Synthesis and characterization of silver(I) derivatives containing acylpyrazolonate and phosphino ligands: X-ray crystal structures of monomeric [Ag(Q)(PPh3)2] and of dimeric [{Ag(Q)(PiBu3)}2] (Q = 1-phenyl-3-methyl-4-tert-butylacetylpyrazolon-5-ato)

New silver(I) acylpyrazolonate derivatives [Ag(Q)], [Ag(Q)(PR₃)]₂ and [Ag(Q)(PR₃)₂] (HQ = 1-R¹-3-methyl-4-R²(CO)pyrazol-5-one, HQ^Bn = R¹ = C₆H₅, R² = CH₂C₆H₅; HQ^CHPh2 = R¹ = C₆H₅, R² = CH(C₆H₅)₂; HQ^nPe = R¹ = C₆H₅, R² = CH₂C(CH₃)₃; HQ^tBu = R¹ = C₆H₅, R² = C(CH₃)₃; HQ^fMe = R¹ = C₆H₄-p-CF₃, R² = CF₃; HQ^fEt = R¹ = C₆H₅, R² = CF₂CF₃; R = Ph or iBu) have been synthesized and characterized in the solid state and solution. The crystal structure of 1-(4-trifluoromethylphenyl)-3-methyl-5-pyrazolone, the precursor of proligand HQ^fMe and of derivatives [Ag(Q^nPe)(PPh₃)₂] and [Ag(Q^nPe)(PiBu₃)]₂ have been investigated. [Ag(Q^nPe)(PPh₃)₂] is a mononuclear compound with a silver atom in a tetrahedrally distorted AgO₂P₂ environment, whereas [Ag(Q^nPe)(PiBu₃)]₂ is a dinuclear compound with two O₂N-exotridentate bridging acylpyrazolonate ligands connecting both silver atoms, their coordination environment being completed by a phosphine ligand.     

Alternative syntheses and reactivity of platinum(II) terpyridyl acetonitrile complexes

New direct syntheses of [Pt(trpy)(NCCH₃)](CF₃SO₃)₂2 (where trpy = 2,2′:6′,2′′-terpyridine) and [Pt(tBu₃-trpy)(NCCH₃)](CF₃SO₃)₂3 (where tBu₃-trpy = 4,4′,4″-tri-tert-butyl-2,2′:6′,2″-terpyridine) via the displacement of acetonitrile from [Pt(NCCH₃)₄](CF₃SO₃)₂ have been developed. The synthetic utility of 2 was investigated in reactions with triphenylphosphine (PPh₃), 2,6-dimethylphenyl isocyanide (CN-Xyl), 2,5-dimethyl-2,5-diisocyanohexane (TM4), and tert-butyl isocyanide (CN-tBu). Whereas the expected substitution products were observed for reactions with PPh₃, CN-Xyl, and CN-tBu, dealkylation of TM4 occurred to afford [Pt(trpy)(CN)](CF₃SO₃) 6. The structures of [Pt(trpy)L]²⁺ dications show little intermolecular interactions in the solid state, with the exception of the tBu₃-trpy complex 3 which exists as head-to-tail dimers with a Pt-Pt distance of 3.29 Å. The cyano product 6 was found to stack in infinite chains of cations with a Pt-Pt distance of 3.45 Å.     

Silver(I) methanesulfonate complexes containing diphosphine ligands: Spectroscopic and structural characterization

1:1 and 2:1 adducts of diphosphine ligands R₂P(R′)_nPR₂ (dppm: R = Ph, R′ = CH₂, n = 1; dppe: R = Ph, R′ = CH₂, n = 2; dppp: R = Ph, R′ = CH₂, n = 3; dppb: R = Ph, R′ = CH₂, n = 4; dppf: R = Ph, R′ = ferrocenyl, n = 1) with silver(I) methanesulfonate have been synthesized and characterized both in solution (¹H, ³¹P NMR) and in the solid state (IR, single crystal X-ray structure analysis). The two different stoichiometries have been found to depend on the molar ratio of ligand to metal employed and the nature of the diphosphine ligand. In AgO₃SMe:dppp,dppb (1:1)₂, in the [Ag(P^P)₂Ag] arrays, the silver atoms are also bridged by anion oxygen atoms, in disparate fashion commensurate with the different Ag?Ag distances.     

