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The Banert cascade of propargylic azides can be promoted by simple silver salts, and the triazafulvene intermediate can be intercepted by carbon nucleophiles. Various indoles (>25 examples, up to 92% yield) and electron-rich heterocycles were effective. The Mayr nucleophilicity parameter (N) was found to correlate to the reaction efficiency, which enabled the formation of C(sp(3))–C(sp(2)) and C(sp(3))–C(sp(3)) bonds under otherwise identical conditions from structurally dissimilar nucleophiles.

The reaction of 2-(tBuNCH)C6H4TeCl with silver salts of weakly coordinating anions, AgX {X = O3SCF3, SbF6, or Al[OC(CF3)3]4}, provided the aryltellurenyl salts [2-(tBuNCH)C6H4Te](O3SCF3) (1), [2-(t...

Four [Ag–Ag]2+ unit-encapsulated trimetallic cages 1–4 were synthesized from one new tripodal ligand L and silver salts in different solvent systems by a one-pot method. The formation of coordination cages occurred simultaneously with the condensation of amino groups and ketone. The remarkable structural feature of cages 1–4 is their spontaneous incorporation of [Ag–Ag]2+ cationic units. Moreover, the argentophilic interactions are modulated by the uncoordinated amino substituents. The study herein shows that modification and subtle changes of the cage structures could be realized by a one-pot synthetic method.

An operationally simple and highly selective Au/Ag bimetallic-catalyzed cross-dehydrogenative biaryl coupling between pyrazoles and fluoroarenes has been developed. With this reaction, a wide range of biheteroaryl products can be obtained in moderate to good yields with excellent functional group compatibility. The exact role of silver salts, previously overlooked in most gold-catalyzed transformations, has been carefully investigated in this biaryl coupling. Insightful experimental and theoretical studies indicate that silver acetate is the actual catalyst for C–H activation of electron-poor arenes, rather than the previously reported gold(I)-catalyzed process. An unprecedented Au/Ag dual catalysis is proposed, in which silver(I) is responsible for the activation of electron-poor fluoroarenes via a concerted metalation–deprotonation pathway, and gold(III) is responsible for the activation of electron-rich pyrazoles via an electrophilic aromatic substitution process. Kinetic studies reveal that ArFnAu(III...

The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity. Often high thermal energy required to promote olefination leads to multiple site functionalization. To this aim we established a photoredoxcatalytic system constituting a merger of palladium/organo-photocatalyst that forges oxidative olefination in an explicit regioselective fashion of diverse arenes and heteroarenes. Visible light plays a significant role in executing ‘regio-resolved’ Fuijiwara-Moritani reaction without the requirement of silver salts and thermal energy. The catalytic system is also amenable towards proximal and distal olefination aided by respective directing groups (DGs), which entails the versatility of the protocol in engaging the entire spectrum of C(sp2)-H olefination. Furthermore, streamlining the synthesis of natural products, chiral molecules, drugs and diversification through late-stage functionalizations underscore the importance of this sustainable protocol. The photoinduced attainment of this regioselective transformation is mechanistically established through control reactions, kinetic studies and theoretical calculations.

In the present investigation, the precursor complex [Pt(ppy)(PPh3)(Cl)], 3, ppy = 2-phenylpyridinyl, undergoes the chloride abstraction reaction using various AgX (X = PF6, BF4, NO3 and CH3COO) salts. Depending on the nature of anions in AgX salts (coordinating or noncoordinating), the products can be neutral or ionic. In the cases of NO3 and CH3COO, they can be coordinated to the Pt center so that the neutral complexes [Pt(ppy)(PPh3)(NO3)], 4a, and [Pt(ppy)(PPh3)(CH3COO)], 4b, are formed. In contrast, the ionic complexes [{Pt(ppy)(PPh3)(CH3CN)}PF6], 5a, and [{Pt(ppy)(PPh3)(CH3CN)}BF4], 5b, can be generated when the AgPF6 ([{Ag(CH3CN)4}PF6]) or AgBF4 ([{Ag(CH3CN)4}BF4]) salts are used in which the PF6 and BF4 stand as counteranions. In these two complexes, CH3CN fills the empty ligand position which can be present as solvent or ligand in the initial silver salts. The structures of the new complexes were accurately deduced from the multinuclear (1H, 31P{1H}, 195Pt{1H}) NMR spectroscopy and further authenti...

Readily functionalizable bipyrimidine compounds were prepared for the first time, and their coordination chemistry with silver salts was explored. Solution 1H NMR spectroscopy experiments indicated that the ligands rapidly form complexes with silver(I) salts, and coordination at a first site inhibits coordination of a second cation to the ligand, thus favoring 1:1 complexes in solution. These 1:1 units self-assemble into one-dimensional chains in the solid state, even in the presence of excess Ag(I). Structurally diverse coordination polymers exhibiting different coordination numbers and geometry were characterized by single crystal X-ray crystallography. Our results demonstrate that a modification to the ligand, distal from the binding site, affects the coordination chemistry and supramolecular structure of these complexes.

