The synthesis,NMR (1H, 13C, 119Sn) and IR spectral studies of some di‐ and tri‐organotin(IV) sulfonates: X‐ray crystal structure of [(n‐C4H9)2Sn(OSO2C6H4CH3‐4)2·2H2O]

A number of alkyltin(IV) paratoluenesulfonates, R_nSn(OSO₂C₆H₄CH₃‐4)_4?n (n = 2, 3; R = C₂H₅, n‐C₃H₇, n‐C₄H₉), have been prepared and IR spectra and solution NMR (¹H, ¹³C, ¹¹⁹Sn) are reported for these compounds, including (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), the NMR spectra of which have not been reported previously. From the chemical shift δ(¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn) and ²J(¹H, ¹¹⁹Sn), the coordination of the tin atom and the geometry of its coordination sphere in solutions of these compounds is suggested. IR spectra of the compounds are very similar to that observed for the paratoluenesulfonate anion in its sodium salt. The studies indicate that diorganotin(IV) paratoluenesulfonates, and the previously reported compounds (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), contain bridging SO₃X groups that yield polymeric structures with hexacoordination around tin and contain non‐linear C? Sn? C bonds. In triorganotin(IV) sulfonates, pentacoordination for tin with a planar SnC₃ skeleton and bidentate bridging paratoluenesulfonate anionic groups are suggested by IR and NMR spectral studies. The X‐ray structure shows [(n‐C₄H₉)₂Sn(OSO₂C₆H₄CH₃‐4)₂·2H₂O] to be monomeric containing six‐coordinate tin and crystallizes from methanol–chloroform in monoclinic space group C2/c. The Sn? O (paratoluenesulfonate) bond distance (2.26(2) Å) is indicative of a relatively high degree of ionic character in the metal–anion bonds. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis, Characterization, and Biological Activity of n-Tributyltin Derivatives of Pharmaceutically Active Carboxylates

Summary.  Tributyltin(IV) derivatives of six different pharmaceutically active carboxylates were synthesized. The complexes were characterized by different analytical techniques (elemental analysis; infrared, NMR, and mass spectroscopy). ¹¹⁹Sn NMR data were also recorded in six different coordinating and non-coordinating solvents. The antibacterial activities of the compounds were tested using ten different bacteria relative to the reference drugs ampicillin and cephalexin. Received September 20, 2001. Accepted (revised) December 6, 2001     

Preparation and structures of [2‐(dimethylamino)phenyl]diorganotin(IV) acetates substituted with organophosphorus groups in the α‐position of the acetate ligand

Organotin(IV) carboxylates R₂L^NCSnOC(O)CH₂P(E)Ph₂, where L^NC is an N‐chelating 2‐(dimethylamino)phenyl group, and R/E = Ph/void (1a), Ph/O (1b), Ph/S (1c), Me/void (2a), Me/O (2b) and Me/S (2c), were synthesized, characterized by ¹H, ¹³C, ³¹P and ¹¹⁹Sn NMR, IR and MS spectra, and the solid‐state structures of 1b, 1c, 2b and 2c were determined by single‐crystal X‐ray diffraction. Spectral and structural data showed that the compounds are monomeric in CDCl₃ solution and the solid state, with the organophosphorus groups in the α‐position of the monodentate carboxylate ligands not interacting with the tin atom. Copyright © 2005 John Wiley & Sons, Ltd.     

Solid‐State 17O NMR Spectroscopy of Paramagnetic Coordination Compounds

High‐quality solid‐state ¹⁷O (I=5/2) NMR spectra can be successfully obtained for paramagnetic coordination compounds in which oxygen atoms are directly bonded to the paramagnetic metal centers. For complexes containing V^III (S=1), Cu^II (S=1/2), and Mn^III (S=2) metal centers, the ¹⁷O isotropic paramagnetic shifts were found to span a range of more than 10 000 ppm. In several cases, high‐resolution ¹⁷O NMR spectra were recorded under very fast magic‐angle spinning (MAS) conditions at 21.1 T. Quantum‐chemical computations using density functional theory (DFT) qualitatively reproduced the experimental ¹⁷O hyperfine shift tensors.     

