Solution and solid-state structure of the anion [Ag(2)[closo-CB(11)H(12)](4)](2-)

Addition of the carbene 1,3-dimesitylimidazol-2-ylidene (IMes) to a toluene solution of Ag[closo-CB(11)H(12)] results in the formation of the complex [(IMes)(2)Ag](2)[Ag(2)[closo-CB(11)H(12)](4)], the anionic component of which contains two silver(I) centers bridged by two carboranes in addition to one terminally bound carborane on each metal, in the solid-state. Comparison of the observed (11)B[(1)H] NMR chemical shifts of [(IMes)(2)Ag](2)[Ag(2)[closo-CB(11)H(12)](4)] or Ag[closo-CB(11)H(12)] with [NBu(4)][closo-CB(11)H(12)] in CD(2)Cl(2) demonstrates that the silver ion interacts significantly with the cage in solution. Theoretical investigations using the ab initio/GIAO/NMR method of [closo-CB(11)H(12)](-) and Na[closo-CB(11)H(12)] as model geometries for the silver salts support experimental evidence for these Ag...[BH] interactions in solution.     

Synthesis, reaction and structure of a highly light-stable silver(I) cluster with an Ag4S4N4 core having a tridentate 4N-morpholyl 2-acetylpyridine thiosemicarbazone ligand: use of water-soluble silver(I) carboxylates as a silver(I) source

A novel neutral tetrameric silver(I) cluster [Ag(mtsc)](4) was obtained from reactions of a tridentate (4)N-morpholyl 2-acetylpyridine thiosemicarbazone ligand (N'-[1-(2-pyridyl)ethylidene] morpholine-4-carbothiohydrazide, Hmtsc) and silver(I) sources containing Ag-O bonds (Ag(2)O, Ag(OAc), silver(I) 2-pyrrolidone-5-carboxylate (infinity){[Ag(Hpyrrld)](2)}, silver(I) 5-oxo-2-tetrahydrofurancarboxylate (infinity){[Ag(othf)](2)}, and silver(I) complexes with camphanic acid (infinity){[Ag(ca)]} and (infinity){[Ag(ca)(Hca)]}). The cluster was characterized by elemental analysis, TG/DTA, FTIR and single-crystal X-ray analysis in the solid state. The solution properties of the complexes were investigated using solution molecular weight measurement, ESI-MS and solution ((1)H, (13)C and (31)P) NMR spectroscopy. The obtained cluster is a novel example of a light-stable Ag(I) cluster with a tridentate thiosemicarbazone ligand and the second report of a crystal structure of a thiosemicarbazone silver(I) complex. The reaction of the tetramer with a large excess of PPh(3) gave dimeric complexes, namely, [Ag(micro(S)-mtsc)(PPh(3))](2) and [(PPh(3))(2)Ag(micro(S)-mtsc)(2)Ag]. The chloroform solution of the tetrameric complex showed modest and effective activities against selected bacteria (Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa) and yeasts (Candida albicans and Saccharomyces cerevisiae), respectively, but it did not inhibit the growth of any selected microorganisms in a water-suspension system.     

The coordination chemistry of selenophosphite ligands. Synthesis and characterization of heterometallic tetranuclear clusters [M{CpFe(CO)(2)P(Se)(OR)(2)}(3)](PF(6)) (M = Cu, Ag; R = (n)Pr, (i)Pr) and [Cu(mu-X) {CpFe(CO)(2)P(Se)(O(i)Pr)(2)}](2) (X = Cl, Br)

