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Adamantylisonitrile and benzonitrile were reacted with bulky substituted organotin trihydride [Ar*SnH3] [Ar* = (C6H3-2,6-Trip2), Trip = 2,4,6-triisopropylphenyl]. They do not show any reaction at room temperature as well as at 80 °C. After activation of the organotin trihydride with diethylmethylamine in the isonitrile case three hydrogen atoms were transferred from the tin atom to the isonitrile unit and a carbon tin bond was formed to give an intramolecular adduct between a diorganostannylene and a dialkylamine. Benzonitrile as well as adamantylisonitrile react both with low-valent organotin hydride [Ar*SnH]2. Benzonitrile shows an insertion reaction with the low-valent organotin hydride to yield a dimeric insertion product, whereas the isonitrile carbon atom of adamantylisonitrile abstracts three hydrogen atoms from the low-valent organotin hydride to give an equimolar mixture between (adamantylmethylamido)organostannylene and a bis(isonitrile)distannyne adduct. [ABSTRACT FROM AUTHOR]

A new and highly regioselective direct C-H arylation polymerization (DARP) methodology enables the reproducible and sustainable synthesis of high-performance π-conjugated photovoltaic copolymers. Unlike traditional Stille polycondensation methods for producing photovoltaic copolymers, this DARP protocol eliminates the need for environmentally harmful, toxic organotin compounds. This DARP protocol employs low loadings of commercially available catalyst components, Pd2(dba)3·CHCl3 (0.5 mol%) and P(2-MeOPh)3 (2 mol%), sterically tuned carboxylic acid additives, and an environmentally friendly solvent, 2-methyltetrahydrofuran. Using this DARP protocol, several representative copolymers are synthesized in excellent yields and high molecular masses. The DARP-derived copolymers are benchmarked versus Stille-derived counterparts by close comparison of optical, NMR spectroscopic, and electrochemical properties, all of which indicate great chemical similarity and no significant detectable structural defects in the DARP copolymers. The DARP- and Stille-derived copolymer and fullerene blend microstructural properties and morphologies are characterized with AFM, TEM, and XRD and are found to be virtually indistinguishable. Likewise, the charge generation, recombination, and transport characteristics of the fullerene blend films are found to be identical. For the first time, polymer solar cells fabricated using DARP-derived copolymers exhibit solar cell performances rivalling or exceeding those achieved with Stille-derived materials. For the DARP copolymer PBDTT-FTTE, the power conversion efficiency of 8.4% is a record for a DARP copolymer. [ABSTRACT FROM AUTHOR]

We report the first successful attachment of peptides to tin sulfide clusters. For proof of principle, H-l-Phe hydrazide and Boc-protected dipeptide hydrazides (Boc-l-Ala-l-Ala hydrazide and Boc-l-Val-l-Phe hydrazide) were reacted with keto-functionalized tin sulfide clusters [(R¹Sn)4S6] (A; R¹ = CMe2CH2C(O)Me) and [(R¹Sn)3S4Cl] (B). In the first case, we obtained single crystals of an amino acid functionalized Sn/S cluster, [R²2Sn4S5] (1; R² = (CMe2CH2C(Me)N2C(O)CH(CH2Ph)NC(Me)CH2CMe2), formed after inorganic cluster rearrangement and intramolecular condensation of the amino acid ligand. By means of NMR spectroscopic investigations and ESI/LIFDI mass spectrometry, we demonstrate that both dipeptides are attached to B under retention of the original cluster architecture to yield [(R³Sn)3S4Cl] (2; R³ = CMe2CH2C(NNH-Ala-Ala-Boc)Me) and [(R4Sn)3S4Cl] (3; R4 = CMe2CH2C(NNH-Phe-Val-Boc)Me), as evident from mass spectrometric data of their cations [(R³Sn)3S4]+ (2+) and [(R4Sn)3S4]+ (3+). [ABSTRACT FROM AUTHOR]

The syntheses of the intramolecularly coordinated organotin compounds {Me2N(CH2)3}Ph(X)SnCH2SnPh2X (3, X = I; 4, X = F) and {Me2N(CH2)3}Ph(F)Sn(CH2)3SnPh2F (7) are reported. The compounds have been characterized by elemental analysis, electrospray mass spectrometry, ¹H,¹H DOSY (4), 13C, 19F, and 119Sn NMR spectroscopy, and single-crystal X-ray diffraction analysis. In the solid state, compound 4 is a head-to-tail dimer as a result of unsymmetrical Sn-F-Sn bridges, whereas compound 7 is a monomer with F→Sn intramolecular coordination, giving a six-membered ring. In solution, both 4 and 7 are monomeric. The reactions of both 4 and 7 with fluoride anion in CD2Cl2 have been investigated by variable-temperature 19F and 119Sn NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The syntheses of the 8-membered stannasiloxanes cyclo-[RR'SnOSi(Me2)CH2]2 (5, R = R' = Ph; 6, R = R' = t-Bu; 7, R = Me2N(CH2)3, R' = Ph) is reported. These react with organoelement oxides, providing the novel metallasiloxanes cyclo-[Me2SiCH2(RR')SnOMO] (8, R = R' = Ph, M = t-Bu2Sn; 9, R = R' = t-Bu, M = t-Bu2Sn; 10, R = Me2N(CH2)3, R' = Ph, M = t-Bu2Sn; 11, R = Me2N(CH2)3, R' = Ph, M = Ph2Ge). Among these, compound 11 is the first example of such species being composed of four different group 14 elements in the 6-membered-ring skeleton. On contact with moist air compound 8 surprisingly undergoes Sn-Ph bond cleavage, giving the diorganotinoxo cluster [PhSn(CH2Me2SiO)Sn(μ3-O)(μ-OH)t-Bu2]2 (12), which shows a ladder-type structure. The latter reacts with 2 molar equiv of t-Bu2SnO, affording the Sn6-diorganotin oxo cluster [t-Bu2(μ-OH)Sn(μ3-O)SnPh(CH2Me2SiO)Sn-t-Bu2(μ3-O)]2 (13). The compounds have been characterized by NMR spectroscopy, electrospray mass spectrometry, and in the case of compounds 5-7, 12, and 13 also by single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

The article focuses on the methodologies to avoid the organotin residues contamination in organic synthesis. Topics discussed include the aldehydes allylation analysis, the organotin synthesis, and the organic halides. Also mentioned are the tin oxides analysis, the cross-coupling reaction, and the aryltin trichlorides cross-coupling.

A neworganotin initiator with amino-terminated hyperbranched polysiloxane(HSiSn) for the ring-opening polymerization of cyclic butylene terephthalate(CBT) oligomer was synthesized. Compared with a traditional initiator,butyltin chloride dihydroxide (BCD), HSiSn has a moderate initiatespeed, lower toxicity, and good reactivity. Poly(butylene terephthalate)(PBT) is the ring-opening polymer of CBT, of which the crystallineand molecular weight are almost independent of the initiator used,but the PBT initiated by HSiSn has better thermal stability than thatby BCD. On this basis, a series of new toughened bismaleimide (BD)resins (HSiSn/CBT-BD) were prepared through the in situ formationof PBT during the prepolymerization of BD resin with HSiSn. Comparedwith BCD/CBT-BD and BD resins, HSiSn/CBT-BD resins with small loadingsof CBT (≤5 wt %) have remarkably improved integrated performances,including higher impact strengths, improved flexural, and tensileproperties, better dielectric properties, and excellent heat resistance.These attractive performances are attributed to the unique cross-linkedstructure induced by HSiSn. [ABSTRACT FROM AUTHOR]

