Synthesis and reactivity of gold(III) complexes containing cycloaurated iminophosphorane ligands

Transmetallation reactions of ortho-mercurated iminophosphoranes (2-ClHgC₆H₄)Ph₂PNR with [AuCl₄]⁻ gives new cycloaurated iminophosphorane complexes of gold(III) (2-Cl₂AuC₆H₄)Ph₂PNR [R = (R,S)- or (S)-CHMePh, p-C₆H₄F, ^tBu], characterised by NMR and IR spectroscopies, ESI mass spectrometry and an X-ray structure determination on the chiral derivative R = (S)-CHMePh. The chloride ligands of these complexes can be readily replaced by the chelating ligands thiosalicylate and catecholate; the resulting derivatives show markedly higher anti-tumour activity versus P388 murine leukaemia cells compared to the parent chloride complexes. Reaction of (2-Cl₂AuC₆H₄)Ph₂PNPh with PPh₃ results in displacement of a chloride ligand giving the cationic complex [(2-Cl(PPh₃)AuC₆H₄)Ph₂PNPh]⁺, indicating that the PN donor is strongly bonded to the gold centre.     

Synthesis and reactivity of osmium (VI) nitrido complexes containing pyridine-carboxylato ligands

A series of osmium(VI) nitrido complexes containing pyridine-carboxylato ligands Os^VI(N)(L)₂X (L = pyridine-2carboxylate (1), 2-quinaldinate (2) and X = Cl (a), Br (1b and 2c) or CH₃O (2b)) and [Os^VI(N)(L)X₃]⁻ (L = pyridine-2,6-dicarboxylate (3) and X = Cl (a) or Br (b)) have been synthesised. Complexes 1 and 2 are electrophilic and react readily with various nucleophiles such as phosphine, sulfide and azide. Reaction of Os^VI(N)(L)₂X (1 and 2) with triphenylphosphine produces the osmium(IV) phosphiniminato complexes Os^VI(NPPh₃)(L)₂X (4 and 5). The kinetics of nitrogen atom transfer from the complexes Os^VI(N)(L)₂Br (2c) (L = 2-quinaldinate) with triphenylphosphine have been studied in CH₃CN at 25.0 °C by stopped-flow spectrophotometric method. The following rate law is obtained: −d[Os(VI)]/dt = k₂[Os(VI)][PPh₃]. Os^VI(N)(L)₂Cl (L = 2-quinaldinate) (2a) reacts also with [PPN](N₃) to give an osmium(III) dichloro complex, trans-[PPN][Os^III(L)₂Cl₂] (6). Reaction of Os^VI(N)(L)₂Cl (L = 2-quinaldinate) (2a) with lithium sulfide produces an osmium(II) thionitrosyl complex Os^II(NS)(L)₂Cl (7). These complexes have been structurally characterised by X-ray crystallography.     

Synthesis, characterization and crystal structures of nickel complexes with dissymmetric tetradentate ligands containing a mixed-donor sphere

Four new nickel(II) complexes of dissymmetric tetradentate ligands, containing mixed-ligand donor sets of NSNS or NSNO, have been synthesized. These complexes were prepared by facile template reactions of the appropriate aldehyde and amine in the presence of [Ni(H₂O)₆](BF₄)₂, resulting directly in the desired nickel compounds. The nickel compounds were characterized by analytical, spectroscopic and electrochemical methods. The structures of [Ni(pyzs)]BF₄, [Ni(pyrs)]BF₄ and [Ni(pyzo)]BF₄ (see Scheme 1) have been determined by single-crystal X-ray crystallography, showing the geometry of the nickel ion to be square-planar. Vis–NIR spectra show that the phenolate-containing complexes [Ni(pyzo)]BF₄ and [Ni(pyro)]BF₄ (see Scheme 1) are essentially square-planar in nitromethane, but tetragonal octahedral in methanol, whereas the thiophenolate-containing compounds [Ni(pyzs)]BF₄ and [Ni(pyrs)]BF₄ remain square-planar in both solvents. Titration of the thiophenolate-containing complexes with 1-methylimidazole results in diamagnetic five-coordinated complexes. Electrochemistry shows quasi-reversible reductions to Ni(I) to occur for [Ni(pyzo)]BF₄, [Ni(pyrs)]BF₄ and [Ni(pyro)]BF₄.     

