The in vitro antifungal activity of some dithiocarbamate organotin(IV) compounds on Candida albicans— a model for biological interaction of organotin complexes

The in vitro antifungal activity of the dithiocarbamate organotin complexes [Sn{S₂CN(CH₂)₄}₂Cl₂] ( 1 ), [Sn{S₂CN(CH₂)₄}₂Ph₂] ( 2 ), [Sn{S₂CN(CH₂)₄}Ph₃] ( 3 ), [Sn{S₂CN(CH₂)₄}₂n‐Bu₂] ( 4 ), [Sn{S₂CN(CH₂)₄}Cy₃] {Cy = cyclohexyl} ( 5 ), [Sn{S₂CN(C₂H₅)₂}₂Cl₂] ( 6 ), [Sn{S₂CN(C₂H₅)₂}₂Ph₂] ( 7 ), [Sn{S₂CN(C₂H₅)₂}Ph₃] ( 8 ), [Sn{S₂CN(C₂H₅)₂}₃Ph] ( 9 ) and [Sn{S₂CN(C₂H₅)₂}Cy₃] ( 10 ) has been screened against Candida albicans (ATCC 18804), Candida tropicalis (ATCC 750) and resistant Candida albicans collected from HIV‐positive Brazilian patients with oral candidiasis. All compounds exhibited antifungal activities and complexes 3 and 8 displayed the best results. We have investigated the effect of compounds 1–10 on the cellular activity of the yeast cultures. Changes in mitochondrial function have not been detected. However, all drugs reduced ergosterol biosynthesis. Preliminary studies on DNA integrity indicated that the compounds do not cause gross damage to yeast DNA. The data suggest that these compounds share some mechanisms of action on cell membranes similar to that of polyene but not with azole drugs, normally used in Candida infections. Copyright © 2008 John Wiley & Sons, Ltd.     

Transition metal containing dendrimers based on cyclophosphazene units

The series of complexes [N₃P₃(OC₆H₅)₅OC₆H₄CH₂CN·MCl_n]PF₆, N₃P₃(OC₆H₄CH₂CN)₆·(MCl_n)₆](PF₆)₆, [N₃P₃(OC₆H₅)₅OC₆H₄CH₂CN·MCl_n−1]Cl and [N₃P₃(OC₆H₄CH₂CN)₆·(MCl_n−1)₆]Cl₆, MCl_n=MnCl₂, FeCl₃, CoCl₂, NiCl₂, CuCl₂ have been synthesized by reaction of the corresponding cyclophosphazene ligands: N₃P₃(OC₆H₅)₅OC₆H₄CH₂CN (L₁) and N₃P₃(OC₆H₄CH₂CN)₆ (L₂) with the respective salts MCl_n in CH₃OH as solvent and in presence or absence of NH₄PF₆. The new compounds were characterized by elemental analysis and IR, UV–Vis and EPR spectroscopy as well as electrochemical methods. The reaction of CuCl₂ with the ligand L₁ affords the copper (I) complex. [N₃P₃(OC₆H₅)₅OC₆H₄CH₂CN·Cu]PF₆ instead the expected Cu(II) complex, which was characterized by multinuclear NMR. For comparison, the complex [N₃P₃(OC₆H₅)₅OC₆H₄CH₂CN·ZnCl]PF₆ was also prepared. The hexametalladendrimers of iron exhibits a six-electron reduction while that the correspondent monometalladendrimers exhibit a single one-electron reduction. Upon coordination νCN increase in a similar way to crystal field effects dependence with the metal.     