The triarylstannate lithium compound[{κ1-C-(2-Me2NCH2C6H4)2}{κ2-C, N-(2-Me2NCH2C6H4)}SnLi(THF)2] (3a) was obtained in 63% yield from the reactionof 2-Me2NCH2C6H4Li (1) with SnCl2in THF. Quantitative formation of 3awas also observed on reacting 1with [κ2-C, N-(2-Me2NCH2C6H4)2Sn] (2). Removal ofone THF molecule occurred when 3awas kept in vacuo;this process afforded [{κ1-C-(2-Me2NCH2C6H4)}{κ2-C, N-(2-Me2NCH2C6H4)2}SnLi(THF)2] (3b). Also, THF-free (2-Me2NCH2C6H4)3SnLi (3c) is likewiseaccessible. In the solid state (X-ray) both 3aand 3bare monomeric; notable structural features are the Sn–Lidistances (2.860(6) and 2.72(2) Å, respectively) and the distortionof the tetrahedral geometry at Sn in the direction of a trigonal pyramidalone. In 3a, one of the 2-Me2NCH2C6H4anions is C-bonded to Sn, while N-coordinationoccurs to Li; in 3b, two of the three 2-Me2NCH2C6H4anions are κ2-C,Nbonded. 1H, 13C, 119Sn, and 7Li NMR spectroscopic studiesof the species 3in tolueneshowed thatboth 3aand 3bare monomeric in solution;at temperatures below 253 K, via both the 119Sn and 7Li NMR spectra (toluene-d8), the 119Sn–7Li coupling (289 Hz) is nicely resolved.The exchange of aryl groupings (vide infra) as well as between coordinatedand free-NMe2substituents remains fast on the NMR timescale at 183 K. 2D 1H–1H EXSY spectroscopyconfirmed that the 2-Me2NCH2C6H4groups present in stannate 3band bisaryltin(II) 2undergo chemical exchange. The 2D 7Li–7Li EXSY spectrum points to the occurrence of chemical exchangeof the lithium atoms of stannate 3band aryllithium 1. [ABSTRACT FROM AUTHOR]

Large dielectric constant and band gap are essential for insulating materials used in applications such as capacitors, transistors and photovoltaics. Of the most common polymers utilized for these applications, polyvinyldiene fluoride (PVDF) offers a good balance between dielectric constant, >10, and band gap, 6 eV, but suffers from being a ferroelectric material. Herein, we investigate a series of aliphatic organotin polymers, p[DMT(CH2)n], to increase the dipolar and ionic part of the dielectric constant while maintaining a large band gap. We model these polymers by performing first-principles calculations based on density functional theory (DFT), to predict their structures, electronic and total dielectric constants and energy band gaps. The modeling and experimental values show strong correlation, in which the polymers exhibit both high dielectric constant, ⩾5.3, and large band gap, ⩾4.7 eV with one polymer displaying a dielectric constant of 6.6 and band gap of 6.7 eV. From our work, we can identify the ideal amount of tin loading within a polymer chain to optimize the material for specific applications. We also suggest that the recently developed modeling methods based on DFT are efficient in studying and designing new generations of polymeric dielectric materials. [ABSTRACT FROM AUTHOR]

Thereaction of L1H [L1H = 3-(N9-hypoxanthyl)propanoic acid]with Me3SnCl or (n-Bu3Sn)2O afforded the 1D coordination polymers [Me3Sn(L1)]n(1) and [n-Bu3Sn(L1)]n(2), respectively.A similar reaction between L2H [3-{N9-(2-aminopurinyl)}propanoicacid] with (Ph3Sn)2O in a 2:1 ratio affordeda dimer [(L2)(Ph3Sn)L2{Ph3Sn(H2O)}]·3CH3OH·3H2O (3). The reactions of 2-(N9-adeninyl)aceticacid (L3H) and 3-(N9-adeninyl)propanoic acid (L4H) with (Ph3Sn)2O in a 2:1 ratio afforded insoluble intractableproducts, which, upon addition of dilute HCl in methanol, afforded[{Ph2SnCl3(H2O)}(HL3Me)2Cl]·H2O (4) and [(Ph2SnCl4)(HL4Me)2] (5). Complexes 1–5show an extensivesupramolecular organization in the solid state as a result of severalintermolecular interactions, prominent among which are the interactionsbetween the nucleobases. [ABSTRACT FROM AUTHOR]

The syntheses ofthe intramolecularly coordinated organotin-substitutedtransition metal complexes [RSn{W(CO)3Cp}2][W(CO)3Cp] (2, R = 4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2), [RSn{W(CO)3Cp}Cl2] (4, R =4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2), and [RSn{W(CO)3Cp}Cr(CO)5] (5, R = 4-t-Bu-2,6-{P(O)(OEt)2}2C6H2) are reported. The reaction of compound 2with Ph4P+Br¯ gave the benzoxaphosphastannole[1(P),3(Sn)-Sn[W(CO)3Cp]2OP(O)(Oi-Pr)-6-t-Bu-4-P(O)(Oi-Pr)2-C6H2] (3). The compounds arecharacterized by 1H, 13C, 31P, 119Sn NMR and IR spectroscopy and, except for 3, by single crystal X-ray diffraction analysis. The experimentalwork is accompanied by DFT calculations. [ABSTRACT FROM AUTHOR]

A hexanuclearhexagonal organotin macrocycle [(n-Bu3Sn)6(μ-L)6(I–)2(MeOH)6] (1) was synthesizedin a 1:1 reaction of (n-Bu3Sn)2O and 4,5-dicarboxy-1,3-dimethyl-1H-imidazol-3-iumiodide (LH2I). The molecular structureof 1reveals that it is a 42-membered hexatin macrocyclepossessing a C3(pseudo-S6) symmetry. The alternate up–down arrangementof imidazolium units allows the molecule to assume a chairtopology. The hexagonal packing of these macrocycles, in the solid-state,results in nanoscale one-dimensional channels which entrap two I–ions in close proximity (∼3.7 Å) as aresult of various supramolecular interactions. [ABSTRACT FROM AUTHOR]

Thereactivity of the intramolecularly coordinated organotin(IV)carbonate L(Ph)Sn(CO3) (1), where L standsfor an N,C,N-chelating ligand, 2,6-(Me2NCH2)2C6H3, was studied. The treatment of 1with ferrocene-based carboxylic acids RCOOH afforded theorganotin(IV) dicarboxylates LPhSn(O2CR)2, whereR is ferrocenyl (2), 2-ferrocenylethyl (3), and [(1E)-2-ferrocenyl]ethenyl (4). Surprisingly, compounds 2–4aresensitive to moisture and easily hydrolyze with condensation intothe corresponding hexameric organotin oxo clusters (PhSnO)6(O2CR)6(R = ferrocenyl (5), 2-ferrocenylethyl(6), and [(1E)-2-ferrocenyl]ethenyl(7)) possessing a Sn6O6drumlikecore. On the other hand, treatment of 1with non-carboxylicacids such as HOTf, H3BO3, H3PO3, and t-BuPO3H2affordedthe triflate salt of a cationic organotin(IV) hydroxide {[LPh(H2O)Sn(μ-OH)]2}(OTf)2(8), stannaboroxine LPhSnB2O3(OH)2(9), and organotin(IV) phosphite [L(Ph)Sn(HPO3)]2(10) and phosphonate {[L(Ph)Sn]2(μ-OH2)(μ-t-BuPO3)2} (11), respectively. Compounds 2–11were characterized by elemental analysisand multinuclear NMR spectroscopy, and the molecular structures ofcompounds 6and 9–11were determined by single-crystal X-ray diffraction analysis. Inaddition, compounds 2–7bearing redox-activeferrocenyl groups were studied by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