Facile synthesis and reactivity study of mixed phosphane-isocyanide Pd(II) and Pd(0) complexes

The reaction between an equimolecular mixture of isocyanide CNR (CNR = di-methylphenyl isocyanide (DIC), tert-butyl isocyanide (TIC), triphenyl phosphane (PPh₃) and a dechlorinated solution of the palladium allyl dimers [Pd(η³-allyl)Cl]₂ (allyl = 2-Meallyl, 1,1-Me₂allyl) in stoichiometric ratio yields the mixed derivative [Pd(η³-allyl)(CNR)(PPh₃)] only. Apparently, the mixed derivative represents the most stable species among all the possible ones that might be formed under those experimental conditions. Theoretical calculations are in agreement with the experimental observation and the energy stabilization of the mixed species with respect to the homoleptic derivatives is traced back to an overall push-pull effect exerted by the isocyanide and the phosphane acting synergically. Similar behavior is observed in the case of the synthesis of the palladacyclopentadienyl complexes [Pd(C₄(COOMe)₄)(CNR)(PPh₃)] and of the palladium(0) olefin complexes whose synthesis invariably yields the mixed [Pd(η²-olefin)(CNR)(PPh₃)] derivatives. The paper includes studies on the reactivity toward allylamination in the case of the palladium(II) allyl complexes. A diffractometric investigation on the solid state structures of four different palladium isocyanide-phosphane complexes is also included.     

3D coordination polymers of [2.2]paracyclophane and in situ silver(I) perfluoro-dicarboxylates: effects of the dicarboxylate spacers and conformations on the formation of complexes

Coordination polymers of [2.2]paracyclophane (pcp) with in situ silver(I) perfluoro-dicarboxylates characterized by single crystal X-ray analysis are described. Structures are found to strongly depend on the dicarboxylate spacer (n). With disilver(I) tetrafluorosuccinate ((CF₂)_n(COOAg)₂, n = 2), 3D network with composition of [Ag₄(pcp)(C₂F₄(CO₂)₂)₂] (1) forms in which silver salts afford infinite double chains and pcp act as linkages between chains. Changing the silver salt to disilver hexafluoroglutarate ((CF₂)_n(COOAg)₂, n = 3) produces 3D pillared-layer structure of composition of [Ag₄(pcp)(C₃F₆(CO₂)₂)₂] · THF (2) (THF = tetrahydrofuran), in which silver salts form 2D sheets and pcp act as pillars between the sheets. With silver octafluoroadipate (HO₂C(CF₂)_nCO₂Ag, n = 4), 2-fold interpenetrated diamond structure, [Ag₂(pcp)₂(HO₂CC₄F₈CO₂)₂]₂ · 2toluene (3), is obtained in which silver-anion chains and silver-pcp chains are connected with each other in the perpendicular manner. The three complexes represent unprecedented metal-organic networks of silver(I) multicarboxylates and polycyclic aromatic compounds. Additionally, the effects of the dicarboxylate conformations as well as the solvents on the resulting structures were discussed.     

Ionic metallomesogens derived from silver(I) bis-amine complexes: Structure and mesogenic behavior

Complexes [Ag(NH₂R)₂]X, (X = NO₃, R = -C₆H₄-C_nH_2n+1-p, -C₆H₄-O-C_nH_2n+1-p, -CH₂-C₆H₄-O-C_nH_2n+1-p, n = 6, 8, 10, 12, 14; X = BF₄, R = -CH₂-C₆H₄-O-C_nH_2n+1-p, n = 6, 8, 10, 12, 14; X = OAc, R = -CH₂-C₆H₄-O-C₁₀H₂₁-p; X = CF₃SO₃, R = -CH₂-C₆H₄-O-C₁₀H₂₁-p) have been prepared. They all show S_A mesophases corresponding to two kinds of structures, already present in the solid state. The alkylaniline and alkoxyaniline derivatives adopt a bilayered structure where the cation has an extended centrosymmetric conformation. The benzylamine derivatives contain U-shaped cations giving rise to a bilayered structure which allows microsegregation of the organic part of the molecule from the inorganic Ag?(anion) part. Some degree of interdigitation of the terminal chains is observed for all the complexes with aryl containing ligands.     