Studies on the Radical Cyclization of 3‐Oxopropanenitriles and Alkenes with Cerium(IV) Ammonium Nitrate in Ether Solvents

The radical cyclization of 3‐oxopropanenitriles 1a – 1e and alkenes 2a – 2g with cerium(IV) ammonium nitrate (CAN) in ether solvents was investigated (Tables 1 and 2). In the optimization study, 1,3‐dioxolane, 1,4‐dioxane, 1,2‐dimethoxyethane, Et₂O, and THF were used as ether‐based solvents, and the latter was found to be the most effective solvent in radical cyclizations mediated by cerium(IV). This system (cerium(IV)/THF) was applied to cyclizations of various 3‐oxopropanenitriles and 1,3‐dicarbonyl compounds with alkenes resulting in the formation of 4,5‐dihydrofurans in high yields (Table 2 and Scheme 2). The results of the cerium(IV)/THF radical cyclization were compared with those obtained with manganese(III) acetate/AcOH; the cerium(IV)/THF system turned out to be much more efficient.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis‐(n‐Bu4N)2[PtX2(ox)2], X = Cl,Br, I

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of cis‐(n‐Bu₄N)₂[PtX₂(ox)₂], X = Cl, Br, I By treatment of [PtCl₆]^2— with C₂O₄^2— (ox^2—) in water cis‐(n‐Bu₄N)₂[PtCl₂(ox)₂] ( 1 ) is formed which has been isolated by ion exchange chromatography on diethylaminoethyl cellulose. Exposure of trans‐(n‐Bu₄N)₂[PtX₂(ox)₂], X = Br and I, in dichloromethane yields cis‐(n‐Bu₄N)₂[PtBr₂(ox)₂] ( 2 ) and cis‐(n‐Bu₄N)₂[PtI₂(ox)₂] ( 3 ). The crystal structure of 3 (monoclinic, space group P2₁/c, a = 19.132(1), b = 14.377(1), c = 18.099(1) Å, ß = 113.734(8)°, Z = 4) reveals, that the compound crystallizes as a racemic mixture with C₂ point symmetrical complex anions. The bond lengths in both I′‐Pt‐O^• axes are Pt‐I′ = 2.599 and Pt‐O^• = 2.052 and in the O—Pt—O axis Pt—O = 2.016 Å. The oxalato ligands are nearly plane with O—C—C—O torsion angles of 0.2—3.6°. In the vibrational spectra the PtX′ stretching vibrations are observed at 362 and 365 ( 1 ), 231 and 240 ( 2 ) and 172 and 183 cm^—1 ( 3 ). The PtO^• and PtO stretching vibrations are coupled with internal modes of the oxalato ligands and appear in the range of 400—800 cm^—1. Based on the molecular parameters of the X‐ray determination ( 3 ) and estimated data ( 1 , 2 ) the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants are f_d(PtCl′) = 2.35, f_d(PtBr′) = 2.20, f_d(PtI′) = 1.81 and f_d(PtO^•) = 2.57 ( 1 ), 2.42 ( 2 ) and 2.15 ( 3 ) and f_d(PtO) = 2.65 mdyn/Å. Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 6438.8 ( 1 ), 5988.8 ( 2 ) and 4917.3 ppm ( 3 ).     

Synthesis,characterization and antimicrobial activities of triorganotin(IV) complexes with azo-azomethine carboxylate ligands: crystal structure of a tributyltin(IV) and a trimethyltin(IV) complex

Triorganotin(IV) complexes with polyaromatic azo-azomethine carboxylate ligands viz. 2-{4-hydroxy-3-[(2/4-hydroxyphenylimino)methyl]phenylazo}benzoic acids [H₃L¹/H₃L²] were synthesized by reacting the ligands with either bis-tri-n-butyltin(IV) oxide (for 1 and 4) or trimethyltin(IV) chloride in presence of triethylamine (for 2 and 5) or triphenyltin(IV) hydroxide (for 3 and 6). The complexes were characterized by elemental analysis, UV, IR, NMR, and mass spectrometry. NMR spectroscopic studies of the compounds suggested that the complexes adopt four-coordinate tetrahedral geometry around tin in solution. Molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction. Both complexes have distorted trigonal bipyramidal geometry around tin in the solid state. Compound 1 is a one-dimensional (1-D) double chain coordination polymer which can be described as two different 24- and 30-membered non-porous macrocyclic rings constructed from two tributyltin units and two ligand moieties. The structure of 2 comprises a discrete cyclic centrosymmetric dimer with two lattice water molecules per formula unit. In the dimer, two trimethyltin entities are bridged by two ligand moieties. The dimers are further interconnected with lattice water molecules by multiple O–H?O hydrogen bonds to form a 1-D H-bonded network. The complexes were also screened for their antimicrobial activities.     