SYNTHESIS AND CHARACTERISATION OF DIORGANOANTIMONY(III) COMPLEXES OF THIOSEMICARBAZONES

Abstract

The interaction of the sodium salts of thiosemicarbazones with diphenylantimony chloride in 1:1 molar ratio in benzene solution lead to the formation of derivatives, Ph₂Sb[SC(NH₂)NN: C(R)R′] where R = H; R′ [dbnd] C₆H₅, CH₃OC₆H₄, C₆H₅CH[dbnd]CH, and R′ [dbnd] CH₃; R′[dbnd]C₆H₅, CH₃OC₆H₄, C₆H₄CH₃, respectively. The resulting complexes have been characterised on the basis of elemental analyses and molecular weight determination. The mode of bonding of the ligands with the metal atom has been proposed on the basis of I.R., ¹H and ¹³C NMR studies. All these ligands are found to behave as monofunctional bidentate moiety in these complexes.     

The synthesis of some bidentate ligands containing both phosphine and nitrile groups

Both (C₆H₅)₂P(CH₂)₃CN and (C₆H₅)₂P(CH₂)₄CN have been obtained from the reaction of Br(CH₂)_nCN (n = 3, 4) with (C₆H₅)₂POCH₃ followed by reduction with (C₆H₅)₂SiH₂. These phosphine-nitrile ligands form L₂PdCl₂ complexes which are shown by IR measurements to have trans geometries with the phosphine portions of the ligands coordinated. Reactions of o-BrC₆H₄CN with CH₃(CH₂)₃Li followed by R₂PCl (R = C₆H₅ or (CH₃)₂N) have been used to provide good yields of the corresponding R₂P-o-C₆H₄CN products.     

Synthesis,characterization and crystal structures of 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoic acid and its polymeric and monomeric triorganotin(IV) complexes

Three triorganotin(IV) complexes of composition R₃SnLH (R = Me, Bu and Ph and LH = 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoate) have been synthesized and characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, and IR spectroscopic techniques in combination with elemental analysis. The crystal structures of the carboxylate ligand HO₂CC₆H₄{NN(C₆H₂-4-OH-3,5-(CH₃)₂)}-o in its neutral form and three triorganotin(IV) complexes, viz., polymeric (R₃Sn[O₂CC₆H₄{N–N(H)(C₆H₂-4-O-3,5-(CH₃)₂)}-o])_n (R = Me (1) and Bu (2)) and monomeric Ph₃Sn[O₂CC₆H₄{N–N(H)(C₆H₂-4-O-3,5-(CH₃)₂)}-o] (3) complexes are reported. The polymeric complexes 1 and 2 exist as extended 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 phenoxide O atom of the next carboxylate ligand. The Sn atom in complex 3 has a distorted tetrahedral geometry. In all three complexes, the carboxylate ligand is in the zwitterionic form with the phenolic proton moved to the nearby azo nitrogen atom, in contrast to the free carboxylic acid ligand which is in the azo form.     

Synthesis,characterization and crystal structures of 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoic acid and its polymeric and monomeric triorganotin(IV) complexes

Three triorganotin(IV) complexes of composition R₃SnLH (R = Me, Bu and Ph and LH = 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoate) have been synthesized and characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, and IR spectroscopic techniques in combination with elemental analysis. The crystal structures of the carboxylate ligand HO₂CC₆H₄{NN(C₆H₂-4-OH-3,5-(CH₃)₂)}-o in its neutral form and three triorganotin(IV) complexes, viz., polymeric (R₃Sn[O₂CC₆H₄{N–N(H)(C₆H₂-4-O-3,5-(CH₃)₂)}-o])_n (R = Me (1) and Bu (2)) and monomeric Ph₃Sn[O₂CC₆H₄{N–N(H)(C₆H₂-4-O-3,5-(CH₃)₂)}-o] (3) complexes are reported. The polymeric complexes 1 and 2 exist as extended 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 phenoxide O atom of the next carboxylate ligand. The Sn atom in complex 3 has a distorted tetrahedral geometry. In all three complexes, the carboxylate ligand is in the zwitterionic form with the phenolic proton moved to the nearby azo nitrogen atom, in contrast to the free carboxylic acid ligand which is in the azo form.     