Silver(I) complexes with hydantoins and allantoin: synthesis, crystal and molecular structure, cytotoxicity and pharmacokinetics

Coordination polymers [Ag(L^1,3)]_n (L¹ = hydantoin, L³ = 5,5-dimethylhydantoin), {[Ag(L²)]^.0.5H₂O}_n (L² = 1-methylhydantoin) and [Ag(NH₃)(L⁴)]_n (L⁴ = allantoin) were prepared and characterized by elemental analysis, spectroscopic (IR, FTIR and NMR), thermal and mass spectrometry methods. The crystal structure of {[Ag(1-methylhydantoin)]·0,5H₂O}_n was determined and analyzed. Three 1-methylhydantoinate ligands create a T-shape (CN = 3) coordination sphere around the Ag⁺ ion. Additionally, a short Ag?Ag distance of 2.997 Å was found in the structure resulting in the expanded [3 + 2] environment of a distorted square shape. The [Ag(L²)] entities are bound to each other by the bridging organic ligands. Thus a two-dimensional coordination polymer is created with water molecules located between the layers. In contrast to hydantoins, the allantoin complex contains an additional ammonia molecule in the coordination sphere. Moreover, in the Ag-alla complex the M-organic ligand binding site is shifted to the N-atom of the ureid chain. Free ligands are cytotoxically inactive against human MCF-7 and A549 cancer cell lines and mouse fibroblasts Balb/3T3. The silver hydantoin complexes exhibit a very strong activity against these lines. (The introduction of the methyl groups to the ring slightly increases resistance only against the A549 cell line.) In contrast, the silver complex of allantoin shows only a weak activity which may be related to the presence of the cytotoxic ammonia group in the composition of the compound and/or the different binding site of the ligand. Calculated in silico physiochemical parameters are promising for the future application of the complexes as drugs.     

The structural definition of adducts of stoichiometry AgX:dppf (1:1)(n), X = simple anion, dppf = bis(diphenylphosphino)ferrocene

Single crystal X-ray structural characterizations are recorded for an array of adducts of the form AgX:dppf (1:1)_(n), X = simple (pseudo-)halide or oxy-anion, ‘dppf’ = bis(diphenyl phosphino)ferrocene, for adducts X = Cl (new phase), Br, I, SCN, OCN, CN, NO₃ (new phase), O₂CCH₃, n = 2, the form being dimeric [(dppf-P,P′)Ag(μ-X)₂Ag(P,P′-dppf)], for X = I, SCN, [Ag(μ-X)₂(P-dppf-P′)₂Ag′]; for X = O₂CCF₃, n = ∞, the form is an extended polymer: ?Ag(O · CO · CF₃)(P-dppf-P′)Ag′(O?. A dichloromethane solvate phase of CuI:dppf (1:1)₂ (also centrosymmetric) is also recorded. Synthetic procedures for all adducts have been reported. All compounds have been characterized both in solution (¹H, ¹³C, ³¹P NMR, ESI MS) and in the solid state (IR). The topology of the structures in the solid state was found to depend on the nature of the counterion.     

The double-helicate terpyridine silver(I) compound [Ag2L2](SO3CF3)2 (L = 4′-phenyl-terpyridine) as a building block for di- and mononuclear complexes

The double-helicate dinuclear silver(I) complex [Ag₂L₂](SO₃CF₃)₂ (1) was obtained by reaction of AgSO₃CF₃ with 4′-phenyl-terpyridine (L). Each Ag⁺ ion is coordinated by two N-atoms from one of the ligands and by one N-atom of the other ligand, forming an irregular Ag₂N₆ bi-triangle geometry, with a metallic bond between the two silver ions. Complex 1 reacts with potentially bidentate ligands (L¹), such as 9,10-bis(diphenylphosphino)anthracene (PAnP), 4,4′-dipyridyl or bis(diphenyl phosphino)methane (DPPM), to give the corresponding dinuclear complexes with bridging L¹, [Ag₂L₂(μ-L¹)](SO₃CF₃)₂ (L¹ = PAnP 2, 4,4′-dipyridyl 3 or DPPM 4), whereas on reaction with PPh₃ forms the mononuclear complex [AgL(PPh₃)](SO₃CF₃) 5. Reaction of 1 with the potentially tridentate ligand tris(2-diphenylphosphinoethyl)amine (NP₃) results in complete decomposition of the coordination spheres to form [Ag(NP₃)](SO₃CF₃) 6. Compound 1 shows a strong fluorescence in the solid state with its excitation band at 383.5 nm, the emission band at 535.5 nm and the lifetime of 4.20 ns, but the derived complexes do not show fluorescent properties. The photoluminescence of 1 in various solvents was also studied. The complexes were characterized by ¹H NMR, elemental analysis, IR, MS, UV and single crystal X-ray diffraction.     