Iron(0) pentacarbonyl is an organometallic compound with a long history. It undergoes carbonyl displacement chemistry with various donors (L), leading to molecules of the type Fe(CO)x(L)5–x. The work reported here illustrates that Fe(CO)5 can also act as a ligand. The reaction between Fe(CO)5 with the silver salts AgSbF6 and Ag[B{3,5-(CF3)2C6H3}4] under appropriate conditions resulted in the formation of [(μ-H2O)AgFe(CO)5]2[SbF6]2 and [B{3,5-(CF3)2C6H3}4]AgFe(CO)5, respectively, featuring heterobimetallic {Ag–Fe(CO)5}+ fragments. The treatment of [B{3,5-(CF3)2C6H3}4]AgFe(CO)5 with 4,4′-dimethyl-2,2′-bipyridine (Me2Bipy) and Fe(CO)5 afforded a heterobimetallic [(Me2Bipy)AgFe(CO)5][B{3,5-(CF3)2C6H3}4] species with a Ag–Fe(CO)5 bond and a heterotrimetallic [{Fe(CO)5}2(μ-Ag)][B{3,5-(CF3)2C6H3}4] with a (CO)5Fe–Ag–Fe(CO)5 core, respectively, illustrating that it is possible to manipulate the coordination sphere at silver while keeping the Ag–Fe bond intact. The chemistry of [B{3,5-(CF3)2C6H3}4]AgFe(CO)5 with E...

Reagent-controlled regiodivergent ring-opening reactions of trichloromethylcyclopropane carboxylates have been developed. The regioselectivity of bond cleavage is completely controlled by the proper choice of silver salts; the treatment of trichloromethylcyclopropane with AgBF4 led to C2-C3 bond cleavage and fluorination to afford fluorinated β,γ-unsaturated ester with high stereoselectivity, while the reaction with AgOAc in THF gave a γ,δ-unsaturated ester through the reductive cleavage of the C1-C2 bond.

Dinuclear complexes [Ag2(CF3SO3){(S,S)-(i)Pr-pybox}2][CF3SO3] (1), [Ag2(R-pybox)2][X]2 [R-pybox = 2,6-bis[4-(S)-isopropyloxazolin-2-yl]pyridine (S,S)-(i)Pr-pybox and X = PF6 (2) and BF4 (3); R-pybox = 2,6-bis[(3aS,8aR)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]pyridine (3aS,3a'S,8aR,8a'R)-indane-pybox and X = CF3SO3 (4)], [Ag2{(S,S)-(i)Pr-pybox}{(3aS,3a'S,8aR,8a'R)-indane-pybox}][CF3SO3]2 (5), and [Ag2(R-pybox)3][X]2 [R-pybox = (3aS,3a'S,8aR,8a'R)-indane-pybox and X = CF3SO3 (10), SF6 (11), and PF6 (12)] as well as mononuclear complexes [Ag(R-pybox)2][X] [R-pybox = (S,S)-(i)Pr-pybox and X = SbF6 (6), PF6 (7), and BF4 (8); R-pybox = (3aS,3a'S,8aR,8a'R)-indane-pybox) and X = BF4 (9)] have been prepared by the reaction of the corresponding silver salts and pybox ligands using the appropriate molar ratio conditions. The first gold(I)/pybox complex [Au6Cl4{(S,S)-(i)Pr-pybox}4][AuCl2]2 (13) has been synthesized by the reaction of [AuCl{S(CH3)2}] and (S,S)-(i)Pr-pybox (1:1 molar ratio) in acetonitrile. The structures of the dinuclear (1, 4, 5, 10, and 11) and mononuclear (6 and 9) silver complexes and the hexanuclear gold complex 13 have been determined by single-crystal X-ray diffraction analysis. These studies have been complemented with a solution-state study by NMR spectroscopy, which included structure elucidation, variable-temperature measurements, and diffusion studies using diffusion-ordered spectroscopy (DOSY; for complexes 1, 4, 10, and 12). Complexes 1, 2, 4, and 10 have been assayed as catalysts in the asymmetric addition of phenylacetylene to N-benzylideneaniline.

An aldehyde-selective aerobic Wacker-Tsuji oxidation is developed. Using tert-butyl nitrite as a simple organic redox cocatalyst instead of copper or silver salts, a variety of aldehydes were achieved as major products in up to 30/1 regioselectivity as well as good to high yields at room temperature.

