The dynamics of (57)Fe nuclei in Fe(III)-DNA condensates.

2001

Abstract The dynamics of iron nuclei in the condensates obtained by interaction of Fe III with DNA, Fe III (DNA monomer) 2 , have been investigated by variable temperature 57 Fe Mossbauer spectroscopy. Studies were effected on gel and freeze-dried samples, obtaining nearly coincident values of the parameters isomer shift and nuclear quadrupole splitting in T ranges 20–260 K. Functions ln( A T / A 77.3 ) vs. T , here employed to investigate the dynamics of Fe nuclei, showed linear trends in the T ranges 20–150 and 150–260 K, respectively, the latter with larger slopes. Data coincided for gelled and freeze-dried specimens. No variation of δ or Δ E parameters occurred at the two T intervals, w…

Synthesis and spectroscopic characterization of diethyltin (IV) derivatives of dipeptides: Crystal and molecular structure of diethyltin glycyltrosin…

1992

Dipeptide complexes of the diethyltin(IV) moiety, Et2SnL, have been synthesized, H2L being glycylglycine (H2GlyGly), glycylalanine (H2GlyAla), alanylalanine (H2AlaAla), glycylvaline (H2GlyVal), valylvaline (H2ValVal), glycylmethionine (H2GlyMet), glycyltyrosine (H2GlyTyr). The crystal and molecular structure of the complex Et2SnGlyTyr has been determined by singlecrystal X-ray diffraction. It consists of monomeric units, with the tin atom having a considerably distorted trigonal bipyramidal environment. The dipeptide acts as a tridentate ligand bonding the tin of the C2Sn fragment (equatorial carbon atoms) with the peptide nitrogen atom (equatorial) and axial (monodentate) carboxyl oxygen a…

Synthesis of polymeric alkoxides from dialkyltin(IV) oxides and chloral, and their characterization by mössbauer and infrared spectroscopy

1979

Abstract The reaction of (Alk2SnO)n with OCH·CCl3 gives compounds of elemental formula Alk2SnOCH- (CCI3)O (Alk = Bun, Octn), probably by addition of the Sn-O bond to the carbonyl group. Mossbauer parameters suggest the occurrence of five-coordinated Sn, and polymeric structures with bridging three- coordinating oxygens are proposed. The assumption that C2SnO3 units with trigonal bipyramidal type structures are present is consistent with point-charge model rationalization of the quadrupole splitting. Infrared spectra are in keeping with the proposed structures, suggesting, inter alia, bent C Sn C skeletons, but the analysis of possible ν(Sn-O) modes does not provide conclusive evidence for t…

Synthesis and spectroscopic characterization of R3SnIV derivatives ofN-acetyldipeptides

1993

Triorganotin(IV) derivatives of N-acetyldipeptides R3SnAcDip; RMe, Et, n-Bu, n-Oct, Cy or Ph (HAcDipN-acetylglycylglycine and N-acetylglycylvaline; RMe, n-Bu, Cy, HAcDipN-acetylglycylalanine) were obtained by neutralization of R3SnOH and HAcDip. The complexes were studied by means of 119Sn Mossbauer, IR and 1H, 13C and 119Sn NMR spectroscopy. The CSnC bond angles have been inferred by rationalization of Mossbauer nuclear quadrupole splittings as well as from NMR coupling constants. Correlations of Mossbauer isomer shifts with partial atomic charges on tin atoms have been determined: Polymeric trigonal bipyramidal structures, with near-planar R3Sn units and axial carboxylate (unidentate) and…

The interaction of native DNA with iron(III)- N ,N'-ethylene-bis(salicylideneiminato)-chloride.

2004

Abstract The interaction between native calf thymus deoxyribonucleic acid (DNA) and Fe III - N , N ′ -ethylene-bis (salicylideneiminato)-chloride, Fe(Salen)Cl, was investigated in aqueous solutions by UV–visible (UV–vis) absorption, circular dichroism (CD), thermal denaturation and viscosity measurements. The results obtained from CD, UV–vis and viscosity measurements exclude DNA intercalation and can be interpreted in terms of an electrostatic binding between the Fe(Salen) + cation and the phosphate groups of DNA. The trend of the UV–vis absorption band of the Fe(Salen)Cl complex at different ratios [DNA phosphate ]/[Fe(Salen)Cl] and the large increase of the melting temperature of DNA in …

Crystal and solution structures of di-n-butyltin(IV) complexes of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol and benzoic acid derivatives: E…

2009

Abstract Reactions of nBu2SnCl(L1) (1), where L1 = acid residue of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol, with various substituted benzoic acids in refluxing toluene, in the presence of triethylamine, yielded dimeric mixed ligand di-n-butyltin(IV) complexes of composition [nBu2Sn(L1)(L2–6)]2 where L2 = benzene carboxylate (2), L3 = 2-[(E)-2-(2-hydroxy-5-methylphenyl)-1-diazenyl]benzoate (3), L4 = 5-[(E)-2-(4-methylphenyl)-1-diazenyl]-2-hydroxybenzoate (4), L5 = 2-{(E)-4-hydroxy-3-[(E)-4-chlorophenyliminomethyl]-phenyldiazenyl}benzoate (5) and L6 = 2-[(E)-(3-formyl-4-hydroxyphenyl)-diazenyl]benzoate (6). All complexes (1–6) have been characterized by elemental analyses, IR, 1H,…

7-Amino-2-methylsulfanyl-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxylic acid as the dimethylformamide and water monosolvates at 293 K.

