Structural investigations on diorgano- and triorganotin(IV) derivatives of [meso-tetra(4-sulfonatophenyl)porphine] metal chlorides

Several new complexes of organotin(IV) moieties with MCl_n[meso-tetra(4-sulfonatophenyl)porphine], (R₂Sn)₂MCl_n[meso-tetra(4-sulfonatophenyl)-porphinate]s and (R₃Sn)₄MCl_n [meso-tetra(4-sulfonatophenyl)porphinate]s, [M = Fe(III), Mn(III): n = 1, R = Me, n-Bu; Ph; M = Sn(IV): n = 2, R = Me, n-Bu] have been synthesized and their solid state configuration investigated by infrared (IR) and Mössbauer spectroscopy, and by ¹H and ¹³C NMR in D₂O.The electron density on the metal ion coordinated inside the porphyrin ring is not influenced by the organotin(IV) moieties bonded to the oxygen atoms of the side chain sulfonatophenyl groups, as it has been inferred on the basis of Mössbauer spectroscopy and, in particular, from the invariance of the isomer shift of the Fe(III) and Sn(IV) atoms coordinated into the porphyrin square plane of the newly synthesized complexes, with respect to the same atoms in the free ligand.As far as the coordination polyhedra around the peripheral tin atoms are concerned, infrared spectra and experimental Mössbauer data would suggest octahedral and trigonal bipyramidal environments around tin, in polymeric configurations obtained, respectively, in the diorganotin derivatives through chelating or bridging sulfonate groups coordinating in the square plane, and in triorganotin(IV) complexes through bridging sulfonate oxygen atoms in axial positions.The structures of the (Me₃Sn)₄Sn(IV)Cl₂[meso-tetra(4-sulfonatophenyl)porphinate] and of the two model systems, Me₃Sn(PS)(HPS) and Me₂Sn(PS)₂ [HPS = phenylsulfonic acid], have been studied by a two layer ONIOM method, using the hybrid DFT B3LYP functional for the higher layer, including the significant tin environment. This approach allowed us to support the structural hypotheses inferred by the IR and Mössbauer spectroscopy analysis and to obtain detailed geometrical information of the tin environment in the compounds investigated.¹H and ¹³C NMR data suggested retention of the geometry around the tin(IV) atom in D₂O solution.     

Five new dicarboxylate organotin complexes under hydrothermal condition: Syntheses, characterization and crystal structures of 1D, 2D and 3D polymers constructed from dimeric tetraorganodistannoxane units

Five new diorganotin(IV) complexes of the types {(Me₂Sn)₂[μ₄-(C₈H₃NO₆)](μ₃-O)}_n (1), {(Me₂Sn)₂[μ₃-(C₈H₈O₄)](μ₃-O)}_n (2), {(Me₂Sn)₂[μ₄-(C₈H₁₀O₄)](μ₃-O)}_n (3) {(Me₂Sn)₂[μ₄-(C₈H₁₀O₄)](μ₃-O)}_n (4) and {(Me₂Sn)₂[μ₄-(C₁₀H₁₄O₄)](μ₃-O)}_n (5) have been synthesized by reactions of 5-nitroisophthalic acid, meso-cis-4-cyclohexene-1,2-dicarboxylic, meso-cis-1,4-cyclohexanedicarboxylic acid, meso-cis-1,3-cyclohexanedicarboxylic acid and chiral cis-(1R,3S)-(+)-camphoric acid with trimethyltin chloride under hydrothermal condition. All complexes were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, ¹¹⁹Sn NMR and X-ray crystallography. The structural analyses show that complex 1 has a 1D infinite polymeric chain in which 5-nitroisophthalic acid acts as a tetradentate ligand coordinating to dimethyltin(IV) ions, complexes 2, 3 and 4 possess 2D polymeric structures in which dicarboxylate acid act as tridentate or tetradentate ligands coordinating to dimethyltin(IV) ions, complex 5 possesses a irregular 3D framework in which chiral cis-(1R,3S)-(+)-camphoric acid acts as a tetradentate ligand coordinating to dimethyltin(IV) ions.     

