119Sn NMR Spectroscopy Research Articles

The reaction of (tert-Butoxysilyl)methylmagnesium chlorides with some organotin and organosilicon monochlorides

Interaction between (tert-butoxysilyl)methylmagnesium chlorides of the general formula Me3-n(t-BuO)nSiCH2MgCl, n = 1–3, with some organotin and organosilicon monochlorides has been studied. It has been found that the reaction of the Grignard reagents with trialkyltin chlorides readily proceeds via the methylene carbon with the formation of C-substituted products Me3-n(t-BuO)nSiCH2SnR3, R = Me, n-Bu in high yields. The path of this reaction with Me3SiCl and MePh2SiCl depends on the structure of Grignard compound and chlorosilane electrophilicity. Increasing the number of the tert-butoxy groups in the Grignard reagent has unexpectedly been found to result in the formation of Me3-n(t-BuO)nSiCH2OSiMeR2, R = Me, Ph and decrease of the organosilylmethyl silicon compounds content in the reaction products. The structure of the compounds synthesized has been confirmed by 1H, 13C, 29Si, 117,119Sn NMR spectroscopy and mass spectrometry.

Tin(IV) Schiff base complexes: Synthesis, thermodynamic and anti bacterial investigation, experimental and theoretical studies

A series of five coordinated diorganotin(IV) unsymmetrical Schiff base complexes have been synthesized. The structure determination and characterization of these complexes were made on the basis of UV-Vis, IR, ( 1 H and 119 Sn) NMR spectroscopy as well as elemental analysis. The binding site of the ligand was identified by IR spectroscopic measurement. Computational analyses at the level of DFT were performed to study its electronic and molecular structures. The molecular geometry, infrared vibrational frequencies, HOMO-LUMO energy gap, dipole moment, Mulliken charges, HF energies were calculated. The theoretical results were consistent with the experimental data reported. The Schiff base ligands and synthesized tin(IV) complexes were screened for their in vitro growth inhibiting activity against different strains of bacteria. Results indicated that the complexes exhibited good antibacterial activities than the ligands. Also the thermodynamic formation constants of the Schiff bases as donors with Me 2 SnCl 2 as an acceptor were measured using UV-Vis spectrophotometric titration for 1:1 complex formation at constant ionic strength (I = 0.1 M NaClO 4 ) and at 25 oC. KEY WORDS : Tin(IV) complexes, Thermodynamic parameter, Biological activity, Computational analyses Bull. Chem. Soc. Ethiop. 2019 , 33(1), 77-90 DOI: https://dx.doi.org/10.4314/bcse.v33i1.8

Cis versus Trans: The Coordination Environment about the Tin(IV) Atom in Spirocyclic Amino Alcohol Derivatives.

The syntheses of amino alcohols MeN(CH2 CH2 CMe2 OH)2 (1), MeN(CMe2 CH2 OH)(CH2 CMe2 OH) (2), MeN(CH2 CH2 CH2 OH)(CH2 CMe2 OH) (3), MeN(CH2 CH2 CMe2 OH)(CH2 CMe2 OH) (4), MeN(CH2 CH2 CMe2 OH)(CH2 CH2 OH) (5), and MeN(CH2 CH2 OH) (CH2 CH2 CH2 OH) (6) as well as spirocyclic tin(IV) alkoxides spiro-[nBuN(CH2 CMe2 O)2 ]2 Sn (7), spiro-[MeN(CH2 CH2 CMe2 O)2 ]2 Sn (8), spiro-[para-FC6 H4 N (CH2 CMe2 O)2 ]2 Sn (9), spiro-[MeN(CMe2 CH2 O)(CH2 CMe2 O)]2 Sn (10), spiro-[MeN(CH2 CH2 CH2 O)(CH2 CMe2 O)]2 Sn (11), spiro-[MeN(CH2 CH2 CMe2 O)(CH2 CMe2 O)]2 Sn (12), spiro-[MeN(CH2 CH2 CMe2 O)(CH2 CH2 O)]2 Sn (13) and spiro-[MeN(CH2 CH2 O)(CH2 CH2 CH2 O)]2 Sn (14) are reported. The compounds were characterized by 1 H, 13 C (1-14) and 119 Sn (7-14) NMR and IR spectroscopy, EIMS and single-crystal XRD (2, 7-10 and 13, 14). Graph-set analyses were performed for compounds [(MeNH(CMe2 CH2 OH)(CH2 CMe2 OH)][HC(O)O] (2 a) and 2. The coordination environment about the tin(IV) centre of the spirocyclic compounds and their possible stereoisomers were analysed by DFT calculations (spiro-[MeN(CH2 CMe2 O)2 ]2 Sn, 8-10 and 13).