The contribution of silaalkylphosphonic acids Me3SiCH2P(O)(OH)2 (1) and Me3SiC(CH3)2P(O)(OH)2 (2) as ligands was demonstrated for the first time by the isolation of new diorganotin(IV) phosphonates Et2Sn{OP(O)(OH)CH2SiMe3}(OSO2Me) (3), (Et2Sn)6{O3PC(CH3)2SiMe3}4(OSO2Me)4 (4), and Et2Sn(O3PCH2SiMe3) (5). X-ray crystallographic studies of 1-4 are presented. The structures of 1 and 2 adopt extended motifs by virtue of P-OH···O-P-type hydrogen bonding interactions. The molecular structure of 3 is composed of a dimer formed by bridging hydrogen phosphonate groups, while the sulfonate group appended on each tin atom acts in a μ2-bridging mode to afford the formation of one-dimensional coordination polymer featuring alternate eight-membered [-Sn-O-P-O-]2 and [-Sn-O-S-O-]2 rings. The asymmetric unit of 4 is composed of two crystallographically unique trinuclear tin phosphonate clusters with a Sn3(μ3-PO3)2 core linked together by coordinative association of a μ2-sulfonate group, while the remaining sulfonates are involved in the construction of a two-dimensional self-assembly. The identity of 1-5 in solution was established by IR and multinuclear (¹H, 13C, 31P, 119Sn) NMR spectroscopy. The presence of silaalkyl group in 5 imparts unusual solubility in hydrocarbon, aromatic, and ether solvents. As a consequence, the formation of colloidal particles of 5 featuring rodlike morphology was achieved by ultrasonication of a solution in ethanol-chloroform mixture. [ABSTRACT FROM AUTHOR]

Dilithiostannoles, which are aromatictin-containing ring compounds,were proposed to have stannylene character, as judged from their NMRanalysis. We herein report on the synthesis of silyl-substituted dilithiostannoles,which were characterized by NMR spectroscopy and X-ray diffractionanalysis. The silyl-substituted derivatives also exhibit featurescharacteristic of aromatic dilithiostannoles such as 7LiNMR signals at high-field area and no C–C bond alternationin the stannole rings. Theoretical calculations and the 119Sn NMR chemical shifts revealed that the stannylene character inthe silyl-substituted dilithiostannoles is enhanced due to greaterinteraction between 5p (Sn) and LUMO (butadiene) in comparison tothose in alkyl and aryl derivatives. The 119Sn Mössbauerspectra of dilithiostannoles were measured for the first time, indicatingthat each of the tin atoms in dilithiostannoles can be characterizedas having Sn(II) character. [ABSTRACT FROM AUTHOR]

Four related sterically restricted peri-substitutedacenaphthenes have been prepared containing mixed tin–phosphorusmoieties in the proximal 5,6-positions (Acenap[SnR3][PiPr2]; Acenap = acenaphthene-5,6-diyl;R3= Ph3(1), Ph2Cl(2), Me2Cl (3), Bu2Cl (4)). The degree of intramolecular P–Sn bondingwithin the series was investigated by X-ray crystallography, solutionand solid-state NMR spectroscopy, and density functional theory (DFT/B3LYP/SBKJC/PCM)calculations. All members of the series adopt a conformation suchthat the phosphorus lone pair is located directly opposite the tincenter, promoting an intramolecular donor–acceptor P→Sntype interaction. The extent of covalent bonding between Sn and Pis found to be much greater in triorganotin chlorides 2–4in comparison with the triphenyl derivative 1. Coordination of a highly electronegative chlorine atomnaturally increases the Lewis acidity of the tin center, enhancingthe lp(P)−σ*(Sn–Y) donor–acceptor 3c-4etype interaction, as indicated by conspicuously short Sn–P peridistances and significant 1J(31P,119Sn) spin–spin coupling constants(SSCCs) in the range 740–754 Hz. Evidence supporting the presenceof this interaction was also found in solid-state NMR spectra of someof the compounds which exhibit an indirect spin–spin couplingon the same order of magnitude as observed in solution. DFT calculationsconfirm the increased covalent bonding between P and Sn in 2–4, with notable WBIs of ca. 0.35 obtained, incomparison to 0.1 in 1. [ABSTRACT FROM AUTHOR]

It has been reported that organotin compounds such as triphenyltm or tributyltin (TBT) induce diabetes and insulin resistance. However, histopathological effects of TBT organotin compounds on the Islets of Langerhans and exocrine pancreas are still unclear. In the present study, male KM mice were orally administered with TBT (0.5, 5, and 50 μg/kg) once every 3 days. The fasting plasma glucose levels significantly elevated, and the levels of serum insulin glucagon decreased in the animals treated with TBT for 60 days. In animals treated for 45 days, the number of apoptotic cells in the islets and exocrine pancreas was elevated in a dose- dependent manner. The percentage of proliferating (PCNA- positive) cells was decreased in the islets, while it was increased in exocrine acinar cells. Immunohistochemistry analysis showed that estrogen receptor (ER) and androgen receptor (AR) were present in vascular endotfielium, ductal cells, and islet cells, but absent from pancreatic exocrine cells. TBT exposure decreased die production of estradiol and triiodothyronine and elevated the concentration of testosterone, and resulted in a decrease of ERa expression and an elevation of AR in the pancreas measured by Western boltting. The results suggested that TBT inhibited the proliferation and induced the apoptosis of islet cells via multipathways, causing a decrease of relative islet area in the animals treated for 60 days, which could result in a disruption of glucose homeostasis. The different presence of ERs and AR between the islets and exocrine pancreas might be one of reasons causing different effects on cell proliferation. [ABSTRACT FROM AUTHOR]

Twobis(dithiocarbamate) (bdtc) metallamacrocyclic compounds, 1and 2, and the deuterated analogues 1-d8and 1-d20were readily prepared through self-assembly processesinvolving the corresponding secondary bis(diamines), with two equivalentseach of CS2and dimethyltin(IV) dichloride. Solid-statecharacterization using FTIR, PXRD, and TGA indicated that the solidphases of both macrocycles were amorphous solids. For compound 1, a crystalline phase could only be obtained in the formof a dichloromethane solvate; however, the corresponding crystal latticewas unstable and collapsed rapidly under ambient conditions. The bdtcligands containing para-disubstituted phenylene (compound 1) and bicyclo[2.2.2]octane groups (compound 2) showed rotational motion within the macrocyclic assemblies in thesolid state. For compound 1, the internal rotation ofthe phenylene groups was examined first by 13C NMR CPMASspectroscopy using the 1-d20derivative in which the hydrogen atoms of the pendant phenyl groupshad been substituted with deuterium atoms and also by 2H NMR spin echo experiments using the 1-d8derivative in which the rotating phenylene groups havebeen deuterated. Line shape analysis using a log-Gaussian distributionmodel indicated that the central phenylene rings experience fast 2-foldflip reorientations over the sp2–sp3carbonatom axes, overcoming an activation energy of Ea= 10 kcal/mol with a preexponential factor A= 3.9 × 1014s–1. For compound 2, the 13C CPMAS experiments suggested that thebicyclo[2.2.2]octane moieties also undergo fast internal dynamics,which is in agreement with the higher symmetry of these fragmentswhen compared to the phenylene spacers. [ABSTRACT FROM AUTHOR]

Dialkylstannylene acetals are organotin intermediates widely used to facilitate regioselective monofunctionalization of diols or polyols by electrophiles. Alkylation is both the slowest and the most useful reaction of these intermediates, and this reaction is markedly accelerated by the addition of nucleophiles to the reaction media, usually cesium fluoride in dimethylformamide (DMF) or tetrabutylammonium iodide or bromide in toluene. The regioselectivity may be influenced by aggregation of the dialkylstannylene acetals into dimers and higher oligomers, and by the addition of these nucleophiles. The stabilities and the geometries of the species potentially involved in these processes were examined by using theoretical chemistry methods with di-n-butyldialkoxytin derivatives as examples and fluoride as the nucleophile. Geometry optimizations were performed at B3LYP/6-31G(d,p) level, and single point energies obtained at the MP2/6-311G(2d,p) level with diffuse functions added for fluorine. The LANL2DZdp basis set with diffuse and polarization functions and its effective core potential were used to describe tin. The addition of fluoride to monomeric di-n-butyldialkoxytin derivatives to give fluoridated monomers is predicted to be strongly exothermic, by 187 to 209 kJ/mol, depending on the alkoxyl group. The fluoridated monomers are calculated to react with monomers exothermically to give monofluoridated dimers, except for the di-t-butoxy derivative. Dimer formation on average is about 20 kJ mol-1 more exothermic than for the nonfluoridated monomers alone. Monofluoridated monomers strongly prefer to exist as monomers because the difluoridated dimers are estimated to be 209 to 278 kJ mol-1 less stable at 298 K. [ABSTRACT FROM AUTHOR]

