Synthesis, characterization and hydrolytic behavior of new bis(2-pyridylthio)acetate ligand and related organotin(IV) complexes

The new sodium bis(2-pyridylthio)acetate ligand, Na[(pyS)₂CHCO₂], has been prepared in ethanol solution using 2-mercaptopyridine, dibromoacetic acid and NaOH. New mono- and di-organotin(IV) derivatives containing the anionic bis(2-pyridylthio)acetate have been synthesized from reaction between SnR_nCl_4−n (R = Me, Ph and ⁿBu, n = 1-2) acceptors and Na[(pyS)₂CHCO₂]. Mono-nuclear complexes of the type {[(pyS)₂CHCO₂]R_nSnCl_4−n−1} have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear (¹H and ¹¹⁹Sn) NMR spectral data and X-ray crystallography. ESI-MS spectra of methanol solution of the complexes show the existence of hydrolysed species. Attempts to crystallize the dimethyltin(IV) derivative (3), from acetonitrile solution yield the dimeric dicarboxylatotetramethyldistannoxane (8), which was characterized by single crystal diffraction analysis.     

Synthesis and characterization of new organotin(IV) complexes with polyfunctional ligands

New mono-, di- and tri-organotin(IV) derivatives containing the neutral bis(2-pyridylthio)methane ligand, [(pyS)₂CH₂] and tris(2-pyridylthio)methane ligand, [(pyS)₃CH] have been synthesized from reaction with SnR_nCl_4−n (R = Me, ⁿBu, Ph and Cy, n = 1-3) acceptors. Mono-nuclear adducts of the type {[(pyS)₂CH₂]R_nSnCl_4−n} and {[(pyS)₃CH]R_nSnCl_4−n} have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear (¹H and ¹¹⁹Sn) NMR spectral data. The ¹H and ¹¹⁹Sn NMR and ESI-MS data suggest for the triorganotin(IV) derivatives a complete dissociation of the compounds in solution. The mono- and di-organotin(IV) derivatives show a greater stability in solution, and their spectroscopic data are in accordance with the existence of six-coordinated RSnCl₃N₂ or R₂SnCl₂N₂ species.     

Synthesis and spectroscopic characterization of new triorganotin(IV) complexes with the bis(1‐methyl‐1H‐imidazol‐2‐ylthio)acetate ligand: effects on trout erythrocyte components

Triorganotin(IV) derivatives containing the anionic ligand bis(1‐methyl‐1H‐imidazol‐2‐ylthio)acetate [(S‐tim)₂CHCO₂]⁻ were synthesized from the reaction between R₃SnCl acceptors (R = Me and Ph) and the sodium salt of the ligand. Mono‐nuclear complexes of the type [(S‐tim)₂CHCO₂]SnR₃ were obtained, which were fully characterized by elemental analyses and FT‐IR in the solid state, and by NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy and electrospray ionization mass in solution. The toxic effects shown by these compounds on trout erythrocyte components showed that the toxicity of the organotin(IV) complexes depends on the nature and on the lipophilicity of the substituents on the metal centre. Copyright © 2007 John Wiley & Sons, Ltd.     

Designed synthesis of metal-organic frameworks containing gold(I) cations supported in phosphazene-phosphine polymeric matrices

The reaction of the polyphosphazenes {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂)₂]_x}_n, x = 0.15 (1a), 0.25 (1b), 0.35 (1c), with [Au(THT)Cl] (THT = tetrahydrothiophene) in dichloromethane gave the polymers {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂AuCl)₂]_x}_n, x = 0.15, (2a), 0.25 (2b), 0.35 (2c), respectively. The reaction of (1a) with [Au(PPh₃)₂]PF₆ in refluxing THF led to the replacement of the PPh₃ ligands giving a metal-organic framework of idealized formula {[NP(O₂C₁₂H₈)]_1−x[NP(OC₆H₄PPh₂)₂(AuPF₆)_0.5]_x}_n, x = 0.15, (3a), 0.25 (3b) containing cationic [-Ph₂P-Au⁺-PPh₂-] cross-linking sites. The insoluble polymeric matrix (3a), having pendant PPh₂ groups, was reacted with [Au(THT)Cl] to give the new polymeric framework of composition {[NP(O₂C₁₂H₈)]_0.85[NP(OC₆H₄PPh₂)₂(AuPF₆)_0.5(AuCl)_0.5]_0.15}_n (4).     