Alkyl Triarylstannanecarbodithioates: Synthesis, Crystal Structures, and Efficiency in RAFT Polymerization.

Eight alkyl triarylstannanecarbodithioates were synthesized starting from the corresponding triarylstannyl chlorides. They were fully characterized by IR and 1 H, 13 C, and 119 Sn NMR spectroscopy and mass spectrometry. Their solid-state structures and geometric parameters were determined and compared to those of other classes of thiocarbonylthio compounds. These new organotin derivatives are efficient reversible chain-transfer agents for reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene (St) and n-butyl acrylate (BA), with controlled number-average molecular weights and narrow dispersities (Ð<1.3). In some cases, loss of control of the polymerization was evidenced and supported by the observation of side products by 119 Sn NMR spectroscopy. This phenomenon was attributed to the thermal instability of the Sn-RAFT terminal group.

A Ferrocenyl-Backboned Unsymmetric O,C-Coordinating Ligand and Its Tin Derivatives.

The syntheses of the phosphonyl‐substituted ferrocenyl stannane Fe[{η 5‐C5H3‐1‐SnPh3‐2‐P(O)(O‐iPr)2}{η 5‐C5H4P(O)(O‐iPr)2}] (1) and its iodine derivative Fe[{η 5‐C5H3‐1‐SnPh2I‐2‐P(O)(O‐iPr)2}{η 5‐C5H4P(O)(O‐iPr)2}] (2) are reported. The syntheses of the corresponding salts Fe[{η 5‐C5H3‐1‐SnPh2‐2‐P(O)(O‐iPr)2}{η 5‐C5H4P(O)(O‐iPr)2}]X (3, X=Al{OC(CF3)3}4, 4, X=ClO4, 5, X=HgI3), respectively, are also described. The compounds are characterized by elemental analyses, 1H, 13C, 31P, 119Sn NMR and IR spectroscopy, electrospray ionization mass spectrometry, and, except for 4 and 5, single‐crystal X‐ray diffraction analyses.

Dissolution of Sn, SnO, and SnS in a Thiol-Amine Solvent Mixture: Insights into the Identity of the Molecular Solutes for Solution-Processed SnS.

Binary solvent mixtures of alkanethiols and 1,2-ethylenediamine have the ability to readily dissolve metals, metal chalcogenides, and metal oxides under ambient conditions to enable the facile solution processing of semiconductor inks; however, there is little information regarding the chemical identity of the resulting solutes. Herein, we examine the molecular solute formed after dissolution of Sn, SnO, and SnS in a binary solvent mixture comprised of 1,2-ethanedithiol (EDT) and 1,2-ethylenediamine (en). Using a combination of solution (119)Sn NMR and Raman spectroscopies, bis(1,2-ethanedithiolate)tin(II) was identified as the likely molecular solute present after the dissolution of Sn, SnO, and SnS in EDT-en, despite the different bulk material compositions and oxidation states (Sn(0) and Sn(2+)). All three semiconductor inks can be converted to phase-pure, orthorhombic SnS after a mild annealing step (∼350 °C). This highlights the ability of the EDT-en solvent mixture to dissolve and convert a variety of low-cost precursors to SnS semiconductor material.

Synthesis, Characterization, Spectral Studies, Antibacterial Evaluation, Thermodynamics and DFT Calculations of Dimethyltin(IV) Dichloride Schiff Base.