Solid-state anion interactions in the diastereoisomers of dinuclear ruthenium complexes based on 2,2′-bipyrimidine

The cations in the solid-state structures of meso-(ΛΔ)-[{Ru(bpy)₂}₂(μ-bpm)](PF₆)₄, meso-(ΛΔ)-[{Ru(Me₂bpy)₂}₂(μ-bpm)](tos)₄ · 2CH₃OH · 4H₂O and meso-(ΛΔ)-[{Ru(Me₄bpy)₂}₂(μ-bpm)](tos)₄ · 26H₂O (bpm = 2,2′-bipyrimidine; bpy = 2,2′-bipyridine; Me₂bpy = 4,4′-dimethyl-2,2′-bipyridine; Me₄bpy = 4,4′,5,5′-tetramethyl-2,2′-bipyridine; tos⁻ = toluene-4-sulfonate anion) exhibit similar features including comparable bond lengths and angles, and metal–metal separations of 5.56–5.59 Å. The counter-ions present in the structures reside in the clefts above and below the plane of the bridging ligand, but show considerable variation in location compared with their known occupancy in solution.     

Trimethylstannyl- und Dimethylstannyl-substituierte Pyrrole – Synthesen,Spektren und Strukturen

Trimethylstannyl- and Dimethylstannyl-substituted Pyrroles – Synthesis, Spectra, and Structures Monomeric trimethylstannyl pyrroles, Me₃Sn? R (Me = CH₃ and R = ? NC₄H₄, ? NC₄H₂Me₂-2,5, ? NC₄Me₄-2,3,4,5, ? C₄H₃NMe-1), are synthesized by metathesis reactions from Me₃SnCl with 1(N)- and 2(C)-lithium pyrroles, respectively. An almost similar procedure gives monomeric dimethylstannylbis(pyrroles), Me₂SnR₂ ( 1 a – 3 a ), from Me₂SnCl₂ and 1-Li-pyrrolides (1 : 2 molar ratio) in good yields. Lithiated 1,2,5-trimethylpyrrole and Me₃SnCl forms the compound Me₃Sn? CH₂? C₄H₂Me(-5)NMe ( 8 ), the reaction of Me₂SnCl₂ with 2-lithium-1-methylpyrrole gives oligomeric [Me₂Sn? C₄H₂NMe? ]_x, ( 6 a ). The mass-, NMR, and vibrational spectra have been measured and discussed. The results of the X-ray structure determinations of Me₃Sn? NC₄H₄ ( 1 ) and Me₂Sn(? NC₄Me₄)₂ ( 3 a ) are compared with the structures of the known dimethylmetal pyrroles of Al, Ga, and In.     

Syntheses of rac/meso-{PhP(3-t-Bu-C5H3)2}-Zr{RN(CH2)3NR}, structural analyses of rac-{PhP(3-t-Bu-C5H3)2}Zr{RN(CH2)3NR} (where R is SiMe3 or Ph), and meso to rac isomerization

Syntheses of rac/meso-{PhP(3-t-Bu-C₅H₃)₂}Zr{Me₃SiN(CH₂)₃NSiMe₃} (rac-3/meso-3) and rac/meso-{PhP(3-t-Bu-C₅H₃)₂}Zr{PhN(CH₂)₃NPh} (rac-4/meso-4) were achieved by metallation of K₂[PhP(3-t-Bu-C₅H₃)₂] · 1.3 THF (2) with Zr{RN(CH₂)₃NR}Cl₂(THF)₂ (where R = SiMe₃ or Ph, respectively) using ethereal solvent. These isomeric pairs were characterized by ¹H, ¹³C{¹H}, and ³¹P{¹H} NMR spectroscopy; rac-3 and rac-4 were also examined via single crystal X-ray crystallography. The structures of rac-3 and rac-4 are notable in the tendency of the cyclopentadienyl rings towards η³ coordination. While isolated samples of rac-3/meso-3 and rac-4/meso-4 slowly isomerize in tetrahydrofuran-d₈ to equilibrium ratios, the isomerization rate for 3 is more than 15-fold greater than that for 4. In addition, equilibrium ratios are rapidly reached when isolated samples of rac-3/meso-3 and rac-4/meso-4 are exposed to tetrabutylammonium chloride in tetrahydrofuran-d₈ solvent. We propose that a nucleophile (either chloride or the phosphine interannular linker) brings about dissociation of one cyclopentadienyl ring, thus promoting the rac/meso isomerization mechanism.     