Macrocyclic organotin(IV) carboxylates based on benzenedicarboxylic acid derivatives: Syntheses, crystal structures and antitumor activities

Six new organotin carboxylates based on 1,3-benzenedicarboxylic acid and 1,4-benzenedicarboxylic acid derivatives, namely (Ph₃Sn)₂(2,5-L¹)(C₂H₅OH)₂ (1) (2,5-H₂L¹ = 2,5-dibenzoylterephthalic acid), (Ph₃Sn)₂(2,5-L²)(C₂H₅OH)₂ (2) (2,5-H₂L² = 2,5-bis(4-methylbenzoyl)terephthalic acid), (Ph₃Sn)₂(2,5-L³)(C₂H₅OH)₂ (3) (2,5-H₂L³ = 2,5-bis(4-ethylbenzoyl)terephthalic acid), [(n-Bu₂Sn)₄(4,6-L¹)O₂(OH)(OC₂H₅)]₂·2(C₂H₅OH) (4) (4,6- H₂L¹ = 4,6-dibenzoylisophthalic acid), [(n-Bu₂Sn)₄(4,6-L¹)O₂(OH)(OC₄H₉)]₂·2(C₄H₉OH) (5) and [(n-Bu₂Sn)₄(4,6-L²)O₂(OH)(OC₂H₅)]₂·2(C₂H₅OH) (6) (4,6-H₂L² = 4,6-bis(4-methylbenzoyl)isophthalic acid), have been synthesized. All the organotin carboxylates have been characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopy and X-ray crystallography diffraction analyses. The structural analysis reveals that complexes 1-3 show similar structures, containing binuclear triorganotin skeletons. The significant intermolecular O-H?O hydrogen bonds linked the complexes 1-3 to form a novel 2D network polymer with 38-member macrocycles. In complexes 4-6, two Sn₄O₄ ladders are connected by two 1,3-benzenedicarboxylic acid derivatives to yield ladder-like octanuclear architectures and form macrocycle with 24 atoms. In addition, the antitumor activities of complexes 1-6 have been studied.     

Spectroscopic investigations on the structure and fluxionality of the trihaptocycloheptatrienyl complexes [MX(CO)2(LL)(η3-C7H7)] (M  Mo,W; X  I,Cl; LL  bisphosphine or diamine) and synthesis of the tetracyanoethene adducts [WI(CO)2{Ph2P(CH2)nPPh2}{η3-C9H7(CN)4}] (n = 1 or 2)

Spectroscopic investigations, including ³¹P, ¹H and ¹³C NMR studies, on the formally 6-coordinate bisphosphine complexes [MX(CO)₂{Ph₂P(CH₂)_nPPh₂}(η³-C₇H₇)] (M  Mo, W; X  I, Cl; n = 2 (dppe), n = 1 (dppm); C₇H₇  cycloheptatrienyl) reveal a structure with no molecular plane of symmetry in which inequivalent P-donor atoms are arranged cis-cis and cis-trans to the two mutually cis-carbonyl groups. The dppe complexes exhibit a fluxional process which interconverts inequivalent phosphorus environments. Low temperature ¹H and ¹³C NMR studies on the diamine derivatives [MCl(CO)₂(H₂NCH₂CH₂NH₂)(η³-R)] (M  Mo, W, R  C₇H₇; M  Mo, R  C₃H₅ (allyl)) imply that the non-symmetric structure of the bisphosphine analogues is adopted. The adducts [WI(CO)₂{Ph₂P(CH₂)_n-PPh₂} {η³-C₉H₇(CN)₄}] (n = 1 or 2) are formed by tetracyanoethene addition to the trihapto-bonded cycloheptatrienyl ring of the tungsten complexes [WI(CO)₂-{Ph₂P(CH₂)_nPPh₂}(η³-C₇H₇)] (n = 1 or 2).     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Synthesis,formation constants and reactions of cationic rhodium(I) complexes of nitriles