A number of new 1:1 complexes of SnMe(2)Cl(2) with unsymmetrical tetradentate Schiff base ligand with NNOS coordination sphere have been synthesized and fully characterized by a variety of physico-chemical techniques viz. elemental analysis, molar conductivity, (1)H and (119)Sn NMR, IR and mass spectroscopy. IR spectral data show that the fifth coordination position of tin atom is occupied by an oxygen atom of Schiff base ligands. In the light of titled techniques, trigonal bipyramidal geometry around the tin atom is proposed for the synthesized complexes. The in vitro antibacterial activities of the complexes against Staphylococcus aureus and Escherichia Coli have been studied. It was found that they possess significant antibacterial activity. Also, DFT/B3LYP method was used to analyze the electronic structures and study of the geometries. The thermodynamic formation constants of the complexes were determined spectrophotometrically at 25ºC in DMF solvent.

Different Complexation Behavior of P-Functionalized Ferrocene Derivatives Towards SnCl2 , SnCl4 and SnPh2 Cl2 : Auto-ionization and Redox-Type Reactions.

The novel phosphonyl-substituted ferrocene derivatives [Fe(η(5) -Cp)(η(5) -C5 H3 {P(O)(O-iPr)2 }2 -1,2)] (Fc(1,2) ) and [Fe{η(5) -C5 H4 P(O)(O-iPr)2 }2 ] (Fc(1,1') ) react with SnCl2 , SnCl4 , and SnPh2 Cl2 , giving the corresponding complexes [(Fc(1,2) )2 SnCl][SnCl3 ] (1), [{(Fc(1,1') )SnCl2 }n ] (2), [(Fc(1,1') )SnCl4 ] (3), [{(Fc(1,1') )SnPh2 Cl2 }n ] (4), and [(Fc(1,2) )SnCl4 ] (5), respectively. The compounds are characterized by elemental analyses, (1) H, (13) C, (31) P, (119) Sn NMR and IR spectroscopy, (31) P and (119) Sn CP-MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single-crystal as well as powder X-ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc(1,1') and Fc(1,2) towards tin(II) chloride.

N-Coordinated Tin(II) Trifluoromethanesulfonates and Their Reactions with Transition Metal Carbonyls.

The syntheses of the compounds [L(1)SnCl][M(CO)5(SnCl3)] (3, M = W; 4, M = Cr), [L(1)SnCl]OTf (5), [L(1)SnCl][W(CO)5(SnCl2OTf)] (6), [L(1)SnOTf][OTf] (7), and [L(2)Sn(OTf)2] (8) with L(1) = {2,6-[(CH3)C═N(C6H3-2,6-(i)Pr2)2]C5H3N} (DIMPY) and L(2) = {2-[(CH3)C═N(C6H3-2,6-(i)Pr2)]-6-(CH3O)}C5H3N) is reported. The compounds were characterized by elemental analyses, (1)H, (13)C, (19)F, and (119)Sn NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction analyses (3·1.5C7H8, 5·CH2Cl2, 7·C7H8, 8). For compounds 7 and 8, the experimental work is accompanied by density functional theory calculations.

Practical synthesis of [n]cycloparaphenylenes (n = 5, 7-12) by H2SnCl4-mediated aromatization of 1,4-dihydroxycyclo-2,5-diene precursors.

Cyclic precursors of cycloparaphenylenes (CPPs) containing 1,4-dihydroxy-2,5-cyclohexadien-1,4-diyl units are prepared by modifying a synthetic method developed by Jasti and co-workers for the synthesis of corresponding 1,4-dimethoxy derivatives. Reductive aromatization of the diyl moieties by SnCl2/2 HCl takes place under mild conditions and affords the CPPs in good yields, incorporating 5 or 7-12 phenylene units. Highly strained [5]CPP is synthesized in greater than 0.3 g scale. (119)Sn NMR spectroscopy clarifies the in situ formation of an ate complex, H2SnCl4, upon mixing a 2:1 ratio of HCl and SnCl2, which serves as a highly active reducing agent under nearly neutral conditions. When more than 2 equivalents of HCl, in relation to SnCl2, are used, acid-catalyzed decomposition of the CPP precursors takes place. The stoichiometry of HCl and SnCl2 is critical in achieving the desired aromatization reaction of highly strained CPP precursors.