We propose a novel methodology to synthesize monodisperse gold–silver alloy nanoparticles (NPs) with fine control of size and composition. The synthesis is based on a combination of the coreduction of gold and silver salts for the formation of alloys and the seeded growth approach for the formation of size-controlled NPs. While the simple use of coreduction gives alloy NPs limited to ∼30 nm, the combination of both methods yields spherical alloy NPs with a size that can be controlled between ∼30 and ∼150 nm, with a coefficient of variation smaller than 15%. The alloy NPs can be synthesized to any composition between pure silver and pure gold. We also show that the alloy composition is nonhomogeneous, with a gold-rich core and a silver-rich surface. The transition in the alloy composition is gradual from the core to the surface, resulting in optical properties very similar to the optical properties of a homogeneous alloy, except for the smaller (∼30 nm) NPs. A multilayer Mie model has been introduced to st...

A direct oxidative cross-coupling between terminal alkynes and secondary phosphine oxides was developed. This approach provides an efficient way to construct alkynyl di(phenyl) phosphine oxides from basic materials, and in this process, the silver salts act as a key promoter.

New cyclic and acylic phosphorus-nitrogen compounds have been synthesized in reactions of Hyp-N(SiMe3)PCl2 (hypersilyl = Hyp = (Me3Si)3Si) with silver salts of the perfluorinated anions [CF3CO2](-), [CF3SO3](-), and [C6F5](-). Depending on the choice of the silver salt, not only AgCl but also Me3SiCl elimination could be observed, leading to a transient highly reactive 1,3 dipole molecule. This 1,3 dipole molecule was found to be a key species, which can undergo [3 + 2] cyclization, when a dipolarophile such as acetonitrile is present. Also, dimerization or even cyclo-tetramerization are observed. The occurrence of different reaction channels demonstrates that the hypersilyl moiety can act as a highly reactive functional group. All new compounds have been characterized by single-crystal X-ray diffraction studies.

1,3-Diallylurea and tetraallylurea react with various silver salts to consistently generate one-dimensional coordination polymers in which the allyl arms and urea oxygen atoms are coordinated to silver atoms. Most commonly, ladderlike assemblies are produced.

The intramolecular gold-catalyzed asymmetric hydroamination of allenes was studied by screening a series of mononuclear gold(I) and -(III) complexes in combination with silver salts. Among the various chiral monophosphine and diaminocarbene ligands tried, the best catalysts arose from mononuclear gold(I) complexes synthesized from BINOL-based phosphoramidite ligands. The latest were improved by addition of bulky substituents at specific positions of the BINOL scaffold. The resulting gold(I) complexes were combined with selected silver salts to afford efficient catalysts for intramolecular hydroamination of allenes at room temperature or below, with good conversions and enantioselectivities.

Silver thiolate, which is an organic–inorganic heterostructured material, converts into thiol-derivatized Ag nanoparticles after irradiation with a visible laser. In this study, the visible-laser responses of 4-aminobenzenethiol (4-ABT) and 4,4′-dimercaptoazobenzene (4,4′-DMAB) silver salts were examined to verify that 4,4′-DMAB on Ag converts to 4-ABT on Ag because of the irradiation of light with a wavelength of 514.5 nm, to resolve the issues that result from the surface-enhanced Raman scattering (SERS) characteristics of 4-ABT. Due to the appearance of unpredicted, non-a1-type bands, the SERS spectrum of 4-ABT is very similar to that of 4,4′-DMAB. One explanation for the non-a1-type bands is that they are associated with the charge-transfer chemical-enhancement mechanism of SERS, but a few researchers have attributed them to photoinduced catalytic conversion of 4-ABT on Ag to 4,4′-DMAB. Using 514.5 nm radiation, we recently reported the successful conversion of 4,4′-DMAB on Ag to 4-ABT; however, the r...

New mixed-metal alkoxides of general formula [XCd{Zr2(OPri)9}]n (X = −C2F5, −C6F5, −C6F4-4-H, −NO3, −NCO, −SO3CF3, −O2CCF3, −O2CC2F5, −O2CCH3, −ClO4, −CN, −SO4; n = 1, 2) were obtained by the scission of the Cd–I bond in the iodo heterobimetallic isopropoxide [ICd{Zr2(OPri)9}] (1), whereby the underlying synthetic strategies involve metathesis reactions with silver salts or Lewis acid–base interactions between the Bronsted acid [Zr(OPri)4(HOPri)]2 and bis(fluoroorgano)cadmium (Cd(Rf)2) compounds. The new compounds were characterized by multinuclear NMR spectroscopy, elemental analysis, and mass spectrometry. The results of X-ray diffraction analysis of [(F5C6)Cd{Zr2(OPri)9}] (2), [(4-H-F4C6)Cd{Zr2(OPri)9}] (3), [(F5C2)Cd{Zr2(OPri)9}]2 (4), [(ONO2)Cd{Zr2(OPri)9}]2 (5), [(CH3CO2)Cd{Zr2(OPri)9}] (6), [(O2ClO2)(H5C3N)Cd{Zr2(OPri)9}] (7), [(μ-O2ClO2)Cd{Zr2(OPri)9}]2 (8), [(μ-O2CCF3)Cd{Zr2(OPri)8(O2CCF3)}]2 (9), [(μ-O2CC2F5)Cd{Zr2(OPri)8(O2CC2F5)}]2 (10), [(μ(O,N)-OCN)Cd{Zr2(OPri)9}]2 (11), and [(μ-O2SOCF3)Cd{Z...