Reactions of Rh(ClO₄)(CO)(PPh₃)₂ with nitriles produce new cationic rhodium(I) complexes, [RhL(CO)(PPh₃)₂]ClO₄ [L = CH₃CN (1), CH₃CH₂CH₂CN (2) or C₆H₅CN (3)], whose spectral data suggest that the nitriles are coordinated through the nitrogen atom. Formation constants for the reaction Rh(ClO₄)(CO)(PPh₃)₂ + L ⇋ [RhL(CO)(PPh₃)₂]ClO₄, have been measured to be 1.01 × 10⁵ M⁻¹ (CH₃CN), 1.07 × 10⁵ M⁻¹ (CH₃CH₂CH₂CN) and 2.59 × 10⁴ M⁻¹ (C₆H₅CN) at 25°C in monochlorobenzene. The differences in the formation constants for the different nitriles seem to be predominantly due to differences in ΔH (not to differences in ΔS). The nitriles in 1–3 are readily replaced with nitrogen base ligands (unsaturated nitriles and pyridine) and PPh₃.     

Synthesis and characterization of some organo-all-tin dendrimers with different peripheral substituents

The synthesis of the first all-tin-dendrimer Sn[(CH₂)₄SnPh₃]₄ (2) results from complete hydrostannation of tetra(but-3-enyl)stannane (1) with triphenyltin hydride. Selective cleavage of one phenyl group from each dendron of 2 with anhydrous HCl results in Sn[(CH₂)₄Sn(Cl)Ph₂]₄ (3), which on treatment with LiAlH₄ yields the corresponding hydride derivative Sn[(CH₂)₄Sn(H)Ph₂]₄ (4) containing four reactive Sn-H bonds. The cyclopentadienyl derivative Sn[(CH₂)₄Sn(C₅H₅)Ph₂]₄ (5) as well as the transition metal substituted derivatives Sn[(CH₂)₄Sn{Co(CO)₄}Ph₂]₄ (6), Sn[(CH₂)₄Sn{Fe(CO)₂C₅H₅}Ph₂]₄ (7), and Sn[(CH₂)₄Sn{Mn(CO)₅}Ph₂]₄ (8) have been prepared by coupling of 3 with the appropriate Grignard or sodium derivatives of the transition metal moieties. The new compounds were characterized by elemental analyses, IR, ¹H-, ¹³C- and ¹¹⁹Sn NMR spectroscopy and MALDI-TOF mass spectrometry.     

Polymerization of silicon-containing acetylenes. 5. Polymerization of 1-silyl-1-propynes by TaCl5-based catalysts

Polymerization of homologues of 1-(trimethylsilyl)-1-propyne [CH₃C?CSi(CH₃)₃] was studied. CH₃C?CSi(CH₃)₂(n-C₆H₁₃) ( I ) polymerized with 1 : 1 mixtures of TaCl₅ and organometallic cocatalysts (e.g., Ph₄Sn and Ph₃Bi) to produce in good yields a polymer having a weight-average molecular weight (M _w) over 1 × 10⁶. CH₃C?CSi(CH₃)₂ Ph ( II ) and CH₃C?CSi(C₂H₅)₃ ( III ) formed polymers having M _w's of ～ 5 × 10⁵ in moderate yields in the presence of TaCl₅-based catalysts. In contrast, none of CH₃C?CSi(CH₃)₂(i-C₃H₇), CH₃C? CSi(CH₃)₂(t,-C₄H₉), C₂H₅C?CSi(CH₃)₃, and n,-C₄H₉C?CSi(CH₃)₃ polymerized, which is attributed to the steric effect of the monomers. Some other 1-silyl-1-propynes also failed to polymerize. The three new polymers formed from ( I )–( III ) had the structure \documentclass{article}\pagestyle{empty}\begin{document}$\rlap{--} [{\rm CCH}_{\rm 3} \hbox{=\hskip-2pt=} {\rm C(SiRR'R''}\rlap{--} ]_n$\end{document} according to IR and ¹³C-NMR spectra. They were white solids, soluble in low-polarity solvents (e.g., toluene and chloroform) and stable enough in air at room temperature.     