2010

The molecular structure of 7-amino-2-methylsulfanyl-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxylic acid is reported in two crystal environments, viz. as the dimethylformamide (DMF) monosolvate, C(7)H(7)N(5)O(2)S·C(3)H(7)NO, (I), and as the monohydrate, C(7)H(7)N(5)O(2)S·H(2)O, (II), both at 293 (2) K. The triazolo[1,5-a]pyrimidine molecule is of interest with respect to the possible biological activity of its coordination compounds. While the DMF solvate exhibits a layered structural arrangement through N...O hydrogen-bonding interactions, the monohydrate displays a network of intermolecular O...O and N...O hydrogen bonds assisted by cocrystallized water molecules and weak π-π stacking intera…

(S)-2-[(2-Hydroxybenzyl)azaniumyl]-4-(methylsulfanyl)butanoate

2011

The zwitterionic title compound, C12H17NO3S, is a reduced Schiff base derived from (S)-N-(2-hydroxybenzylidene)methionine. An intramolecular interaction between the N—H and carboxylate groups forms a roughly planar (r.m.s. deviation = 0.1405 Å) five-membered ring containing the H(N), N, Cα, C(carboxylate) and O atoms in a pentagonal conformation. In the crystal, a supramolecular triangle-shaped motif is generated by molecules held together by O—H...O and N—H...O hydrogen bonds.

Self-assembly of extended Schiff base amino acetate skeletons, 2-{[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)]amino}phenylpropionate and 2-{[(E)-1-(2-h…

2007

The organotin(IV) compounds, [Ph 3 SnL 1 H] n  · nCCl 4 ( 1 ), [Me 2 SnL 2 (OH 2 )] ( 2 ), [ n Bu 2 SnL 2 ] ( 3 ), [Ph 2 SnL 2 ] n ( 4 ), [Ph 3 SnL 2 H] n ( 5 ) and [Ph 3 SnL 3 H] n ( 7 ) (L 1  = 2-{[(2 Z )-(3-hydroxy-1-methyl-2-butenylidene)]amino}phenylpropionate and L 2−3  = 2-{[( E )-1-(2-hydroxyaryl)alkylidene]amino}phenylpropionate), were synthesized by treating the appropriate organotin(IV) chloride(s) with the potassium salt of the ligand in a suitable solvent, while [ n Bu 2 SnL 3 (OH 2 )] ( 6 ) was obtained by reacting the acid form of L 3 (generated in situ) with n Bu 2 SnO. These complexes have been characterized by 1 H, 13 C, 119 Sn NMR, ESI-MS, IR and 119m Sn Mossbauer spectro…

Synthesis, characterization, crystal structures and in vitro antistaphylococcal activity of organotin(IV) derivatives with 5,7-disubstituted-1,2,4-tr…

2011

Abstract New organotin(IV) complexes of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine ( dbtp ) and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine ( dptp ) with 1:1 and/or 1:2 stoichiometry were synthesized and investigated by X-ray diffraction, FT-IR and 119 Sn Mossbauer in the solid state and by 1 H and 13 C NMR spectroscopy, in solution. Moreover, the crystal and molecular structures of Et 2 SnCl 2 (dbtp) 2 and Ph 2 SnCl 2 (EtOH) 2 (dptp) 2 are reported. The complexes contain hexacoordinated tin atoms: in Et 2 SnCl 2 (dbtp) 2 two 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine molecules coordinate classically the tin atom through N(3) atom and the coordination around the tin atom shows a …

Computational study of the interaction of proflavine with d(ATATATATAT)2 and d(GCGCGCGCGC)2

2009

Abstract The interaction of proflavine (PR) with two B-DNA decamers of alternating AT and GC sequence, called [deca(dG-dC)]2 and [deca(dA-dT)]2, respectively, was computationally investigated by the ONIOM method, exploiting a three-layer QM/QM/MM hybrid approach. The highest level QM method was applied to the model system, which comprises the intercalation site (5th and 6th base pairs) and the inserted PR molecule. The connecting sugar phosphate backbone was added in the medium layer region. Both higher and medium level layers, differing in the size of the basis set used, were treated by the DFT MPWB1K functional. The full system in the lower layer was described by the empirical AMBER force…

Complexes of organometallic compounds. XLVII. Synthesis of dimethyltin(IV) adenosinate and its characterization by Mössbauer and infrared spectroscopy