Short-term exposure to waterborne free silver has acute effects on membrane current of Xenopus oocytes

Waterborne free silver can cause osmo- and ionoregulatory disturbances in freshwater organisms. The effects of a short-term exposure to extracellular Ag⁺ ions on membrane currents were investigated in voltage-clamped defolliculated Xenopus oocytes. At a holding potential of − 60 mV, ionic silver (1 μM Ag⁺) increased inward currents (=I_Ag) from − 8 ± 2 nA to − 665 ± 41 nA (n = 74; N = 27). I_Ag activated within 2 min of silver exposure and then rose impetuously. This current was largely reversible by washout and repeatable. I_Ag reversed around − 30 mV and rectified slightly at more positive potentials. Na⁺-free bath conditions reduced the silver-induced current to a smaller but sustained current. The response to silver was abolished by the Cl⁻ channel blockers DIDS and SITS, whereas niflumic acid strongly potentiated I_Ag. Intraoocyte injection of AgNO₃ to about 1 mM [Ag]_i strongly potentiated I_Ag. Extracellular application of either dithiothreitol (DTT), a compound known to reduce disulfide bridges, or l-cysteine abolished Ag⁺-activated increase of membrane current. In contrast, n-ethylmaleimide (NEM) which oxidizes SH-groups potentiated I_Ag. Hypoosmotic bath solution significantly increased I_Ag whereas hyperosmolar conditions attenuated I_Ag. The activation of I_Ag was largely preserved after chelation of cytosolic Ca²⁺ ions with BAPTA/AM. Taken together, these data suggest that Xenopus oocytes are sensitive to short-term exposure to waterborne Ag⁺ ions and that the elicited membrane currents result from extra- and intracellular action of Ag⁺ ions on peptide moieties at the oocyte membrane but may also affect conductances after internalization.     

Investigation of the solution behavior of tri-n-butylphosphine copper(I) and silver(I) acetates using P{H} NMR spectroscopy

³¹P{¹H} NMR spectra of metal-organic [(ⁿBu₃P)_mMO₂CMe] (M = Cu, Ag; m = 1, 1.5, 2, 2.5, 3, 3.5, 4) have been studied in the temperature range of 308-178 K. Exchange parameters were determined for the appropriate silver(I) complexes. Possible ligand exchange mechanisms based on dissociative and associative processes are discussed.     

Unsupported intermolecular argentophilic interaction in the dimer of trinuclear silver(I) 3,5-diphenylpyrazolates

The reaction of a solution of sodium 3,5-diphenylpyrazolate, Na[Ph₂pz], with Ag(tht)NO₃ in dichloromethane affords thin needles of unsolvated and light-stable dimer of trimers [Ag₃(μ-3,5-Ph₂pz)₃]₂. The complex is characterized by X-ray crystallography and elemental analysis. The two trimers are rotated anti to each other. Three silver atoms bridged through exobidentate pyrazolate groups form a slightly puckered nine-membered ring with the shortest Ag?Ag intramolecular interaction in the metallocycle of 3.3571(8) Å. The other two silver centers are weakly interacting, Ag(3)?Ag(1) = 3.49 Å and Ag(3)?Ag(2) = 3.52 Å. The intermolecular interaction between the two trimers is Ag?Ag = 2.9712(14) Å. Packing diagram shows the dimer of trimer units are independent. Density Functional Theory calculations show that the M?M interaction is due to dispersion forces. [Ag₃(μ-3,5-Ph₂pz)₃]₂ crystallizes in the monoclinic space group C2/c with a = 22.169(4), b = 15.269(3), c = 22.482(5) Å, β = 103.69(3)° and V = 7394(3) ų.     

From infinite tubular arrays to discrete molecules and back: An example of reversible ring-opening polymerization in silver(I)-diphosphazane chemistry

The reaction of AgX with the diphosphazane ligand, PrⁱN(PPh₂)₂ (L) gives the polymeric complexes, [Ag₂(μ-X)₂(μ-L)]_n (X = NO₃1a or OSO₂CF₃1b). Single crystal X-ray analysis of 1a reveals a novel structural motif formed by interlinking of giant 40-membered rings; the diphosphazane ligand L adopts a unique ‘C_s’ geometry. These polymeric complexes exhibit a completely reversible ring-opening polymerization-depolymerization relationship with the dinuclear and mononuclear complexes, [{Ag(μ-L)(X)}₂] (X = NO₃2a, X = OSO₂CF₃2b) and [Ag(κ²-L)₂]X (X = NO₃3a, X = OSO₂CF₃3b).     

