SNX1 Research Articles

NH3(CH2)4NH3]SnX4 (X = Br, I): Dion-Jacobson type 2-D perovskites with short interlayer spacing.

Two-dimensional tin(II) halide perovskites stand as an environmentally benign alternative to Pb(II) halide perovskites. However, they are often challenging to make due to the oxidation of Sn(II) ion to more stable Sn(IV) ion. Here we report hybrid tin bromide and iodide perovskites: (1,4-BDA)Sn(IV)Br6 and (1,4-BDA)Sn(II)X4 (where X = Br, I; 1,4-BDA = 1,4-diammoniumbutane) with 0D and 2D structures, respectively. Their synthesis, structural characterization and photophysical properties are reported. They show bandgaps in the 1.94-2.70 eV range.

Expansion of the polynomial Set Sn(x1, x2, x3) in terms of Jacobi polynomials

Expansion of the polynomial Set Sn(x1, x2, x3) in terms of Jacobi polynomials

Preparation, characterization of mixed-valence antimony-tin phosphomolybdic polyoxometalates and application in the cyclohexanone oxidation in the presence of hydrogen peroxide

In this work, a series of polyoxometalates (POMs), as soluble salts of formula Sn1.5PMo12O40, SbPMo12O40 and H 3-x Sn x1 Sb x2 PMo 12 O 40 (x=2x 1 +3x 2 and x 1 , x 2 = 0–0.75) were synthesized using the cationic exchange method under stoichiometric conditions. They were characterized and tested in the oxidation of cyclohexanone using hydrogen peroxide in the absence of organic solvent, co-catalyst phase transfer compounds or surfactants. UV–Visible and X-ray photoelectron spectroscopic analyses showed a partially reduced state of POM with coexistence of the couples Mo(VI)/Mo(V), Sb(V)/Sb(III) and Sn(IV)/Sn(II), without affecting their structure, results confirmed by FT-IR and Raman spectroscopies. The reversible cyclic voltammetry analysis evidenced the valence change of the Mo species, Mo(VI)/Mo(V). The POMs are found to be active in the cyclohexanone oxidation reaction and among them the most efficient is H 0.75 Sb 0.75 PMo 12 O 40 with 49% of adipic acid yield.

Sn7Br10S2: The First Ternary Halogen‐Rich Chalcohalide Exhibiting a Chiral Structure and Pronounced Nonlinear Optical Properties

AbstractInfrared nonlinear optical (IR NLO) materials are significant in laser technology for civil and military uses. Here, we report the synthesis, structural chemistry and NLO properties of a halogen‐rich chalcohalide Sn7Br10S2. Its noncentrosymmetric (NCS, P63) structure can be considered as partially aliovalent anion substitution of SnBr2 (P63/m) induced centrosymmetric (CS) to NCS structural transformation. The 3D ∞[Sn(1)6Sn(2)6Br6X6]6− (X=Br/S) channel framework consists of Sn(1)BrX2 and Sn(2)X3 trigonal pyramids. It exhibits excellent NLO performance, including a strong phase‐matchable NLO response of 1.5 × AgGaS2and high laser‐induced damage threshold of 6.3 × AgGaS2.Investigation of the structure–NLO performance relationship confirms that the effective arrangement of Sn(1)BrX2 and Sn(2)X3 units predominantly contributes to the large SHG response. These results indicate Sn7Br10S2 is a potential IR NLO candidate and provides a new feasible system for promising NLO materials.

Sn7 Br10 S2 : The First Ternary Halogen-Rich Chalcohalide Exhibiting a Chiral Structure and Pronounced Nonlinear Optical Properties.

Infrared nonlinear optical (IR NLO) materials are significant in laser technology for civil and military uses. Here, we report the synthesis, structural chemistry and NLO properties of a halogen-rich chalcohalide Sn7 Br10 S2 . Its noncentrosymmetric (NCS, P63 ) structure can be considered as partially aliovalent anion substitution of SnBr2 (P63 /m) induced centrosymmetric (CS) to NCS structural transformation. The 3D ∞ [Sn(1)6 Sn(2)6 Br6 X6 ]6- (X=Br/S) channel framework consists of Sn(1)BrX2 and Sn(2)X3 trigonal pyramids. It exhibits excellent NLO performance, including a strong phase-matchable NLO response of 1.5 × AgGaS2 and high laser-induced damage threshold of 6.3 × AgGaS2 .Investigation of the structure-NLO performance relationship confirms that the effective arrangement of Sn(1)BrX2 and Sn(2)X3 units predominantly contributes to the large SHG response. These results indicate Sn7 Br10 S2 is a potential IR NLO candidate and provides a new feasible system for promising NLO materials.

Effects of the van der Waals Interactions on Structural and Electronic Properties of CH3NH3(Pb,Sn)(I,Br,Cl)3 Halide Perovskites.

