Central Tin Research Articles

Tin(IV) compounds of tridentate thiosemicarbazone Schiff bases: Synthesis, characterization, in-silico analysis and in vitro cytotoxicity

Twelve tin(IV) compounds (5–16) derived from four tridentate thiosemicarbazone Schiff bases of 4-methyl-3-thiosemicarbazide with 2-hydroxy-3-methoxybenzaldehyde (1, 2) and 4-phenyl-3-thiosemicarbazide with 2,3-dihydroxybenzaldehyde (3, 4) of the general formulae [R2Sn(Ln)] and [Sn(Ln)2] (where R = Ph or Me; Ln = 1, 2, 3 and 4) were synthesized and characterized by elemental analysis, IR, UV–vis, mass spectrometry and multinuclear NMR (1H, 13C and 119Sn) spectroscopy. X-ray crystallographic data was obtained for 11′, a 2:1 co-crystal between Ph2Sn(L2) (11) and 3-methoxysalicylaldehyde azine, and Me2Sn(L2) (12) where L2H2 is 2-(2-hydroxy-3-methoxybenzylidene)-N-phenylhydrazinecarbothioamide. The analysis revealed distinct coordination geometries for 11 and 12 approaching trigonal–bipyramidal. In the crystal of 11′, supramolecular dimers arising from amineNH…S(thiolate) hydrogen bonding and {…HNCS}2 synthons are evident; π(chelate ring)…π(oxidobenzylidene) stacking is also apparent. In the crystal of 12, supramolecular, helical chains are generated by a combination of amineNH…O(phenoxide) hydrogen bonding and Sn…S secondary bonding. The cytotoxic activity of the compounds against a panel of ten cancer cell lines, [HT29 (colon), U87 and SJ-G2 (glioblastoma), MCF-7 (breast), A2780 (ovarian), H460 (lung), A431 (skin), DU145 (prostate), BE2-C (neuroblastoma) and MIA (pancreas), and one normal cell line, MCF-10A (normal breast)] were investigated. The thiosemicarbazone Schiff bases 1 and 4 as well as the diphenyltin(IV) compounds showed a strong ability to inhibit the growth of cancer cells, with particular selectivity against HT29, MCF-7, A2780, A431, BE2-C, SJ-G2 and MIA cell lines. The structure–activity relationship of all these compounds were studied by evaluating the effect of alkyl and aryl groups attached on the thiosemicarbazone backbone, the methoxy/hydroxyl groups present at the meta-position of the phenyl ring and alkyl or aryl groups bound to the tin center.

Organotin (IV) based Rabeprazole and Pregabalin Complexes Formation and Biocidal Investigation

Abstract New organotin (IV) complexes with NaL1 (sodium salt of 2-[[4-(3-methoxy-propoxy) 3-methylpyridin-2-yl]methylsulfinyl]benzimidazol-1-ide) and NaL2 (sodium salt of 3- aminomethyl-5-methylhexanoic acid) were synthesized by the reaction of diorganotin (IV) and triorganotin (IV) salt (Bu3SnCl, Ph3SnCl, Bu2SnCl2, Me2SnCl2) using the solvent (dry toluene) by constant stirring and refluxing. All the organotin (IV) complexes were characterized by different diagnostic techniques such as FT-IR (Infra-red) and UV-visible spectroscopy. The results exhibited that ligand NaL1 (sodium salt) is attached to tin metal by a nitrogen atom of benzimidazole ring and the oxygen atom of the sulfonyl group. While ligand NaL2 (sodium salt) coordinate with tin(IV) moiety through oxygen atom of the carboxylate group. The newly synthesized complexes 1 & 2 of ligand NaL1 (sodium salt) showed trigonal bipyramidal geometry while complexes 3 & 4 octahedral geometry around tin(IV) centre. The organotin(IV) complexes 5-7 of ligand NaL2 (sodium salt) have the tetrahedral geometry around tin(IV) centre. The synthesized complexes (1-7) were tested for antifungal and antibacterial microbial activities. All the complexes showed significant antibacterial and anti-fungal activities against tested bacterial and fungal strains.