A neutral selenium donor ligand, [CpFe(CO)(2)P(Se)(OR)(2)] is used for the construction of Cu(I) and Ag(I) complexes with a well-defined coordination environment. Four clusters [M{CpFe(CO)(2)P(Se)(OR)(2)}(3)](PF(6)), (where M = Cu, R = (n)Pr, ; R = (i)Pr, and M = Ag, R = (n)Pr, ; R = (i)Pr, ) are isolated from the reaction of [M(CH(3)CN)(4)(PF(6))] (where M = Cu or Ag) and [CpFe(CO)(2)P(Se)(OR)(2)] in a molar ratio of 1 : 3 in acetonitrile at 0 degrees C. The reaction of [CpFe(CO)(2)P(Se)(O(i)Pr)(2)] with cuprous halides in acetone produce two mixed-metal, Cu(I)(2)Fe(II)(2) clusters, [Cu(mu-X) {CpFe(CO)(2)P(Se)(O(i)Pr)(2)}](2) (X = Cl, ; Br, ). All six clusters have been fully characterized spectroscopically ((1)H, (13)C, (31)P, and (77)Se NMR, IR), and by elemental analyses. X-Ray crystal structures of and consist of discrete cationic clusters in which three iron-selenophosphito fragments are linked to the central copper or silver atom via selenium atoms. Both clusters and crystallize in the noncentrosymmetric, hexagonal space group P6[combining macron]2c. The coordination geometry around the copper or silver atom is perfect trigonal-planar with Cu-Se and Ag-Se distances, 2.3505(7) and 2.5581(7) A, respectively. X-Ray crystallography also reveals that each copper center in neutral heterometallic clusters and is trigonally coordinated to two halide ions and a selenium atom from the selenophosphito-iron moiety. The structures can also be delineated as a dimeric unit which is generated by an inversion center and has a Cu(2)X(2) parallelogram core. The dihedral angle between the Cu(2)X(2) plane and the plane composed of Cp ring is found to be 24.62 and 84.58 degrees for compound and , respectively. Hence the faces of two opposite Cp rings are oriented almost perpendicular to the Cu(2)X(2) plane in , but are close to be parallel in . This is the first report of the coordination chemistry of the anionic selenophosphito moiety [(RO)(2)PSe](-), the conjugated base of a secondary phosphine selenide, which acts as a bridging ligand with P-coordination on iron and Se-coordination to copper or silver.     

Synthesis and crystal structure of a novel decanuclear silver cluster complex [Ag(SC6H2Pri(3)-2,4,6)](10).2CHCI3.C2H5OH

The cluster [Ag(SC6H2Pri(3)-2,4,6)]10 (1) contains a 20-membered ring of alternating silver and sulfur atoms, which is compactly folded; the sulfur atoms are doubly bridging and each silver atom exhibits linear two-coordination in the primary Ag-S interactions.     

Group 11 complexes with the bis(3,5-dimethylpyrazol-1-yl)methane ligand. How secondary bonds can influence the coordination environment of Ag(I): the role of coordinated water in [Ag2(mu-L)2(OH2)2](OTf)2

The complexation properties of the ligand bis(3,5-dimethylpyrazol-1-yl)methane (L) towards group 11 metals have been studied. The reaction in a 1 : 1 molar ratio with [Cu(NCMe)4]PF6 or Ag(OTf) complexes gives the mononuclear [CuL(NCMe)]PF6 (1), with crystallographic mirror symmetry, or dinuclear [Ag2(mu-L)2](OTf)2 (2) (OTf = trifluoromethanesulfonate) in which the ligand bridges both silver centres, an unprecedented mode of coordination for this type of ligands. Compound 2 crystallizes with two water molecules and forms a supramolecular structure through classical hydrogen bonding. The reaction in a 2 : 1 ratio affords in both cases the four-coordinated derivatives [ML2]X (M = Cu, X = PF6 (3); Ag, X = OTf 4). The treatment of [Ag(OTf)(PPh3)] with the ligand L gives [AgL(PPh3)]OTf (5). The gold(I) derivative [Au2(C6F5)2(mu-L)] (6) has also been obtained by reaction of L with two equivalents of [Au(C6F5)(tht)]. These complexes present a luminescent behaviour at low temperature; the emissions being mainly intraligand but enhanced after coordination of the metal. Compounds 1-4 have been characterized by X-ray crystallography. DFT studies showed that, in the silver complex 2, coordination of H2O to Ag in the binuclear complex is favoured by formation of a hydrogen-bonding network, involving the triflato anion, and releasing enough energy to allow distortion of the Ag2 framework.     