Diamino-di-tert-butylsilane als Bausteine cyclischer (SiN)2−, (SiNBN)2−, (SiN2Sn)- und spirocyclischer (SiN2)2Si-, (SiN2Sn)2S-Verbindungen

Diamino-di-tert-butylsilanes - Building Blocks for Cyclic (SiN)₂, (SiNBN)₂, (SiN₂Sn), and Spirocyclic (SiN₂)₂Si, (SiN₂Sn)₂S Compounds The aminochlorosilanes (Me₃C)₂SiClNHR ( 1 : R?H, 2 : R?Me) are obtained by the ammonolysis ( 1 ) respectively aminolysis ( 2 ) of di-tert-butyldichlorosilane in the n-hexane. The dilithium derivative of diamino-di-tert-butylsilane reacts with FSiMe₂R′ ( 3 : R′?Me, 4 : R′?F) in a molar ratio 1 : 2 to give the 1,3,5-trisilazanes 3 and 4 , (Me₃C)₂SiNHSiMe₂R′, in a molar ratio 1 : 1 with F₃SiN(SiMe₃)₂ to give the 1,3-diaza-2,4-disilacyclobutane 5 , (Me₃C)₂Si(NH)₂SiFN(SiMe₃)₂, and with F₂BN(SiMe₃)₂ to give the 1,3,5,7-tetraaza-2,6-dibora-4,8-disilacyclooctane 6 , [(Me₃C)₂SiNH-BN(SiMe₃)₂-NH]₂. The dilithium derivative of di-tert-butyl-bis(methylamino)silane reacts with SiF₄ with formation of the 1,3,5-trisilazane 7 , (Me₃C)₂Si(NMeSiF₃)₂, and the spirocycic compound 8 , [(Me₃C)₂Si(NMe)₂]₂Si, with SnCl₂ the cyclosilazane 9 , (Me₃C)₂SiNMe₂ is obtained. The dilithium derivative of 3 reacts with SnCl₂ to give the cyclo-1,3-diaza-2-sila-4-stannylen 10 , (Me₃C)₂Si(NSiMe₃)₂Sn. The oxidation of 10 with elemental sulfur leads to the formation of the spirocyclus 11 , [(Me₃C)₂Si(NSiMe₃)₂SnS]₂.     

The molecular and electronic structure of radical cations derived from tetramethyltin and hexamethylditin: An SCF-MO study

Molecular geometries and energies have been calculated, using the semi-empirical MNDO method for the closed-shell species SnMe₄, Sn₂Me₆, and (SnMe₃)⁺; and using the UHF-MNDO method for the radicals (SnMe₄)⁺, (Sn₂Me₆)⁺ and SnMe₃^.. The radical cation (SnMe₄)⁺ is calculated to have C_3v skeletal symmetry, with a C_2v isomer some 15 kJ mol^?1 higher in energy. The dinuclear radical cation (Sn₂Me₆)⁺ is calculated to be a σ(SnSn) radical, of D_3d skeletal symmetry: although the calculated Sn(5s) spin density is extremely low, the tin atoms are far from planarity. Calculated spin densities are compared with experimental hyperfine couplings.     

Die molekül- und kristallstruktur von trimethylzinnazid Me3SnN3

The electrophilic cleavage reaction of (Me₃Sn)₂CN₂ with the Me₃SiN₃ in diluted ethereal solution affords well-formed crystals of Me₃SnN₂ in excellent yield; the azide was investigated by single crystal X-ray methods. Me₃SnN₃ crystallizes in the pseudohexagonal space group P2/b2/n2₁/n with Z = 4, d_c = 1.960 g cm^?3; a = 1172.5(6); b = 679.5(4); c = 875.5(5) pm; V = 697.55 ų.A total of 480 unique non-zero reflections was obtained at room temperature; refining the structure with anisotropic temperature factors for all non-hydrogen atoms and with isotropic temperatures factors for the hydrodgen atoms resulted in a conventional R-value of 0.024. Exactly planar Me₃Sn-groups are linked in zig-zag-chains by linear N₃-groups while the tin atoms adopt almost ideal symmetric trigonal bipyramidal coordination; the methyl groups of the Me₃Sn moieties are arranged in a staggered conformation along the c-axes.     