Molecular and Supramolecular Structures of 1‐Phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H2L) and its Complexes with Diphenyllead(IV) Chloride and Acetate

Reaction of 1‐phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H₂L) with diphenyllead(IV) dichloride and acetate afforded the complexes [PbPh₂Cl₂(H₂L)₂] and [PbPh₂L]. The ligand and the complexes were characterized by elemental analyses, ¹H and ¹³C NMR spectroscopy and X‐ray crystallography. In the asymmetric unit of crystals of the ligand there are four independent molecules of H₂L and four molecules of water, which associate in the lattice as two independent sheets. The complex [PbPh₂Cl₂(H₂L)₂]·4MeOH has slightly distorted all‐trans octahedral geometry around the lead atom, and the fact that the ligand is S‐bound rather than O‐bound suggests that PbPh₂Cl₂ behaves as a “soft” Lewis acid. Hydrogen bonds involving NH groups, Cl atoms and MeOH molecules form a three‐dimensional supramolecular structure. In [PbPh₂L]·Me₂CO, the L^2? anion bridges between two metal centres, binding to one strongly via the N and S atoms and weakly via the O atom, and to the other via the O atom, thus creating polymeric chains along the b axis. The double deprotonation and metallation of H₂L induce significant changes in its configuration and lengthen the C‐S and C‐O bonds, suggesting an evolution of the dianion towards a thiol‐enol form.     

Synthesis,Spectroscopic Characterization,DFT Calculations,and Dynamic Behavior of Mononuclear Macrocyclic Diorganotin(IV) Bis‐Dithiocarbamate Complexes

Nine mononuclear diorganotin(IV) dithiocarbamate complexes 1 – 9 with 19‐, 20‐ and 21‐membered macrocyclic structures were synthesized from dimethyl, di‐n‐butyl, and diphenyltin(IV) dichloride and three bis‐dithiocarbamate ligands derived from secondary bis‐amines having aromatic spacer groups. All compounds were characterized by elemental analysis, mass spectrometry, and spectroscopic methods (IR and ¹H, ¹³C, and ¹¹⁹Sn NMR). Additionally, quantum chemical DFT calculations were performed for the dimethyltin(IV) derivatives in order to model the molecular structures. For one compound series the NMR spectra showed a concentration‐dependent behavior in solution, which was analyzed in detail and permitted to postulate the existence of an equilibrium with the corresponding [2+2] macrocycles.     

Titanium(IV) polynuclear hydroxo complexes stabilized in solution by [PW11O39]7? heteropolyanion

[PW₁₁O₃₉]^7– heteropolyanion (HPA) stabilizes Ti(IV) in aqueous solution at Ti:PW₁₁ ratios from 1 to 12 and pH 1–3. Ti(IV) is completely precipitated under these conditions in the absence of HPA. Differential dissolution phase analysis, optical, IR,³¹P and¹⁷O NMR spectra show that one Ti(IV) ion is incorporated into the Keggin lattice. The other ions, most probably, are located on the HPA surface in the form of oligomeric hydroxo fragments: [PW₁₁Ti^IVO₄₀·Ti_n–1 ^IVO_xH_y]^k–. Both types of Ti(IV) ions bind peroxo groups on interaction of the complex with H₂O₂.     

Coordination behaviour of the 2‐(N,N‐dimethylaminomethyl)phenyl ligand towards the di‐t‐butylchlorotin(IV) moiety

{2‐(N,N‐Dimethylaminomethyl)phenyl}(di‐t‐butyl)tin(IV)chloride, {2‐[(CH₃)₂NCH₂]C₆H₄}Sn(t‐Bu)₂ Cl, has been prepared and characterized using NMR and crystallography. This is the first example of a triorganotin(IV) halide containing the 2‐[(CH₃)₂NCH₂]C₆H₄—group as a C,N‐chelating ligand with a weak intramolecular Sn—N interaction because of the steric hindrance of t‐butyl groups. The interatomic Sn—N distance is elongated to 2.904(14) Å and the central tin atom is distorted trigonal bipyramidal. Copyright © 2004 John Wiley & Sons, Ltd.     