Synthesis and characterization of the bimetallic polymers [MS4Ag2(Hmimt)2]n (where M = Mo or W,Hmimt = 1-methylimidazoline-2(3H)-thione): crystal structures of [WS4Ag2(Hmimt)2]n and [Ag2I2(Hmimt)]n

The title compounds were synthesized by the reactions of [NH₄]₂[MS₄] (M = Mo, W), AgI and Hmimt in acetone and characterized by IR, ¹H NMR and UV–Vis spectroscopy. The polymeric structure of [WS₄Ag₂(Hmimt)₂]_n was determined by X-ray crystallography. In this compound, there are two distinctly different coordination modes for the silver atoms. One Ag atom has a pseudo-tetrahedral geometry with one terminal monodentate-S Hmimt, two μ₂-S bridging Hmimt and one S atom of a monodentate WS₄ unit. The other is surrounded by four sulfur atoms belonging in pairs to two WS₄ fragments; the coordination geometry is distorted tetrahedral. The [WS₄Ag₂(Hmimt)₂]_n polymer represents the first example of tetrathiometalate anions [MS₄]²⁻ (M = Mo, W, or V) coordinated to another metal atom in a monodentate fashion. In both crystal structures determined the Hmimt ligands are present in the thione form, with coordination taking place via the sulfur atom only.     

Ligand and counterion control of Ag(I) architectures: assembly of a {Ag8} ring cluster mediated by hydrophobic and Ag...Ag interactions

A strategy combining ligand design and counterion variation has been used to investigate the assembly of silver(I) complexes. As a result, dinuclear, octanuclear, and polymeric silver(I) species have been synthesized by complexation of the rigid aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and cis-3,5-diamino-trans-tert-butyldimethylsilylanyloxycyclohexane (DATC) with silver(I) triflate, nitrate, and perchlorate. The compositions of these aggregates, established by X-ray crystallography and elemental analysis, are [{Ag(DAHC)}2](CF3SO3)2 (1), [{Ag(DAMC)}2](CF3SO3)2 (2), [{Ag(DAMC)}2](NO3)2 (3), [{Ag(DATC)}6{Ag(DAHC)}2](NO3)8 (4), and [{Ag(DATC}n](NO3)n (5), where the DAHC present in 4 is formed by in situ hydrolysis of the acid labile silyl ether group. The type of aggregate formed depends both upon the noncoordinating O-substituent of the ligand and the (also noncoordinating) counterion, with the normal preference of the ligand topology for forming Ag2L2 structures being broken by introduction of the bulky, lipophilic O-tert-butyldimethylsilyl (TBDMS) group. Of particular note is the octanuclear silver ring structure 4, which is isolated only when both the O-TBDMS group and the nitrate counteranion are present and is formed from four Ag2L2 dimers connected by Ag...Ag and hydrogen-bonding interactions. Diffusion rate measurement of this {Ag8} complex by 1H NMR (DOSY) indicates dissociation in CD3OD and CD3CN, showing that this supramolecular ring structure is formed upon crystallization, and establishing a qualitative limit to the strength of Ag...Ag interactions in solution. When solutions of the {Ag8} cluster in methanol are kept for several days though, a new UV-vis absorption is observed at around 430 nm, consistent with the formation of silver nanoparticles.     

Electrochemical synthesis and structural characterization of silver(I) complexes of N-2-pyridyl sulfonamide ligands with different nuclearity: influence of the steric hindrance at the pyridine ring and the sulfonamide group on the structure of the complexes

A new series of silver complexes, [AgL], of the anionic forms of potentially bidentate N-2-pyridyl sulfonamide ligands [N-(3-methyl-2-pyridyl)-p-toluenenesulfonamide (HTs3mepy), N-(3-methyl-2-pyridyl)mesitylenesulfonamide (HMs3mepy), N-(4-methyl-2-pyridyl)-p-toluenesulfonamide (HTs4mepy), and N-(6-methyl-2-pyridyl)mesitylenesulfonamide (HMs6mepy)] have been prepared by an electrochemical procedure. In addition, heteroleptic complexes of composition [AgLL'] (L' = 1,10-phenanthroline and 2,2'-bipyridine) were obtained when the coligand L' was added to the electrolytic phase. The complexes were characterized by microanalysis, IR and (1)H NMR spectroscopy, and LSI mass spectrometry. In the cases of the compounds [Ag(Ts3mepy)](n)() (1), [Ag(4)(Ms3mepy)(4)] (2a), [Ag(Ms3mepy)](n)() (2b), [Ag(4)(Ms6mepy)(4)] (3a), [Ag(2)(Ms6mepy)(2)](n)() (3b), [Ag(2)(Ms3mepy)(2)(phen)(2)] (5), [Ag(2)(Ms6mepy)(2)phen] (7), and [Ag(2)(Ts4mepy)(2)(bipy)(2)] (8), characterization was also carried out by single-crystal X-ray diffraction. Compounds 1 and 2b present a polymer structure formed by an {AgN(2)} digonal core. Compounds 2a and 3a are tetranuclear and also have a distorted {AgN(2)} digonal core. Compound 3b is based on binuclear distorted {AgN(2)} digonal units joined by an intermolecular sulfonyl oxygen atom to produce a stairlike polymer structure. The heteroleptic complexes 5 and 8 are dimeric with a distorted {AgN(4)} tetrahedral geometry, while compound 7 shows two different geometries around the metal, distorted {AgN(2)} digonal and {AgN(4)} tetrahedral. The supramolecular structures of all species are organized by pi,pi-stacking, C-H...pi, or C-H...O interactions.     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C(CPh)]n with a NP3 Ligand

