Temperature-dependent 119Sn Research Articles

Cyclic Distannene or Bis(stannylene) with a Ferrocenyl Backbone: Synthesis, Structure, and Coordination Chemistry.

1,1'-Dilithioferrocene was reacted with 2 equiv of isopropyl (Ar*) or methyl (Ar') substituted terphenyl tin(II) chloride. Reaction product 1, carrying the bulkier terphenyl substituent Ar*, displays a bis(stannylene) structure in the solid state without formation of a tin-tin bond. Temperature-dependent solution 119Sn NMR spectroscopy, however, revealed a dynamic interplay between bis(stannylene) (100 °C) and cyclic distannene (-80 °C). In contrast to 1, the less bulky Ar' substituent results in a cyclic distannene 2. On the basis of temperature-dependent 119Sn NMR spectroscopy the Sn-Sn bond of compound 2 was preserved up to 100 °C. Both compounds were further characterized by solid-state 119Sn NMR spectroscopy as well as 119Sn and 57Fe Mössbauer spectroscopy. 1 reacted as a chelating ligand with nickel and palladium complexes [Ni(cod)2] and [Pd(nbe)3] (nbe = norbornene). In the resulting coordination compounds the nonstabilized stannylene acts as a donor as well as an acceptor ligand and shows a dynamic switch from donor to acceptor behavior in the monopalladium complex.

Transport and NMR characteristics of the skutterudite-related compound Ca3Rh4Sn13

We report the electronic properties of the Yb3Rh4Sn13-type single crystalline Ca3Rh4Sn13 by means of the electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, as well as 119Sn nuclear magnetic resonance (NMR) measurements. The negative sign of the Hall coefficient and Seebeck coefficient at low temperatures suggests that the n-type carriers dominate the electrical transport in Ca3Rh4Sn13, in contrast to the observations in Sr3Rh4Sn13 which has a p-type conduction. Such a finding indicates a significant difference in the electronic features between these two stannides. Furthermore, we analyzed the temperature-dependent 119Sn NMR spin-lattice relaxation rate for Ca3Rh4Sn13, (Sr0.7Ca0.3)3Rh4Sn13, and Sr3Rh4Sn13 to examine the change of the electronic Fermi-level density of states (DOS) in (Sr1-xCax)3Rh4Sn13. It indicates that the Sn 5s partial Fermi-level DOS enhances with increasing the Ca content, being consistent with the trend of the superconducting temperature. Since the total Fermi-level DOS usually obeys the same trend of the partial Fermi-level DOS, the NMR analysis provides microscopic evidence for the correlation between the electronic DOS and superconductivity of the (Sr1-xCax)3Rh4Sn13 system.

Hyperfine Interactions and Metal Atom Dynamics in a Number of Stannyl Phosphide Compounds and the Detailed Crystal Structure of Triphenyltin Chloride Revisited

Temperature-dependent 119Sn Mossbauer effect (ME) spectroscopy has been used to elucidate the hyperfine parameters (isomer shift and quadrupole splitting) as well as the dynamics of the motion of tin in three triphenyltin phosphide complexes, namely P(SnPh3)3 (C54H45PSn3, 1), P7(SnPh3)3 (C54H45P7Sn3, 2), and [Na(benzo-15-crown-5)][P(SnPh3)2] (C50H50NaO5PSn2, 3), as well as in triphenyltin chloride (4). Although the isomer shifts are very similar for all four compounds, the quadrupole splitting is dependent upon their detailed structures. The metal atom vibrations are essentially isotropic with respect to the principal symmetry axis passing through the tin atom and the triphenyltin moiety. The crystal structure of triphenyltin chloride has been re-determined at four different temperatures, and the root-mean-square amplitudes-of-vibration of the metal atom have been evaluated from the crystallographic Ui,j values and compared with the corresponding data derived from the Mossbauer measurements. These metal atom dynamics have been compared with those of the stannyl phosphide complexes derived from ME data and related to their structural details. The sensitivity of the ME technique with respect to elucidating the metal atom dynamics is demonstrated in detail.