Synthesis and reactivity of iron carbonyl clusters containing alkynethiolate ligands

The new cluster Li[Fe₃(μ₃,η¹-SCCFc)(CO)₉] reacts with ClAuPPh₃ to afford compound [Fe₃Au(μ₄,η²-CCFc)(CO)₉(PPh₃)], which exhibits an isomeric equilibrium in solution with the cluster [Fe₃Au(μ₃,η²-CCFc)(CO)₉(PPh₃)].The rupture of C-S bonds in the thioethers Me₃SiCCSCCR (R = Fc, SiⁱPr₃) in the presence of Fe₃(CO)₁₂, yields to the clusters [Fe₃(μ-SCCSiⁱPr₃)(μ-CCSiMe₃)(CO)₉] and [Fe₃(μ,η²-(SiⁱPr₃)CCCCSiMe₃)(μ₃-S)(CO)₉] together with the unexpected compounds [Fe₂(μ-SCC(H)R)(CO)₆] (R = SiMe₃, SiⁱPr₃).Additionally, the dinuclear derivatives [Fe₂(μ-SCCR)(μ-CCR′)(CO)₆] (R = Fc, R′ = SiMe₃; R = SiMe₃, R′ = Fc; R = SiMe₃; R′ = SiⁱPr₃) have also been obtained. These compounds have been spectroscopically characterized and the crystal structure of some of them has been solved.     

Synthesis and solid-state molecular structures of nitrosoalkane complexes of iron porphyrins containing methanol, pyridine, and 1-methylimidazole ligands

Nitrosoalkanes belong to the family of C-nitroso compounds and are known to bind to the iron center in heme proteins. We have prepared and characterized a series of new nitrosoalkane heme model complexes of the form (por)Fe(RNO)(L) (por=porphyrinato dianion; R=isopropyl; L=MeOH, pyridine, 1-methylimidazole) by infrared and 1H NMR spectroscopy and X-ray crystallography. Within the set of octaethylporphyrinato (OEP) compounds, the infrared stretching frequencies of the NO groups decrease in the order (OEP)Fe(iPrNO)(MeOH).MeOH (1433 cm-1) > (OEP)Fe(iPrNO)(py) (1429 cm-1) > (OEP)Fe(iPrNO)(1-MeIm) (1423 cm-1), reflecting the increased backdonation of electron density in the 1-methylimidazole derivative. The molecular structures of the compounds as determined by crystallography reveal N-binding of the nitrosoalkane ligands to the formally ferrous metal centers.     

Synthesis and structure of rhodium complexes containing extended terpyridyl ligands

The reaction of the extended terpyridyl ligands, 4^′-(4^′′′-pyridyl)-2, 2^′:6^′,2″-terpyridine (qtpy), and 4^′-phenyl-2,2^′:6^′,2^′′-terpyridine (ptpy) with RhCl₃ and [tpyRhCl₃] (where tpy=2,2^′:6^′,2^′′-terpyridine) has been investigated. This has led to the isolation and characterisation of four new complexes. All the new complexes have had their molecular structures confirmed via X-ray crystallography studies. It has been shown that, consistent with related systems, changes in the electronic properties of the coordinated ligand results in modulation of the electrochemical and photophysical properties of the complex to which it is coordinated.     