Silver(I) poly(1,2,3-benzotriazolyl)borate complexes containing mono- and bidentate phosphine coligands

New silver(I) derivatives [Ag{H_nB(btz)_4 − n}(PR₃)_x] (n = 1 or 2, x ranging from 1 to 3), containing monodentate tertiary phosphines and anionic poly(benzotriazol-1-yl)borates, have been prepared from the reaction of AgNO₃ with PR₃ (R = Ph, o-tolyl, m-tolyl, p-tolyl, Bns) and K[H₂B(btz)₂], or K[HB(btz)₃] (Hbtz = 1,2,3-benzotriazole). When the reaction between K[H₂B(btz)₂] and AgNO₃ was carried out in the presence of dppe (1,2-bis(diphenylphosphino)ethane), or dppf (1,1′-bis(diphenylphosphino)ferrocene), compounds [Ag{H₂B(btz)₂}]₂(L) (L = dppe or dppf) formed, the diphosphine acting as a bidentate bridging P₂-donor. Solid state and solution properties of all complexes have been investigated through analytical and spectroscopic measurements (IR, ¹H, ³¹P NMR), the ¹H and ³¹P NMR spectra being interpreted in terms of equilibria that involve mono- and di-nuclear complexes. Adducts [Ag{HB(btz)₃}(PPh₃)₃] · (1/2H₂O) and [Ag{H₂B(btz)₂}]₂ (dppf) have been characterised by single crystal X-ray studies. In the former, the HB(btz)₃ is unidentate in an NAgP₃ coordination environment; the latter is a dimer, the dppf bridging the two silver atoms, while the H₂B(btz)₂ ligand, which chelates one silver, bridges to the second also, the array having 2-symmetry.     

Synthesis, spectroscopy and structural characterization of silver(I) complexes containing unidentate N-donor azole-type ligands

From the interaction between azole-type ligands L and AgX (X = NO₃ or ClO₄) or [AgX(PPh₃)_n] (X = Cl, n = 3; X = MeSO₃, n = 2), new ionic mononuclear [Ag(L)₂]X and [Ag(PPh₃)₃L][X] or neutral mono-([Ag(PPh₃)_nL(X)]) or di-nuclear ([{Ag(PPh₃)(L)(μ-X)}₂]) complexes have been obtained which have been characterized through elemental analysis, conductivity measurements, IR, ¹H NMR and, in some cases, also by ³¹P{¹H} NMR spectroscopy, and single-crystal X-ray studies. Stoichiometries and molecular structures are dependent on the nature of the azole (steric hindrance and basicity), of the counter ion, and on the number of the P-donor ligands in the starting reactants. Solution data are consistent with partial dissociation of the complexes, occurring through breaking of both Ag-N and Ag-P bonds.     

The synthesis, structure, and characterization of three novel 1D nitrogen-heterocyclic copper(I)-diphosphine polymers

At ambient temperature, three 1D nitrogen-heterocyclic Cu(I)-diphosphine polymers, {[Cu₂(dppm)₂(BF₄)₂(pyz)](CH₂Cl₂)₂}_n (1), {[Cu₂(dppm)₂(4,4′-bpy)(CF₃SO₃)](CF₃SO₃)(CH₃OH)}_n (2), {[Cu₂(dppe)₂ (phen)₂](ClO₄)₂(CH₂Cl₂)}_n (3) (dppm = bis(diphenylphosphino)methane, dppe = bis(diphenylphosphino)ethane, pyz = pyrazine, 4,4′-bpy = 4,4′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by X-ray crystallography, luminescence, IR, ¹H, and ³¹P NMR. Structure analysis shows that 1 is a 1D linear polymer, 2 is a 1D stair-shaped polymer, and 3 is a 1D W-shaped polymer. A photoluminescent study of them shows that they exhibit fluorescent emission bands at ca. 555 nm, 535 nm and 557 nm, respectively.     

The synthesis and cyclic voltammetry of select ferrocene piano-stool isocyanide complexes

Ferrocene piano-stool isocyanide complexes ([CpFeL₃]⁺, Cp = η⁵-C₅H₅, L = tert-butyl isocyanide (1), cyclohexyl isocyanide (2), and 2,6-dimethylphenyl isocyanide (3)) are formed by chemical oxidation of ferrocene in the presence of a stoichiometric amount of isocyanide ligand (1:3). The complexes are characterized by elemental analysis, routine spectroscopic methods (IR, ¹H NMR, ¹³C NMR, and UV-Vis), and cyclic voltammetry.     