Mechanistic studies on the cascade conversion of 1,3-dihydroxyacetone and formaldehyde into α-hydroxy-γ-butyrolactone.

The chemical synthesis of commercially and industrially important products from biomass-derived sugars is absolutely vital to establish biomass utilization as a sustainable alternative source of chemical starting materials. α-Hydroxy-γ-butyrolactone is a useful synthetic intermediate in pharmaceutical chemistry, and so novel biomass-related routes for its production may help to validate this eco-friendly methodology. Herein, we report the specific catalytic activity of homogeneous tin halides to convert the biomass-derived triose sugar 1,3-dihydroxyacetone and formaldehyde into α-hydroxy-γ-butyrolactone. A detailed screening of catalysts showed the suitability of tin catalysts for this reaction system, and isotope experiments using [D2]paraformaldehyde, substrate screening, and time profile measurements allowed us to propose a detailed reaction pathway. In addition, to elucidate the activated species in this cascade reaction, the effect of additional water and the influence of additional Brønsted acids on the reaction preferences for the formation of α-hydroxy-γ-butyrolactone, lactic acid, and vinyl glycolate were investigated. The active form of the Sn catalyst was investigated by (119)Sn NMR spectroscopy.

Atomistic description of thiostannate-capped CdSe nanocrystals: retention of four-coordinate SnS4 motif and preservation of Cd-rich stoichiometry.

Colloidal semiconductor nanocrystals (NCs) are widely studied as building blocks for novel solid-state materials. Inorganic surface functionalization, used to displace native organic capping ligands from NC surfaces, has been a major enabler of electronic solid-state devices based on colloidal NCs. At the same time, very little is known about the atomistic details of the organic-to-inorganic ligand exchange and binding motifs at the NC surface, severely limiting further progress in designing all-inorganic NCs and NC solids. Taking thiostannates (K4SnS4, K4Sn2S6, K6Sn2S7) as typical examples of chalcogenidometallate ligands and oleate-capped CdSe NCs as a model NC system, in this study we address these questions through the combined application of solution 1H NMR spectroscopy, solution and solid-state 119Sn NMR spectroscopy, far-infrared and X-ray absorption spectroscopies, elemental analysis, and by DFT modeling. We show that through the X-type oleate-to-thiostannate ligand exchange, CdSe NCs retain their Cd-rich stoichiometry, with a stoichiometric CdSe core and surface Cd adatoms serving as binding sites for terminal S atoms of the thiostannates ligands, leading to all-inorganic (CdSe)core[Cdm(Sn2S7)yK(6y-2m)]shell (taking Sn2S76– ligand as an example). Thiostannates SnS44– and Sn2S76– retain (distorted) tetrahedral SnS4 geometry upon binding to NC surface. At the same time, experiments and simulations point to lower stability of Sn2S64– (and SnS32–) in most solvents and its lower adaptability to the NC surface caused by rigid Sn2S2 rings.

Solid-state NMR and Raman spectroscopy to address the local structure of defects and the tricky issue of the Cu/Zn disorder in Cu-poor, Zn-rich CZTS materials.