Synthetic, structural and biological studies of organotin(IV) complexes of schiff bases derived from pyrrol-2-carboxaldehyde

Some new organotin(IV) complexes having general formulae R₂MCl[L] and R₂M[L]₂ were synthesized by the reactions of Me₂MCl₂ with Schiff bases [5-Mercapto-4-(pyrrolcarboxalideneamino)-s-triazole, 5-Mercapto-3-methyl-4-(2-pyrrolcarboxalideneamino)- s-triazole, 3-Ethyl-5-mercapto-4-(2-pyrrolcarboxalideneamino)-s-triazole] in 1:1 and 1:2 molar ratios. All of the compounds were characterized by elemental analysis, molar conductance, IR, UV, ¹H, ¹³C and ¹¹⁹Sn NMR spectral studies. The IR and ¹H NMR spectral data suggest the involvement of azomethine nitrogen in coordination with the central metal atom. With the help of the above-mentioned spectral studies, penta and hexacoordinated environments around the central metal atoms in the 1:1 and 1:2 complexes, respectively, have been proposed. Finally, the free ligands and their metal complexes were tested in vitro against some pathogenic bacteria and fungi to assess their antimicrobial properties.     

Speciation and NMR Spectrometric Studies of Interaction of Di- and Tri-organotin(IV) Moieties with 5′-Guanosine Monophosphate and Guanosine in Aqueous Solution

Potentiometric studies of the interaction of (Me₂Sn)²⁺ and (Me₃Sn)⁺ with 5′-guanosine monophosphate [(5′-HGMP)^2?, abbreviated as (HL-1)^2?] and guanosine [(HGUO), abbreviated as (HL-2)] in aqueous solution (I = 0.1 mol·dm^?3 KNO₃, 298.15 ± 0.1 K) were performed, and the speciation of various complex species was evaluated as a function of pH. The species that exist at physiological pH ~7.0 are Me₂Sn(HL-1)/[Me₂Sn(HL-2)]²⁺ (87.0/88.8 %), [Me₂Sn(HL-1)(OH)]^?/[Me₂Sn(HL-2)(OH)]⁺ (3.0/0 %) and [Me₂Sn(HL-1H_?1)]/[Me₂Sn(HL-2H_?1)]²⁺ (9.4/6.6 %) for 1:1 dimethyltin(IV):5′-guanosine monophosphate/dimethyltin(IV): guanosine systems, whereas for the corresponding 1:2 systems, the species are Me₂Sn(HL-1)/[Me₂Sn(HL-2)]²⁺ (44.0/92.0 %), [Me₂Sn(HL-1H_?1)]/[Me₂Sn(HL-2H_?1)]²⁺ (5.0/6.0 %), Me₂Sn(OH)₂ (49.0/0 %), [Me₂Sn(HL-1)(OH)]^?/[Me₂Sn(HL-2)(OH)]⁺ (1.5/2.0 %), and [Me₂Sn(OH)]⁺ (1.0/0 %). For 1:1 trimethyltin(IV):5′-guanosine monophosphate/trimethyltin(IV):guanosine systems, only [Me₃Sn(HL-1)]^?/[Me₃Sn(HL-2)]⁺ (99.9 %) are found at pH = 7.0, whereas for 1:2 systems, [Me₃Sn(HL-1)]^?/[Me₃Sn(HL-2)]⁺ (49.8/100 %), Me₃Sn(OH) (15.0/0 %) and [Me₃Sn(HL-1)(OH)]^2?/Me₃Sn(HL-2)(OH) (0.2/0 %) are the species found. No polymeric species were detected. Beyond pH = 8.0, significant amounts of [Me₂Sn(OH)]⁺, Me₂Sn(OH)₂, [Me₂Sn(OH)₃]^? and Me₃Sn(OH) are formed. Multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR studies at different pHs indicated a distorted octahedral geometry for the species Me₂Sn(HL-1)/[Me₂Sn(HL-2)]²⁺ in dimethyltin(IV)-(HL-1)^2?/(HL-2) systems and a distorted trigonal bipyramidal/distorted tetrahedral geometry for the species [Me₃Sn(HL-1)]^?/[Me₃Sn(HL-2)]⁺ in trimethyltin(IV)-(HL-1)^2?/(HL-2) systems.     