1977

Synthesis and spectroscopic characterization of dimethyl-, di-n-butyl-, di-t-butyl-and diphenyl-tin(iv) derivatives of dipeptides: Crystal and molecu…

1992

The dipeptide complexes R2SnL listed below have been synthesized: (a) Me2SnL; H2L = glycylalanine (H2GlyAla), glycylvaline (H2GlyVal), glycylmethionine (H2GlyMet), glycyltryptophan (H2GlyTrp), glycyltyrosine (H2GlyTyr); (b) nBu2SnL; H2L = H2GlyAla, H2GlyVal; (c) nBu2SnL.H2O; H2L = glycylglycine (H2GlyGly), H2GlyAla; (d) tBu2SnL; H2L = H2GlyAla, H2GlyVal; (e) tBu2SnGlyGly. H2O; (f) Ph2SnL; H2L = H2GlyAla, H2GlyVal, H2GlyTyr, H2GlyTrp; (g) Ph2Sn(HGlyVal)2. The crystal and molecular structures of nBu2SnGl Val have been determined by single-crystal X-ray diffraction. The polyhedron around tin is a distorted trigonal bipyramid, analogous to that of Et2SnGlyTyr (see Vornefeld et al., Appl. Organo…

Complexes of organometallic compounds. LI. The correlation between 119Sn Mössbauer isomer shifts and partial atomic charges on tin in R3SnL compounds

1985

Abstract The 119Sn Mossbauer isomer shift parameters, δ, of compounds R3SnL (R = AlK, Ph; L = F, Cl, OH, OR′, CN, NCS, NCO, N3) have been correlated to partial atomic charges on tin QSn, calculated according to a valence state electronegativity equalization procedure carried out by the CHELEQ program. A unique δ/QSn correlation has been obtained for all the five-coordinated R3SnL species by using average δ parameters for the AlK3IV derivatives.

The structure and dynamics of Cl-substituted tetraphenyl- and tetrabenzyl-tin(IV)

1999

Abstract The crystal and molecular structure of (o-ClC6H4CH2)4Sn has been determined by X-ray crystallography. Tin is in a slightly distorted environment. The molecular dynamics of (p-ClC6H4)4Sn, (o-ClC6H4)4Sn and (o-ClC6H4CH2)4Sn have been investigated by variable temperature 119Sn Mossbauer spectroscopy (VTMS). A Debye-solid behaviour has been detected for (p-ClC6H4)4Sn, where, on the other hand, no influence by hydrogen–chlorine interaction on the magnitude of the dynamics data and functions seems to occur. For the o-Cl-substituted derivatives, a non-Debye-solid character could be advanced.

Tin(IV), Monomethyltin(IV), and Dimethyltin(IV) Complexes with thiol sulfur and heterocyclic nitrogen donors: Molecular dynamics and structure by119S…

1995

The molecular dynamics of the complexes Sn(SPyN)4 (1), SnCl2(SPyN)2 (2), MeSn(SPy)3 (3), MeSnCl(SPyN)2 (4), Me2Sn(TCy)2 (5), Me2SnCl(TOx) (6), and Me2Sn(TUr) (7) [HSPy = 2-mercaptopyridine; HSPyN = 2-mercaptopyrimidine; HTCy = 2-thiocytosine; HTOx = 8-thioquinoline; H2TUr = 2-thiouracil] has been investigated by variable temperature 119Sn Mossbauer spectroscopy. The area under the resonant peaks has been determined as function of temperature, from which Debye temperatures and cut-off frequencies, as well as recoil-free fractions (Lamb Mossbauer factor) and mean square displacements of 119Sn, have been calculated. By fingerprint procedures on the basis of literature data, monomeric structure…

Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydro…

2009

Two new polymeric triorganotin(IV) complexes R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n ([Me3Sn(LH)] n : 1) and ([Ph3Sn(LH)] n : 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared. Both compounds have been characterized by 1H, 13C, 119Sn NMR, IR and 119Sn Mossbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alco…

The interaction of organotins with native DNA

1992

The compounds R2SnCl2 and R3SnCl (RMe, Et, nBu, nOct, Ph, in ethanol solution) as well as the aqueous species [Me2Sn(OH2)n]2+ and [Me3Sn(OH2)2]+, react with aqueous native DNA, yielding solid phases. According to the pointcharge model treatment of the 119Sn Mossbauer parameter nuclear quadrupole splitting, trans-octahedral R2Sn(O2PXY)2, and trigonalbipyramidal R3Sn(O2PXY), (RMe, Et, nBu), would occur in the pellets, the tin atoms being coordinated by phosphodiester groups of the nucleic acid. The precipitates from Ph2SnIV would consist of the DNA complex as well as of the Ph2SnIV distannoxane obtained by hydrolysis of the reactant, whilst nOct2SnCl2, nOct3SnCl and Ph3SnCl would mainly yield…

Studies on some antimony(III) complexes with tridentate schiff base ligands

1981

Abstract The antimony(III) complexes FSb(Sab), ClSb(Sab) and ClSb(Sat) containing dianonic, potentially tridentate Schiff-base ligands with ONO(Sab 2− ) and ONS(Sat 2− ) donor atoms have been prepared and characterized. The mass spectra of these derivatives are reported. The occurrence of chelation by the tridentate ligand is inferred from the infrared data. The antimony-121 Mossbauer parameters at 4.2 K are reported. The magnitudes and the positive sign of eQV zz suggest a consistent p-character of the antimony lone-pair orbital. Observed differencies in the isomer shift and eQV zz values are discussed on the basis of the likely distribution of electron density around antimony.