Organosilicon(IV) and organotin(IV) complexes as biocides and nematicides: synthetic,spectroscopic and biological studies of N∩N donor sulfonamide imine and its chelates

A brief account is given of the synthesis and stereochemistry and the antibacterial, antifungal, nematicidal and insecticidal behaviour of organosilicon(IV) and organotin(IV) complexes of a biologically potent ligand, 2‐acetylfuransulfaguanidine. The unimolar and bimolar substitution products have been characterized by elemental analyses, conductance measurements, molecular weight determinations, and spectral studies, viz. IR, ¹H NMR, ¹³C NMR, UV, ²⁹Si NMR and ¹¹⁹Sn NMR spectra. The data support the binding of the nitrogen atom to the metal atom in R₃M(N^∩N), [R₂M(N^∩N)₂ and R₂M(N^∩N)Cl [(R = Me/Ph and M = Si(IV) and Sn(IV)] types of complex. Based on these studies, with coordination number five and six a trigonal bipyramidal and an octahedral geometry have been proposed for the resulting derivatives. The free ligand (N^∩NH) and its respective metal complexes were tested in vitro against a number of microorganisms to assess their antimicrobial properties. The results are indeed positive. In addition to these studies, the complexes also show good nematicidal and insecticidal properties. The results of these findings have been discussed in detail. Copyright © 2004 John Wiley & Sons, Ltd.     

Microwave‐assisted synthesis,spectroscopy and biological aspects of binuclear titanocene chelates of isatin‐2,3‐bis(thiosemicarbazones)

The reactions of bis(cyclopentadienyl)titanium(IV) chloride with a new class of bis(thiosemicarbazones) (H₂L), derived by condensing isatin with different N(4)‐substituted thiosemicarbazides, have been studied both by a conventional stirring method and also using microwave technology. Binuclear products of type [{(η⁵‐C₅H₅)₂TiCl} ₂(L)] have been isolated in both cases. Tentative structural conclusions are drawn for the reaction products based upon analysis, electrical conductance, magnetic moment and spectral (UV‐visible, IR, ¹H NMR and ¹³C NMR) data. FAB mass spectra of these compounds were also recorded to confirm the binuclear structures. Studies were conducted to assess the growth inhibiting potential of the ligands and complexes against various fungal, viral and bacterial strains. Copyright © 2008 John Wiley & Sons, Ltd.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis‐(n‐Bu4N)2[Pt(ECN)2(ox)2], E = S,Se

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of cis‐(n‐Bu₄N)₂[Pt(ECN)₂(ox)₂], E = S, Se By exposure of trans‐(n‐Bu₄N)₂[Pt(ECN)₂(ox)₂], E = S and Se, in dichloromethane cis‐(n‐Bu₄N)₂[Pt(SCN)₂(ox)₂] ( 1 ) and cis‐(n‐Bu₄N)₂[Pt(SeCN)₂(ox)₂] ( 2 ) are formed. The crystal structure of 1 (triclinic, space group P1¯, a = 10.789(1), b = 11.906(1), c = 18.580(1)Å, α = 85.619(10), β = 85.272(10), γ = 75.173(10)°, Z = 2) reveals, that the compound crystallizes as a racemic mixture with C₂ point symmetrical complex anions. The bond lengths in both S′‐Pt‐O^˙ axes are Pt‐S′ = 2.321 and Pt‐O^˙ = 2.048 and in the O‐Pt‐O axis Pt‐O = 2.007Å. The oxalato ligands are nearly plane with O‐C‐C‐O torsion angles of 1.4 — 3.9°. The via S′ bound linear thiocyanate groups are coordinated with Pt‐S′‐C angles of 102.6°. In the vibrational spectra the PtE′ stretching vibrations are observed at 327 — 330 ( 1 ) and 217 — 231 cm^—1 ( 2 ). The PtO^˙ and PtO stretching vibrations are coupled with internal vibrations of the oxalato ligands and appear in the range of 400 — 800 cm^—1. Based on the molecular parameters of the X‐ray determination ( 1 ) and estimated data ( 2 ) the IR and Raman spectra are assigned by normal coordinate analysis. The valence force constants are f_d(PtS′) = 2.08, f_d(PtSe′) = 1.78, f_d(PtO^˙) = 2.45 ( 1 ) and 2.27 ( 2 ) and f_d(PtO) = 2.65 ( 1 ) and 2.60 mdyn/Å ( 2 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 4925.9 ( 1 ), 4783.0 ( 2 ) and δ(⁷⁷Se) = 161.7 ppm with the coupling constant ¹J(SePt) = 366.2 Hz.     