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.     

Spectroscopic and structural studies of the 2D Mn(II) coordination polymer from a bridging Noxa, Npy bidentate ligand; tetra-n-butylammonium[5-(3-pyridyl)-1,3,4-oxadiazole-2-thiolate]

A coordination polymer {[Mn(3-pyt)₂(H₂O)₂][N(n-Bu)₄]⁺[3-pyt]⁻}_n (3) has been synthesized from the reaction of tetra-n-butylammonium[5-(3-pyridyl)-1,3,4-oxadiazole-2-thiolate] {[N(n-Bu)₄]⁺[3-pyt]⁻} and Mn(OAc)₂ · 4H₂O. The ligand and the Mn(II) complex 3 have been characterized by elemental analyses, IR, ¹H and ¹³C NMR spectroscopy, in addition 3 has also been studied crystallographically. The single crystal X-ray structure of the 3 shows that the ligand is bonded to Mn(II) via its pyridyl and oxadiazole nitrogen atoms. This bonding pattern connects the Mn(II) centres to afford an uniform two dimensional coordination frame work where the [Mn(3-pyt)₂(H₂O)₂]_n molecules are stacked in a parallel layers. The overall arrangement of molecules in crystal lattice results in open channels in which the enclosed tetra-n-butylammonium cations are stabilized by anionic oxadiazole molecules through N⁺···S⁻ ionic interactions.     

Organotin(IV) azepane dithiocarbamates: Synthesis and characterization of the first organotin(IV) complexes with seven-membered cyclic dithiocarbamates

Abstract

We report the synthesis and spectroscopic characterization of the first organotin(IV) complexes with cyclic seven-membered dithiocarbamate ligands: the azepane-1-carbodithioate and the homopiperazine-1,4-bis-carbodithioate with two different organotin entities, di-n-butyltin and tri-cyclohexyltin: [(C₄H₉)₂Sn{S₂CN(CH₂)₆}₂] (3), [(C₆H₁₁)₃Sn{S₂CN(CH₂)₆}] (4), and [(C₆H₁₁)₃Sn}₂ (μ-S₂CN(C₅H₁₀)NCS₂)] (5). Compounds (3–5) are air-stable both in solid-state and in solution, and were characterized by elemental analyses, IR, FAB⁺–MS, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy. Their molecular structures were unambiguously established by single-crystal X-ray diffraction studies. The geometrical arrangement around the tin atom can be described as distorted octahedral for (3) and distorted trigonal bipyramid for (4) and (5). The coordination mode for both ligands is considered as asymmetric bidentate, as happens in other organotin(IV) dithiocarbamates. Furthermore, (4) and (5) do not exhibit intermolecular secondary interactions, while (3) presents intermolecular interactions between the tin and a sulfur atom with the reciprocally neighboring molecule, giving rise to a zig-zag polymeric structure.     