A two-dimensionalcoordination polymer [(n-Bu3Sn)4(μ-L)2(4,4′-bipy)]n(1) was prepared in a reactionbetween (n-Bu3Sn)2O, (E)-5-(pyridin-4-yl-methyleneamino)isophthalic acid (LH2), and 4,4′-bipyridine (4,4′-bipy). The structureof 1is built by the interlinking of 82-membered macrocyles.The generation of the 2D coordination polymer is facilitated by themultisite coordination capability of the dianionic ligand (L2–) as well as involvement of 4,4′-bipyridine as an ancillaryligand. [ABSTRACT FROM AUTHOR]

Thesyntheses of the enantiopure ferrocenylphosphonic diamide (3aR,7aR)-2-ferrocenyl-3a,4,5,6,7,7a-octahydro-1,3-dimethyl-1,3,2-benzodiazaphosphole2-oxide ((R,R)-FcP(O)(DMCDA), (R,R)-1) and its enantiomer(S,S)-FcP(O)(DMCDA) ((S,S)-1) are reported. Their ortho lithiationand subsequent treatment with Ph3SnCl selectively providedthe corresponding tetraorganotin derivatives FcP(O)(DMCDA)SnPh3((R,R,RP)-2and (S,S,SP)-2) in a diastereoselective ratio of 88:12. The absoluteconfiguration of the major diastereomer was confirmed by single-crystalX-ray diffraction analysis. DFT calculations revealed that kineticeffects of the lithiation step cause the high diastereoselectivityof the formation of (R,R,RP)-2. Further functionalizationof (R,R,RP)-2with elemental iodine gave the enantiopure organotiniodide derivatives FcP(O)(DMCDA)SnInPh3–n((R,R,RP)-3:, n= 1; (R,R,RP)-4, n= 2, (R,R,RP)-5, n= 3). The triorganotin fluoride FcP(O)(DMCDA)SnFPh2((R,R,RP)-6) was obtained by the reaction of (R,R,RP)-3in dichloromethane with aqueous KF solution. The reactionof the compound (R,R,RP)-3with silver triflate gave the R,R,RP-configuratedtriorganotin triflate FcP(O)(DMCDA)SnPh2(OTf) (7), which exists as a contact ion pair in the solid state and showsdynamic behavior in solution. The reaction of 7withPh3PO afforded the corresponding organotin salt [FcP(O)(DMCDA)SnPh2(OPPh3)][OTf] ((R,R,RP)-8). [ABSTRACT FROM AUTHOR]

The reactions of the in situ preparedorganotin(I) compounds RSnSnRwith diaryl dichalcogenides ArEEAr provided, depending on the ratioof the reactants, the intramolecularly coordinated heteroleptic organotin(II)chalcogenoarylates RSnEAr (1, R = 2,6-(Me2NCH2)2C6H3, E = S, Ar= Ph; 2, R = 2,6-(Me2NCH2)2C6H3, E = Se, Ar = Ph; 3, R = 2,6-(Me2NCH2)2C6H3, E = Te, Ar = Ph; 6, R = 4-t-Bu-2,6-{P(O)(O-i-Pr)2}2C6H2, E = Se, Ar = Ph; 7, R = 4-t-Bu-2,6-{P(O)(O-i-Pr)2}2C6H2, E = Te, Ar = Ph; 8, R = 4-t-Bu-2,6-{P(O)(O-i-Pr)2}2C6H2, E = Se, Ar = 2-C5H4N) and the corresponding organotin(IV) compoundsRSn(EAr)3(4, R = 2,6-(Me2NCH2)2C6H3, E = S, Ar = Ph; 5, R = 2,6-(Me2NCH2)2C6H3, E = Se, Ar = Ph; 10, R = 4-t-Bu-2,6-{P(O)(O-i-Pr)2}2C6H2, E = S, Ar = 2-C5H4N), respectively. Compound 10undergoes a thermallyinitiated cyclization reaction to give the benzoxaphosphastannolederivative {1(P),3(Sn)-Sn(S-Py)2-OP(O)(O-i-Pr)-6-t-Bu-4-P(O)(Oi-Pr)2}C6H2(11). The compounds werecharacterized by 1H, 13C, 31P, 119Sn, and 125Te NMR and IR spectroscopy, electrosprayionization mass spectrometry, and single-crystal X-ray diffractionanalysis. The intramolecular Sn–N and Sn–O distancesrange between 2.501(3) (2) and 2.815(3) Å (4) and between 2.407(2) (8·C7H8) and 2.497(2) Å, respectively. Compounds 6and 7show intermolecular secondary Sn···Sninteractions at distances of 3.8876(3) and 3.8379(5) Å, respectively. [ABSTRACT FROM AUTHOR]

Thesyntheses are reported of the 1,1,5-trimethyl-2,8-dioxa-5-aza-1-stannabicyclo[3.3.0]octaneMeN(CH2CH2O)2SnMe2(1), its monosodium aminoalcoholate adduct [MeN(CH2CH2O)2SnMe2·MeN(CH2CH2ONa)(CH2CH2OH)]2(2), and the hexanuclear organotin oxo cluster [MeN(CH2CH2O)2SnMe2·Me2SnO]3(3). The compounds were characterizedby 1H, 13C, and 119Sn NMR spectroscopy,electrospray ionization mass spectrometry, and single-crystal X-raydiffraction analysis. In the solid state, compound 1isa tetramer that is brought about by intermolecular O→Sn interactions.In solution, however, it shows a monomer ⇌ dimer equilibriumthat is fast on the 1H, 13C, and 119Sn NMR time scales at room temperature. All compounds show intramolecularN→Sn interactions at Sn–N distances ranging between2.378(3) Å (2) and 3.026(3) Å (3·0.25H2O). Compound 3can formally beregarded as a molecular dimethyltin oxide being trapped by head-to-tailcomplexation with a stannabicyclooctane. In solution, it slowly fallsapart into 1and Me2SnO. [ABSTRACT FROM AUTHOR]

Organotin compounds are toxic and endocrine disrupting compounds, which have been intensively used as antifouling paints for ship hulls and thus are widely spread in the environment. They are suspected to cause imposex, the formation of male characteristics in female gastropods, because of the activation of retinoid X receptor (RXR) at very low environmental concentrations. Here we report the development and optimization of a bioluminescent yeast assay for the detection of organotin compounds based on the interaction with a hybrid RXR and subsequent expression of a reporter luciferase gene. This assay is highly specific toward organotin compounds and natural ligands of the RXR. It detects tributyltin and triphenyltin in nanomolar concentrations (detection limits were found to be 30 nM and 110 nM, respectively) and allows small-scale high-throughput analyses. Furthermore it was possible to measure tributyltin directly in untreated spiked sediments. Thus, the results provided within one working day can be used for the assessment of bioavailability and mixture effect of organotin compounds in environmental samples. [ABSTRACT FROM AUTHOR]

Thesynthesis of the bis(crown ether)-substituted organostannanesX2Sn(CH2-[16]-crown-5)2(3, X = I; 4, X = Br; 5, X = Cl; 6, X = F) and X2Sn(CH2-[13]-crown-4)2(10, X = I; 11, X = Br; 12, X = F) is reported. The compounds have been characterized by 1H, 13C, 19F, and 119Sn NMRspectroscopy, elementalanalyses, and electrospray ionization mass spectrometry (ESI-MS).Single-crystal X-ray diffraction analyses reveal a distorted-octahedral cis,cis,trans configurationof the tin atoms in compounds 4–6and 10–12as a result of intramolecularO→Sn coordination. The ability of the host molecules to formmono- and ditopic complexes with various halide salts in differentsolvents, including water, has been investigated by NMR spectroscopyand ESI-MS. [ABSTRACT FROM AUTHOR]