Metal atom dynamics of phthalocyanin tin complexes: SnPc and SnPc2

High purity samples of SnPc and SnPc2 (Pc=phthalocyanin, C32H16N82−) have been examined by temperature-dependent 119Sn Mössbauer effect (ME) spectroscopy in order to elucidate the metal atom dynamics over the temperature range 94<T<301K. Contrary to earlier reported data, the temperature-dependence of the recoil-free fraction, f, of the Sn atom is distinctly different for the two structures, and the root-mean-square-amplitude-of-vibration has been determined for the two Sn atom sites. The metal atom motion in SnPc is essentially isotropic over the above temperature range with respect to the symmetry axis involving the Pc ligand, the metal atom, and the lone pair of electrons.

Static and dynamic disorder in organotin compounds: A bis(amido)stannylene coordinated by N, N′-diisopropyl-1,8-diamidonaphthalene

The root-mean-square amplitude of vibration of the tin atom in the bis(amido)stannylene Sn[1,8-(N i Pr) 2C 10H 6] has been determined from temperature-dependent 119Sn Mössbauer effect measurements over the range 98 < T < 225 K and compared with the U i, j value extracted from a single crystal X-ray diffraction study. The large difference in these values (at 238 K) is associated with the flexibility in the bonding between the Sn center and chelating diamido ligand in this complex.

Bonding and Metal-Atom Dynamics in Two Unique Sn(I)−Sn(III) Complexes

Two recently reported tin complexes, which incorporate both Sn(I) and Sn(III) sites in their structure, have been examined by temperature-dependent 119Sn Mössbauer effect (ME) spectroscopy. The distinct hyperfine parameters of the two sites make it possible to assign relative occupancies of the two sites (at 90 K) on the basis of the recoil-free fraction data extracted from the ME spectra. The temperature dependencies of the recoil-free fractions, elucidated from the ME spectra, show that the metal-atom dynamics are very similar for the two sites in the temperature range 90<T<150 K.

Syntheses, crystal structures and coordination modes of tri- and di-organotin derivatives with 2-mercapto-4-methylpyrimidine

The organotin (IV) derivatives of 2-mercapto-4-methylpyrimidine (Hmpymt) R 3SnL (R = Ph 1, PhCH 2 2, n-Bu 3), R 2SnCl m L n ( m = 1, n = 1, R = CH 3 4, Ph 5, n-Bu 6, PhCH 2 7; m = 0, n = 2, R = CH 3 8, n-Bu 9, Ph 10, PhCH 2 11) were obtained by the reaction of the organotin(IV) chlorides R 3SnCl or R 2SnCl 2 with 2-mercapto-4-methylpyrimidine hydrochloride (HCl · Hmpymt) in 1:1 or 1:2 molar ratio. All complexes 1– 11 were characterized by elemental analyses, IR, 1H, 13C and temperature-dependent 119Sn NMR spectra. Except for complexes 3 and 6, the structures of complexes 1, 2, 4, 5, 7, 8– 11 were confirmed by X–ray crystallography. Including tin-nitrogen intramolecular interaction, the tin atoms of complexes 1– 7 are all five-coordinated and their geometries are distorted trigonal bipyramidal. While the tin atoms of complexes 8– 11 are six-coordinated and their geometries are distorted octahedral. Besides, the ligand adopts the different coordination modes to bond to tin atom between the complexes 1, 6, 7 and 2, 3, 4, 5, 8– 11. Furthermore, intermolecular Sn⋯N or Sn⋯S interactions were recognized in crystal structures of complexes 4, 7 and 11, respectively.

The O,C,O-Coordinating Pincer-Type Ligand {2,6-[P(O)(OEt)2]2-4-t-Bu-C6H2}- in Organotin Chemistry. Halide Exchange, Cyclization, and Novel Coordination Mode

Reactions in solution of the hypercoordinated organotin chlorides {2,6-[P(O)(OEt)2]2-4-t-Bu-C6H2}SnCl2X (X = Ph, Cl) with fluoride ions have been studied using temperature-dependent 119Sn and 31P N...