Investigations on organotin,organolead, lead(IV), and lead(II) dithiolates

Bis(triorganometal) 1,2-dithiolates (R₃M)₂S₂R′ [(HS)₂R′ = C₇H₈S₂ for toluene-dithiol-3,4 (H₂TDT); M = Sn, Pb; R = Ph; or (HS)₂R′ = C₁₀H₁₄S₂ for 1,2-dimethyl-4,5-bis(mercaptomethyl)benzene (H₂DBB); M = Sn, R = CH₃, C₆H₅; M = Pb, R = C₆H₅], diorganometal 1,2-dithiolates R₂MS₂R′ [(HS)₂R′ = C₆H₆S₂ for 1,2-dimercaptobenzene (H₂DMB); M = Pb, R = CH₃, C₂H₅, C₆H₅; or (HS)₂R′ = H₂TDT; M = Sn, R = CH₃, C₆H₅; M = Pb, R = C₆H₅; or (HS)₂R′ = H₂DBB; M = Sn, R = CH₃, C₆H₅; M = Pb, R = CH₃, C₂H₂, C₆H₅; or (HS)₂R′ = C₈H₆N₂S₂ for 2,3-dimercaptoquinoxaline (H₂QDT); M = Pb, R = C₆H₅] and some lead(IV) and lead(II) dithiolates Pb(S₂R′)_n [(HS)₂R′ = H₂DMB, n = 2; (HS)₂R′ = H₂TDT, n = 2; (HS)₂R′ = H₂DBB, n = 1 or 2] have been prepared. Vibrational, ¹H NMR, and Mössbauer spectroscopic data are consistent with pentacoordination of tin in R₂SnTDT and with tetracoordination of tin in R₂SnS₂R′ and (R₃Sn)₂S₂R′ in the solid state. The soluble compounds are monomeric in solution. Coupling constants for the methyltin compounds indicate tetracoordination in solution.     

The hydrogenphosphate complex of (1,5-cyclooctadiene)iridium(I), {[Bu4N][(1,5-COD)Ir · HPO4]}n: synthesis, spectroscopic characterization, and ES-MS of a new, preferred precursor to HPO4 and Bu4N stabilized Ir(0)n nanoclusters

The synthesis and characterization of a previously unknown, rare organometallic-phosphate complex, {[Bu₄N][(1,5-COD)Ir · HPO₄]}_n (1), is described. Characterization of 1 was accomplished by elemental analysis, electrospray mass spectrometry (ES-MS), and ¹H and ¹³C NMR which established the symmetry of the product as at least C₂ or C_s. The ES-MS reveals an interesting, Ir(I) to Ir(III) oxidative process with intense peaks displaying the ¹⁹¹Ir/¹⁹³Ir isotopic distribution patterns expected for the fragments [(1,5-COD)Ir^III(HPO₄)₂]⁻, [(C₈H₁₁)₂(Ir^III)₂(PO₄)(HPO₄)(H₂O)]⁻, and [(C₈H₁₁)₂(Ir^III)₂(PO₄)(HPO₄)(H₂O)₂]⁻. These fragments, in turn, provide evidence for a structure with two HPO₄²⁻ groups attached to a single Ir, for example ring structures (of at least such C₂ or C_s symmetry) such as {[Bu₄N][(1,5-COD)Ir · HPO₄]}₂. Complex 1 is significant since it is known to be the preferred, compositionally precise precursor to the prototype example of a recently discovered class of novel, HPO₄²⁻ and Bu₄N⁺ stabilized nanoclusters, (Bu₄N)_2n²ⁿ⁺[Ir(0)_n · (HPO₄)_n]²ⁿ⁻. Such nanoclusters are being extended, via their analogous hydrogenphosphate-organometallic precursors (1,5-COD)M^{+ or 2+}/HPO₄²⁻ (M=Rh(I), Ru(II), Pt(II)) to their corresponding, catalytically active [M(0)_n · (HPO₄)_n]²ⁿ⁻ nanoclusters.     

Tricarbonylmanganese(I) derivatives of [Di(pyrazolyl)(2-pyridyl)methyl]aryl scorpionates