The material Cu2ZnSn(S,Se)4 (CZTS) offers a promising indium-free alternative to Cu(In,Ga)Se2 for the absorber layer in thin-film solar cells. It is known that the highest solar energy conversion efficiencies are reached for Cu-poor, Zn-rich CZTS compositions and that too much disorder at the Cu and Zn sites can have a negative impact on the device performance. In this article, we investigate the structures of [VCu + ZnCu] A-type and [2ZnCu + ZnSn] B-type defect complexes and their impact on the long-range Cu/Zn disorder. To that end, we use (119)Sn, (65)Cu, and (67)Zn solid-state NMR and Raman spectroscopy to characterize powdered CZTS samples. For both A- and B-type substitutions, our NMR investigations demonstrate the clustering of the complexes. Moreover, we show that (A+B)-type compounds should be considered as A-type and B-type compounds, since no interaction seems to exist between [VCu + ZnCu] and [2ZnCu + ZnSn] defect complexes. In addition, it is worth noting that [2ZnCu + ZnSn] complexes have only a minor impact on the level of disorder at the Cu and Zn sites. In contrast, [VCu + ZnCu] complexes seem to restrain the random distribution of Cu at the Zn site and of Zn at the Cu site; i.e., the long-range Cu/Zn disorder. Raman characterization of the CZTS samples was also conducted. The Q = I287/I303 and the newly introduced Q' = I338/(I366 + I374) ratios determined from Raman spectra collected at 785 nm turn out to be very sensitive to the level of Cu/Zn disorder. Moreover, they can be used to differentiate the nature of the substitution in slow-cooled materials.

Tin Oxide Nanoparticles and SnO2 /SiO2 Hybrid Materials by Twin Polymerization Using Tin(IV) Alkoxides.

Twin polymerization was used to prepare composite materials composed of SnO2 nanoparticles entrapped in a polymer matrix. Novel, well-defined tin-containing molecular precursors, so-called twin monomers, were synthesized by transesterification starting from Sn(OR)4 (R=tBu, tAm) to give Sn(OCH2 C4 H3 O)4 (1), [Sn(OCH2 C4 H3 S)4 ⋅HOCH2 C4 H3 S]2 (2), [Sn(OCH2 -2-OCH3 C6 H4 )4 ⋅HOCH2 -2-OCH3 C6 H4 ]2 (3), [Sn(OCH2 -2,4-(OCH3 )2 C6 H3 )4 ⋅HOCH2 -2,4-(OCH3 )2 C6 H3 ]2 (4), 2,2'-spirobi[4H-1,3,2-benzodioxastannine] (5), 2,2'-spirobi[6-methylbenzo(4H-1,3,2)-dioxastannine] (6), and 2,2'-spirobi[6-methoxybenzo(4H-1,3,2)dioxastannine] (7). 13 C and 119 Sn NMR spectroscopy in the solid state and in solution as well as IR spectroscopy and elemental analysis were used to characterize the tin alkoxides. The molecular structures of compounds 2 and 3 were determined by single-crystal X-ray diffraction analysis. The moisture sensitivity of the tin(IV) alkoxides was demonstrated by the formation of the tin oxocluster [Sn3 (μ3 -O)(μ2 -OH)(μ2 -OCH2 C4 H3 S)3 (OCH2 C4 H3 S)6 (HOCH2 C4 H3 S)]2 (2 a), a hydrolysis product of compound 2. Polymerization reactions in the melt (for 1 and 5) and in solution (for 2-4) resulted in cross-linked nanocomposites of the type polymer/SnO2 . Subsequent oxidation of the composites gave SnO2 with BET surface areas up to 178 m2 g-1 . Simultaneous twin polymerization of compounds 5-7 with the silicon derivative 2,2'-spirobi[4H-1,3,2-benzodioxasiline] resulted in the formation of polymer/SnO2 /SiO2 hybrid materials. Oxidation gave porous materials with SnO2 nanoparticles embedded in a silica network with BET surface areas up to 378 m2 g-1 . The silica acts as a crystal growth inhibitor, which prevents sintering of the SnO2 nanoparticles 20-32 nm in size.