CIDNP 1H study of the photolysis of 7-sila- and 7-germa-norbornadienes

The photochemical decomposition of 7-sila- and 7-germa-norbornadienes (Ia,b) was studied by the CIDNP ¹H technique. The reactions proceeds by a two-step mechanism via the reversible formation of singlet biradicals, II. The triplet biradical (II), formed as a result of S-T conversion of (II)(S), irreversibly decomposes giving Me₂E (E = Si, Ge). The insertion of Me₂E into the CBr bond of PhCH₂Br and the SnCl bond of Me₃SnCl occurs via a radical mechanism, as deduced from the CIDNP effects observed in these reactions.     

Die chemie der schweren carben-analogen R2M,M = Si,Ge, Sn: XI. Reaktionen von thermisch erzeugten dimethylsilylen mit CC-mehrfachbindungen

Phenylated alkynes form 1,4-disila-cyclohexadienes (VIII–X) with thermally generated Me₂Si (200°C). Bulky substituents (CMe₃, SiMe₃) prevent the addition. The strained cycloalkyne, 3,3,6,6-tetramethyl-1-thia-cycloheptyne-4 (XI), however, yields the known silirene XII (2,2,6,6,8,8-hexamethyl-8-sila-4-thia-bicyclo[5.1.0^Δ1.7]octane); its transformation to the 1,4-disila-cyclohexadiene is prevented by steric effects. Thermally stable, 1,3-dienes give, depending on their substitution pattern, 1-sila-cyclopentenes-2 or -3. A mechanism is proposed giving the observed products via an initial 1,2-addition.     

Synthesis and properties of cross-conjugated ��,�ء�-bis-dimethylamino ketones and dinitriles with N-acetyl- and N-benzylpiperidine cycles

Reactions of N-acetyl- and N-benzyl-4-piperidones with aminal of ??-dimethylaminoac-rolein yielded ketocyanines bearing piperidine cycle. Reaction of 3-dimethylamino-1,1,3-trimethoxypropane with 1-acetylpiperidin-4-ylidenemalononitrile in the presence of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄), resulted in cross-conjugated ??,???-dimethylamino dinitrile. Protonation of ketocyanines bearing N-acetyl- and N-benzyl-piperidine cycles with Et₂O·HBF₄ (1 equiv.) furnished piperidinium salts, while protonation of the latter with Et₂O·HBF₄ (2 equiv.) afforded doubly charged 4-hydroxypolymethine salts. Unlike protonation, reaction of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-acetylpiperidin-4-one with Me₂SO₄ involved only the oxygen atom and led to a singly charged 4-methoxypolymethine salt. Methylation of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-benzylpiperidin-4-one with Me₂SO₄ (1 equiv.) involved cyclic nitrogen atom and resulted in piperidinium salt; heating of the latter with the excess of Me₂SO₄ afforded doubly charged bis-methoxysulfonate. Starting from 4-methoxytetrahydropyridinium salts, meso-methoxythiapentacarbocyanine dyes were synthesized.     

Hexaorgano-substituted triatomics R3XYZR3: the configurations of organometallic sulphides (R3M)2S and the crystal and molecular structure of thio-bis[triphenyltin(IV)]

Crystals of thio-bis[triphenyltin(IV)], S(Ph₃Sn)₂, are orthorhombic, space-group P2₁2₁2₁, with a = 18.469(5), b = 17.648(5), c = 9.848(6) Å and Z = 4. The SnS distances are 2.405(9) and 2.417(7) Å and SnSSn angle is 107.3(2)°: there are no anomalous features in the structure analogous to those in O(Ph₃Sn)₂-MNDO calculations for a series of organometallic sulphides (Me₃M)₂S⁺ⁿ (M = Be, B, C, N, Si, P) indicate that the inversion barrier to linearity increases monotonically, and the skeletal bending force constant at linearity decreases correspondingly as the group Me₃M becomes more electro-negative.     