The cobalt(II) chloride catalyzed Peterson rearrangement reactions between sulfinyldi-(pyrazolyl) and aryl(pyridyl)methanone derivatives yield di(pyrazolyl)(pyridyl)hetero-scorpionate ligands. Reaction of these ligands with Mn(CO)₅Br in the presence of a silver salt produces the monometallic complexes {[κ³-PhC(pz)₂(2-py)]Mn(CO)₃}(O₃SCF₃) (1a), {[κ³-PhC(pz)₂(2-py)]Mn(CO)₃}(PF₆) (1b), {[κ³-PhC(^4-Mepz)₂(2-py)]Mn(CO)₃}(PF₆) (2), {[κ³-p-BrC₆H₄C(pz)₂(2-py)]Mn(CO)₃}(PF₆) (3), and the bimetallic complexes [(CO)₃Mn{m-C₆H₄[C(pz)₂(2-py)]₂}Mn(CO)₃](BF₄)₂ (5a) and {m-C₆H₄[C(pz)₂(2-py)Mn(CO)₃]₂}(PF₆)₂ (5b) (pz = pyrazolyl ring, py = pyridyl ring). These octahedral manganese complexes show interesting structural diversity, with the complexes being organized in the solid state into complex supramolecular structures by an array of non-covalent forces.     

Syntheses and characterization of triorganotin complexes: X-ray crystallographic study of triorganotin pyridinedicarboxylates with trinuclear, 1D polymeric chain and 2D network structures

A series of new triorganotin(IV) pyridinedicarboxylates [(C₂H₅)₃NH][(Me₃Sn)₃(2,6-pdc)₂(H₂O)₂] (1), [(C₂H₅)₃NH][(Ph₃Sn)₃(2,6-pdc)₂(H₂O)₂] (2), [(C₂H₅)₃NH]{[(PhCH₂)₃Sn]₃(2,6-pdc)₂(H₂O)₂} (3), [Me₃Sn(3,5-pdc)]_n (4), [Ph₃Sn(3,5-pdc)]_n (5), [(PhCH₂)₃Sn(3,5-pdc)]_n (6), [(Me₃Sn)₂(2,5-pdc)]_n (7), [(Ph₃Sn)₂(2,5-pdc)]_n (8) and {[(PhCH₂)₃Sn]₂(2,5-pdc)}_n (9) were synthesized by the reaction of trimethyltin(IV), triphenyltin(IV) or tribenzyltin(IV) chloride with 2,6(3,5 or 2,5)-H₂pdc (pdc = pyridinedicarboxylate) when triethylamine was added. Complexes 1-9 have been characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR analyses. Among them complexes 1, 5 and 7 have also been characterized by X-ray crystallographic diffraction analyses. Complex 1 has a trinuclear structure and forms a 2D supramolecular structure due to the coordinated water molecules via hydrogen bonds to the pendant O atoms of the carboxyl groups and the N atoms derived of the pyridine ring. Complex 5 forms a 1D polymeric chain by the intermolecular Sn?N (N atom derived of pyridine ring) interactions. Complex 7 has a network structure where 2,5-pyridinedicarboxylate acts as a tetradentate ligand coordinated to trimethyltin(IV) ions.     

Über Chalkogenolate. 179. Kupfer(I)-thioxanthate und Thioxanthatocuprate(I)

On Chalcogenolates. 179. Copper(I) Thioxanthates and Thioxanthatocuprates(I) Copper(I) thioxanthates Cu[S₂C? SR], where R = C₂H₅, ⁿC₄H₉, and CH₂? C₆H₅, have been prepared by two procedures and studied by means of diverse methods. They are soluble in ethanolic and acetonic solutions containing the corresponding [S₂C? SR]^? ions in excess to yield thioxanthatocuprates(I) [Cu_n(S₂C? SR)_n+1]^?. The compounds [(C₆H₅)₄P][Cu_n(S₂C? SC₂H₅)_n+1] with n = 1, 4, 6 have been isolated. The existence of [(C₆H₅)₄P][Cu₄(S₂C? SC₄H₉)₅] and [(C₆H₅)₄P][Cu₆(S₂C? SCH₂? C₆H₅)₇] has been ascertained.     