Stannacycloalkyl and stannepinyl derivatives of dipeptides

1994

Stannacyclohexyl and stannacycloheptyl derivatives of dipeptides (CH2)nSnAA · xH2O (H2AA = H2GlyGly, with n = 5, x = 2 or n = 6, x = 1; H2AA = H2GlyAla, H2GlyVal, H2GlyMet, with n = 5, 6, x = 1) and stannepinyl glycylglycinate monohydrate have been obtained by the reaction of (CH2)nSnCl2 or stannepinyl dichloride with Na2AA. According to infrared and 119Sn Mossbauer data of the solid compounds, AA acts as a tridentate ONN ligand and tin has a trigonalbipyramidal environment. An analogous structure has been inferred from 1H, 13C, and 119Sn NMR data for the undissociated molecules in methanol solution.

Di- and Tri-organotin(IV) Complexes ofN-Acetyltriglycine andN-Benzoyltriglycine: Synthesis and Spectroscopic Characterization

1996

Di- and tri-organotin(IV) derivatives of N-acetyltriglycine and N-benzoyltriglycine (HA) were obtained by refluxing equimolar mixtures of the ligand and the organotin(IV) oxide or hydroxide in methanol or acetone. According to the spectroscopic data, triorganotin(IV) derivatives adopt a trigonal-bipyramidal structure in which the planar R 3 Sn IV unit is bonded by a monodentate carboxylate group and a donor group, presumably the amide C=O. The reaction of HA with the appropriate diorganotin(IV) compounds gave both dicarboxylates R 2 SnA 2 , with six-coordinated tin, and dimeric tetra-organodistannoxanes {[R 2 SnA] 2 O}2, in which the tin atoms are essentially five-coordinated.

Interactions of organotins with biological systems

1992

The bonding and structure in the environments of tin atoms in organotin-biological molecules has been investigated by 119Sn Mossbauer spectroscopy, mainly through the rationalization of the nuclear quadrupole splitting parameter by pointcharge model approaches. Organotin moieties R2SnIV and R3SnIV (R = Me, nBu, Ph) generally assume trigonal-bipyramidal type configurations in membranes of human erythrocytes, when incubated with whole erythrocytes and erythrocyte ghosts at the level of micromolar (μmol dm−3) organotin per mg of membrane protein. Corresponding structures are assumed by Me2SnIV and Me3SnIV in the cytoplasm. Ethanolic Me2SnCl2 yielded distorted trans-octahedral species when reac…

The interaction of native DNA with Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine

2007

The interaction of native calf thymus DNA with the Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine (ZnL(2+) and CuL(2+)), in 1 mM Tris-HCl aqueous solutions at neutral pH, has been monitored as a function of the metal complex-DNA molar ratio by UV absorption spectrophotometry, circular dichroism (CD) and fluorescence spectroscopy. The results support for an intercalative interaction of both ZnL(2+) and CuL(2+) with DNA, showing CuL(2+) an affinity of approximately 10 times higher than ZnL(2+). In particular, the values of the binding constant, determined by UV spectrophotometric titration, equal to 7.3x10(4) and 1.3x10(6)M(-1), for ZnL(2+) and CuL…

DFT Calculations of the Electric Field Gradient at the Tin Nucleus as a Support of Structural Interpretation by119Sn Mössbauer Spectroscopy

2005

DFT calculations, using an all-electron basis set and with full geometry optimization, were performed on 34 Sn(II) and Sn(IV) compounds of known structure and (119)Sn Mössbauer parameters, to obtain the theoretical values of the electric field gradient components, V(xx), V(yy), and V(zz), at the tin nucleus. These were used to determine the quantity V = V(zz)[1+ 1/3((V(xx) - V(yy))/((V(zz))(2)](1/2), for each investigated compound, which is related to the quadrupole splitting (DeltaE) parameter according to DeltaE = 1/2eQV, where e is the electronic charge and Q is the quadrupole moment of the tin nucleus. The linear fitting of the correlation plot of the experimental DeltaE, versus the cor…

Complexes of organometallic compounds XXXIII. The coordination chemistry of dimethyl and diphenylthallium(III) ith tridentate ligands

1973

Summary Several novel complexes Na[Me 2 TIL] and Na[Ph 2 TIL] (L 2− =dianion tridentate ligands with S, N, and O donor atoms) were synthesized, and investigated by infrared spectroscopy in the solid state, and by electronic and PMR spectroscopy in solution. Suggestions for the configuration of the complex anions are advanced and the nature of species present in solution is discussed.