The chloro-bridged heterobimetalliccomplex (η6-hexamethylbenzene)Ru(dmp)(μ-Cl)2Sn(CH3)2Cl2was designed,synthesized, and characterizedby various spectroscopic methods, viz. IR, 1H and 13C NMR, and ESI MS, and single-crystal X-ray crystallographyas an approach toward multitargeting metal-based potential anticancerdrug candidates. In vitro DNA binding studies confirmed the bindingaffinity of the complex toward the minor groove of DNA, which is furthervalidated by docking studies. Furthermore, the complex exhibited significantinhibitory effects on topoisomerase Iα at a very low concentration(∼8 μM). The cytotoxicity of the complex against HeLaand HepG2 cancer cell lines was evaluated, which revealed significantregression in cancerous cells in comparison with the standard drug. [ABSTRACT FROM AUTHOR]

Thesyntheses of the heteroleptic organostannylene chromium pentacarbonylcomplexes [4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2(X)SnCr(CO)5] (2, X = ClO4; 3, X = OTf)and [4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2(L)SnCr(CO)5][ClO4] (4, L = p-Me2NC5H4N; 5, L = Ph3PO) are reported. In complex 2, as its toluene solvate 2·C7H8, and 3, asits toluene solvate 3·0.5C7H8, the perchlorate and triflate anions coordinate the tin atom atSn–O distances of 2.170(3) and 2.178(3) Å, respectively.In the complexes 4and 5, however, the perchlorateanion is displaced from the tin atom by the 4-dimethylaminopyridineand triphenylphosphane oxide donor, respectively, to give salt-likesolid-state structures. In addition to the single-crystal X-ray diffractionstudies all compounds were characterized by multinuclear NMR and IRspectroscopy, electrospray mass spectrometry, and elemental analysis.DFT calculations with subsequent NBO analyses reveal the bonding ofboth the 4-dimethylaminopyridine and triphenylphosphane oxide to bedonor–acceptor-like with charge transfer from these donor moleculesto the tin atoms. [ABSTRACT FROM AUTHOR]

Thecomplexation chemistry of the stannylene Sn{N[Si(CH3)3]2}2, first reported by Lappert in the1970s, was investigated by 119Sn NMR chemical shift measurements.To this end, experimental NMR data and theoretical density functionaltheory (DFT) calculations were combined to get an insight into theinteraction between the stannylene and various solvent molecules withσ- and/or π-coordinating power. Small variations in themeasured 119Sn chemical shifts revealed a donor–acceptorinteraction with the solvent molecules. In comparison to the noncoordinatingsolvent cyclohexane taken as a reference, a weak coordination wasobserved with aromatic solvent molecules (benzene and toluene) anda much stronger coordination with the σ-donors THF and pyridine.Pyridine was confirmed to be the strongest donor, as evidenced byits large upfield chemical shift Δδ(119Sn)of 635 ppm. The experimental chemical shifts were reproduced by DFT(NMR) calculations, demonstrating similar trends in the interactionstrength with the σ- and π-donors. The stannylene Sn{N[Si(CH3)3]2}2showed the abilityto react with Fe(CO)5and Fe2(CO)9in the molar ratio 1/1 to provide L2SnFe(CO)4complexes. With a molar excess of Fe2(CO)9, L2Sn[Fe(CO)4]2was generated irreversibly.Upon prolonged UV irradiation in the presence of W(CO)6, in the molar ratio 1/1, a mixture of L2SnW(CO)5and two (L2Sn)2W(CO)4complexeswas generated. [ABSTRACT FROM AUTHOR]

Thereactions of 3-(N9-adeninyl) propanoic acid (LH) with various di- andtriorganotin oxides have been investigated. Thus, the reaction of di-tert-butyltin oxide (t-Bu2SnO)3in a 3:1 ratio afforded the dinuclear derivative [t-Bu2Sn(μ-OH)L]2·7H2O (1). A similar reaction involving bis(tri-n-butyltin)oxide, (n-Bu3Sn)2O, in a 2:1 ratio afforded the one-dimensional (1D) coordinationpolymer [n-Bu3SnL·0.33H2O]n(2). Similarly the reactionwith (n-Bu2SnO)nin a 2:1 ratio afforded the tetranuclear [{n-Bu2Sn}2(μ3-O)(μ-OH)L]2(3). On the other hand, asimilar reaction in a 1:1 ratio also gave the tetranuclear product[{n-Bu2Sn}2(μ3-O)L2]2(4). The molecular structureof 1reveals a central dinuclear Sn2O2motif where the two tin centers are bridged by two μ-OHgroups. Each tin is bound with a monodentate carboxylate group; theCO unit of these carboxylates is involved in an intramolecularhydrogen bonding with the bridging OH unit. The supramolecular structureof 1reveals the formation of a 1D zigzag chain mediatedby intermolecular hydrogen bonding interaction through the Watson-Crickor the Hoogsteen faces. 2is a 1D coordination polymerformed by the successive bridging of triorganotin units by the carboxylateligand L. The supramolecular structure of 2reveals thattwo 1D coordination polymers interact to generate novel adenine homotrimersformed as a result of alternating Watson-Crick–Watson-Crickand Hoogsteen–Watson-Crick interactions. The molecular structuresof 3and 4reveal them to be tetranuclearpossessing a ladder-like structure. The essential difference betweentheir molecular structures is that in 4there are fourcarboxylate ligands, while in 3there are only two. Bothof these complexes reveal intramolecular and intermolecular hydrogenbonding and π···π stacking interactions.The nematicidal activity of 1–3 wasexamined against Caenorhabditis elegans. Compound 2was found to be highly active, effecting a high mortalityeven at very low concentrations such as 25 or 10 ppm. [ABSTRACT FROM AUTHOR]

A catalytic process for the chemo- and regioselective functionalization of nonprotected carbohydrates has been developed. This novel process allows selective thiocarbonylation, acylation, and sulfonylation of a particular hydroxy group in a particular carbohydrate in the simultaneous presence of structurally similar carbohydrates such as anomers. In addition, the chemoselectivity can be switched by regulating only the length of the alkyl chain in the organotin catalyst. [ABSTRACT FROM AUTHOR]

Facile carbon–tin bond activation in the reactionof 2-(trimethylstannyl)pyridine(1) with the organolanthanide complexes Cp*2LaCH(TMS)2(2a) and [Cp*2LaH]2(2b) yields Cp*2La(2-pyridyl) (3), as well as Me3SnCH(TMS)2and Me3SnH, respectively. At room temperature, ethylene then undergoesinsertion into the resulting La–C(pyridyl) bond followed bycarbostannolysis to catalytically generate 2-(2-(Me3Sn)ethyl)pyridine(4) or, with extended reaction times, 6-ethyl-2-(2-(trimethylstannyl)ethyl)pyridine(5). In contrast to 1, 6-methyl-2-(trimethylstannyl)pyridine(6) is unreactive, likely reflecting steric constraints.With terminal alkynes, this catalytic heterocycle–SnMe3activation/carbostannylation process affords tin-functionalizedconjugated enynes. Thus, at 60 °C 2bcatalyzes theconversion 1+ 1-hexyne to yield (E)-2-butyl-1-(Me3Sn)-oct-1-en-3-yne in a 60:1 ratio E:Zisomer ratio. This reaction is available to α-monosubstitutedand α-disubstituted terminal alkynes, while α-trisubstitutedalkynes are too hindered for reaction. The catalytic cycle is proposedto proceed via a spectroscopically detectable Me3Sn–alkynylintermediate which undergoes insertion into a Cp*2La–alkynylbond to produce the conjugated alkynyl product, which is subsequentlyprotonolyzed from the Cp*2La center by a new terminal alkynesubstrate molecule. NMR spectroscopic and kinetic data support theproposed pathway and indicate turnover-limiting alkyne insertion. [ABSTRACT FROM AUTHOR]