Dinuclear organotin compounds carrying naphthylene- and biphenylene-spacer groups

The reaction of XMg−CH2−Y−CH2−MgX [Y = 2,6−naphthylene (−C10H6−) or 1,1’−biphenylene (−C12H8−); X = Cl or Br] with two molar equivalents of Ph3SnCl or Ph2(Me3SiCH2)SnI gave Ph3Sn−CH2−C10H6−CH2−SnPh3 (1), Ph3Sn−CH2−C12H8−CH2−SnPh3 (2) and Ph2(Me3SiCH2)Sn−CH2−C12H8−CH2−Sn(CH2SiMe3)Ph2 (3), respectively, in good yields. Reaction of 2 with elemental iodine gave, via selective Sn-Ph bond cleavage, the corresponding bis(iododiphenylstannyl) derivative Ph2ISn−CH2−C12H8−CH2−SnIPh2 (4) and iodobenzene. Compounds 1–4 were characterized by spectroscopic methods, mass spectrometry and single-crystal X-ray diffraction analysis. The tin centers in 1−3 exhibit tetrahedral coordination geometries, both in solution and the solid state. For the bis(iododiphenylstannyl) derivative 4, the tin atoms show tetrahedral geometries only in solution, as deduced from the 119Sn NMR spectra. In the solid state, the metal atoms have distorted trigonal-bipyramidal environments as result of intermolecular I→Sn donor-acceptor interactions. In consequence, the crystal structure of 4 is composed of 2D coordination polymers, which are reinforced by C−H⋅⋅⋅I and C−H⋅⋅⋅π contacts.

New tri- and di-alkylstannyl 2-(1H-indol-3-yl)ethanoates: synthesis, characterization and biological screenings

A series of triorganotin(IV) compounds {Me3SnL (1), Bu3SnL (2), Ph3SnL (3)} and di-organotin(IV) complexes {Me2SnL2 (4), Bu2SnL2 (5) and Ph2SnL2 (6)}, where Me = methyl, Bu = butyl, Ph = phenyl and L = 2-(1H-indole-3-yl)acetate) have been synthesized and characterized by FT-IR and multinuclear NMR (1H-, 13C- and 119Sn-NMR) spectroscopy. Tri- and diorganotin(IV) derivatives exhibited five- and six-coordinate geometries, respectively, in solid state as evident from the Δν value. Five-coordinate trigonal bipyramidal and six-coordinate octahedral geometry was assigned to 1 and 4 in solution state based on NMR data as evident from 2J(119Sn,1H) and 1J(119Sn-13C) coupling constant values, which was further attested by 119Sn NMR. Single crystal XRD analysis on 1 revealed that it exhibited polymeric crystal structure with distorted trigonal bipyramidal geometry around the tin center with two unequal Sn–O bonds. The screening of the synthesized compounds for cytotoxicity showed good activity in comparison to cis-platin. They have also displayed moderate to good antimicrobial activities.

Tributyltin(IV) ferulate, a novel synthetic ferulic acid derivative, induces autophagic cell death in colon cancer cells: From chemical synthesis to biochemical effects

Ferulic acid (FA) is a natural phenolic phytochemical that has low toxicity and exhibits therapeutic effects against various diseases, behaving as an antioxidant. FA also displays modest antitumor properties that have been reported at relatively high concentrations. With the aim of improving the anti-tumor efficacy of FA, we synthesized the novel compound tributyltin(IV) ferulate (TBT-F). The coordination environment at the tin center was investigated spectroscopically. Following synthesis, chemical characterization and computational analysis, we evaluated TBT-F effects in colon cancer cells. The results showed that TBT-F, at nanomolar range concentrations, was capable of reducing the viability of HCT116, HT-29 and Caco-2 colon cancer cells. On the other hand, FA was completely inefficacious at the same treatment conditions. Cell viability reduction induced by TBT-F was associated with G2/M cell cycle arrest, increase in membrane permeabilization and appearance of typical morphological signs. TBT-F-induced cell death seemed not to involve apoptotic or necroptotic markers whereas autophagic vacuoles appearance and increase in LC3-II and p62 autophagic proteins were observed after treatment with the compound. The autophagy inhibitor bafylomicin A1 markedly prevented the effect of TBT-F on colon cancer cells, thus indicating that autophagy is triggered as a cell death process.Taken together, our results strongly suggest that the novel ferulic derivative TBT-F is a promising therapeutic agent for colon cancer since it is capable of triggering autophagic (type-II) cell death that may be important in case of resistance to classic apoptosis.