Two silver(I) complexes were prepared by the reaction of [Ag(C(CPh)]n with NP3 [NP3 = N(CH2CH2PPh2)3] or with NP3 and [Cu(CH3CN)4]ClO4. Complex 1 [(Ag2Cl(NP3)2)(Ag5(C(CPh)6)] contains both NP3 and PhC(C- ligands. The complex cation is (Ag2Cl(NP3)2)+, in which two Ag(NP3)+ cations were bridged by a Cl- donor. The anion is (Ag5(C(CPh)6)-, where five Ag+ ions are linked by six C(CPh- to form a pentanuclear cluster. Complex 2 only contains NP3 ligand, where the silver center adopts a trigonal-bipyramidal geometry. Crystal data for 1: C133H116Ag7Cl3N2P6, Mr = 2789.54, triclinic, space group P, a = 13.0780(2), b = 15.3678(2), c = 31.2041(3) (A), α = 91.3928(7), β = 90.9328(8), γ = 96.0244(4)o, V = 6233.8(1) (A)3, T = 293(2) K, Z = 2, Dc = 1.486 g/cm3, F(000) = 2796, μ = 1.266 mm-1, the final R = 0.0746 and wR = 0.1953 for 16475 observed reflections with I > 2σ(I). Crystal data for 2: C42H42AgClNO4P3, Mr = 861.00, trigonal, space group R3, a = 17.451(1), b = 17.451(1), c = 11.3985(7) (A), V = 3006.0(3) (A)3, T = 293(2) K, Z = 3, Dc = 1.427 g/cm3, F(000) = 1326, μ = 0.731 mm-1, the final R = 0.0251 and wR = 0.0663 for 1499 observed reflections with I > 2σ(I).     

Synthesis, crystal structure, quantum chemical calculations, DNA interactions, and antimicrobial activity of [Ag(2-amino-3-methylpyridine)(2)]NO(3) and [Ag(pyridine-2-carboxaldoxime)NO(3)

[Ag(2-amino-3-methylpyridine)(2)]NO(3) (1) and [Ag(pyridine-2-carboxaldoxime)NO(3)] (2) were prepared from corresponding ligands and AgNO(3) in water/ethanol solutions, and the products were characterized by IR, elemental analysis, NMR, and TGA. The X-ray crystal structures of the two compounds show that the geometry around the silver(I) ion is bent for complex 1 with nitrate as an anion and trigonal planar for complex 2 with nitrate coordinated. ESI-MS results of solutions of 2 indicate the independent existence in solution of the [Ag(pyridine-2-carboxaldoxime)](+) ion. The geometries of the complexes are well described by DFT calculations using the ZORA relativistic approach. The compounds were tested against 14 different clinically isolated and four ATCC standard bacteria and yeasts and also compared with 17 commonly used antibiotics. Both 1 and 2 exhibited considerable activity against S. lutea , M. lutea , and S. aureus and against the yeast Candida albicans , while 2-amino-3-methylpyridine is slightly active and pyridine-2-carboxaldoxime shows no antimicrobial activity. In addition, the interaction of these metal complexes with DNA was investigated. Both 1 and 2 bind to DNA and reduce its electrophoretic mobility with different patterns of migration, while the ligands themselves induce no change.     