The reactions of 1,8-diaminonaphthalene with paraformaldehyde and secondary phosphines (HPR2, R = Ph, Cy) directly afford N,N′-bis(phoshinomethyl)dihydroperimidines H2C(NCH2PR2)2C10H6 (R = Ph (1a), Cy (1b)), the methylene group of which undergoes chelate-assisted double C–H activation with [RhCl(PPh3)3] to afford dihydroperimidine-derived N-heterocyclic pincer carbene (per-NHC) complexes [RhCl{═C(NCH2PR2)2C10H6}] (R = Ph (2a), Cy (2b)). Insight into the mechanism of these C–H activation processes is provided by the reaction of 1b with [IrCl(CO)(PPh3)2] to provide the dihydroperimidinyl-hydrido complex [IrHCl(CO){CH(NCH2PR2)2C10H6}] (3b), which in turn reacts with silver salts Ag[Y] to afford, via hydride abstraction and subsequent C–H activation, the per-NHC ligated salts [IrHCl(CO){═C(NCH2PR2)2C10H6}] ([4b]Y, Y = PF6, SbF6, PO2F2).

Mixtures of silver salts AgX (X = NO3, CF3CO2, CF3SO3) with M[Au(C6F5)2] (M = NBu4, PPh4) gave respectively the ionic mixed-metal clusters [M2{(C6F5)4Au2Ag2X2}]n (1, X = NO3; a, M = NBu4; b, M = PPh4) and [M{(C6F5)4Au2Ag2X}]n, (2a,b, X = CF3CO2; 3a,b, X = CF3SO3). The degree of aggregation n of these cluster compounds depends strongly on the method of isolation (solvent evaporation or precipitation); for example, recrystallization of 1a gave a crystalline salt of the tetraanion [(C6F5)4Au2Ag2X2]24– as well as the polymer [(NBu4)2{(C6F5)4Au2Ag2(NO3)2}]n. The aurophilic Au···Au interactions strongly influence the photoemission wavelength. The anion X has remarkably little effect on the luminescence color but strongly influences the conformation of the polyanionic chains, leading to a variety of solid-state structures, from well-defined dimers (1a1) to linear (1b) and curved (1a2, 2a) polymeric chain aggregates.

Simple silver salts and dicationic palladium bis(N-heterocyclic carbene) complexes were found to be effective and complementary catalysts for Nazarov cyclizations of divinyl β-keto esters. A steric...

Stable and isolable cyclometalated monomethyl Au(III) complexes are readily available from the precursor (tpy)Au(Me)Cl, prepared from (tpy)AuCl2 and excess SnMe4. Reaction of (tpy)Au(Me)Cl with suitable silver salts generates (tpy)Au(Me)(X) (X = OAc, OTf). Ligand exchange reactions with (tpy)Au(Me)(OTf) provide the cationic monomethyl Au(III) adducts [(tpy)Au(Me)(L)][OTf] (L = PPh3, THT).

A new synthetic method for the preparation of di-μ-chlorobis[π-1-chloro-1-aryl-2-(2′,2′-diarylvinyl)allyl]palladium(II) complexes has been developed from the reaction of arylvinylcyclopropenes with a Pd(II) complex along with a novel dehydrogenative rearrangement of arylvinylcyclopropenes via di-μ-chlorobis[π-1-chloro-1-aryl-2-(2′,2′-diarylvinyl)allyl]palladium(II) complexes to produce 7H-benzo[c]fluorene derivatives in good yields under mild conditions. A stoichiometric amount of silver salts or a catalytic amount of strong Bronsted acid HOTf can be the promoter or the catalyst for this interesting dehydrogenative rearrangement.