Various R/Ar-functionalized tin 5,10,15-tris-(pentafluorophenyl)corrolate derivatives are reported herein including the first ferrocenyltin corrolate species. The isopropyl, sec-butyl-, 2-methyl-n-butyl-, phenyl-, 2-thienyl-, and ferrocenyltin species have been prepared and characterized through 1H, 13C, and 119Sn HMQC NMR spectroscopy, mass spectrometry, UV--vis and photoluminescent spectroscopy, and cyclic voltammetry studies. JC/H-Sn NMR spectroscopic couplings and ring-current effects (upfield shifting) were determined for the R--Sn axial hydrogen and carbon atoms. This report adds to older conceptually similar reports, by, i.e., Janson et al. (J. Am. Chem. Soc. 1969, 91, 5210) and Walker et al. (J. Am. Chem. Soc. 1983, 105, 6923-6929), as discussed herein. Such NMR spectroscopic aspects are discussed for these model systems. Compound Sn--Ph bond cleavage was achieved by treatment with I2. [ABSTRACT FROM AUTHOR]

The syntheses of the novel alkanolamine N-(CH2CMe2OH)2(CH2CH2CH2OH) (2), the novel amino-trialkoxides of tin of the type [N-(CH2CMe2O)2(CH2)nOSnOR]m (3: m = 1, n = 2, R = t-Bu; 4: m = 2, n = 3, R = f-Bu; 5: m = n = 2, R = 2,6-Me2C6H3; 6: m = 2, n = 3, R = 2,6-Me2C6H3) and the related trinuclear tin oxoclusters [ (LSnOSnL) (LSnOR) ] [L = N-(CH2CMe2O)2(CH2CH2O), 7: R = t-Bu; 8: R = 2,6-Me2C6H3] and the pentanuclear tin oxocluster [LSnOSn-(OH)2OSnL·2LSnOH], [9, L = N(CH2CMe2O)2(CH2CH2O)] are reported. The compounds are characterized by elemental analyses, multinuclear (¹H, 13C, 119Sn, ¹H-¹H cosy, ¹H-13C HSQC) NMR spectroscopy, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analyses (3, 4·C7Hg, 5, 7, S O.5C7Hg, 9·6H2O). [ABSTRACT FROM AUTHOR]

The anionic speciation of chlorostannate (II) ionic liquids, prepared by mixing 1-alkyl-3-methylimidazolium chloride and tin (II) chloride in various molar ratios, XsnCl2, was investigated in both solid and liquid states. The room temperature ionic liquids were investigated by 119Sn NMR spectroscopy, X-ray photoelectron spectroscopy, and viscom-etry. Crystalline samples were studied using Raman spectroscopy, single-crystal X-ray crystallography, and differential scanning calorimetry. Both liquid and solid systems (crystal-lized from the melt) contained [SnCl3]- in equilibrium widi Cl- when XSnCl2 < 0.50, [SnCl3]- in equilibrium with [Sn2Cl5]- when XsnCl2 > 0.50, and only [SnCl3]- when XSnCl2 = 0.50. Tin(II) chloride was found to precipitate when XSncl2 < 0.63. No evidence was detected for the existence of [SnCl4]2- across the entire range of XsnCl2, although such anions have been reported in the literature for chlorostannate (II) organic salts crystallized from organic solvents. Furthermore, the Lewis acidity of the chlorostannate(II)-based systems, expressed by their Gutmann acceptor number, has been determined as a function of the composition, Xsncl2 to reveal Lewis acidity for XSnCl2 > 0.50 samples comparable to the analogous systems based on zinc (II). A change of the Lewis basicity of die anion was estimated using ¹H NMR spectroscopy, by comparison of the measured chemical shifts of the C-2 hydrogen in the imidazolium ring. Finally, compositions containing free chloride anions (XSnCl2 < 0.50) were found to oxidize slowly in air to form a chlorostannate (IV) ionic liquid containing the [SnCl6]2- anion. [ABSTRACT FROM AUTHOR]

A series of diorganotin complexes of dithiocarbamates[Sn(C4H9)2(S2CN(RR′)2)2] (R, R′ = ethyl (1); R =methyl, R′ = butyl (2); R, R′ = butyl (3); R = methyl, R′ = hexyl (4); and [Sn(C6H5)2(S2CN(RR′)2)2] (R, R′ = ethyl (5); R =methyl, R′ = butyl (6); R, R′ = butyl (7); R = methyl, R′ = hexyl (8) were synthesized.Single-crystal X-ray structures of 2, 3,and 8were determined. Thermogravimetric analysis (TGA)showed single-step decomposition for the complexes 1, 3, and 5–8, and double-stepdecomposition for the complexes 2and 4between195 °C and 325 °C. Complexes 1–4were used as single-source precursors for the depositionof SnS thin films by aerosol-assisted chemical vapor deposition (AACVD)at temperatures from 400 °C to 530 °C. Orthorhombic SnSthin films were deposited from all four complexes at all depositiontemperatures. The films were characterized by UV–vis spectroscopy,powder X-ray diffraction (p-XRD), Raman spectroscopy, scanning electronmicroscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), andalso electrical resistivity measurements. [ABSTRACT FROM AUTHOR]

The reaction of CuCl-catalyzed coupling of thiol esterwith organostannane has been theoretically investigated using densityfunctional calculations. This reaction takes place with CuCl as acatalyst, giving the product ketone and an organotin sulfide. Therelatively low overall activation barrier calculated (26.0 kcal/mol)supports the experimental fact that this reaction proceeds under mildreaction conditions. The conversion of the resulting Cu(I) thiolateintermediate (D) to the benzoisothiazole (E) was found to proceed via an one-step process. The relatively highoverall activation barrier calculated (35.8 kcal/mol) supports theexperimental fact that this reaction proceeds under harsher reactionconditions. The influence of hybridization of the carbon atom bondedto sulfur on the reaction was also discussed. [ABSTRACT FROM AUTHOR]

The catalytic regioselective monosulfonylation of nonprotected carbohydrates using organotin dichloride under mild conditions is examined. The carbohydrates were chemo- and regioselectively converted to the corresponding monosulfonates in the presence of monoakohols using catalytic dibutyltin dichloride. The regioselectivity of the sulfonylation is attributed to the intrinsic character of the carbohydrates derived from the relative stereochemistry between their hydroxy groups. [ABSTRACT FROM AUTHOR]

The synthesis of the intramolecularly coordinated diorganotindibromide[Me2(i-PrO)SiCH2]2SnBr2(2) is reported. It has been characterizedby elemental analysis, electrospray mass spectrometry, 1H, 13C, 29Si, and 119Sn NMR spectroscopy,and single-crystal X-ray diffraction analysis. In compound 2the tin atom is [4 2]-coordinate and shows a strongly distortedoctahedral configuration. The intramolecular O→Sn coordinationresults in two four-membered chelate rings with Sn–O distancesbetween 2.853(4) and 2.946(4) Å. DFT and MP2 calculations revealthese intramolecular interactions to be electrostatic. Also reportedare 119Sn and 29Si NMR studies on the interactionbetween dimethyltin dihalides (R2SnX2; R = Me,Me2N(CH2)3, X = Br, Cl) with trimethylethoxysilane(Me3SiOEt) and hexamethyldisiloxane (Me3SiOSiMe3), respectively. [ABSTRACT FROM AUTHOR]