Variable coordination modes of NO2(-) in a series of Ag(I) complexes containing triorganophosphines, -arsines,and -stibines. Syntheses,spectroscopic characterization (IR, 1H and 31P NMR,electrospray ionization mass), and structures of [AgNO2(R(3)E)(x)] adducts (E = P,As, Sb,x = 1-3)

Adducts of triorganophosphine, triphenylarsine, and triphenylstibine with silver(I) nitrite have been synthesized and characterized both in solution ((1)H, (31)P NMR) and in the solid state (IR, single-crystal X-ray structure analysis). In addition aggregates of AgNO(2) and ER(3) (E = P, As, Sb) have been identified in solution by electrospray ionization mass spectrometry (ESI-MS). The topology of the structures in the solid state was found to depend on the nature of ER(3) and on the stoichiometric ratio AgNO(2):ER(3). The adducts AgNO(2):EPh(3) (1:1) (E = P or Sb) are one-dimensional polymers, the role of NO(2)(-) being to bridge successive metal atoms by coordination of the two oxygens to one silver atom and the nitrogen lone pair to a successive Ag. The adduct AgNO(2):P(o-tolyl)(3) (1:1) is mononuclear, due to steric hindrance of the phosphine, the nitrite being O,O'-bidentate, a rare example of a quasi-linear P-Ag-X array. AgNO(2):P(p-F-C(6)H(4))(3) (1:1) is a dimer, the nitrite being coordinated through both oxygens, the first unidentate, the second bridging bidentate. P(o-tolyl)(3) and Pcy(3) form 1:2 adducts, also mononuclear, the nitrite still an O,O'-chelate. In contrast, the adduct AgNO(2):AsPh(3) (1:2) is a centrosymmetric dimer, essentially an aggregate of a pair of [Ag(O(2)N)(AsPh(3))(2)] arrays with one nitrite oxygen being the bridging atom. The adducts AgNO(2):EPh(3) (1:3) (E = As, Sb) are mononuclear, the nitrite behaving as a consistently strong O,O'-chelate. The E = As adduct is a triclinic solvated form, whereas the unsolvated E = Sb species is monoclinic. ESI-MS spectra of acetonitrile solutions of these complexes show the existence of [Ag(ER(3))](+), [Ag(CH(3)CN)](+), [Ag(CH(3)CN)(2)](+), [AgCl(2)](-), [Ag(NO(2))(2)](-), [Ag(ER(3))(CH(3)CN)](+), and [Ag(ER(3))(2)](+) as well as higher aggregates [Ag(2)(NO(2))(ER(3))(2)](+), [Ag(2)(NO(2))(3)](-) and [Ag(2)Cl(2)(NO(2))](-), which are less prevalent.     

Formation of mono-, bi-, tri-, and tetranuclear Ag(I) complexes of C3-symmetric tripodal benzimidazole ligands

The C3-symmetric tripodal ligand tris(2-benzimidazolylmethyl)amine (ntb) and its alkyl-substituted derivatives tris(N-R-benzimidazol-2-ylmethyl)amine (R = methyl, Mentb; R = ethyl, Etntb; R = propyl, Prntb) react with various silver(I) salts to afford mononuclear [Ag(Prntb)(CF3SO3)].0.25H2O, 1, binuclear [Ag2(Mentb)2](CF3SO3)2.H2O, 2, trinuclear [Ag3(Etntb)2](ClO4)3.CH3OH, 3, and tetranuclear [Ag4(ntb)2(CH3CN)2(CF3CO2)2](CF3CO2)2.2H2O, 4. All four complexes have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. The Ag(I) ion in 1 is coordinated to the three imine nitrogen atoms of the Prntb ligand and one oxygen atom of the trifluoromethanesulfonate anion in a distorted tetrahedral environment. Dinuclear 2 has C2 symmetry with each Ag(I) atom trigonally coordinated by two arms of one Mentb and one arm of another. Trinuclear 3 has C3 symmetry with a Ag3 regular triangle sandwiched between a pair of Etntb ligands such that one arm of each ligand is involved in linear coordination about an Ag(I) atom. In the tetranuclear complex 4, two linearly coordinated Ag(I) atoms lying on the molecular C2 axis are bridged by a pair of ntb ligands and the remaining pendant arm of each ntb ligand is attached to another Ag(I) atom whose tetrahedral coordination sphere is completed by an acetonitrile molecule and a chelating trifluoroacetate anion. Complexes 2 and 3 may be regarded as an aggregation of two tridentate ligands by a silver dimer and a trinuclear cluster with weak Ag...Ag interactions, respectively, while in 4 the aggregation of two tripodal ligands by four Ag(I) ions affords a multicomponent internal cavity. The packing modes of complexes 1-3 are dominated by weak supramolecular pi...pi and CH...pi interactions. Hexagonal or square channels are generated in 1 and 2, and a honeycomb layer structure is formed in 3 with solvate molecules and counteranions occupying the voids. The crystal structure of 4 consists of a three-dimensional network consolidated by NH...O and OH...O hydrogen bonds.     