In hybrid perovskite materials like CH3NH3PbI3, methylammonium (MA) lead iodide (MAPI), the orientation of the MA+ cations and their ordering can significantly affect the structure of the inorganic framework. Although the states near the band edges are known to be primarily derived from the Pb and halogen orbitals rather than from the organic ion, the latter may have an indirect effect through their impact on the structural relaxation. In this work, we investigate both the structural relaxation effects of the inorganic framework in response to the MA+ orientation and their impact on the electronic structure near the band edges. Calculations are performed for MA(Pb,Sn)X3 with (X = I, Br, and Cl) materials for both Pb- and Sn-based compounds. The work focuses on the high-temperature α-phase, which is nominally cubic if averaged over all possible MA orientations and in which no alternating rotations of the octahedral occur, so that the unit cell is the smallest possible. The effects of van der Waals (vdW) corrections to density functional theory on the structural relaxation are investigated. Our results reveal that the vdW interactions between the MA+ cation and the inorganic framework can strongly affect the optimized orientation and position of the molecule and the resulting distortion of the inorganic framework. Consequently, it also affects the electronic properties of the materials and specifically can change the band structure from direct to indirect band gaps. The robustness of this result is studied by comparing hybrid functional calculations and quasiparticle self-consistent GW calculations as well as spin–orbit coupling.

PROBABILITY MEASURES ON ℂ ARISING FROM THE JACOBI–SZEGÖ PARAMETERS FOR CONTINUOUS DUAL HAHN POLYNOMIALS

In this paper, we shall construct probability measures on ℂ, which can be expressed by the Mellin convolution product of the modified Bessel functions. Our measures on ℂ are related to the Jacobi–Szegö parameters for the continuous dual Hahn polynomials Sn(x2, a, b, c) under the special choice of parameters a, b, c. This paper contains new materials which go further than our previous results in Ref.7. The most interesting thing is that the Mellin convolution of two modified Bessel functions can again be expressed in terms of the modified Bessel functions, by choosing parameters a, b, c appropriately. The origin of our research in this direction goes back to the Bargmann–Fock representation of the classical non-Gaussian random variables.5–8 Our results would have a potential to be related to the higher powers of creation and annihilation operators acting on a new class of interacting Fock spaces.

NMR espectroscopic parameters of HX and Si (Sn)X4 (X = H, F, Cl, Br and I) and SnBr4−nIn model compounds

The NMR spectroscopic parameters are largely influenced by relativistic effects. They are highly dependent on the electronic behavior inside the spatial regions occupied by nuclei.Full relativistic calculations of indirect nuclear spin–spin couplings at random phase level of approach (RPA) in the title compounds with reoptimized Dyall cVTZ basis sets are given. A comparison with the results of calculations with other basis sets that are mostly used within the non-relativistic (NR) domain is presented. We analyzed the dependence of that couplings with the speed of light over the whole range of values, from the full relativistic to the NR regimes. Within this last regime, calculations at the second-order level of approach (SOPPA) indicated that electron correlation effects may not be as important for nuclear magnetic shieldings, but they must be included with care for J-coupling calculations. From these calculations, we determined that relativity enlarges the electron correlation effects of the J-couplings of HBr and HI.Because the results of nuclear magnetic shielding calculations within polarization propagators at the RPA level were reliable, we were able to show a new and easy procedure to obtain absolute nuclear magnetic shieldings on reference compounds for both Si and Sn nuclei: σ[Si(CH3)4]=421.28±29.33ppm and σ[Sn(CH3)4]=3814.96±79.12ppm. They were obtained from experimental chemical shifts and accurate nuclear magnetic shielding calculations on different molecular systems.

Synthesis, characterization and X-ray crystal structures of seven-coordinate pentagonal-bipyramidal zinc(II), cadmium(II) and tin(IV) complexes of a pentadentate N3S2 thiosemicarbazone

New complexes of the general formula, [M(H2dap4NMetsc)(H2O)2](NO3)2·H2O (M=Zn2+, Cd2+; H2dap4NMetsc=2,6-diacetylpyridinebis(4N-methylthiosemicarbazone) and [Sn((dap4NMetsc)X2] (X=Ph, Cl and I) (dap4NMetsc=the doubly deprotonated form of 2,6-diacetylpyridine bis(4N-methylthiosemicarbazone) have been synthesized and structurally characterized by a variety of physico-chemical techniques. X-ray crystallographic structure determination shows that in the zinc and cadmium complexes, the bis(thiosemicarbazone) ligand coordinates as a neutral N3S2 pentadentate chelating agent through the two azomethine nitrogen atoms, the pyridine nitrogen atom and the two thione sulfur atoms. The N3S2 donors of the ligand occupy the equatorial plane and the two aqua ligands occupy the sixth and seventh axial positions of the seven-coordinated cadmium(II) and zinc(II) ions. In the tin(IV) complexes, however, the thiosemicarbazone is coordinated to the tin(IV) ion as a dinegatively charged pentadentate chelating agent via the pyridine nitrogen atom, the two azomethine nitrogen atoms and the two thiolate sulfur atoms. The two apical positions of the seven-coordinate tin(IV) ion are occupied by either phenyl, chlorido or iodido ligands. In each of the complexes, the overall geometry adopted by the metal ion may be considered as a distorted pentagonal-bipyramid.