NEW PHOSPHINATO ORGANO- AND HALOTIN(IV) DERIVATIVES, ADDUCTS AND COMPLEXES: SYNTHESIS AND SPECTROSCOPIC STUDY

Five new phosphinato derivatives, adducts and complexes have been synthesized and characterized by infrared and Mössbauer spectroscopies. Based on their spectroscopic data discrete or infinite chain structures are proposed, the phosphinate ion behaving as a bicoordinating bridging or a monocoordinating ligand, the environments around the tin (IV) centers being octahedral or trigonal bipyramidal. In Me4N(SnPh2)2(H2PO2)2Cl3 and Cl2Sn(H2PO2)2NMe4H2PO2, the cation is involved in electrostatic interactions with the anions.

Co-crystallization of Oxalate Salts of Monoprotonated Amines with a Double Sn-Ph Bond Cleavage

Two oxalate compounds [(C4H7N2)3][Sb(C2O4)3] (1) and [(Et3NH)][SnPhCl(C2O4)2] (2), have been isolated and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P21/c with a=13.3944 (6) A, b=11.3554 (5) A, c=16.3314 (7) A, β=107.206 (1), V=2372.82 (18) A3 and Z=4. Compound 2 crystallizes in the monoclinic system, space group P21/n with a=8.6903 (4) A, b=15.3844 (8) A, c=20.3144 (10) A, β=100.869 (2), V=2667.2 (2) A3 and Z=4. The complex-anion [Sb(O2CCO2)3]3- of the compound 1 adopts a distorted pentagonal pyramidal arrangement with monochelating oxalates. The asymmetric unit of 1 consists of three 2-methyl-1H-imidazolium cations, C4H7N2+, three oxalate anions, C2O42-, and one antimony (III) ion, Sb3+. From a supramolecular point of view, in 1 complex-anions are connected by cations through N-H•••(O,O) and N-H•••O hydrogen bonds involving the two oxalates of the basal plane into sheets which are then connected via the remaining oxalate and cations through N-H•••O hydrogen bonds to give rise to a three-dimensional structure. The complex-anion of 2 is comprised of a tin centre linked to a chlorine atom and a phenyl group, and cis-chelated by two oxalates in a distorted octahedral fashion. Each triethylammonium cation is connected to the complex-anion through bifurcated N-H•••(O,O) hydrogen bonds. These interactions lead to a discrete structure. A double Sn-C bond cleavage has occurred during the process of the formation of the compound 2. In both complounds 1 and 2, one cation exhibits some positional disorder.

Antimicrobial and Antioxidant Activities of Diorganotin(IV) Complexes Synthesized from 1,2,4-Triazole Derivatives

Novel diorganotin(IV) complexes were synthesized from 1,2,4-triazole Schiff base ligands which were synthesized by reaction between the 4-amino-5-phenyl-1,2,4-triazole-3-thiol and salicyaldehyde derivatives. The bonding and geometry of the diorganotin(IV) complexes were evaluated by using different spectroscopic techniques such as FT-IR, mass, 1H, 13C & 119Sn NMR. The different spectroscopic techniques revealed the tridentate (ONS) mode of chelation of Schiff base ligands and pentacoordinated environment around the central tin metal which was satisfied with azomethine nitrogen, phenolic oxygen, thiolic sulfur and metal-carbon bond of alkyl/aryl group. The Schiff base ligands and their organotin(IV) complexes were tested for their in vitro antimicrobial and antioxidant activities to examine the biological outline of complexes in comparison to standard drugs. The results of activities data revealed that diorganotin(IV) complexes are more active than Schiff base ligands and some diorganotin(IV) complexes are even more active than the standard drugs. In all the synthesized complexes, compound 9 (Bu2SnL2) and 10 (Ph2SnL2) were most potent and can be used in future clinical trials.