1,1′-Bis(stannyl)- and 1,1′-Bis(chlorostannyl)ferrocenes Studied by Multinuclear Magnetic Resonance, Temperature-Dependent 57Fe- and 119Sn-Mössbauer Spectroscopy, and Electrochemistry

The 1,1′-bis(chlorostannyl)-substituted ferrocenes Fe(C5H4–SnMe2Cl)2 (2), Fe(C5H4–SnMeCl2)2 (3) and Fe(C5H4–SnCl3)2 (4) were prepared, starting from 1,1′-bis(trimethylstannyl)ferrocene (1). Treatment of the chlorides with Li[AlH4] afforded the 1,1′-bis(hydridostannyl)-subsituted ferrocenes Fe(C5H4–SnMe2H)2 (5), Fe(C5H4–SnMeH2)2 (6) and Fe(C5H4-SnH3)2 (7), respectively. All complexes 1–7 were studied by 1H-, 13C-, and 119Sn-NMR spectroscopy with 1D and 2D techniques. The compounds 1–4 were investigated by temperature-dependent 119Sn- and 57Fe-Mössbauer spectroscopy. The electrochemistry of 1–5 gave evidence of reversible one-electron oxidation processes. The molecular structure of 1,1′-bis(trichlorostannyl)ferrocene (4) was determined by X-ray structural analysis, and there was no indication of intra- or intermolecular Sn···Cl···Sn interactions. This direct structural information proved to be consistent with both the Mössbauer and the solution NMR spectroscopic data.

Spectroscopic studies for adducts of 2-aminopyrimidine with tin(IV) halides and tin(II) chloride. Cis– trans isomerism in tetrabromobis(2-aminopyrimidine)tin(IV)

The complexes [SnCl 4(Apyrim) 2], 1, [SnBr 4(Apyrim) 2], 2 and [SnCl 2(Apyrim)] 2, 3, have been prepared and structurally characterized in the solid state by means of 119Sn Mössbauer spectroscopy, determination of lattice dynamics by temperature-dependent 119Sn Mössbauer spectroscopy, and by vibrational studies. Conductivity measurements and UV spectra in solution are also reported. A cis octahedral structure ( C 2) is proposed for [SnCl 4(Apyrim) 2] while for [SnBr 4(Apyrim) 2] both cis ( C 2) and trans ( C 2 h ) isomers are proposed to be present in the solid state, in an 1:1 molar ratio. An asymmetrically bridged dimer structure is proposed for [SnCl 2(Apyrim)] 2. From the variable-temperature Mössbauer effect, the Debye temperature for 1–3 were determined to be 150, 139 and 117, respectively. A computational study was attempted, utilizing a PM3 Hamiltonian in order to investigate the prevailing isomer of each of the studied species both in the gas phase and in simulated solvent bulk (COSMO model).

Pr 2Sn 2O 7 and Sm 2Sn 2O 7 as High-Temperature Shift Thermometers in Variable-Temperature 119Sn MAS NMR

Two shift thermometers have been developed in order to determine the exact sample temperature at elevated temperatures in MAS NMR. The probe was calibrated for different temperatures and bearing pressures using the structural phase transition NMR spectra of carbon tetrabromide (319.86 K), DABCO (351.08 K), rubidium nitrate (437 K), and lithium sodium sulfate (791 K). Temperature-dependent 119Sn MAS NMR spectra of Pr 2Sn 2O 7 and Sm 2Sn 2O 7 were then recorded. The temperature dependence is caused by the hyperfine interaction between the paramagnetic electron spin and the 119Sn nucleus. Pr 2Sn 2O 7 proved to be an extremely sensitive linear high-temperature shift thermometer: its sensitivity is 14.1 ppm/K at room temperature and 2.7 ppm/K at 790 K. Sm 2Sn 2O 7 also proved to be very sensitive to temperature, although its dependence was not linear. At room temperature its sensitivity is 1.1 ppm/K. The temperature dependence of the shift can be fitted to an equation derived from the Van Vleck equation, taking into account the ground and the first excited states of Sm 3+.