Preparations and Photosensitizing Properties of 2,7,12,17-Tetra-n-propylporphycenatotin(IV) Dihalide Complexes

Abstract 2,7,12,17-Tetra-n-propylporphycenatodihalotin(IV) complexes ([Sn(TPrPc)X2], X = F, Cl, and Br) were synthesized and their photophysical properties were investigated. These complexes exhibit strong absorptions in the red region (600–630 nm). Strong quenching was observed during the fluorescence emission of the dibromotin(IV) complex, which is caused by an intramolecular heavy-atom effect. The complexes emit NIR phosphorescence in 1-iodopropane at room temperature and the intensity of the emission of the dibromotin(IV) complex is found to be smaller than that of the dichlorotin(IV) complex. The quantum efficiency (ΦΔ) of generation of singlet oxygen using the dibromotin(IV) complex is the highest among the porphycenatotin(IV) complexes (ΦΔ = 0.79). Photooxidation of 1,3-diphenylisobenzofuran catalyzed by the complexes upon irradiation with red light (over 600 nm) was studied and a rapid oxidation of the substrate was observed when using the dibromotin(IV) complex.

Fourier transform Raman spectra of tin(IV) tetraphenylporphyrin complexes

Solid state non-resonance Raman spectra of a series of tin(IV) meso-tetraphenylporphyrin complexes Sn(TPP)X2, and the free ligand H2TPP, have been collected using 1064 nm laser excited Fourier transform Raman spectroscopy. The application of this technique to strongly coloured and fluorescent compounds is thereby demonstrated. The axial ligands X- include a set of eight O-bound anions of widely differing basicity, and the four halides. The relationships between Raman band frequencies and the nature of the axial ligands are examined. The data are compared with previously published empirical correlations between Raman frequencies and geometrical parameters.

The reaction of hexaphenylditin with inorganic acids: New mixed oxidation state compounds of Tin

The solvolysis of hexphenylditin by a variety of inorganic acids leads to the formation of compounds having the empirical formula SnX3. Tin-119 Mossbauer spectroscopy shows that these compounds should be formulated as Sn(II)Sn(IV)X6: in some of these compounds the non-bonding electron pair of the Sn(II) is stereochemically inactive.

Preparation, properties, and structures of bis(O-ethyl dithiocarbonato)-dihalogenotin(IV) and di-µ-thio-bis[bis(O-ethyl dithiocarbonato)tin(IV)

The complexes [Sn(S2COEt)2X2], X = Cl, Br, or I, have been isolated as stable crystalline compounds. The corresponding complexes [Sn(S2COEt)3X] and [Sn(S2COEt)X3] could not be isolated, it being postulated that the former rearranges to yield the dimeric compound [(EtOCS2)2SnS2Sn(S2COEt)2]. Structure determinations carried out by single-crystal X-ray diffraction methods of [Sn(S2COEt)2Br2] and [Sn(S2COEt)2l2] show that in both cases the tin atom is six-co-ordinate with the halide atoms cis(Sn–Br, l = 2.54, 2.75 A). The mutually trans Sn–S distances in each complex are shorter (2.52 A) than the Sn–S distances trans to the halide [2.59 (bromide), 2.64 A(iodide)]. For [Sn(S2COEt)2Br2], the cell is monoclinic, space group C2/c, with a= 14.27(1), b= 16.894(8), c= 6.360(5)A, β= 100.41 (5)°, Z= 4; R was 0.037 for 1 342 ‘observed’ reflections. For [Sn(S2COEt)2l2], the cell is monoclinic, space group P21/n, with a= 14.026(6), b= 11.210(4), c= 10.203(4)A, β= 91.96(3)°; Z= 4, R being 0.030 for 2 512 ‘observed’ reflections.

Tin(IV) Halide Chelates with 2,2′-Bipyridine N-Oxide

Abstract 2,2′-Bipyridine N-oxide(N-bipyO) yields 1:1 complexes with SnCl4 and SnBr4 and a 3:1 complex with SnI4, by interaction between ligand and salt solutions in carbon tetrachloride. Characterization studies of these complexes led to their formulation as cis-[Sn(N-bipyO)X4] (X=Cl or Br) and [Sn(N-bipyO)3]I4. N-bipyO functions as a bidentate O,N-chelating agent in these complexes, coordinating through the N[sbnd]O oxygen and through the nitrogen of the pyridine fragment.

On theT-ideal generated by a standard identity

We determine the structure of the ideal of identities of degreen +1 in theT-ideals To(sn(x1,…,xn)) and To(un(x1,…,xn)), wheres n is the standard identity and un the unitary identity of degreen.