Theoretical and Experimental in vitro Antifungal and Antitumor Activities of Organotin(IV) Derivatives of 3-(4-nitrophenyl)-2-methylacrylic acid

Di- and triorganotin(IV) derivatives of 3-(4-nitrophenyl)-2-methylacrylic acid (HL), i.e., [n-Bu2SnL2] (1), [Me2SnL2] (2), [n-Bu3SnL]n (3) [Me3SnL]n (4) and [Ph3SnL]n (5) were synthesized and characterized by the elemental analysis, FT-IR and multinuclear (1H and 13C) NMR. The IR analysis showed a chelating/bridging bidentate coordination of the ligand in diorganotin(IV)/triorganotin(IV) derivatives resulting in the formation of 6/5 coordinated tin centers, respectively, in the solid state. The NMR study indicated a decrease in the coordination number of tin in the complexes in solution form. The triorganotin(IV) complexes (3, 5) showed promising in vitro antifungal and antitumor properties comparable to standard drugs used and were found more cytotoxic than the diorganotin(IV) derivatives (1, 2). Molecular docking studies carried out on tubulin as receptor showed a similar mode of antitumor action for complex 5 and standard drug vincristine. The docking analysis for antifungal activity of complex 3 as model compound showed hydrogen bonding, polar and hydrophobic interactions with the target proteins of the fungal strains.

(N,N-Diiso-propyl-dithio-carbamato)tri-phenyl-tin(IV): crystal structure, Hirshfeld surface analysis and computational study.

The crystal and mol-ecular structures of the title triorganotin di-thio-carbamate, [Sn(C6H5)3(C7H14NS2)], are described. The mol-ecular geometry about the metal atom is highly distorted being based on a C3S tetra-hedron as the di-thio-carbamate ligand is asymmetrically chelating to the tin centre. The close approach of the second thione-S atom [Sn⋯S = 2.9264 (4) Å] is largely responsible for the distortion. The mol-ecular packing is almost devoid of directional inter-actions with only weak phenyl-C-H⋯C(phen-yl) inter-actions, leading to centrosymmetric dimeric aggregates, being noted. An analysis of the calculated Hirshfeld surface points to the significance of H⋯H contacts, which contribute 66.6% of all contacts to the surface, with C⋯H/H⋯C [26.8%] and S⋯H/H⋯H [6.6%] contacts making up the balance.

Synthesis and characterizations of bis(phenoxy)‐amine tin(II) complexes for ring‐opening polymerization of lactide

ABSTRACTA series of tin(II) complexes supported by N2O2 bis(phenol)‐amine ligands were prepared from the reactions of the corresponding ligands with Sn[N(SiMe3)2]2 in benzene at room temperature. The ligands were designed to have different substituted group at the ortho‐position on the aryl rings (R = tBu, CH3) and N‐containing side arm (E = CH2NEt2 and pyridine) giving a variation of tin(II) complexes (R = tBu, E = CH2NEt2, 2a; R = tBu, E = py, 2b; R = CH3, E = CH2NEt2, 2c; R = CH3, E = py, 2d). All complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. The single‐crystal X‐ray crystallography revealed that all complexes have a monomeric four‐coordinate tin center with a distorted seesaw structure. All complexes are active for solvent‐free polymerization of l‐lactide at 120 °C giving poly(l‐lactide) with narrow to moderate dispersity (Ð = 1.12–1.56). In the presence of benzyl alcohol during the polymerization, the resulting polymer was found to be linear having benzyl alcohol as the end group while, in the absence of benzyl alcohol, the polymer was cyclic. The large tBu group at the ortho‐position was found to decrease polymerization activity while the more basic CH2NEt2 group was found to increase the polymerization activity. The polymerization of rac‐lactide under a similar condition gave PLA having a slight heterotactic bias for all catalysts. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2104–2112

Bis‐aroylhydrazone based on 2,2′‐bis substituted diphenylamine for synthesis of new binuclear organotin (IV) complexes: Spectroscopic characterization, crystal structures, in vitro DNA‐binding, plasmid DNA cleavage, PCR and cytotoxicity against MCF7 cell line

