is constrained by the bc ligand in a planar five-membered C4Sn heterocycle. The 119Sn NMR spectrum of 1 displays a triplet of triplets pattern signal, which is unexpected given the absence of a Sn-H signal in the 1H NMR, IR spectrum, and X-ray crystallographic data. However, a comparison with other organotin compounds featuring a Sn atom bonded to carboranes reveal similar multiplets in their 119Sn NMR spectra, likely arising from long-range nuclear spin-spin coupling between the carboranyl 11B and 119Sn nuclei. Compound 3 displays structural and spectroscopic characteristics typical of conjugated alkenes.

Engineered organotin(IV) and vanadium(V) derivatives with distinct coordination modes and luminescent properties for the efficient detection and quantification of permanganate ions.

The distinction in coordination modes of metal complexes leads to their versatile structural features and unique properties. Here, we report two tetradentate Schiff base ligands (H2L1 and H2L2) bearing N2O2 donor sets, tactically selected to provide distinct coordination modes with different metal ions. The ligands were utilized to synthesize their organotin(IV) (1-4) and vanadium(V) (5) derivatives. The synthesized compounds were characterized using elemental analysis, FT-IR spectroscopy, multi-nuclei NMR (1H, 13C, and 119Sn) spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The organotin(IV) derivatives (1-4) displayed hepta-coordination around both the Sn centres as they were achieved in their dimeric form. Contrariwise, the vanadium(V) compound (5) was isolated as a mononuclear entity exhibiting penta-coordinated geometry around the vanadium centre. The variation in the coordination modes was evident in their UV-vis and fluorescence spectra. The organotin(IV) compounds (1-4) exhibited a strong emission band centred at 468nm when excited at a wavelength of 360nm whereas the vanadium(V) (5) derivative displayed poor fluorogenic response. Compound 1 was further explored for the fluorogenic chemo-sensing of permanganate ions (MnO4-) amongst various anions by quenching response. A detailed investigation of the recognition of permanganate ions was accomplished by spectrofluorometric, spectroscopic (119Sn NMR), mass spectrometric, and computational studies.