A novel cadmium(II) coordination polymer containing two kinds of independent one‐dimensional chain

The structure of the title compound, catena‐poly[[cadmium(II)‐di‐μ‐chlorido‐μ‐(1,4‐diazoniabicyclo[2.2.2]octane‐1‐carboxylato)] [[aquachloridocadmium(II)]‐di‐μ‐chlorido] dihydrate], {[Cd(C₈H₁₅N₂O₂)Cl₂][CdCl₃(H₂O)]·2H₂O}_n, contains two kinds of independent one‐dimensional chain, viz. {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}_n and {[CdCl₃(H₂O)]⁻}_n, and uncoordinated water molecules. Each Cd^II cation in the {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}_n chain is octahedrally coordinated by two pairs of bridging chloride ligands and two O atoms from different bridging carboxylate groups. Cd^II cations in the {[CdCl₃(H₂O)]⁻}_n chain are also octahedrally surrounded by four bridging chloride ligands, one terminal chloride ligand and one coordinated water molecule. Hydrogen bonds between solvent water molecules and these two independent chains generate a three‐dimensional framework containing two‐dimensional zigzag layers.<!?tpb=18pt>     

Synthesis,Theoretical Calculation,and Biological Studies of Mono- and Diphenyltin(IV) Complexes of N-Methyl-N-hydroxyethyldithiocarbamate

In this study, chlorophenyltin(IV) [(C₆H₅)(Cl)Sn(L)₂] and diphenyltin(IV) [(C6H5)2Sn(L)2] of N-methyl-N-hydroxyethyldithiocarbamate were prepared and characterized using various spectroscopic methods (FTIR, ¹H, ¹³C, and ¹¹⁹Sn NMR) and elemental analysis. The FTIR and NMR spectral data, used to establish the structure of the compounds, showed the formation of the complexes via coordination to the two sulfur atoms from the dithiocarbamate ligand and the respective phenyltin(IV) derivatives. This coordination mode was further explored by DFT calculations, which showed that the bonding around the Sn center in [(C6H5)2Sn(L)2] was more asymmetric compared to the bonding around [(C₆H₅)(Cl)Sn(L)₂]. However, the Sn–S bonds in [(C₆H₅)(Cl)Sn(L)₂] were found to be more covalent than those in [(C6H5)2Sn(L)2]. Furthermore, the charge density of the frontier orbitals showed that the Sn atom in the complexes is relatively electrophilic and the Sn atom in [(C6H5)2Sn(L)2] has a lower atomic dipole moment than that of [(C₆H₅)(Cl)Sn(L)₂]. The cytotoxicity and anti-inflammatory study revealed that [(C6H5)2Sn(L)2], with the higher number of phenyl substituents, has a higher potency than [(C₆H₅)(Cl)Sn(L)₂]. The bio-efficacy study of these complexes as cytotoxic and anti-inflammatory agents showed that the complexes possessed moderate to high activity in comparison to the camptothecin and diclofenac in each case. Nevertheless, the diphenyltin(IV) derivative [(C6H5)2Sn(L)2] was found to possess a better activity than its counterpart due to the number of phenyl rings attached to the Sn center.     

Three AgI,CuI and CdII coordination polymers based on the new asymmetrical ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole: syntheses,characterization and emission properties

The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C₁₇H₁₃N₅O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag^I, Cu^I and Cd^II metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF₆}_n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu₂I₂( L )₂]·C₄H₈O₂}_n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )₂(NO₃)₂]·2CH₄O·0.65H₂O}_n, were obtained. The experimental results show that ligand L coordinates easily with linear Ag^I, tetrahedral Cu^I and octahedral Cd^II metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.     