A strategy for the formation of heterometallic coordination polymers based on novel copper(II) and cobalt(III) heteroleptic complexes (acacCN)Cu(dpm) and (acacCN)Co(dpm)(2) (acacCN = 3-cyanoacetylacetonate; dpm = dipyrrin) is presented. Using dipyrrins appended with a p- or m-pyridyl group, dpm-4py and dpm-3py, four novel copper and cobalt complexes were prepared and characterized both in solution and in the solid state. These two classes of complexes show different electrochemical properties upon investigation by cyclic voltammetry in CH(2)Cl(2). While the copper complexes show only irreversible reduction processes, the voltammogram of the cobalt species reveals the presence of two quasi-reversible reductions. In the solid state, the copper(II) compounds self-assemble to form one-dimensional architectures upon coordination of the peripheral pyridyl group to the copper center, as characterized by single-crystal X-ray diffraction. Owing to the filled coordination sphere of the octahedral cobalt centers, the (acacCN)Co(dpm-py)(2) compounds crystallize as isolated molecules. Upon reaction with silver salts, these complexes form crystalline heterometallic architectures with different organization and dimensionality, depending on the nature of the metal center and the position of the nitrogen atom in the pyridyl group. The two copper complexes lead to the formation of trinuclear species, {[(acacCN)Cu(dpm-py)](2)Ag}(+), resulting from coordination of the pyridyl groups to the silver cations. However, while meta-functionalized complexes self-assemble into an extended architecture via weak interaction of the peripheral nitrile of the acacCN ligand to the Ag(+) cation, this interaction is not present in the para-functionalized analogue. In both networks based on the Ag(BF(4)) salt, coordination of the tetrafluoroborate anion to the silver center in the rather rare chelate mode is observed. Upon assembly of the cobalt metallatectons with silver salts, two-dimensional (2D) coordination polymers are obtained in crystalline form, resulting, however, from different sets of interactions. Indeed, no coordination of the peripheral nitrile of the acacCN ligand is observed in the network incorporating the m-pyridyl-appended dpm; coordination of the pyridyl groups to the silver center and d(10)-d(10) interactions lead to a 2D architecture. In the case of the para analogue, a 2D honeycomb network is observed owing to coordination of the Ag(I) ion to two pyridyl nitrogen atoms and to one peripheral nitrile group of a acacCN ligand. This latter polymer represents a geometrical hybrid of the networks reported in the literature based on homoleptic Co(dpm-4py)(3) and Cr(acacCN)(3) complexes.

Stepwise synthesis and structural characterization of two-dimensional (2-D) coordination polymer frameworks with positive charged or neutral cavities are reported. First, reactions of bis(4-pyridylmethyl)sulfide (L) with silver salts (1: nitrate and 2: perchlorate) afforded the respective double-stranded one-dimensional (1-D) chains [Ag(L)NO3]n (1) and {[Ag2(L)2](ClO4)2}n (2), both of which are stabilized by face-to-face π−π interactions. In this case, the silver(I) center in the nitrato complex 1 shows four-coordinated distorted tetrahedral geometry, whereas that of the perchlorato complex 2 exhibits a distorted trigonal planar geometry. The difference of these structures indicates that the coordination ability of the anions has important effects on the silver(I) coordination environments. Interestingly, the perchlorato 1-D complex 2 allows further reactions with bridging ligands such as 4,4′-bipyridine (bpy) and terephthalate (tp2−) to give a 2-D positive-charged network {[Ag2(L)2(bpy)]·(ClO4)2·C6H6}n (...

Three homochiral 3D frameworks are assembled based on periodically ordered arrays of helices built from axial chiral 3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl ligands and linearly coordinated Ag(I) ions. The aggregation behavior of silver salts and the ditopic ligand in solutions was investigated by a variety of techniques, including (1)H NMR, UV-vis, CD, GPC and MALDI-TOF. The cationic polymer skeleton exhibits an unprecedented conformational polymorphism in the solid-state, folding into two-, three- and four-fold helices with NO(3)(-), PF(6)(-) and ClO(4)(-) as the counteranion, respectively. The two-fold helices cross-link via argentophilic Ag-Ag interactions to form sextuple helices, which lead to a three-dimensional (3D) chiral framework. The three-fold or four-fold helices, on the other hand, self-associates in pairs to form three-dimensional tubular architectures. This anion-dependent self-assembly behavior can be rationalized by considering the sizes, geometries and binding abilities of the counteranions and subsequent chain conformation to minimize steric repulsions and maximize secondary interactions.

New main-group metal dipyrrinato complexes [M(4-pyrdpm)3], where M = Ga3+ or In3+ and 4-pyrdpm is the anion of 5-(4-pyridyl)dipyrrin (4-pyrdpmH), have been synthesized and incorporated into metal-organic frameworks (MOFs) by reacting the dipyrrinato complexes with silver(I) salts. MOFs formed with AgOTf (OTf = O3SCF3) and AgSbF6 gave frameworks with three-dimensional (10,3) and two-dimensional (6,3) topologies, respectively. In contrast, AgPF6 produced both (10,3) and (6,3) network topologies, suggesting that the PF6 anion has little preference for templating (10,3) versus (6,3) frameworks within this system. These findings update an earlier MOF study that examined the role of these anions in templating related heterometallic MOFs which used [Fe(4-pyrdpm)3] and [Co(4-pyrdpm)3] metalloligands. All of the dipyrrin compounds reported here have been characterized by single-crystal X-ray crystallography, including the first crystallographically characterized example of a 1,2,3-unsubstituted free-base dipyrrin, 4-pyrdpmH.