Functionalized cyclopalladated compounds with bidentate Group 15 donor atom ligands: the crystal and molecular structures of [{Pd[5-(COH)C6H3C(H)NCy-C2,N](Cl)}2(μ-Ph2PRPPh2)] (R=CH2CH2, Fe(C5H4)2], [Pd{5-(COH)C6H3C(H)NCy-C2,N}(Ph2PCH2PPh2-P,P)][PF6] and [Pd{5-(COH)C6H3C(H)N(Cy)-C2,N}(Ph2PCH2CH2AsPh2-P,As)][PF6]

The chloro-bridged dinuclear compound [{Pd[5-(COH)C₆H₃C(H)N(Cy)-C2,N]}(μ-Cl)]₂ (1), reacts with tertiary diphosphines in 1:1 molar ratio to give [{Pd[5-(COH)C₆H₃C(H)NCy-C2,N](Cl)}₂(μ-Ph₂PRPPh₂)] (R: CH₂, 2; CH₂CH₂, 3; (CH₂)₄, 4; (CH₂)₆, 5; Fe(C₅H₄)₂, 6; trans-CHCH, 7; C≡C, 8). Treatment of 1 with Ph₂PCH₂CH₂AsPh₂ (arphos) gives the dinuclear complex [{Pd[5-(COH)C₆H₃C(H)N(Cy)-C2,N](Cl)}₂(μ-Ph₂PCH₂CH₂AsPh₂)] (9). The reaction of 1 with tertiary diphosphines or arphos in 1:2 molar ratio in the presence of NH₄PF₆ yields the mononuclear compounds [Pd{5-(COH)C₆H₃C(H)NCy-C2,N}(Ph₂PRPPh₂-P,P)][PF₆] (R: (CH₂)₄, 10; (CH₂)₆, 11; Fe(C₅H₄)₂, 12; 1,2-C₆H₄, 13; cis-CHCH, 14; NH, 15) and [Pd{5-(COH)C₆H₃C(H)N(Cy)-C2,N}(Ph₂PCH₂CH₂AsPh₂-P,As)][PF₆] (16). ¹H-, ³¹P-{¹H}- and ¹³C-{¹H}-NMR, IR and mass spectroscopic data are given. The crystal structures of compounds 3, 6, 9 and 16 have been determined by X-ray crystallography.     

Nature of the complexes formed by alkali metal halides with phosphine oxides

Reaction of alkali metal halides (MX) with methylenediphosphine oxides and various related compounds in nonaqueous solutions leads to the formation of complex compounds. The compositions, properties, and stabilities of these compounds, which have been studied in detail in acetonitrile, are determined by the nature of the cations and anions of the alkali metal halides. Formation of neutral complexes with the composition [MX · L] and cationic complexes with the composition [ML]⁺ has been established. The most characteristic representative of complexes of the first type is [NaI · L]; in the complexes studied, L=R₂P(O)CH₂P(O)R₂ (R=Bu, BuO, or Ph), Ph₂P(O)CH₂P(O) (OC₂H₅)CH₂P(O)Ph₂ and (p-OCH₃C₆H₄)₂P(O)CH₂P(O)(C₆H₄CF₃-p)₂. Compound [LiL]⁺ is characteristic of complexes of the second type; the compounds containing Ph₃P(O), Ph₂P(O)CH₂P(O)Ph₂, and Ph₂P(O)CH₂P(O)(OC₂H₅)CH₂P(O)Ph₂ as ligands have been studied. Stability constants of the complexes [NaI · L] and [LiL]⁺ have been determined by measuring the dependence of the electrical conductivity of solutions of the alkali metal halides in acetonitrile on the concentration of the ligands. The complex-forming power of phosphine oxides increases with increase in the number of P=O groups. Stabilities of the complexes [NaI · L] with ligands with identical structure decrease with increase in the electronegativity of the substituents on the phosphorus atoms.     