Synthesis and pyrolysis of silicon and tin containing poly(2,2′-dioxy-1,1′-biphenoxy-phosphazenes)

The polyphosphazene {[NP(O₂C₁₂H₈)]_0.5[NP(OC₆H₄Br)₂]_0.5}_n (1) [(O₂C₁₂H₈) = 2,2′-dioxy-1,1′-biphenyl] that, as an strictly alternating copolymer, can be considered nearly as the homopolymer [NP(O₂C₁₂H₈)NP(OC₆H₄Br)₂]_n, was reacted first with ^tBuLi in THF at −78 °C to give the intermediate [NP(O₂C₁₂H₈)NP(OC₆H₄Li)₂]_n (2) and subsequently with the chlorosilanes SiMe₃Cl and SiMe₂(C₆H₅)Cl or with the chlorostannane SnMe₃Cl, to obtain the new polyphosphazenes {(NP[O₂C₁₂H₈])_0.5[NP(OC₆H₄SiMe₃)₂]_0.5−x[NP(OC₆H₅)(OC₆H₄SiMe₃)]_x}_n (3a) (x = 0.15-0.5), {(NP[O₂C₁₂H₈])_0.5[N(POC₆H₄SiMe₂Ph)₂]_0.2[NP(OC₆H₅)(OC₆H₄SiMe₂Ph)]_0.3}_n (3b), and {(NP[O₂C₁₂H₈])_0.5[NP(OC₆H₅)(OC₆H₄SnMe₃)]_0.5}_n (4), having a very regular distribution of the silicon or tin organometallic sites along the chains. The pyrolysis of the polymers in air at 800 °C gave microcrystalline residues (characterized by IR, XRD, SEM and TEM-EDXA) consisting on phases of SiO₂ · P₂O₅ · P₂O_7.9 · SiP₂O₇, or, in the case of the tin derivative, almost pure SnP₂O₇. The results indicate that, while part of the Si content is lost during the pyrolysis, almost all the tin in the original polymer was incorporated to the final residue.     

Syntheses, crystal structures of a series of copper(II) complexes and their catalytic activities in the green oxidative coupling of 2,6-dimethylphenol

Three mixed-ligand Cu^II complexes bearing iminodiacetato (ida) and N-heterocyclic ligands, namely, [Cu₂(ida)₂(bbbm)(H₂O)₂] · H₂O (1), [Cu₂(ida)₂(btx)(H₂O)₂] · 2H₂O (2) and [Cu₂(ida)₂(pbbm)(H₂O)₂] · H₂O · 3CH₃OH (3) (bbbm = 1,1^′-(1,4-butanediyl)bis-1H-benzimidazole, btx = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, pbbm = 1,1^′-(1,3-propanediyl)bis-1H-benzimidazole), in addition to three fcz-based Cu^II complexes, namely, {[Cu(fcz)₂(H₂O)₂] · 2NO₃}_n (4), {[Cu(fcz)₂(H₂O)] · SO₄ · DMF · 2CH₃OH · 2H₂O}_n (5) and {[Cu(fcz)₂Cl₂] · 2CH₃OH}_n (6) (fcz = 1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-l-yl) methyl]ethanol) have been prepared according to appropriate synthetic strategies with the aim of exploiting new and potent catalysts. Single crystal X-ray diffraction shows that 1 and 2 possess similar binuclear structures, 3 features a 2D pleated network, and 4 exhibits a 1D polymeric double-chain structure. Complexes 1-6 are tested as catalysts in the green catalysis process of the oxidative coupling of 2,6-dimethylphenol (DMP). Under the optimized reaction conditions, these complexes are catalytically active by showing high conversion of DMP and high selectivity of PPE. The preliminary study of the catalytic-structural correlations suggests that the coordination environment of the copper center have important influences on their catalytic activities.     

A ferrocenyl-bridged intramolecularly coordinated bis(diorganostannylene): Synthesis, molecular structure and reactivity of [4-t-Bu-2,6-{P(O)(O-i-Pr)2C6H2Sn}C5H4]2Fe