The Rh(II) mononuclear complexes [(PNPtBu)RhCl][BF4] (2), [(PNPtBu)Rh(OC(O)CF3)][OC(O)CF3] (4), and [(PNPtBu)Rh(acetone)][BF4]2 (6) were synthesized by oxidation of the corresponding Rh(I) analogs with silver salts. On the other hand, treatment of (PNPtBu)RhCl with AgOC(O)CF3 led only to chloride abstraction, with no oxidation. 2 and 6 were characterized by X-ray diffraction, EPR, cyclic voltammetry, and dipole moment measurements. 2 and 6 react with NO gas to give the diamagnetic complexes [(PNPtBu)Rh(NO)Cl][BF4] (7) and [(PNPtBu)Rh(NO)(acetone)][BF4]2 (8) respectively. 6 is reduced to Rh(I) in the presence of phosphines, CO, or isonitriles to give the Rh(I) complexes [(PNPtBu)Rh(PR3)][BF4] (11, 12) (R = Et, Ph), [(PNPtBu)Rh(CO)][BF4] (13) and [(PNPtBu)Rh(L)][BF4] (15, 16) (L = tert-butyl isonitrile or 2,6-dimethylphenyl isonitrile), respectively. On the other hand, 2 disproportionates to Rh(I) and Rh(III) complexes in the presence of acetonitrile, isonitriles, or CO. 2 is also reduced by triethylphosphine and water to Rh(I) complexes [(PNPtBu)RhCl] (1) and [(PNPtBu)Rh(PEt3)][BF4] (11). When triphenylphosphine and water are used, the reduced Rh(I) complex reacts with a proton, which is formed in the redox reaction, to give a Rh(III) complex with a coordinated BF4, [(PNPtBu)Rh(Cl)(H)(BF4)] (9).

MeNH(2) reacts with silver salts AgX (2:1) to give [Ag(NH(2)Me)(2)]X [X = TfO = CF(3)SO(3) (1.TfO) and ClO(4) (1.ClO(4))]. Neutral mono(amino) Rh(III) complexes [Rh(Cp*)Cl(2)(NH(2)R)] [R = Me (2a), To = C(6)H(4)Me-4 (2b)] have been prepared by reacting [Rh(Cp*)Cl(mu-Cl)](2) with RNH(2) (1:2). The following cationic methyl amino complexes have also been prepared: [Rh(Cp*)Cl(NH(2)Me)(PPh(3))]TfO (3.TfO), from [Rh(Cp*)Cl(2)(PPh(3))] and 1.TfO (1:1); [Rh(Cp*)Cl(NH(2)R)2]X, where R = Me, X = Cl, (4a.Cl), from [Rh(Cp*)Cl(mu-Cl)]2 and MeNH2 (1:4), or R = Me, X = ClO4 (4a.ClO4), from 4a.Cl and NaClO4 (1:4.8), or R = To, X = TfO (4b.TfO), from [Rh(Cp*)Cl(mu-Cl)](2), ToNH(2) and TlTfO (1:4:2); [Rh(Cp*)(NH(2)Me)(tBubpy)](TfO)(2) (tBubpy = 4,4'-di-tert-butyl-2,2'-bipyridine, 5.TfO), from 2a, TlTfO and tBubpy (1:2:1); [Rh(Cp*)(NH(2)Me)(3)](TfO)2 (6.TfO) from [Rh(Cp*)Cl(mu-Cl)](2) and 1.TfO (1:4). 2-6 constitute the first family of methyl amino complexes of rhodium. 1 and 4a.ClO(4) react with acetone to give, respectively, the methyl imino complexes [Ag{N(Me)=CMe(2)}()]X [X = TfO (7.TfO), ClO(4) (7.ClO(4))], and [Rh(Cp*)Cl(Me-imam)]ClO(4) [8.ClO(4), Me-imam = N,N'-N(Me)=C(Me)CH(2)C(Me)(2)NHMe]. 7.X (X = TfO, ClO(4)) are new members of the small family of methyl acetimino complexes of any metal whereas 8.ClO4 results after a double acetone condensation to give the corresponding bis(methyl acetimino) complex and an aldol-like condensation of the two imino ligands. The acetimino complex [Ag(NH=CMe(2))(2)]ClO(4) reacts with [Rh(Cp*)Cl(imam)]ClO(4) [1:1, imam = N,N'-NH=C(Me)CH(2)C(Me)(2)NH(2)] to give [Rh(Cp*)(imam)(NH=CMe(2))](ClO(4))(2) (9a.ClO(4)). 8.ClO(4) reacts with AgClO(4) (1:1) in MeCN to give [Rh(Cp*)(Me-imam)(NCMe)](ClO(4))2 (9b.ClO(4)), which in turn reacts with XyNC (Xy = C(6)H(3)Me(2)-2,6) or with MeNH(2) (1:1) to give [Rh(Cp*)(Me-imam)L](ClO(4))(2) [L = XyNC (9c.ClO(4)), MeNH(2) (9d.ClO(4))]. 6.TfO reacts with acetophenone to give [Rh(Cp*){C,N-C(6)H(4)C(Me)=N(Me)-2}(NH(2)Me)]TfO (10a.TfO), the first complex resulting from such a condensation and cyclometalation reaction. In turn, 10a.TfO reacts with isocyanides RNC (1:1) at room temperature to give [Rh(Cp*){C,N-C(6)H(4)C(Me)=NMe-2}(CNR)]TfO [R = tBu (10b.TfO), Xy (10c.TfO)], or 1:12 at 60 degrees C to give [Rh(Cp*){C,N-C(=NXy)C(6)H(4)C(Me)=N(Me)-2}(CNXy)]TfO (11.TfO). The crystal structures of 9a.ClO(4).acetone-d6, 9c.ClO(4), and 10a.TfO have been determined.