Synthesis, characterization, and in vitro antimicrobial activity of organotin(IV) complexes with triazolo-pyrimidine ligands containing exocyclic oxy…

2005

Abstract Tri-organotin(IV) complexes of the triazolo-pyrimidine derivatives 4,5-dihydro-5-oxo-[1,2,4]triazolo-[1,5 a ]pyrimidine (5HtpO), 4,7-dihydro-5-methyl-7-oxo-[1,2,4]triazolo-[1,5 a ]pyrimidine (HmtpO), and 4,5,6,7-tetrahydro-5,7-dioxo-[1,2,4]triazolo-[1,5 a ]pyrimidine (H 2 tpO 2 ), and the diorganotin derivative n -Bu 2 Sn(tpO 2 ), were synthesized and characterized by means of infrared and 119 Sn Mossbauer spectroscopy. In all the complexes obtained the triazolopyrimidines act as multidentate ligands producing polymeric structures. A trigonal bipyramidal arrangement of the ligands around the tin atom is proposed for triorganotin(IV) derivatives, with organic groups on the equatoria…

Complexes of dichlorophenyl and trichloro-antimony(V) moieties with dianionic tridentate ligands

1981

Synthesis and x-ray crystal structure of dimethyltin(IV) dithiocyanate bihydrate adduct with a crown ether

1985

Me 2 Sn(NCS) 2 (OH 2 ) 2 . 18-crown-6 cristallise dans P2 1 /n avec Z=2; affinement jusqu'a R=0,058

Synthesis and spectroscopic characterization of dicyclohexyltin derivatives of dipeptides, andin vitro effects against MDA-MB 231 breast cancer cells…

1992

Dicyclohexyltin derivatives Cy2SnL (Cy = cyclohexyl) of the dipeptides H2L, glycylglycine, glycylalanine, alanylglycine, glycylvaline, glycylmethionine, glycylphenylalanine and glycyltyrosine, have been obtained by neutralization of Cy2SnO and H2L. The crystal structures of Cy2SnL (L = glycylglycinate, glycylalaninate) have been determined by single X-ray diffraction. Tin in each case has a distorted trigonal bipyramidal environment with the dipeptide acting as a tridentate NNO-ligand. From IR-data, and in some cases from 119Sn Mossbauer and 119Sn NMR data, analogous molecular structures are inferred for the other compounds Cy2SnL. Spectroscopic data indicate that the solid-state structures…

Mono-aryltin(IV) and mono-benzyltin(IV) complexes with pyridine-2-carboxylic acid and 8-hydroxyquinoline. X-ray structure of p-chloro-phenyl-tris(8-q…

1999

Abstract Complexes RSn(O2CPy)3·2H2O and RSn(Ox)3, (PyCOOH=pyridine-2-carboxylic acid, HOx=8-hydroxyquinoline, R=o- and p-Tolyl, o- and p-ClC6H4=o- and p-ClPh, o-ClC6H4CH2=o-ClBenzyl; besides, R=Ph in RSn(Ox)3) have been synthesized and characterized by elemental analysis and determination of molecular weights in CHCl3 solutions. The structure of p-ClPhSn(Ox)3·2CHCl3 has been determined by X-ray diffractometry. The 7-coordinated tin atom of the monomeric compound is in the center of a pentagonal bipyramid formed by (p-ClPh)C and O and N atoms of the chelating Ox− ligands. The latter type of structure would hold for all complexes according to 119Sn Mossbauer (including the determination of th…

Mono- and polynuclear hydroxo complexes of monophenylthallium(III)

1974

Summary The hydrolysis of PhTl(OH)ClO4 has been studied in a medium 0.3 M in NaClO4 by a potentiometric technique. The complexes formed by the hydrolysis reactions together with their formation constants have been determined by the general minimizing computer programme LETAGROP. The hydrolysis species observed in the pH range 3–5 are the mononuclear [(PhTlOH)(OH)], the dinuclear [(PhTlOH)2(OH)]+ and the dimer [(PhTlOH)2(OH)2]. The formation constants are log *β11=−4.92±0.2, log *β21=−1.52±0.03 and log *β22=−6.11±0.05. Stepwise reactions are then postulated whose formation constants are respectively log (*β21/*β11)=3.40±0.25, log (*β22/*β21)=−4.59±0.08 and log (*β22/*β112)=3.73±0.09.

Mossbauer spectroscopic studies on the molecular dynamics of organotin(IV) polymers

1981

Abstract Linear organotin(IV) polymers with tin appended to the polymer chain or inserted into the polymer backbone have been characterized by Mossbauer spectroscopy. The lattice dynamics of three representative examples of these classes, as well as of a cross-linked organotin(IV) polymer, have been investigated by temperature-dependent Mossbauer spectroscopy. It has been shown that parameters associated with polymers having low interchain interactions practically correspond to those of molecular, non-coupled, solids.