Structural studies of silver(I) coordination polymers with aryl iodide derived ligands

This paper reports novel silver polymers, built with iodine--silver interactions, with interesting structural motifs. Four silver(I) coordination polymers of the aryl iodide derived ligands, triiodobenzoic acid (HL1), tris(4-iodophenyl)amine (L2), and 5,7-diiodo-8-hydroxyquinoline (HL3), have been synthesized and characterized by X-ray crystallography. Treatment of Ag(CH3COO) with HL1 yielded [Ag(L1)] (1), whose structural analysis revealed 2D layers of ladders connected through weak Ag...I interaction. Reactions of AgClO4 and L2 in benzene and nitrobenzene afforded, respectively, two different products, [Ag(L2)(H2O)]ClO4.C6H6(2) and [Ag(L2)(ClO4)](3). While the structure of 2 could be described as a 2D layer of square and octagons perpendicular to [100], complex 3 is formed by 2D layers of the same topology of 2 (8(2).4), alternating as ABAB. In contrast, complex 4, [Ag2(H2L3)(CF3SO3)3], obtained by reaction of Ag(CF3SO3) and HL3, was found to consist of a 2D layer based on columnar arrays AgH2L3-Ag(triflate). The solid-state FT-IR and 109Ag NMR spectra of theses complexes are discussed on the basis of their crystal structures.     

Gas phase synthesis, structure and unimolecular reactivity of silver iodide cluster cations, Ag(n)I(m)(+) (n = 2-5, 0 < m < n)

Multistage mass spectrometry (MS(n)) experiments reveal that gas phase silver iodide cluster cations, Ag(n)I(m)(+), are readily built up in a stepwise fashion via ion-molecule reactions between mass selected silver (Ag(3)(+) and Ag(5)(+)) or silver hydride (Ag(2)H(+) and Ag(4)H(+)) cluster cations and allyl iodide, in contrast to their reactions with methyl iodide, which solely result in ligation of the clusters. The stoichiometries of these clusters range from 1 < or = n < or = 5 and 1 < or = m < or = 4, indicating the formation of several new subvalent silver iodide clusters. Collision induced dissociation (CID) experiments were carried out on each of these clusters to shed some light on their possible structures. The products arising from CID of the Ag(n)I(m)(+) clusters are highly dependent on the stoichiometry of the cluster. Thus the odd-electron clusters Ag(4)I(2)(+) and Ag(5)I(+) fragment via loss of a silver atom. In contrast, the even-electron cluster ions all fragment via loss of AgI. In addition, Ag(2)I(2) loss is observed for the Ag(4)I(3)(+) and Ag(5)I(2)(+) clusters, while loss of Ag(3)I(3) occurs for the stoichiometric Ag(5)I(4)(+) cluster. DFT calculations were carried out on these Ag(n)I(m)(+) clusters as well as the neutrals associated with the ion-molecule and CID reactions. A range of different isomeric structures were calculated and their structures are described. A noteworthy aspect is that ligation of these silver clusters by I can have a profound effect on the geometry of the silver cluster. For example, D(3h) Ag(3)(+) becomes C(2v) Ag(3)I(+), which in turn becomes C(2h) Ag(3)I(2)(+). Finally, the DFT predicted thermochemistry supports the different types of reaction channels observed in the ion-molecule reactions and CID experiments.     