Syntheses of the intramoleculariy coordinated organotin(I) compound {4-t-Bu-2,6-[P(0)(0-t-Pf)2]2C6,H2Sn}2 (2), which crystallized in two different pseudopolymorphs 2 and 2-C7H8, of the diorganostannylene {4-t-Bu-2,6-[P(0)(0-i-Pr)2]2C6H2}2Sn (3) and of the organotin(II) acetate 4-t-Bu-2,6-[P(0)(0-i-Pr)2]2C6H2SnOAc (4) are reported. The compounds were characterized by multinuclear NMR, IR (3 and 4), UV--vis spectroscopy (2), electrospray ionization mass spectrometry (3 and 4), and single-crystal X-ray diffiraction analyses. Density functional theory calculations on compound 2 revealed the stabilizing effect of the intramolecular P=0 → Sn coordination. [ABSTRACT FROM AUTHOR]

The reaction of (n-Bu3Sn)2O with pyridine-2,6-dicarboxylic acid (L1H2) in a 1:1 ratio resulted in the formation ofa one-dimensional(1D) coordination polymer [(n-Bu3Sn)2(n-Bu2Sn)2(μ-L1)2(μ-OH)2]n(1). The formation of 1is accompanied by a Sn–butylbond cleavage reactioninvolving half of the organotin units. The formation of the 1D coordinationpolymer is facilitated by the multisite coordination capability ofthe dianionic ligand L1. The reaction of (n-Bu3Sn)2O with pyridine-2,5-dicarboxylic acid (L2H2) or pyridine-3,5-dicarboxylicacid (L3H2), on the other hand,results in the generation of the two-dimensional (2D) coordinationpolymers [(n-Bu3Sn)2(μ-L2)]n(2) and [(n-Bu3Sn)4(μ-L3)2]n(3), respectively. The formation of 2and 3emphasizes the importance of the relativeorientation of the coordinating units in the multisite coordinationligand. Compounds 1–3show a richsupramolecular architecture in their solid state as a result of multiplesecondary interactions. Investigation of the fate of the reactionsof (n-Bu3Sn)2O with pyridinedicarboxylic acids in the presence of a bridging ligand was carriedout. In all the cases when the reactions were carried out in the presenceof 4,4′-bipyridine (4,4′-bipy), 1D coordination polymers[(n-Bu3Sn)2(μ-L1)(μ-4,4′-bipy)]n(4), [(n-Bu3Sn)2(μ-L3)(μ-4,4′-bipy)]n(5), and [(n-Bu3Sn)2(μ-L2)(μ-4,4′-bipy)]n(6) are formed. In these cases,the 4,4′-bipyridine ligand serves as one of the connectorsthat link the organotin units. Interestingly, in the presence of 4,4′-bipyridine, Sn–butylbond cleavage does nottake place. While the 1D coordination polymers 4and 5form three-dimensional supramolecular architectures in theirsolid state, compound 6possesses a 2D supramoleculararchitecture. [ABSTRACT FROM AUTHOR]

The reaction of the tin(II) (iminophosphinoyl)(thiophosphinoyl)methanediide[(PPh2NSiMe3)(PPh2S)CSn:]2(1) with AdNCO (Ad = adamantyl), ArNCO (Ar =2,6-Pri2C6H3), and [RhCl(cod)]2in THF afforded [(PPh2NSiMe3)(PPh2S)C{C(O)N(Ad)}Sn:] (2), [(PPh2NSiMe3)(PPh2S)C¯{C(O)N(Ar)}Sn:] (3), and[(PPh2NSiMe3)(PPh2S)C{Rh(cod)}(SnCl)](4), respectively. Compounds 2–4have been characterized by NMR spectroscopy and X-ray crystallography. [ABSTRACT FROM AUTHOR]

A general method for the synthesis of cage-carbon-functionalized cyclopentadienyl iron and cyclopentadienyl ruthenium tricarbadecaboranyl complexes has been developed that employs palladium-catalyzed Sonogashira, Heck, and Stille cross-coupling reactions directed at a cage-carbon haloaryl substituent. The key Li+[6-(p-XC6H4)-nido-5,6,9-C3B7H9-] (X = I (1), Br (2), Cl (3)) haloaryl-tricarbadecaboranyl anionic ligands were synthesized in high yields via the reaction of the arachno-4,6-C2B7H12- anion with the corresponding p-halobenzonitriles (p-XC6H4-CN). The reactions of the salts 1-3 with (η5-C5H5)Fe(CO)2I and (η5-C5H5)Ru(CH3CN)3PF6 were then used to produce the haloaryl complexes 1-(η5-C5H5)-2-(p-XC6H4)-closo-1,2,3,4-MC3B7H9 (M = Fe, X = I (4), Br (5), Cl (6) and M = Ru, X = I (7), Br (8), Cl (9)). The sonication-promoted Sonogashira coupling reactions of 4 with terminal alkynes catalyzed by Pd(dppf)2Cl2/CuI yielded the alkynyl-linked derivatives 1-(η5-C5H5)-2-p-RC6H4-closo-1,2,3,4-FeC3B7H9 (R = (PhC≡C)- (10), (CH3CH2C(O)OCH2C≡C)- (11), ((η5-C5H5)Fe(η5-C5H4CηC))- (12)). Heck reactions of 4 with terminal alkenes catalyzed by Pd(OAc)2 yielded the alkene-functionalized products 1-(η5-C5H5)-2-p-RC6H4-closo-1,2,3,4-FeC3B7H9 (R = (PhCH2CH-CH)- (13), (CH3(CH2)2CH-CH)- (14)), while the Stille cross-coupling reactions of 4 with organotin compounds catalyzed by Pd(PPh3)2Cl2 afforded the complexes 1-(η5-C5H5)-2-p-RC6H4-closo-1,2,3,4-FeC3B7H9 (R = Ph- (15), (CH2-CH)- (16), (CH2-CHCH2)- (17)). These reactions thus provide facile and systematic access to a wide variety of new types of functionalized metallatricarbadecaboranyl complexes with substituents needed for potential metallocene-like biomedical and/or optoelectronic applications. [ABSTRACT FROM AUTHOR]

The synthesis of crowded peri-5-bromo-6-(organostannyl)acenaphthenesis described. Reaction of 5,6-dibromoacenaphthene with 1 equiv of n-BuLi at −40 °C in diethyl ether followed byaddition of the appropriate organotin reagent at 0 °C gave 5-bromo-6-(triphenylstannyl)acenaphthene(1), 5-bromo-6-(chlorodiphenylstannyl)acenaphthene (2), bis(6-bromoacenaphthen-5-yl)diphenylstannane (3), bis(6-bromoacenaphthen-5-yl)dibenzylstannane (4),bis(6-bromoacenaphthen-5-yl)dibutylstannane (6), andbis(6-bromoacenaphthen-5-yl)dichlorostannane (7) in lowto medium yields (10–56%). 4was converted into5-iodo-6-bromoacenaphthene (5) by stirring overnightin the presence of a large excess of iodine. The new compounds werefully characterized spectroscopically. 119Sn NMR spectrasuggest and interaction between the tin atoms and the neighboringperi halogen atoms. Single-crystal X-ray studies on 1–4and 6–8revealedSn···X distances which are significantly less thanthe sum of the van der Waals radii, while DFT calculations indicateWiberg bond indices of up to 0.11. Furthermore, there is evidenceof the onset of 3c–4e bonding, though according to naturalpopulation analysis, the charge on tin is close to +2 in all compoundsstudied. Electrostatic interactions may thus be another importantdriving force for the close Br···Sn interactions, alongwith the small covalent (donor–acceptor) contributions. [ABSTRACT FROM AUTHOR]