Synthesis and characterization of diorganotin(IV) derivatives of 2-mercaptopyridine and crystal structure of diphenyl pyridine-2-thiolatochlorotin(IV)

1994

Diorganotin(IV) derivatives of 2-mercaptopyridine (HSPy), R2Sn(SPy)2, R2SnCl(SPy) (R = Me, iPr, nBu, tBu, Cy, Ph) and Cy2SnBr(SPy), were obtained from R2SnX2 (X = Cl, Br) and NaSPy. Ph2SnCl(SPy) crystals, as determined by singlecrystal X–ray diffraction, are monoclinic in the space group P21/n. Tin forms with the bidentate SPy ligand a four–membered chelate ring with a short NSnS bite angle of 64.8(1)° leading to a heavily distorted trigonal–bipyramidal environment about tin. Apical Cl–Sn–N angle = 156.1(1)° equatorial C–Sn–C angle = 121.9(2)°. From 119Sn Mossbauer and IR data, analogous structures are inferred for the other solid compounds R2SnX(SPy), and distorted octahedral molecular str…

ChemInform Abstract: Synthesis and Characterization of Diorganotin(IV) Derivatives of 2- Mercaptopyridine and Crystal Structure of Diphenyl Pyridine-…

2010

Diorganotin(IV) derivatives of 2-mercaptopyridine (HSPy), R2Sn(SPy)2, R2SnCl(SPy) (R = Me, iPr, nBu, tBu, Cy, Ph) and Cy2SnBr(SPy), were obtained from R2SnX2 (X = Cl, Br) and NaSPy. Ph2SnCl(SPy) crystals, as determined by singlecrystal X–ray diffraction, are monoclinic in the space group P21/n. Tin forms with the bidentate SPy ligand a four–membered chelate ring with a short NSnS bite angle of 64.8(1)° leading to a heavily distorted trigonal–bipyramidal environment about tin. Apical Cl–Sn–N angle = 156.1(1)° equatorial C–Sn–C angle = 121.9(2)°. From 119Sn Mossbauer and IR data, analogous structures are inferred for the other solid compounds R2SnX(SPy), and distorted octahedral molecular str…

The interaction of S,N-coordinated dimethyltin(IV) derivatives with deoxyribonucleic acid: structure and dynamics by119Sn Mössbauer spectroscopy

1999

Complexes Me2SnCl(SPy) and Me2SnCl(SPym) (HSPy = 2-mercaptopyridine; HSPym = 2-mercaptopyrimidine), from ethanol solutions, interact with aqueous calf-thymus DNA yielding condensed phases with probable Me2Sn(SPy,SPym) (DNA monomer) stoichiometries of 1:1; the condensation of DNA is inferred originated from electrostatic bonding between complex cations Me2Sn(SPy,SPym)+ and the phosphate oxygen of the phosphodiester groups. Octahedral-or trigonal-bipyramidal tin environments are inferred from the point-charge model treatment of the 119Sn Mossbauer parameter nuclear quadrupole splitting, considering the bonding by S and N, or only S donor atoms from the ligand, as well as possible coordination…

Semi-empirical MNDO study of the structure of some diorganotin (IV) glycylglycinates

1993

The geometrical structures of some diorganotin glycylglycinates have been obtained using the MNDO semi-empirical method. A good agreement with the experimental diffractometric data was found.

Synthesis, spectroscopic characterization and in vitro antimicrobial activity of diorganotin(IV) dichloride adducts with [1,2,4]triazolo-[1,5-a]pyrim…

2006

Abstract The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react with diorganotin dichlorides giving the addition compounds Me2SnCl2(tp)2, Et2SnCl2(tp)2, Me2SnCl2(dmtp)2, Et2SnCl2(dmtp)2, Bu2SnCl2(dmtp), Ph2SnCl2(dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of the organic groups bound to tin. The compounds have been characterized by means of infrared, 119Sn Mossbauer and 1H AND 13C NMR spectroscopy. The ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonal bipyramidal structures, with the organi…

New organotin(IV) complexes with L-Arginine,Nα-t-Boc-L-Arginine and L-Alanyl-L-Arginine.Synthesis, structural investigations and cytotoxic activity

2010

Abstract Novel diorganotin(IV) derivatives of l -Arginine (HArg), N α -( tert -Butoxycarbonyl)- l -Arginine (Boc–Arg–OH) and l -Ala- l -Arg (H 2 Ala–Arg), H 2 NC( NH)NH(CH 2 ) 3 CH(NHR′)CO 2 H, where R′ = H in HArg, R′ = C(O)OC(CH 3 ) 3 in Boc–Arg–OH, R′ = H 2 NCH(CH 3 )CO in H 2 Ala–Arg and triorganotin(IV) derivatives of Boc–Arg–OH have been synthesized and structurally characterized. The complexes were investigated by FT-IR and 119 Sn Mossbauer in the solid state and by 1 H, 13 C, 119 Sn and 1 H– 1 H COSY NMR spectroscopy, in solution. The spectroscopic characterization leading to the proposed molecular structures was accomplished on the basis of these experiments. l -Arginine appears to…