Synthesis and Structural Characterization of Base-Stabilized Oligomeric Heterovinylidenes

Metalation of the (iminophosphoranyl)phosphine PPh2CH2(PPh2═NSiMe3) (1) with an equimolar amount of n-BuLi afforded the monolithium salt [Li{CH(PPh2)(PPh2═NSiMe3)}(THF)2] (2). The reaction of 2 with GeCl2·1,4-dioxane has led to the formation of a germavinylene moiety, which trimerized to form a new heterocyclic cage compound, [{(PPh2═NSiMe3)(PPh2)C═Ge:}{(PPh2═NSiMe3)(PPh2)C}2Ge→Ge:] (3). A similar reaction of the lithium methanide complex 2 with SnCl2 afforded the stannavinylidene moiety, which underwent a "head-to-tail" cycloaddition to form a stable 1,3-distannacyclobutane, 4. A trapping reaction of 4 with diiron nonacarbonyl gave the novel iron stannavinylidene complex 5. The solid-state structure analysis of 5 reveals that it contains two stannavinylidene moieties bonded in a Sn-P "head-to-tail" fashion, with one of the tin(II) centers coordinating to a Fe(CO)4 moiety. The X-ray structures of 2-5 have been determined by X-ray crystallography. In addition, the dynamic behavior of 5 has been studied by means of variable-temperature (31)P and (119)Sn NMR spectroscopy.

Straightforward synthesis of novel cyclic metallasiloxanes supported by an N,C,N-chelating ligand

The reaction of an N,C,N-intramolecularly coordinated tin(IV) carbonate LSn(Ph)(CO3) (1) and antimony(III) and bismuth(III) oxides (LMO)2 (where M = Sb (2), Bi (3) and L = C6H3-2,6-(CH2NMe2)2) with (HO)SiPh2(O)SiPh2(OH) in 1 : 1 (in the case of 1) or 1 : 2 molar ratio (in the cases of 2 and 3) gave the metallasiloxanes cyclo-LSn(Ph)(OSiPh2)2O (4) and cyclo-LM(OSiPh2)2O (where M = Sb (6) and Bi (7)) containing six-membered MSi2O3 rings. Alternatively, the compounds 4, 6 and 7 can be also prepared reacting Ph2Si(OH)2 and compounds 1, 2 and 3, respectively, in the molar ratio of either 2 : 1 (for 4) or 4 : 1 (for 6 and 7). The reaction of Ph2Si(OH)2 with 1 in 1 : 1 molar ratio gave cyclo-Ph2Si(OSnL(Ph)O)2SiPh2 (5) containing an eight-membered Sn2Si2O4 stannasiloxane ring. The analogous eight-membered stibasiloxane derivative cyclo-Ph2Si(OSbLO)2SiPh2 (8) was obtained as well, while attempts to synthesize the bismuth analogue failed. Compounds 1-3 react with the siloxane cyclo-(Me2SiO)3 providing either eight-membered metallasiloxanes cyclo-LSn(Ph)(OSiMe2O)2SiMe2 (9) and cyclo-LSb(OSiMe2O)2SiMe2 (10) or the six-membered bismutasiloxane cyclo-LBi(OSiMe2)2O (11). All compounds were characterized with the help of elemental analysis, (1)H, (13)C, (29)Si and (119)Sn NMR spectroscopy, and single crystal X-ray diffraction analyses (except 9 and 10).

1.2.2.Synthesis, crystal structure and in vitro anti-tumor activity of dibutyltin complex of 2,4-dichloro-5-fluorobenzoic acid

The dibutyltin complex of 2,4-dichloro-5- fluorobenzoic acid, [(2,4-Cl 2 -5-FC 6 H 2 C(O)OSnBu 2 ) 2 O] 2 (Bu = CH 2 CH 2 CH 2 CH 3 ) ( 1 ), has been synthesized and characterized by elemental analysis, FT-IR, 119 Sn NMR spectroscopy, and Xray single crystal diffraction. Compound 1 is a centrosymmetric dimmer with two distinct types of carboxylate moieties and tin atoms with distorted trigonal bipyramidal geometries. The in vitro anti-tumor activity of 1 against two human tumor cell lines was found to be higher than that for cis-platin [cis diaminedichloroplatinum( II)] used clinically. Supporting information : FT-IR, 119 Sn NMR, X-Ray, Proliferation inhibitory rate, Cif file.