[Structure: see formula]. As demonstrated by 1H, 13C, and 109Ag NMR, a pi-alkyne-Ag complex and then an alkynyl silver are in situ formed from alkyne and silver salt in conditions related to those used for Ag-catalyzed alkynylation or for Ag/Pd-catalyzed sp-sp2 cross-coupling reactions. This finding allows for a rationale of the mechanisms of these reactions.

With their tantalizingly tangled structures, molecular knots have undeniable aesthetic appeal. But they haven’t found any particular practical use—until now. Chemists at the University of Manchester led by David A. Leigh have discovered a molecular knot that catalyzes reactions via anion abstraction (Science 2016, DOI: 10.1126/science.aaf3673). Last year, Leigh’s group reported a pentafoil molecular knot with a central cavity so good at sequestering chloride it plucked the anion out of glassware (J. Am. Chem. Soc. 2015, DOI: 10.1021/jacs.5b06340). “That made us think that maybe we could use this very strong, selective anion binding for something useful,” Leigh says. The insight led his group to discover it can use the same knot to pull halide ions off of certain substituents to form carbocations. The knot structure is crucial to the reaction, he says, because it creates the perfect anion-binding pocket. Leigh notes that silver salts do this same type of halide

Reaction of [(HBpz(3))RhCl(2)(PPh(3))] (Hpz = pyrazole) with silver salts AgA (A = BF(4), NO(3), SbF(6)) affords the unexpected heterotrinuclear compounds [[(HBpz(3))Rh(PPh(3))(mu-Cl)(2)](2)Ag]A (A = BF(4) (1), NO(3) (2), SbF(6) (3)). The compounds have been fully characterized by IR, (1)H, (31)P[(1)H], and (13)C[(1)H] NMR spectroscopy and FAB(+) mass spectrometry. The solid structure of compound 1 was determined by single-crystal X-ray diffraction. The cation consists of two (HBpz(3))RhCl(2)(PPh(3)) units bonded to a silver atom through two double mu-Cl bridges in an unusual distorted square-planar arrangement.

Facilitated gas transport in membranes is a diffusion/reaction system in which at least one reactant is spatially confined. Despite longstanding interest in this process, the consequences of spatial constraint have generally been overlooked. They are examined here in the cases of transport of the acid gases CO2, H2S, and SO2 in solutions of alkali and of ethylene in solutions of silver salts. Diffusion potentials are shown to be significant in each case, playing a role that complements spatial constraints. Nonetheless, at least in the ethylene case, fluxes calculated using an analysis that enforces spatial constraints but neglects ionic interactions are indistinguishable from those generated by an analysis that accounts for both.

The reaction of the complexes cis,trans-[OsI(Me)(CO)2(PMe3)2] and fac-[OsI(Me)(CO)3(PMe3)] with silver salts (AgX) and bis- and tris(pyrazol-1-yl)methane ligands affords the complexes [Os(COMe)((pz...

The sorption mechanism of 1-butene in dry silver salt-doped perfluorosulfonate membranes and the anion effect on the σ−π complexation of Ag+/1-butene were investigated. The interaction energy, ΔE, ...