Synthesis and characterization of tin(IV) and organotin(IV) 1,4-dimethylpiperazine-2,5-dione (cyclosarcosylsarcosine) adducts

The complexes [{SnCl4(L)}n]1, (SnBuCl3(L)2]2 and [{SnR2Cl2(L)}n](R = Me 3 or Ph 4)[L = cyclosarcosylsarcosine (1,4-dimethylpiperazine-2,5-dione)] have been prepared and structurally characterized in the solid state by means of 119Sn Mossbauer spectroscopy, the determination of lattice dynamics by temperature-dependent 119Sn Mossbauer spectroscopy and by vibrational studies. The structure of complex 4 has been determined by X-ray crystallography and consists of infinite zigzag polymeric chains of trans-diphenyltin(IV) bridged by ketonic oxygen atoms. Each tin(IV) atom is surrounded by two carbons [Sn–C 2.129(7), 2.146(8)A; C–Sn–C 160.1 (3)°], two chlorides [Sn–Cl 2.450(2)A, Cl–Sn–Cl 98.5(1)°] and two oxygen atoms [Sn–O 2.370(6), 2.468(6)A; O–Sn–O 86.1(2)°]. Tin-119 Mossbauer and vibrational data are discussed in terms of the crystal structure and the proposed structures. From the variable-temperature Mossbauer effect, the Debye temperatures for 1–4 were determined to be 144, 102, 128 and 123 K respectively.

The configuration and lattice dynamics of complexes of dialkyltin(IV) with adenosine 5′-monophosphate and phenyl phosphates

The dialkyltin (IV) complexes of the mononucleotide adenosine 5′-monophosphate (AMP) and of phenyl phosphate, SnR2(AMP)·2H2O (R = Me or Bun) and SnR2[PO3(OPh)](R = Me, Et, or Bun), have been prepared and structurally characterized in the solid state by means of 119Sn Mössbauer spectroscopy, determination of lattice dynamics by temperature-dependent 119Sn Mössbauer spectroscopy, and by vibrational studies using conventional and Fourier-transform i.r. spectroscopy. The known diphenyl phosphate complexes SnR2[PO2(OPh)2]2(R = Me, Et, or Bun) have been similarly investigated, particularly with respect to their lattice dynamics. A distorted-octahedral configuration is proposed for the tin environment in the complexes SnR2(AMP)·2H2O (which appear to be phosphate-only bonded species) and SnR2[PO3(OPh)], involving a trifurcated oxygen atom and bent SnC2 skeletons; these units appear to be embedded into two-dimensional solid-state polymers originating from intermolecular bridging of the phosphate groups. The regular octahedral structure, with linear SnC2 skeletons, which has been inferred for the complexes SnR2[PO2(OPh)2]2, as well as their polymeric, sheet-like, nature, has been confirmed.

Lattice dynamics of alkali metal intercalated tin compounds from temperature dependent Mössbauer studies

Temperature dependent 119Sn Mössbauer Effect experiments have been carried out on SnS 2, SnS and a number of alkali-metal intercalated stannic sulfide absorbers over the temperature range 78 ≤ T ≤ 320°K. The intercalation of SnS 2 with Na and K in liquid ammonia at 295±5°K does not lead to a single intercalation phase, but rather to a complex system including SnS 2 (M) and reduced tin, primarily in the form of SnS. Approximate effective lattice temperatures for the three different tin sites in the complex solid have been estimated from the temperature dependence of the area under the resonance curve, making the free-atom mass assumption. Washing and annealing experiments on the alkali metal containing samples are also discussed.

Lattice dynamics of proton and gamma irradiated Nb3Sn from temperature dependent119Sn Mossbauer studies

Lattice dynamics of proton and gamma irradiated Nb3Sn from temperature dependent119Sn Mossbauer studies