Diorganotin(IV) Complexes of Methyl 2-{[(E)-8-Oxo-5, 8-dihydroquinolin-5-ylidene]hydrazino}benzoate

2012

Three cis-bis{5-[(E)-2-(2-carbomethoxyphenyl)-1- diazenyl]quinolinolato}-diorganotin(IV), R2Sn(L)2, complexes [R = Me (1), Ph (2) and Bz (3)] were synthesized and characterized by 1H-, 13C-, 119Sn- NMR, IR, and 119Sn Mössbauer spectroscopic techniques in combination with elemental analysis. The structure of diphenyltin(IV) complex Ph2Sn(L)2 (2) was determined by single-crystal X-ray crystallography as its tri-benzene solvate. Each complex was found to adopt a distorted cis-R2 octahedral arrangement around the tin atom with the quinolinolato ligands being N,O-chelating; the oxygen atoms are trans to each other. The complexes retain their solid- state structure in non-coordinating solvents as…

Triorganotin(IV) derivatives of 7-amino-2-(methylthio)[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylic acid. Synthesis, spectroscopic characterization, …

2010

Triorganotin(IV) complexes of the 7-amino-2-(methylthio)[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylic acid (HL), Me 3 SnL(H 2 O), ( 1 ), [ n -Bu 3 SnL] 2 (H 2 O), ( 2 ), Ph 3 SnL(MeOH), ( 3 ), were synthesized by reacting the amino acid with organotin(IV) hydroxides or oxides in refluxing methanol. The complexes have been characterized by elemental analysis, 1 H, 13 C and 119 Sn NMR, IR, Raman and 119 Sn Mossbauer spectroscopic techniques. Single crystal X-ray diffraction data were obtained for compounds ( 2 ) and ( 3 ). Ph 3 SnL(MeOH) presents a trigonal bipyramidal structure with the organic groups on the equatorial plane and the axial positions occupied by a ligand molecule, coordinated …

Synthesis and spectroscopic characterization of organotin derivatives ofN-benzoylglycylglycine

1991

Di- and tri-organotin derivatives of N-benzoylglycylglycine (HBzGlyGly) were synthesized and characterized by infrared, 1H, 13C NMR and 119Sn Mossbauer spectroscopy. Diorganotin derivatives appear to be dimer distannoxanes ([R2SnBzGlyGly]2O)2 (R = CH3, n-C4H9, n-C8H17) with a ladder-type structure where tin atoms are five-coordinated and N-benzoylglycylglycine alternatively acts as a unidentate or bridging bidentate ligand through the carboxylate group. For triorganotin derivatives R3SnBzGlyGly (R= CH3, n-C4Hg) we propose a polymeric structure where N-benzoylglycylglycine bridges planar SnC3 units through the carboxylate group.

The dynamics of 57Fe nuclei in Fe(II)-DNA and [Fe(II)(1-methyl-2-mercaptoimidazole)2]-DNA condensates.

2002

Abstract Alcoholic solutions of FeCl 2 and Fe II (Hmmi) 2 Cl 2 (Hmmi=1-methyl-2-mercaptoimidazole) induce calf thymus DNA condensation from aqueous solutions buffered at pH 7.4. A 1:1 Fe II –(DNA monomer) stoichiometry is assumed. The 57 Fe Mossbauer hyperfine parameters suggest an octahedral coordination environment, severely distorted, in both Fe II –(DNA monomer) and [Fe II (Hmmi) 2 ]–(DNA monomer) condensates. The dynamic properties of iron nuclei in freeze-dried samples were investigated by means of variable temperature 57 Fe Mossbauer spectroscopy. Mean square displacements, 〈 x 2 〉( T ), were calculated, such as the effective vibrating mass and the Mossbauer lattice temperature of th…

Syntheses, Mössbauer and infrared spectroscopic investigations on tin(II) chloride adducts with purine and pyrimidine bases and nucleosides

1982

Abstract The synthesis of two types of tin(II) complex SnCl2·L·CH3OH (L = adenosine, cytidine and inosine) and SnCl2·L2·CH3OH (L = adenine and cytosine) are described. The complexes are characterised by their infrared and 119Sn Mossbauer data. The Mossbauer shift data suggest that the bonds between tin(II) chloride and the donor atoms of the ligands are relatively weak.