Synthesis and characterization of novel S,N and Se,N homodimetallic Ag(I)-complexes

Novel C2-symmetric doubly bidentate Se,N and S,N-ligands based on a readily available Tr?ger's base backbone were synthesized and fully characterized. Their coordination properties were studied in dinuclear Ag(I)-complexes employing (1)H, (77)Se and (1)H-(15)N HETCOR NMR spectroscopy as well as X-ray diffraction crystallography. In solution, a single ligand can accommodate two silver atoms by coordination to nitrogen and sulfur or selenium. The investigations in the solid state revealed the presence of a pentacoordinated silver atom (NSO(3) and N(3)Se(2) donor sets are influenced by the solvent employed during the crystallization). In the solid state, the Ag(I)-complex with the S,N-ligand 2b forms dimeric structures bridged by the two perchlorate counterions. The analogous Se,N-ligand 2c coordinates to Ag(I) and forms polymeric enantiomerically pure helices, although the crystal is racemic.     

Pyrrole-appended derivatives of O-confused oxaporphyrins and their complexes with nickel(II), palladium(II), and silver(III)

Condensation of 2,4-bis(phenylhydroxymethyl)furan with pyrrole and p-toluylaldehyde formed, instead of the expected 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin, a pyrrole addition product [(H,pyr)OCPH]H(2); this product can formally be considered as an effect of hydrogenation of 3-(2'-pyrrolyl)-5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin ([(pyr)OCPH]H). The new oxacarbaporphyrinoid presents the (1)H NMR spectroscopy features of an aromatic molecule, including the upfield shift of the inner H21 atom. Insertion of NiCl(2) or PdCl(2) into [(H,pyr)OCPH]H(2) gave two structurally related organometallic complexes, [(pyr)OCP]Ni(II)] and [(pyr)OCP]Pd(II)], in which the metal ions are bound by three pyrrolic nitrogens and the trigonally hybridized C21 atom of the inverted furan. The reaction of [(H,pyr)OCPH]H(2) with silver(I) acetate yields a stable Ag(III) complex [(C(2)H(5)O,pyr)OCP]Ag(III)] substituted at the C3 position by the ethoxy and pyrrole moieties. The macrocyclic frame of [(H,pyr)OCPH]H(2) is conserved. Addition of trifluoroacetic acid to [(C(2)H(5)O,pyr)OCP]Ag(III)] yielded a new aromatic complex [(pyr)OCP]Ag(III)](+). The structures of [(pyr)OCP]Ni(II)] and [(C(2)H(5)O,pyr)OCP]Ag(III)] have been determined by X-ray crystallography. In both molecules the macrocycles are only slightly distorted from planarity and the nickel(II) and silver(III) are located in the NNNC plane. The dihedral angle between the macrocyclic and appended-pyrrole planes of [(pyr)OCP]Ni(II)] reflects the biphenyl-like arrangement with the NH group pointing out toward the adjacent phenyl ring on the C5 position. Tetrahedral geometry around the C3 atom was detected for [(C(2)H(5)O,pyr)OCP]Ag(III)]. The Ni[bond]C and Ag[bond]C bond lengths are similar to other nickel(II) or silver(III) carbaporphyrinoids where the trigonal carbon atom coordinates the metal ion. The trend detected in the (13)C chemical shifts for the appended-pyrrole resonances has been rationalized by the extent of effective conjugation between the macrocycle and the appended pyrrole moiety controlled by the hybridization of the C3 atom and the metal ion oxidation state. The dianionic or trianionic macrocyclic core of the pyrrole-appended derivatives is favored to match the oxidation state of nickel(II), palladium(II), or silver(III), respectively.     

(CF(3))(4)Au(2)(C(5)H(5)N)(2)] - a new alkyl gold(ii) derivative with a very short Au-Au bond

A new gold(ii) species [(CF(3))(4)Au(2)(C(5)H(5)N)(2)] with a very short unsupported Au-Au bond (250.62(9) pm) was generated by photo irradiation of a silver aurate, [Ag(Py)(2)][Au(CF(3))(2)], unambiguously characterized by (19)F and (109)Ag NMR studies.     