Group 4 metallocene complexes with pendant nitrile groups

The preparation of a new functionalized cyclopentadienyl ligand bearing a nitrile pendant substituent, (C₅H₄CMe₂CH₂CN)^? is reported. The corresponding lithium salt of this ligand (1) was prepared by the reaction of in situ lithiated acetonitrile with 6,6-dimethylfulvene. The ligand was subsequently utilized for the synthesis of group 4 metal complexes [(η⁵–C₅H₄CMe₂CH₂CN)₂MCl₂] (M = Ti, 2; M = Zr, 3; M = Hf, 4), [(η⁵–C₅H₅) (η⁵–C₅H₄CMe₂CH₂CN)MCl₂] (M = Ti, 7; M = Zr, 8), and [(η⁵-C₅Me₅) (η⁵ C₅H₄CMe₂CH₂CN)₂ZrCl₂] (9). Alternative route to 2 comprised the preparation of half-sandwich complex [(η⁵–C₅H₄CMe₂CH₂CN)TiCl₃] (6). The prepared compounds were characterized by common spectroscopic methods and the solid state structures of complexes 2, 3, 4, 7, and 9 were determined by the single-crystal X-ray diffraction analysis. In addition, compound 7 was converted to the corresponding dimethyl derivative [(η⁵–C₅H₅) (η⁵–C₅H₄CMe₂CH₂CN)TiMe₂] (10) and also treated with the chloride anion abstractor Li[B(C₆F₅)₄] to generate the cationic complex with the coordinated nitrile group, as suggested by the NMR spectroscopy. A formation of yet another cationic complex was observed upon treating compound 10 with (Ph₃C)[B(C₆F₅)₄].     

Tetraphenyl-and tetratolylantimony complexes with N,N-dialkyldithiocarbamate ligands: Synthesis, X-ray diffraction analysis, and 13C and 15N CP/MAS NMR studies

Crystalline tetraphenylantimony and tetratolylantimony complexes with N,N-dialkyldithiocarbamate ligands [Sb(C₆H₅)₄(S₂CNR₂)] (R = CH₃, C₂H₅, and C₃H₇ and R₂ = (CH₂)₆) were synthesized by ligand exchange reactions and studied by ¹³C and ¹⁵N CP/MAS NMR spectroscopy. X-ray diffraction analysis revealed that the complex [Sb(n-CH₃-C₆H₄)₄{S₂CN(C₃H₇)₂}] exists as the single molecular form, while [Sb(C₆H₅)₄{S₂CN(CH₂)₆}] exists as two molecular conformers. The ¹³C and ¹⁵N signals were assigned to the positions of the atoms in the isomeric structures [Sb(C₆H₅)₄{S₂CN(CH₂)₆}] in terms of different degrees of double bonding in the formally single =N-C(S)S-bond.     

Synthesis and structural characterization of diorganotin(IV) esters of salicylidene-amino acids

Eight diorganotin esters of salicylidene-L-tryptophan(Sal-T) and salicylidene-L-valine(Sal-V), [(n-Bu)₂Sn(Sal-T)] (1), [(n-Bu)₂Sn(Sal-V)] (2), [Ph₂Sn(Sal-T)] (3), [Ph₂Sn(Sal-V)] (4), [(PhCH₂)₂Sn(Sal-T)] (5), [(PhCH₂)₂Sn(Sal-V)] (6), [(4-ClC₆H₄CH₂)₂Sn(Sal-T)] (7) and [(4-ClC₆H₄CH₂)₂Sn(Sal-V)] (8) have been synthesized and characterized by elemental analysis, IR and ¹H NMR. The crystal structures of compounds 1 and 2 have been determined by X-ray single crystal diffraction. Their structures show the tin atoms of two compounds are rendered five-coordinated in distorted trigonal bipyramidal geometries.     