Synthesis, structural characterization and reactivity of new tin bridged ansa-bis(cyclopentadiene) compounds: X-ray crystal structures of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)

The organo-tin compounds, Me₂Sn(C₅H₄R-1)₂ (R = Me (1), Prⁱ (2), Bu^t (3), SiMe₃ (4)) and Me₂Sn(C₅Me₄R-1)₂ (R = H (5), SiMe₃ (6)), were prepared by the reaction of Me₂SnCl₂ with the lithium or sodium derivative of the corresponding cyclopentadiene. Compounds 1-6 have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn). In addition the molecular structures of 5 and 6 were determined by single crystal X-ray diffraction studies. The transmetalation reaction of 1-6 with ZrCl₄ or [NbCl₄(THF)₂] gave the corresponding metallocene complexes in high yields.     

Tin-element exchange: Formation and multinuclear NMR characterisation of mixtures of the type C(SnMe3)n(MMe3)4-n (M = Si,Pb; n = 0–3)

Treatment of tetrakis(trimethylstannyl)methane with one equivalent of methyllithium followed by one equivalent of Me₃MCl gives mixtures of the type C(SnMe₃)_n(MMe₃)_4-n (M = Si, Pb; n = 0?3), which have been characterised by multinuclear (¹³C, ²⁹Si, ¹¹⁹Sn, ²⁰⁷Pb) NMR. The main component (ca. 40%) is in each case (Me₃Sn)₃ CMMe₃, but considerable amounts of the other tetrametallamethanes are also present.     

Asymmetric ring opening of meso-epoxides with B-halobis(2-isocaranyl)boranes 2-dIcr2BX

Hydroboration of commercially available (+)-2-carene (96% ee) with either BH₂Cl·SMe₂ or BCl₃/Me₃SiH, provides chemically pure B-chlorobis(2-isocaranyl)borane (2-^dIcr₂BCl) whereas B-bromobis(2-isocaranyl)borane (2-^dIcr₂BBr) could only be prepared by Matteson’s BBr₃/Me₃SiH procedure in high chemical yield and purity. The enantiomeric excess achieved with 2-^dIcr₂BCl (78%), was significantly higher than those realized with the previously explored reagent, ^dIpc₂BCl (41%), especially for meso-cyclohexene oxide. The new reagent, 2-^dIcr₂BBr also showed considerable improvements in enantiomeric excesses, in the cases of meso-cyclopentene oxide (67%) and meso-cis-2,3-butene oxide (78%) than those achieved with the previously reported reagent, ^dIpc₂BBr (57% and 61%, respectively).     

The crystal structure of triphenyltin isothiocyanate

The crystal structure of Ph₃SnNCS has been determined by single crystal X-ray diffraction. The crystals are monoclinic, P2₁, a = 19.02(3), b = 11.67(2), c = 15.49(2)Å;, β = 95.64(10)°, Z = 8. The molecules are arranged in infinite zig-zag S…SnNCS…Sn&.sbnd; chains similar to those in Me₃SnNCS, but with slightly longer SnN, shorter SnS bonds, and almost planar SnC₃ units. Principal mean bond lengths and angles are: SnN, 2.22(5); NC, 1.17(8); CS, 1.58(7); SSn, 2.92(1); SnC, 2.09(3); CC, 1.38(2)Å; SnNCm 161(4); CSSn, 97(3); SSnN, 175(3) and CSnC, 119.8(1.5)°.     

Synthesis of mono meso-pyridyl 21,23-dithiaporphyrins and unsymmetrical non-covalent porphyrin dimers

A new method has been developed to synthesize 21,23-dithiaporphyrins having one pyridyl group at the meso position. The method required easily available unknown precursors and the condensation resulted in mono meso-pyridyl 21,23-dithiaporphyrins as single products in 8-11% yield. Two of the three mono meso-pyridyl N₂S₂ porphyrins were used to synthesize non-covalent unsymmetrical porphyrin dimers containing one N₂S₂ and one N₄ porphyrin cores.