The intramolecularly coordinated heteroleptic stannylene [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂]SnCl serves as synthon for the synthesis of the ferrocenyl-bridged bis(diorganostannylene) [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂SnC₅H₄]₂Fe (1) which in turn reacts with W(CO)₆ and Cr(CO)₄(C₇H₈) to provide the corresponding transition metal complexes [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂Sn{W(CO)₅}C₅H₄]₂Fe (2) and [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂SnC₅H₄]₂Fe · Cr(CO)₄ (3), respectively. Reaction of compound 1 with sulphur and atmospheric moisture gave, under partial tin-carbon and oxygen-carbon bond cleavage, a tetranuclear organotin-oxothio cluster 5. All compounds were characterized by ¹H, ¹³C, ³¹P, and ¹¹⁹Sn NMR, and IR spectroscopy, as well as by single-crystal X-ray diffraction analysis. Compounds 1 and 3 were also investigated by Mössbauer spectroscopy. Cyclovoltametric studies reveal the influence of the organostannyl moieties on the redox-behaviour of compounds 1-3 in comparison with unsubstituted ferrocene.     

Assembly of silver(I) coordination polymers incorporating pyromellitic acid and N-heterocyclic ligands

Five mixed ligands coordination polymers [Ag₄(apym)₂(pma)·(H₂O)₂]_n (1), {[Ag₄(dmapym)₄(pma)·(H₂O)₂]·(H₂O)₆}_n (2), [Ag₂(apyz)₂(H₂pma)·(H₂O)₄]_n (3), {[Ag₄(apyz)₂(pma)·(H₂O)₂]·(H₂O)₂}_n (4) and [Ag₄(NH₃)₈(pma)·(H₂O)₆]_n (5) (apym = 2-aminopyrimidine, dmapym = 4, 6-dimethyl-2-aminopyrimidine, apyz = 2-aminopyrazine, H₄pma = pyromellitic acid) were synthesized and characterized. For 1 and 2, as the substituents change from H to methyl, the dimensions of 1–2 decrease from three-dimension (3D) to one-dimension (1D) due to the steric effect of methyl groups. For 3 and 4, as the ratios of Ag₂O/apyz/pma vary from 1:1:1 to 2:1:1, the structure of 3 is a 1D ladder structure built from Ag-apyz double chains and pma anions, while the structure of 4 is a two-dimension (2D) grid. As excess ammonia is added to above four reaction systems, the structure of 5 contains unprecedented {[Ag(NH₃)₂]⁺}_n chains and pma anions. The substituent on the pyrimidyl ring, ratios of reactants, solvent systems and ligand isomers intensively influence the coordination environments of metal ion and the coordination modes of the carboxyl group, and thus determine the structures of the coordination polymers. The photoluminescent properties of 1–5 were also investigated.     

Synthesis and characterization of some organotin(IV) adducts containing a related series of pyridines: Crystal structure of [SnMe2Cl2(bu2bpy)]

Organotin(IV) complexes of [SnR_(4−n)Cl_n] (n = 2, R = Me, ⁿBu; n = 1, R = Ph) react with the bidentate pyridyl ligand 4,4′-di-tert-butyl-2,2′-bipyridine (bu₂bpy) to give hexa-coordinated adducts with the general formula [SnR_(4−n)Cl_n(bu₂bpy)]. However, the reaction of these organotin(IV) complexes with the corresponding monodentate ligand 4-tert-butylpyridine (bupy) resulted in the formation of the hexa-coordinated complex [SnMe₂Cl₂(bupy)₂] and the penta-coordinated complexes [SnR_(4−n)Cl_n(bupy)] (n = 2, R = ⁿBu; n = 1, R = Ph). Moreover, the reaction of the above organotin(IV) complexes with 4,4′-trimethylenedipyridine (tmdp) yields hexa-coordinated adducts with the general formula [SnR₂Cl₂(tmdp)] (R = Me, ⁿBu) and the penta-coordinated complex [ClPh₃Sn-μ-(tmdp)SnPh₃Cl] in the solid state. The resulting complexes have been characterized by multinuclear NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy and elemental analysis. NMR data shows that the triphenyltin(IV) adducts are not stable in solution and dissociate to give tetra-coordinated tin(IV) complexes. The X-ray crystal structure determination of [SnMe₂Cl₂(bu₂bpy)] reveals that the tin atom is hexa-coordinated in an octahedral geometry with a trans-[SnMe₂] configuration.