Diorganotin(IV)-2-mercaptopyrimidine complexes

1998

The complexes formed between the diorganotin(IV) moieties, R 2 Sn(IV), and the ligand 2-mercaptopyrimidine, (H)SPym, were investigated. Complexes R 2 SnHal(SPym) and R 2 Sn(SPym) 2 [R = Me, i Pr, n Bu, i Bu, t Bu, cyclohexyl(Cy), Ph] were synthesized, and characterized by elemental analysis. In the solid state, chelation of SPym through S and N donors was established by IR spectroscopy, and the nature of the environment of tin centers was investigated by 119 Sn Mossbauer spectroscopy. From the dynamics of 119 Sn nuclei determined by variable-temperature measurements on representative compounds [Me 2 SnCl(SPym) and Cy 2- SnBr(SPym)], as well as by point-charge model treatment of nuclear quad…

Synthesis of diorganotin(IV) complexes with nucleosides and their Characterization by Mössbauer and infrared spectroscopy

1984

Abstract A number of new complexes of R 2 Sn IV with adenosine, guanosine, inosine, cytidine and uridine were synthesized by reaction of ribonucleosides with diorganotin oxide in hot methanol. The complexes were characterized by infrared and 119 Sn Mossbauer spectroscopy as O(2′), O(3′) (diorganostannylene) nucleosides; the occurence of dimers with three-co-ordinate oxygen atoms is inferred on the basis of spectroscopic data.

Synthesis and structural characterisation of copper(I,II) complexes mimetic of "blue copper" proteins active site

2005

Organotin(IV) Adducts of 5,7-Diphenyl-1,2,4-triazolo[1,5-a] pyrimidine and 5,7-Ditertbutyl-1,2,4-triazolo[1,5-a] pyrimidine

2007

DFT calculations of the electric field gradient of tin compounds: a structure elucidation tool by 119Sn Mossbauer spectroscopy.

2004

The interaction of native calf thymus DNA with Fe(III)- dipyrido[3,2-a:2’,3’-c]phenazine chloride

2007

Complessi di di- e triorganostagno(IV) con [1,2,4]triazolo-[1,5-a]pirimidina e suoi derivati 5- e 7-sostituiti

2004

Synthesis of copper(II) complexes of new carbon-scorpionate ligands

2009

A set of new “carbon-based” scorpionate ligands based on S- and N-containing heterocyclic moieties have been synthesized. They offer the advantage of a higher stability with respect to the “classical” boron-based scorpionate ligands and also a certain degree of hydrophilicity. The synthesis of these ligands was accomplished by the coupling reaction of the N-methylimidazolyllithium with a suitable electrophilic partner. The reaction yield ranges from 40% to 65%. Preliminary results on the synthesis and characterization of the related copper(II) complex are also presented.

Synthesis and structural characterization of new Bis(pyrazolyl)thioimidazolyl)borate ligands [NNS] donor and their relate complexes

2007

Studio computazionale della interazione tra proflavina e i polinucleotidi poly(dA-dT).poly(dA-dT) e poly(dG-dC).poly(dG-dC).

2006

The interaction of native calf thymus DNA with Zn(II)-N,N'-bis(5,5'-triethylammoniomethyl-salicylidene)phenylendiimine

2006

The interaction between native calf thymus deoxyribonucleic acid (DNA) and Fe-III-N,N'-ethylene-bis (salicylideneiminato)chloride, Fe(Salen)Cl, was investigated in aqueous solutions by UV-visible (UV-vis) absorption, circular clichroisin (CD), thermal denaturation and viscosity measurements. The results obtained from CD, UV-vis and viscosity measurements exclude DNA intercalation and can be interpreted in terms of an electrostatic binding between the Fe(Salen)(+) cation and the phosphate groups of DNA. The trend of the UV-vis absorption band of the Fe(Salen)Cl complex at different ratios [DNA(phosphate)]/[Fe(Salen)Cl] and the large increase of the melting temperature of DNA in the presence …

L-Arginine, Na-Boc-L-Arginine and L-Alanyl-L-Arginine complexes of Organotin(IV) ions. Synthesis and structural investigations

2007

Synthesis and structural characterisation of copper complexes mimetic of “blue copper” proteins active site

2007

Synthesis and characterization of triphenyltin(IV) complexes of azocarboxylates. Crystal structures of a ligand, HO2CC6H4{N=N(C6H3-4-OH(C(H)=NC6H4CH3…

2005

CCDC 836072: Experimental Crystal Structure Determination

2015

Related Article: Maria Assunta Girasolo, Loredana Canfora, Piera Sabatino, Domenico Schillaci, Elisabetta Foresti, Simona Rubino, Giuseppe Ruisi, Giancarlo Stocco|2012|J.Inorg.Biochem.|106|156|doi:10.1016/j.jinorgbio.2011.09.010

CCDC 836073: Experimental Crystal Structure Determination

2015

Related Article: Maria Assunta Girasolo, Loredana Canfora, Piera Sabatino, Domenico Schillaci, Elisabetta Foresti, Simona Rubino, Giuseppe Ruisi, Giancarlo Stocco|2012|J.Inorg.Biochem.|106|156|doi:10.1016/j.jinorgbio.2011.09.010