Alkyl‐Tethered Bis‐Phosphoryl Compounds with two 1,3,2‐Benzodiazaphosphorinone Units; Oxidation,Complexation, and X‐Ray Structure Analysis of Selected Compounds

The reaction of the bis‐chlorophosphines 1 a – 1 d with bis(2‐chloroethyl)amine hydrochloride in the presence of triethylamine and with various trimethylsilylamines led to a new class of bis‐phosphorus ligands 2 a – 2 c and 3 a – 3 g . ³¹P‐NMR studies suggested that the bis‐phosphorus ligands undergo rotation reactions about the alkyl bridge in polar solvents. Compounds 2 a – 2 c showed initially only one sharp singlet each in their ³¹P‐NMR spectra. After a few days at room temperature, two signals were observed. Similar results were observed for 3 a – 3 g . In the solid state, the two phosphorus atoms in 2 c are not equivalent, as was confirmed by the observation of two signals in the solid state ³¹P‐NMR spectrum. Oxidation reactions of 2 a – 2 c by the hydrogen peroxide‐urea 1 : 1 adduct (NH₂)₂C(:O) · H₂O₂ led to the formation of the corresponding phosphoryl compounds 4 a – 4 c . Reaction of 2 a and 3 a with Pt[COD]Cl₂ (COD = 1.5‐Cyclooctadiene) furnished the complexes 5 and 6 . The NMR spectra suggested that the two chlorine atoms are in cis position. X‐ray structure analyses were conducted for 2 a , which exhibits twofold symmetry; 2 c , which is linked into dimers by hydrogen bonds C–H…O; and 6 , confirming the cis configuration.     

Bioactive versatile azomethine complexes of organotin(IV) and organosilicon(IV)

Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R₂MCl(TSCZ) and R₂M(TSCZ)₂ (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and ¹H, ¹³C ²⁹Si and ¹¹⁹Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.     

Two conformers in the solid state for a novel organotin(IV) complex of a phosphoramidate: Syntheses, spectroscopic study and crystal structures of several new organotin(IV) complexes of N-benzoylphosphoric triamides

Several novel organotin(IV) complexes with formula SnCl₂(CH₃)₂(X)₂, X = C₆H₅C(O)NHP(O)(NC₄H₈)₂ (1), C₆H₅C(O)NHP(O)(NC₅H₁₀)₂ (2), C₆H₅C(O)NHP(O)[N(CH₃)(C₆H₁₁)]₂ (3), C₆H₅C(O)NHP(O)[NH-C(CH₃)₃]₂ (4) were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR spectroscopy and elemental analysis. The structures have been determined for each of the four compounds. Compound 1 exists in the form of two symmetrically independent molecules in the crystalline state due to differences in their similar torsion angles. In all of the four structures there are intramolecular -Sn-Cl?H-N- hydrogen bonds, in addition to weak C-H?O and C-H?Cl hydrogen bonds. Both ¹H and ¹³C NMR spectra show the coupling of ^119/117Sn nuclei with methyl proton and carbon atoms. The δ(³¹P) of these complexes are in upfields with respect to their corresponding reported ligands. The spectroscopic and structural properties of these complexes were compared with those corresponding ligands.     

Synthesis,structural characterization and in vitro cytotoxic activity of novel polymeric triorganotin(IV) complexes of urocanic acid

Two novel triorganotin carboxylate complexes of the biologically active urocanic acid have been synthesized and characterized. Elemental analysis, melting point, spectroscopic techniques – IR, ¹H, ¹³C and ¹¹⁹Sn NMR – mass spectrometry and X‐ray diffraction studies have been used for structural characterization. Crystal structures of the tin(IV) derivatives show that urocanic acid acts as a bridging bidentate ligand through its imidazole nitrogen atom and its carboxylic group, producing a polymeric one‐dimensional chain. The molecular structures of the complexes, catena‐poly‐tri(n‐butyl)tin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (1) and catena‐poly‐triphenyltin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (2), present a distorted trigonal–bipyramidal configuration. This is further confirmed by ¹¹⁹Sn NMR in the solid state. The tin(IV) derivatives form double‐stranded ribbons via N―H^…O―H bonds. Nevertheless, the compounds are essentially monomeric in solution, with a tetrahedral configuration as observed by ¹¹⁹Sn NMR in solution. The cytotoxic activity of the titled compounds has been tested against six human cell lines and the corresponding IC₅₀ values are reported. Both tin(IV) compounds have a high to very high in vitro cytotoxic activity against the tumor cell lines K562, HCT‐15 and MCF‐7. Compound 1 is 86 times more active than cisplatin in the HTC‐15 cell line. Copyright © 2012 John Wiley & Sons, Ltd.