Reactions of bis[bis(trimethylsilyl)amino]tin and thedimer of[bis(trimethylsilyl)amino]tin chloride with various carbodiimidesgive pure corresponding tin(II) guanidinates in essentially quantitativeyields. Heteroleptic bis(trimethylsilyl)amido ({R-NC[N(SiMe3)2]N-R}SnN(SiMe3)2)- and chloro-substituted({R-NC[N(SiMe3)2]N-R}SnCl) tin(II) guanidinateswere obtained from reactions of N,N′-diisopropyl-, N,N′-dicyclohexyl-, N,N′-bis(4-methylphenyl)-, and N-[3-(dimethylamino)propyl]-N′-ethylcarbodiimides,respectively. Homoleptic tin(II) guanidinates {R-NC[N(SiMe3)2]N-R}2Sn were obtained from the N,N′-bis(4-methylphenyl)- and N-[3-(dimethylamino)propyl]-N′-ethyl-substitutedcarbodiimides. Similar reactions of N,N′-bis(2,6-diisopropylphenyl)-and N,N′-bis(trimethylsilyl)carbodiimide,respectively, having the bulkiest substituents of the series, failedto take place under various conditions. The complexes prepared werecharacterized as monomers in solution by 1H, 13C, and 119Sn NMR spectroscopy in C6D6and THF-d8. The solid-state NMR spectrawere recorded for structure comparison. X-ray diffraction studiesof one homoleptic monomer, two heteroleptic chloro complexes withthe structures of two different types of dimers, and the oxidationproduct of the heteroleptic bis(trimethylsilyl)amido-substituted guanidinateacentrosymmetric (guanidinato)tin(IV) oxidewere performed onappropriate crystals. Attempts to prepare homoleptic types of isopropyl-and cyclohexyl-substituted tin(II) guanidinate complexes were unsuccessful.The structures were also evaluated by DFT methods. [ABSTRACT FROM AUTHOR]

Organotin-mediated regioselective protection has been extensively used in organic synthesis for many years. However, the mechanistic origin of the resulting regioselectivity is still not clear. By the comparison of the steric and stereoelectronic effects controlling the geometry of five-membered rings formed from neighboring group participation, from intramolecular acyl group migration, or from orthoester transesterification on pyranoside rings, a theory on the pattern resulting from the reaction with dibutyltin oxide is presented. It is thus suggested that the regioselectivity of organotin-mediated protection is controlled by analogous steric and stereoelectronic effects as in neighboring group participation and acyl group migration, mainly dependent on the stereoelectronic effects of the pyranoside itself, and not related to complex stannylene structures. An organotin protection mechanism is also suggested, emanating from steric and stereoelectronic effects, nucleophilicity, and organotin acyl migration. [ABSTRACT FROM AUTHOR]

The reaction between either GeCl2(1,4-dioxane)or SnCl2and 2 equiv of the lithium phosphide [{(Me3Si)2CH}P(C6H4-2-SMe)]Li(tmeda)gives thecorresponding diphosphatetrylenes [{(Me3Si)2CH}P(C6H4-2-SMe)]2E [E = Ge (10), Sn (11)] in good yields. Both 10and 11crystallize as discrete monomers in which theGe and Sn atoms are coordinated by both P and S atoms. Although 10and 11crystallize as racemic mixtures ofthe RRand SSdiastereomers, variable-temperatureNMR experiments suggest that, in solution, these compounds are indynamic equilibrium with small amounts of the corresponding RSand SRdiastereomers. DFT calculationsreveal that the lowest-energy minima for both 10and 11possess racstereochemistry; two higher-energyminima were located for each of 10and 11, both of which have mesostereochemistry. The twocalculated mesodiastereomers differ in the locationof the sulfur and phosphorus substituents within the pseudo-trigonal-bipyramidalstructures. Both 10and 11decompose onexposure to light, generating the diphosphine {(Me3Si)2CH}(C6H4-2-SMe)P-P(C6H4-2-SMe){CH(SiMe3)2} (14) as the major product. [ABSTRACT FROM AUTHOR]

Triphenyltin (TPhT) is a biocide used worldwide in agriculture, especially in rice crop farming. The distribution and dissipation of TPhT in rice fields, as well as uptake of TPhT and other phenyltin compounds (monophenyltin, MPhT, and diphenyltin, DPhT) is still unknown at present. In this study, speciation analysis of phenyltin compounds was carried out in soil and water from a rice field where TPhT was applied during rice seeding according to legal application rates in Brazil. The results indicate the degradation of biocide and distribution of tin species into soil and water. To evaluate whether TPhT is taken up by plants, rice plants were exposed to three different TPhT application rates in a controlled mesocosm during 7 weeks. After this period, tin speciation was determined in soil, roots, leaves, and grains of rice. Degradation of TPhT was observed in soil, where DPhT and MPhT were detected. MPhT, DPhT, and TPhT were also detected in the roots of plants exposed to all TPhT application rates. Only TPhT was detected in leaves and at relatively low concentration, suggesting selective transport of TPhT in the xylem, in contrast to DPhT and MPhT. Concentration of phenyltin species in rice grains was lower than the limit of detection, suggesting that rice plants do not have the capability to take up TPhT from soil and transport it to the grains. [ABSTRACT FROM AUTHOR]

The treatment of an intramolecularly coordinated organotin(IV) dichloride, [2,6-(Me2NCH2)2C6H3](Ph)SnCl2(1), with Li2E (E = S, Se, Te) afforded thermally stable dimeric diarylstannanethione [{2,6-(Me2NCH2)2C6H3}(Ph)Sn(μ-S)]2(2) and monomeric diarylstannaneselone and -tellurone [{2,6-(Me2NCH2)2C6H3}(Ph)SnE] (E = Se (3), Te (4)). Compounds 2–4were characterized by means of elemental analyses and 1H, 13C, 77Se, 119Sn, and 125Te NMR spectroscopy. The molecular structures of 2and 4were determined by single-crystal X-ray diffraction analysis. Solution NMR studies revealed dependence of the structure of compounds 2and 3on the solvent (C6D6or CDCl3). In addition, the synthesis of dimeric stannanetellurone [{2,6-(Me2NCH2)2C6H3}(Bu)Sn(μ-Te)]2(5) showed an influence of the organic group R (R = Bu or Ph) on the structure of diorganotin(IV) tellurides 4and 5. [ABSTRACT FROM AUTHOR]

The organotin(IV) compounds [Me2Sn(L)2] (1), [Et2Sn(L)2] (2), [nBu2Sn(L)2] (3), [nOct2Sn(L)2] (4), [Ph2Sn(L)2] (5), and [PhOSnL]6 (6) have been synthesized from the reactions of 1-(4-chlorophenyl)-1-cyclopentanecarboxylic acid (HL) with the corresponding diorganotin(IV) oxide or dichloride. They were characterized by IR and multinuclear NMR spectroscopies, elemental analysis, cyclic voltammetry, and, for 2, 3, 4 and 6, single crystal X-ray diffraction analysis. While 1-5 are mononuclear diorganotin(IV) compounds, the X-ray diffraction of 6 discloses a hexameric drumlike structure with a prismatic Sn6O6 core. All these complexes undergo irreversible reductions and were screened for their in vitro antitumor activities toward HL-60, BGC-823, Bel-7402, and KB human cancer cell lines. Within the mononuclear compounds, the most active ones (3, 5) are easiest to reduce (least cathodic reduction potentials), while the least active ones (1, 4) are the most difficult to reduce. Structural rearrangements (i.e., Sn-O bond cleavages and trans-to-cis isomerization) induced by reduction, which eventually can favor the bioactivity, are disclosed by theoretical/electrochemical studies. [ABSTRACT FROM AUTHOR]

Free radical hydrostannylation of olefins with differing steric and electronic demands have been carried out using the chiral, nonracemic stannanes (1R,2S,5R)-menthyldiphenyltin hydride (7), bis[(1R,2S,5R)-menthyl]phenyltin hydride (8), and tris[(1R,2S,5R)-menthyl]tin hydride (9). These reactions resulted in adducts 16–18with yields that were found to depend on the nature of the substituents on both alkene and stannane and could be carried out at low temperature initiated by triethylborane and oxygen; MenPh2SnH (7) reacted with tert-butyldimethyl(1-phenylvinyloxy)silane (1) at −78 °C to afford adduct 19in near-quantitative yield. Somewhat surprisingly, addition of small quantities of diphenyl diselenide to these reactions failed to improve the outcome under any circumstances. [ABSTRACT FROM AUTHOR]