Synthesis, structural characterization and antibacterial activity of diorganotin(IV) complexes with ONO tridentate Schiff bases containing pyridine ring

Abstract Five organotin(IV) complexes, were obtained by reaction of SnR 2 Cl 2 (R = Ph, Me, Bu) with ONO donor Schiff bases. The synthesized complexes have been investigated by elemental analysis and IR, 1 H NMR, and 119 Sn NMR spectroscopy. These data show that the Schiff base acts as a tridentate dianionic ligand and coordinates via the imine nitrogen and two oxygen atoms. The X-ray crystallography of complex 4 shows a dimeric structure for this molecule. The in vitro antibacterial activities of the Schiff bases and their complexes have been evaluated against Gram-positive ( Bacillus subtilis and Staphylococcus aureus ) and Gram-negative ( Escherichia coli and Pseudomonas aeruginosa ) bacteria and compared with the standard antibacterial drugs.

Cyclic and Linear Polyferrocenes with Silicon and Tin as Alternating Bridges

The synthesis and characterization of ferrocene-based oligomers that contained two different elements (Si and Sn) as alternating bridges is described for the first time. The salt-metathesis reaction of R(2) Si[(C(5) H(4) )Fe(C(5) H(4) Li)](2) (R=Me, Et) with R'(2) SnCl(2) (R'=Me, nBu, tBu) afforded a mixture of oligomers (6(Me) SnMe(2), 6(Et) SnMe(2), 6(Me) SnnBu(2), 6(Et) SnnBu(2), 6(Me) SntBu(2), and 6(Et) SntBu(2)). These oligomers were characterized by (1) H, (13) C, (29) Si, and (119) Sn NMR spectroscopy and by mass spectrometry. MS (MALDI-TOF) studies of 6(Et) SnMe(2) revealed the presence of linear (l) and cyclic (c) species that contained up to 20 ferrocene moieties. The molecular weights of the polymers were determined by gel-permeation chromatography (GPC) and by dynamic-light scattering (DLS). GPC analysis revealed average molecular weights of 2100-6300 Da with respect to polystyrene as a standard. DLS analysis yielded very similar results. Some compounds, c-(6(Me) SnMe(2) )(1), c-(6(Me) SntBu(2))(2), c-(6(Et) SnMe(2))(1), c-(6(Et) SntBu(2))(2), l-(6(Me) SnnBu(2) )(2), and l-(6(Me) SnnBu(2))(3), which contained up to six ferrocene moieties, were isolated in their pure form either by column chromatography or by crystallization. The Si- and Sn-bridged macrocycles that contained four ferrocene units (c-(6(Me) SntBu(2))(2) and c-(6(Et) SntBu(2))(2)) were structurally characterized by single-crystal X-ray analysis.

Reactivity of a Tin(II) (Iminophosphinoyl)(thiophosphinoyl)methanediide Complex Toward Sulfur: Synthesis and 119Sn Mössbauer Spectroscopic Studies of [{(μ-S)SnC(PPh2═NSiMe3)(PPh2═S)}3Sn(μ3-S)

Reaction of [(PPh(2)═NSiMe(3))(PPh(2)═S)CSn:](2) (1) with elemental sulfur in toluene afforded [{(μ-S)Sn(IV)C(PPh(2)═NSiMe(3))(PPh(2)═S)}(3)Sn(II)(μ(3)-S)] (2) and [CH(2)(PPh(2)═NSiMe(3))(PPh(2)═S)] (3). Compound 2 comprises a Sn(II)S moiety coordinated with the Sn(IV) and S atoms of a trimeric 2-stannathiomethendiide {(PPh(2)═NSiMe(3))(PPh(2)═S)CSn(μ-S)}(3). Compound 2 has been characterized by NMR spectroscopy, (119)Sn Mössbauer studies, X-ray crystallography, and theoretical studies. (119)Sn NMR spectroscopy and Mössbauer studies show the presence of Sn(IV) and Sn(II) atoms in 2. X-ray crystallography suggests that the Sn(II)S moiety does not have multiple bond character. Theoretical studies illustrate that the C(methanediide)-Sn bonds comprise a lone pair orbital on each C(methanediide) atom and an C-Sn occupied σ orbital.