Luminescent complexes of silver(I) with pyridylbis(3-hexamethyleneiminyl thiosemicarbazone): effect of the counterion on the nuclearity

The reaction of pyridylbis(3-hexamethyleneiminyl thiosemicarbazone) (H(2)Plhexim) with various silver(I) salts and metal-ligand ratios led to the isolation of different complexes of the formulae [Ag(NO(3))(H(2)Plhexim)]·H(2)O (1), [Ag(2)(NO(3))(H(2)Plhexim)(CH(3)OH)](NO(3)) (2), [Ag(2)(ClO(4))(2)(H(2)Plhexim)] (3), [Ag(HPlhexim)]·xH(2)O (4), [Ag(HPlhexim)] (4a), [Ag(2)(Plhexim)(PPh(3))(4)]·2MeOH (5) and [Ag(4)(Plhexim)(2)]·DMF (6). The complexes were fully characterized by elemental analysis, ESI mass spectrometry, IR and NMR ((1)H, (31)P) spectroscopy. The structures of 4a, 5 and 6 were also identified by single crystal X-ray structure determination. The concentration dependence on the absorption spectra of the methanolic solutions indicates polymerization equilibria in the ground state in both the ligand and the complexes. While H(2)Plhexim is essentially non-fluorescent, complexes 1-5 fluoresce more strongly by comparison. This fluorescent behavior is consistent with the monomeric or dimeric nature of the complexes.     

Synthese,Schwingungsspektren und Kristallstrukturen der Nitratoargentate (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN und (Ph4P)[Ag2(NO3)3]

Synthesis, Vibrational Spectra, and Crystal Structures of the Nitrato Argentates (Ph₄P)[Ag(NO₃)₂(CH₃CN)]·CH₃CN and (Ph₄P)[Ag₂(NO₃)₃] Tetraphenylphosphonium bromide reacts in acetonitril suspension with excess silver nitrate to give (Ph₄P)[Ag(NO₃)₂(CH₃CN)]·CH₃CN ( 1 ), whereas (Ph₄P)[Ag₂(NO₃)₃] ( 2 ) is obtained in a long‐time reaction from (Ph₄P)Br and excess AgNO₃ in dichloromethane suspension. Both complexes were characterized by vibrational spectroscopy (IR, Raman) and by single crystal structure determinations. 1 : Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1781.5(3), b = 724.8(1), c = 2224.2(3) pm, β = 96.83(1)°, R₁ = 0.0348. 1 contains isolated complex units [Ag(NO₃)₂(CH₃CN)]^?, in which the silver atom is coordinated by the chelating nitrate groups and by the nitrogen atom of the solvated CH₃CN molecule with a short Ag—N distance of 220.7(4) pm. 2 : Space group I2, Z = 4, lattice dimensions at 193 K: a = 1753.4(4), b = 701.7(1), c = 2105.5(4) pm, R₁ = 0.072. In the polymeric anions [Ag₂(NO₃)₃]^? each silver atom is coordinated in a chelating manner by one nitrate group and by two oxygen atoms of two bridging nitrate ions. In addition, each silver atom forms a weak π‐bonding contact with a phenyl group of the (Ph₄P)⁺ ions with shortest Ag···C separations of 266 and 299 pm, respectively, indicating a (4+1) coordination of silver atoms.     

Tetraphosphinite resorcinarene complexes: silver(I) capsule complexes

Resorcinarene tetraphosphinite ligands, P4, react with silver(I) trifluoroacetate or silver(I) triflate, AgX, to give the corresponding [Ag4X4(P4)] complexes. The resorcinarene skeleton in these complexes adopts a boat conformation with the silver(I) phosphinite units on the horizontal, rather than the upright, arene units of the resorcinarene. The [Ag4X4(P4)] complexes react with free P4 ligand to yield the [Ag2X2(P4)] or [AgX(P4)] complexes, which are characterized in solution by NMR spectroscopy to have a conformation opposite to that of the [Ag4X4(P4)] complexes; the silver(I) phosphinite groups are on the upright arene rings of the resorcinarene "boat" instead of the horizontal arene units. There is an easy equilibrium between these complexes. When X = triflate, the [Ag4X4(P4)] complexes disproportionate and add aqua ligands during slow crystallization to give "capsule complexes", which are characterized crystallographically as [Ag10(O3SCF3)10(OH2)6(P4)2], [Ag10(O3SCF3)6(OH2)8(P4)2][O3SCF3]4, or [Ag13(O3SCF3)13(OH2)7(P4)2] depending on the resorcinarene tetraphosphinite ligand P4 used. These unusual capsule complexes are formed by the tail-to-tail self-assembly of pairs of [Ag4(P4)]4+ units linked by additional silver ions that bind to the phenyl substituents of one resorcinarene through {Ag(eta2-C6H5)}+ binding and to the bridging triflate ligands, aqua ligands, or both of the other resorcinarene unit.