New dinuclear organotin (IV) complexes, Me4Sn2L, Ph4Sn2L and Bu4Sn2L, have been synthesized from reaction of R2SnCl2 (R = Me, Ph and Bu) with a 2,2′‐bis‐substituted diphenylamine arοylidene hydrazone, H4L. The synthesized compounds were investigated by elemental analysis and infrared, 1H‐NMR and 119Sn‐NMR spectroscopy. The structures of H4L, Me4Sn2L and Bu4Sn2L were also confirmed by X‐ray crystallography. H4L molecules adopt (E)‐configuration and keto‐tautomeric form in the solid state. In all complexes, the bis‐hydrazone acts as a tetra‐anionic ligand with two contiguous ONO tridentate domains that coordinate the two R2Sn moieties in the enolate form. The coordination environments of both tin centers are five‐coordinate. DNA‐binding studies were performed by UV–Vis spectroscopy, and the results indicate that the synthesized compounds significantly interact with calf thymus‐DNA in the intercalative mode. The results of polymerase chain reaction assay show that all the compounds affect on amplification of DNA, and complexes are more effective than ligands. The in vitro cytotoxicity against the human breast cancer line (MCF7) was determined using the MTT assay, and H4L and the dibutytin complex showed higher activity.

Bis(μ2-4-nitrophenolato)bis(4-nitrophenolato)di-μ3-oxido-octaphenyltetratin chloroform sesquisolvate [+ solvate]: a tetranuclear stannoxane

The title tetranuclear stannoxane, [Sn4(C6H5)8(C6H4NO3)4O2]·1.5CHCl3·solvent, crystallized with two independent complex molecules, A and B, in the asymmetric unit together with 1.5 molecules of chloroform. There is also a region of disordered electron density, which was corrected for using the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18]. The oxo-tin core of each complex is in a planar `ladder' arrangement and each Sn atom is fivefold SnO3C2 coordinated, with one tin centre having an almost perfect square-pyramidal coordination geometry, while the other three Sn centres have distorted shapes. In the crystal, the complex molecules are arranged in layers, composed of A or B complexes, lying parallel to the bc plane. The complex molecules are linked by a number of C—H...O hydrogen bonds within the layers and between the layers, forming a supramolecular three-dimensional structure.

Cover Feature: Heptacoordinate Structures of Organotin Halides with Three Phosphine Donors: Halogen‐Substituent Effect on Geometry (Eur. J. Inorg. Chem. 26/2019)

The Cover Feature shows four types of heptacoordinate structures for organotin halides with three phosphine donors. Introduction of a different halogen at the tin center significantly influences the heptacoordinate geometry in the solid state. The difference in electronegativity of the halogen atoms appears to contribute to the structural modification, because a strongly electronegative halogen facilitates the formation of a structure that is highly distorted with respect to the tetrahedral geometry (Bent's rule). More information can be found in the Full Paper by H. Kameo, H. Nakazawa et al.

Synthesis, characterization and the use of organotin(IV) dithiocarbamate complexes as precursor to tin sulfide nanoparticles by heat up approach

The reactions of dimethyltin(IV)chloride with different N-alkyl-N-phenyl dithiocarbamate ligands in 1 mol equivalence yielded complexes of the type [(CH3)2SnL1L3] (1) and [(CH3)2SnL2L3] (2), where (alkyl = methyl (L1), ethyl= (L2) and butyl (L3). The complexes were characterized using spectroscopic techniques (FTIR, 1H, 13C and 119Sn), and elemental analysis. The crystal structure of complex (1) was also reported. The geometry of the complex is octahedral around the tin ion; two dithiocarbamates acted as bidentate chelating ligands through the sulfur atoms at the opposite ends to the tin atom of the organotin group. The dithiocarbamato ligands showed unequal distances to the tin center, resulting in asymmetrical unit and distortion of the expected octahedral geometry. Thermal decomposition studies of all the complexes (using TGA/DTG under nitrogen) indicated different decomposition pathways and the formation of tin sulfide (SnS, with Herzenbergite structure) as final residues. However, the thermolysis of these complexes using the heat-up method at a temperature below 300 °C and in the presence of a capping agent (oleylamine) afforded a different phase of tin sulfide (SnS2, with Berndtite structure). The as-synthesized nanoparticles (NPs), represented as SnS2 (1) and SnS2 (2) for the tin sulfides synthesized using complexes (1) and (2) respectively, were characterized using XRD, TEM and UV spectrophotometry. The average particles sizes of both SnS2 NPs were found to be approximately 2.0 nm, which agrees well with the calculated size from the XRD peak (001) obtained as 2.34 nm for SnS2 (1) and 2.94 nm for SnS2 (2). The optical properties showed that both types of nanoparticles exhibited a blue shift in their band gap energy with respect to their bulk.