Kinetics and thermodynamics of proton transfer to CpRu(dppe)H: Via dihydrogen bonding and (η-H2)-complex to the dihydride

The interaction between Cp^∗RuH(dppe) and a series of proton donors (HA) of increasing strength: CFH₂CH₂OH (MFE), CF₃CH₂OH (TFE), (CF₃)₂CHOH (HFIP), p-nitrophenol, CF₃COOH and HBF₄ has been investigated spectroscopically by variable-temperature IR, UV-Vis, and NMR spectroscopy in solvents of differing polarity (n-hexane, dichloromethane and their mixture). The low-temperature IR study shows the establishment of a hydrogen-bond which involves the hydride ligand as the proton accepting site. The basicity factor E_j for the hydride was found to be 1.39. All techniques indicate that an equilibrium exists between the dihydrogen-bonded complex and the cationic dihydrogen complex, [Cp^∗Ru(η²-H₂)(dppe)]⁺, the formation of which is shown here for the first time. The proton transfer from HFIP is characterized by ΔH^° = −8.1 ± 0.6 kcal mol⁻¹ and ΔS^° = −17 ± 3 eu. The activation parameters for the subsequent irreversible isomerization leading to the classical dihydride complex, [Cp^∗Ru(H)₂(dppe)]⁺, are ΔH^‡ = 20.9 ± 0.8 kcal mol⁻¹ and ΔS^‡ = 9 ± 3 eu as determined from ¹H NMR spectroscopy for protonation by HBF₄. Computational results at the DFT/B3PW91 level confirm the experimentally observed hydride basicity increase on descending the Group from iron to ruthenium and also the formation of the non-classical complex as an intermediate, prior to the thermodynamically favored dihydride.     

Structure diversity of silver(I) [1,1′-bis(diphenylphosphino)cobaltocenium] complexes: Effect of counteranions

Single crystal X-ray structural characterizations are recorded for an array of adducts of the form {AgX:[dppc][PF₆]}_n (n = 1 or 2), [dppc][PF₆] = 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate, X = Cl, Br, NO₃, NO₂, C₆H₅CO₂, CF₃CO₂. Synthetic procedures for all adducts are reported. All compounds have been fully characterised by elemental analysis and spectroscopic techniques. The structures in the solid state were found to depend on the nature of the counterion, for X = NO₃, NO₂, the complex being monomeric {[dppc-P,P′]Ag(NO₃)₂} or {[dppc-P,P′]Ag(NO₂)}, for X = Cl, Br, C₆H₅CO₂, CF₃CO₂, the complex is a dimer.     

Synthesis and structural characterization of adducts of silver(I) carboxylate salts AgX (X = CF3COO, CH3COO) with ER3 (E = P, As; R = Ph, cy, o-tolyl) and oligodentate aromatic bases derivative of 2,2′-bipyridyl, L, AgX:PR3:L (1:1:1)

Twenty-one adducts of the form AgX:ER₃:L (1:1:1) (X = CF₃COO (‘tfa’), CH₃COO (‘ac’), E = P, As; R = Ph, cy, o-tolyl; L = 2,2′-bipyridyl (‘bpy’)-based ligand) have been synthesized and characterized by analytical, spectroscopic (IR, far-IR, ¹H, ¹⁹F and ³¹P NMR) and single crystal X-ray diffraction studies. The resulting complexes are predominantly of the form [(R₃E)AgL]⁺X⁻, with a trigonal EAgN₂ coordination environment, the planarity of which may be perturbed by the approach of anion or solvent. The carboxylate anions have been found to be uni-, or semi-bidentate, or also completely ionic, as in the complexes [Ag(PPh₃)(bpy)(H₂O)](tfa) and [Ag(PPh₃)(dpk · H₂O)](tfa) (‘dpk · H₂O’ = bis(2-pyridyl)ketone (hydrated)). The complexes Agac:PPh₃:dpa (1:1:1) and Agac:P(o-tol)₃:dpa:MeCN (1:1:1:1) are dinuclear, with bridging unidentate acetate and terminal unidentate dpa (‘dpa’ = bis(2-pyridyl)amine).