Syntheses and crystal structures of triorganotin(IV) complexes of schiff base derived from 4‐amino‐5‐phenyl‐4H‐1,2,4‐trizole‐3‐thiol

Four triorganotin complexes of the types [(Ph₃Sn)(C₁₅H₁₀FN₄S)] ( 3 ), [(CH₃)₃Sn(C₁₅H₁₀FN₄S)]_n ( 4 ), [(Ph₃Sn)(C₁₃H₉FN₄S₂)] ( 5 ), and [(CH₃)₃Sn(C₁₃H₉FN₄S₂)]_n ( 6 ) have been obtained by Schiff base compound 1 (derived from 4‐fluorobenzaldehyde) and compound 2 (derived from thiophene‐2‐carboxadehyde) with triorganotin chloride in the presence of sodium ethoxide. All the complexes were characterized by elemental analysis, IR, and NMR spectroscopies, and X‐ray diffraction analyses, which revealed that complexes 3 and 5 are mononuclear structures, complex 4 and 6 are one‐dimensional zigzag infinite chains via N → Sn and S → Sn bonding interactions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:583–591, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20481     

Synthesis of (adamantylimido)vanadium(V)-alkyl complexes containing aryloxo ligands and their use as the catalyst precursors for ring-opening metathesis polymerization of norbornene, and ring-opening polymerization of tetrahydrofuran

Various (adamantylimido)vanadium(V) dialkyl complexes containing aryloxo ligands, V(NAd)(CH₂SiMe₃)₂(OAr) [Ad = 1-adamantyl (1); Ar = Ph (a), 4-FC₆H₄ (b), 2,6-F₂C₆H₃ (c), 2,6-Me₂C₆H₃ (d), C₆F₅ (e)], have been prepared and identified. These complexes were employed as the catalyst precursors for ring-opening metathesis polymerization (ROMP) of norbornene (NBE) in the presence of PMe₃ at 80 °C. The activity was strongly affected by the aryloxo substituent and increased in the order: C₆H₅ < 4-FC₆H₄ < 2,6-Me₂C₆H₃ << 2,6-F₂C₆H₃, C₆F₅. The same trend was observed in the ROMPs by the arylimido-aryloxo analogues, V(NAr′)(CH₂SiMe₃)₂(OAr) (2a-e; Ar′ = 2,6-Me₂C₆H₃), under the same conditions, and the activities by the arylimido analogues were generally higher than the adamantylimido analogues in most case. The (imido)vanadium(V) complexes containing O-2,6-F₂C₆H₃ (1,2c) or OC₆F₅ (1,2e) exhibited high catalytic activities, and these results strongly suggest that electronic as well as steric factors play a role. Living ring-opening polymerization of THF proceeded in the presence of V(NAd) (CH₂SiMe₃)(OAr)₂ (Ar = 2,6-Me₂C₆H₃, C₆F₅) and [Ph₃C][B(C₆F₅)₄], affording high molecular weight polymers with narrow molecular weight distributions (ex. M_n = 2.11 × 10⁵, M_w/M_n = 1.18).     

The reaction of organotin compounds with derivatives of triarylmethane in CH2Cl2

The reaction of RSnMe₃ with the triarylmethyl salts Ph₃CBF₄, (C₆Cl₅)₃CSbCl₆ and (p-NO₂C₆H₄)₃CBr was studied. It was shown that the reaction of RSnMe₃ (R  CH₃, CH₂CHCH₂, C₁₃H₉ (9-fluorenyl), C₉H₇ (indenyl), PhCC and CN) with Ph₃CBF₄ is an electrophilic substitution process and that Ph₃CR is formed quantitatively. The reactions of PhSnMe₃ with Ph₃CBF₄ and RSnMe₃ (R  CH₃, CH₂CHCH₂, Ph and PhCC) with (C₆Cl₅)₃SbCl₆ are redox processes. (p-NO₂-C₆H₄)₃CBr only reacts with RSnMe₃ when R is a strong electron withdrawing group (R  9-fluorenyl, indenyl and cyclopentadienyl) and (p-NO₂C₆H₄)₃CR and (p-NO₂C₆H₄)₃C^. are formed. It is assumed that the reactions which give (p-NO₂C₆H₄)₃CR and (p-NO₂C₆H₄)₃C^. are independent.