The Synthesis of Quinoline‐based Tin Complexes with Pendant Schiff Bases

Whilst pursuing the synthetic utility of quinoline‐based tin complexes, Me2Sn(Quin‐NO2)2 (1) and Ph2Sn(Quin‐NO2)2 (2) (Quin‐NO2 = 5‐nitroquinolino‐8‐oate) were synthesized bearing coordinatively inert nitro groups. Conventional reduction methodologies successfully converted 1 to Me2Sn(Quin‐NH2)2 (3) and 2 to Ph2Sn(Quin‐NH2)2 (4) (Quin‐NH2 = 5‐aminoquinolino‐8‐oate). The synthetically useful amine groups proved difficult to exploit in the presence of the central tin atom, however, a complete Schiff base functionalized Sn complex of the dimethyltin pro‐ligand Me2Sn(Quin‐py)2 (6) was successfully synthesized from 5‐[(pyridin‐2‐ylmethylene)amino]quinolin‐8‐ol (HQuin‐py; 5) in good yield via an alternative strategy exploiting the oxophilic tendencies of tin. All species were fully characterized by NMR (including 119Sn NMR spectroscopy), HR‐ESI MS and single‐crystal X‐ray diffraction, and preliminary studies of their supramolecular potential are also discussed.

New diorganotin(IV) complexes of Schiff base derived from 4‐amino‐3‐hydrazino‐5‐mercapto‐4H‐1,2,4‐triazole: Synthesis, structural characterization, density functional theory studies, atoms‐in‐molecules analysis and antifungal activity

New diorganotin(IV) complexes of a Schiff base (HL) having general formula R2Sn(L)Cl (where L is the monoanion of HL and R = n‐Bu or Ph) have been synthesized and characterized using elemental analysis, infrared, NMR (1H, 13C, 119Sn) and UV–visible spectroscopies and mass spectrometry. These investigations suggest that in these 1:1 monomeric derivatives the Schiff base ligand acts in a monoanionic bidentate manner coordinating through the Ophenolic and Nazomethine, with proposed distorted trigonal bipyramidal geometry around tin with Ophenolic and two organic groups in the equatorial plane and the Nazomethine and the third organic group in axial positions. The proposed structures have been validated by density functional theory (DFT)‐based quantum chemical calculations at the B3LYP/6‐31G(d,p)/Def2‐SVP (Sn) level of theory. The simulated UV–visible spectrum was obtained with the time‐dependent DFT method in the gas phase and in the solvent field with the integral equation formalism–polarizable continuum model. A comparative analysis of the experimental vibrational frequencies and simulated harmonic frequencies indicates a good correlation between them. An insight into the intramolecular bonding and interactions among bonds in organotin(IV) complexes of HL was obtained by means of natural bond orbital analysis. The topological and energetic properties of the electron density distribution for the tin–ligand interaction in R2Sn(L)Cl have been theoretically calculated at the bonds around the central tin atom in terms of atoms‐in‐molecules theory. The R2Sn(L)Cl complexes were screened for their in vitro antifungal activity against chosen fungal strains.