Chiral (S,S)-(Phebox)PtCl complex 2 [Phebox = bis(oxazolyl)phenyl] and its cationic complexes (Phebox)Pt(OTf) (3) and [(Phebox)Pt(H2O)](BF4) (4) were synthesized by the transmetalation reaction of (Phebox)SnMe3 (1) with K[PtCl3(C2H4)](H2O) and subsequent treatment with silver salts. Both cationic complexes 3 and 4 readily reacted with N-phenylbenzaldimine (7) to afford the corresponding chiral aldimine complexes [(Phebox)Pt(aldimine)](X) (8, X = OTf; 9, X = BF4), which were subjected to alkylation with organolithium reagents resulting in 82% ee of the product amine (S)-10b.

[reaction: see text] Cobalt oxazoline palladacyclic (COP) complex 4 containing acetate as a bridging ligand is an excellent catalyst for asymmetric intramolecular aminopalladation to synthesize 4-vinyloxazolidin-2-ones in 91-98% ee. In contrast to previously reported Pd(II) catalysts, COP-OAc (4) promotes the asymmetric cyclization of (Z)-allylic N-tosylcarbamates without prior activation by silver salts.

The N-alkylated azatitanatranes N ( C H Z C H ~ N R ) ~ T ~ C I [R = Me (l), Et (2), i-Pr (3)] have been prepared and 1 and 3 structurally characterized by X-ray crystallography: 1, orthorhombic, Pmna, a = 1 1.293(3) A, b = 1 1.977(3) A, c = 9.722(3) A, V = 1314.96 A3, Z = 4, R = 0.0629; 3, cubic, Pa3, a = 15.928(4) A, V = 4040.95 A3, Z = 8, R = 0.0792. The halide ligand in 2 and 3 could be replaced by more labile ligands by chloride abstraction using the appropriate silver salts. A single-crystal X-ray structure analysis of N ( C H ~ C H Z N E ~ ) ~ T ~ O S O ~ C F ~ (4), the first azatrane-triflate to be reported, was carried out. Crystal data for 4: triclinic, Pf (No. 2), a = 16.039(4) A, b = 16.473(4) A, c = 8.954(3) A, a = 105.75’, 0 = 106.17(2)’, y = 107.54(2)’, V = 1996.33 A3, Z = 4, R = 0.0842. The titanium amido complexes reported here may find use as building blocks in more complex structural arrays.

The one-electron oxidized linear pentanuclear nickel complexes [Ni5(tpda)4(H2O)(BF4)](BF4)2 (1) and [Ni5(tpda)4(SO3CF3)2](SO3CF3) (2) have been synthesized by reacting the neutral compound [Ni5(tpda)4Cl2] with the corresponding silver salts. These compounds have been characterized by various spectroscopic techniques. Compound 1 crystallizes in the monoclinic space group P21/n with a = 15.3022(1) A, b = 31.0705(3) A, c = 15.8109(2) A, β = 92.2425(4)°, V = 7511.49(13) A3, Z = 4, and compound 2 crystallizes in the monoclinic space group C2/c with a = 42.1894(7) A, b = 17.0770(3) A, c = 21.2117(4) A, β = 102.5688(8)°, V = 14916.1(5) A3, Z = 8. X-ray structural studies reveal an unsymmetrical Ni5 unit for both compounds 1 and 2. Compounds 1 and 2 show stronger Ni−Ni interactions as compared to those of the neutral compounds.

A new practical protocol that avoids the stoichiometric use of either thallium or silver salts for the synthesis of the title compound is described.

Reaction of the 1-β-chloroethyl-substituted 1H-phosphirene complex 2 with silver salts results in formation of the acceptor-substituted 1H-phosphirene complexes 3; decomposition of the latter furni...

Helical coordination polymers have been obtained from the self-assembly of silver salts and the bidentate pyridazine (pydz), which include [Ag(pydz)](NO3), [Ag(pydz)](CF3SO3), containing 21 helices of different periods, and the unusual 41 helical species [Ag(pydz)2](BF4).

Chemists from the University of Karlsruhe, Germany, have developed a technique to convert ozonides into differently substituted derivatives without destroying the ozonide ring. These results give chemists a way to study these exquisitely sensitive compounds that are important intermediates in synthetic organic chemistry. The new method allows preparation of ozonides that cannot be made by direct ozonolysis of olefins. It also gives a way to trap unstable ozonides to prove that they are intermediates in reactions with ozone. Organic chemistry professor Karl Griesbaum described the technique at the national meeting of the American Chemical Society held last month in San Francisco. Working with graduate student Konrad Schlindwein, Griesbaum ozonized l,2,3,4-tetrachloro-2-butene on a polyethylene support to get 3,4-bis(chloromethyl)-3,5-dichloro-l,2,4-trioxolane. Reaction of this ozonide with silver salts resulted in substitution of the ring chlorines. Silver methoxide gave the 3,5-dimethoxy ozonide, silver a...