3411 Maximizing the Value of Your Trial Innovation Network Hub Liaison Team

OBJECTIVES/SPECIFIC AIMS: The University of Washington (UW) CTSA Hub Liaison Team has directed and facilitated work required to bring TIN multisite trials to the CTSA hub and its affiliates by: (1) Connecting hub and affiliate investigators with the services offered by the Trial and Recruitment Innovation Centers, (2) identifying investigators at academic and non-academic institutions to act as co-investigators on multisite trials, (3) supporting the local and affiliate human research protection programs and investigators throughout the life-cycle of the study, (4) maximizing CTSA and local study team resources to develop and monitor study-specific volunteer recruitment and retention plans. The UW CTSA TIN Hub Liaison Team has worked to achieve these objectives via the following methods designed for generalization and dissemination. METHODS/STUDY POPULATION: (1) Providing consultations to investigators interested in the services offered by the Trial and Recruitment Innovation Centers. (2) Hub and affiliate investigators at academic and non-academic institutions are identified by a variety of approaches, including the engagement of existing CTSA hub regional collaboration networks, utilizing EHR data from CTSA developed phenotypes and targeted “Investigator Engagement Packets”. (3) Ensuring regulatory oversight and compliance is challenging in the new age of single IRB review. Establishing a flexible reliance office, engaging with the central TIN IRBs and providing guidance and resources to local study teams ensures investigator confidence in the integrity of the protocol approval and study activity processes. (4) The CTSA Hub Liaison team has developed a Recruitment and Retention Plan template and holds recruitment and retention planning meetings with the CTSA study teams engaging in TIN studies. RESULTS/ANTICIPATED RESULTS: It is anticipated that The Hub Liaison Team: (1) Will contribute to the TIN’s process improvement to bring regionally appropriate studies to the CTSA hub and affiliates. (2) Identify ideal investigators to engage both in proposal submission and co-investigating multisite trials. (3) Collect, compare and improve regulatory and contract approval cycle times. (4) Monitor and support screening, accrual and retention of study volunteers. DISCUSSION/SIGNIFICANCE OF IMPACT: Due to low prevalence of disease, challenges related to identifying and randomizing study volunteers and urgency to address clinical and public health issues, multisite study design is an essential option for NCATS. The Trial Innovation Network is an exciting approach to leverage local and national resources to provide infrastructure to improve multisite clinical and observational trial conduct. The University of Washington CTSA hub has developed and piloted methods to achieve the mission of the TIN, by recruiting investigators and realizing trial objectives, with the hope that these methods could be utilized by other CTSA TIN Hub Liaison Teams.

Influence of coordinating groups of organotin compounds on the Fries rearrangement of diphenyl carbonate.

In this paper, the Fries rearrangement of diphenyl carbonate (DPC) catalyzed by organotin compounds with different coordination groups was studied for the first time. The electronic effect and steric hindrance of the coordinating groups were discussed with respect to the reactivity of DPC rearrangement. The results showed that both the electronic effect and steric hindrance of the coordinating groups influenced the acidity of the active tin centers and then affected the catalytic performance of organotin as a Lewis acid for the rearrangement of DPC, and the influence of the electronic effect is greater than that of steric hindrance. The catalytic activity is in the order of BuSnO(OH) > Bu2SnO > Bu2Sn(OCOC11H23)2 > BuSnCl3 > Bu3SnOSnBu3 > Bu3SnCl, and Bu2SnO showed the best catalytic activity due to its strong electron absorption effect, small steric hindrance, and good stability. Under the optimum reaction conditions, the conversion of DPC was up to 93%, and the yields of phenyl salicylate (PS) and xanthone (XA) were 62% and 28%, respectively. In addition, a reaction mechanism of DPC rearrangement catalyzed by the organotin compounds was speculated. This research can provide vigorous theoretical data support to control the byproducts produced by DPC rearrangement in the process of DPC synthesis. It also provides a new route for the preparation of PS and XA.

Molecular structures, DFT studies and their photophysical properties in solution and solid state. Microwave-assisted multicomponent synthesis of organotin bearing Schiff bases

A couple of luminescent organotin compounds derivated from ligands-ONO were obtained by multicomponent microwave assisted synthesis in short time (15 min) and good yields: ((E)-8, 8-8-diphenylbenzo[d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (1) and (E)11, 13- di-tert-butyl, 8- diphenylbenzo [d] naphtho [1,2-h][1,3,6,2] dioxazastannonine (2)). Both compounds were fully characterized by NMR (1H, 13C, and 119Sn; 2D-NMR, HETCOR and COSY), UV–Vis, IR, and high-resolution mass spectrometry. The X-ray structures of two complexes demonstrate that the tin atoms adopt a bipyramidal trigonal geometry. The 119Sn NMR chemical shifts of the tin atom in the complexes are also consistent with the presence of pentacoordinate tin centers. The photophysical properties in solution and solid state, DFT, and voltammetry the two complexes have been determined.