Synthesis, multinuclear magnetic resonance and crystal structures of Pt(II) complexes containing amines and bidentate carboxylate ligands

A novel synthetic method for the synthesis of the complexes cis-Pt(amine)₂R(COO)₂ is compared to two other methods involving the use of either barium dicarboxylate or sodium carboxylate. Pt(II) compounds with monodentate and bidentate amines were studied. The reaction involves the use of a silver dicarboxylato complex, which is the intermediate in the new synthetic procedure. The crystal structure of the silver intermediate with the ligand 1,1-cyclobutanedicarboxylate (1,1-CBDCA) was determined by X-ray diffraction. The crystal Ag₂(1,1-CBDCA) has a very interesting 3-D extended structure. The complexes cis-Pt(amine)₂R(COO)₂ were studied in solution by multinuclear (¹H, ¹³C and ¹⁹⁵Pt) magnetic resonance spectroscopy, but the solubilities are very low. D₂O was found to be the best solvent. In ¹⁹⁵Pt NMR, the complexes containing bidentate amines forming five-membered chelates were observed at higher fields than those containing monodentate amines. The resonances of the NH₃ compounds were also found at lower fields than the primary amine complexes. All the dicarboxylato ligands form six-membered chelates except 1,2-CBDCA, whose Pt(II) compounds were observed at lower fields than the others. The crystal structures of Pt(en)(1,1-CBDCA), Pt(Meen)(1,1-CBDCA) and Pt(en)(benzylmalonato) were confirmed by X-ray diffraction methods. Several compounds are disordered. The crystals are stabilized by intermolecular hydrogen bonds between the -NH₂ groups and the carboxylato O atoms.     

Synthesis, structures, photoluminescent and electroluminescent properties of boron complexes with anilido-imine ligands

Syntheses of three new N-arylanilido-arylimine bidentate Schiff base type ligand precursors, ortho-C₆H₄[NH(2,6-ⁱPr₂C₆H₃)](CHNAr¹) [Ar¹ = p-FC₆H₄ (2a); C₆H₅ (2b); p-OMeC₆H₄ (2c)], and their four-coordinated boron complexes, ortho-C₆H₄[N(2,6-ⁱPr₂C₆H₃)](CHNAr¹)BF₂ [Ar¹ = p-FC₆H₄ (3a); C₆H₅ (3b); p-OMeC₆H₄ (3c)] are described. The boron complexes 3a-3c were synthesized from the reaction of BF₃(OEt₂) with the lithium salt of their corresponding ligand. All complexes were characterized by ¹H and ¹³C NMR spectroscopy and molecular structures of complexes 3a and 3c were determined by X-ray crystallography. The photophysical properties of complexes 3a-3c were briefly examined. All three complexes display bright green fluorescence in solution and in the solid state. Electroluminescent devices with complex 3c as the emitter were fabricated. These devices were found to give green emission with maximum current efficiency of 2.92 cd/A and maximum luminance of 670 cd/m².     

Copper(II) complexes of bidentate ligands containing nitrogen and sulfur donors: Synthesis, structures, electrochemistry and catalytic properties

Two nitrogen and sulfur containing ligands, 1-methyl-4-((4-methylimidazol-5-yl)methylthio)benzene (NS-mim) (1) and 1-methyl-4-(2-pyridylmethylthio)benzene (NS-mpy) (2) were synthesized and a series of their Cu(II) complexes, 3-10, prepared. The imidazole-containing complexes (3-6) have the form [Cu(NS-mim)₂(solvent)₂](X)₂ where X = ClO₄, BF₄and [Cu(NS-mim)₂(Y)₂] where Y = Cl or Br and the pyridine-containing complexes (7-10) have the form [Cu(NS-mpy)₂]X₂ (where X = ClO₄, BF₄) and [Cu₂(NS-mpy)₂Y₄] (where Y = Cl or Br). These complexes were characterized by a combination of elemental analysis, FAB-MS and electrochemistry. The X-ray structure of the imidazole-containing [Cu(NS-mim)₂(DMF)₂](ClO₄)₂ (3) was determined and it showed the copper(II) coordinated only by the nitrogen donors while the sulfurs remain uncoordinated. In comparison, the X-ray structure of the pyridine-containing [Cu₂(NS-mpy)₂(Cl)₄] (9) shows a dinuclear copper(II) complex with the nitrogens and the sulfurs coordinated along with a terminal chloride and two μ-chloro atoms bridging the coppers. Cyclic voltammetry studies indicated that the complexes undergo quasi-reversible one-electron reductions in acetonitrile at potentials between 0.31 and 0.51 V versus SCE. The complexes were found to be active for the oxidation of di-tert-butyl catechol (DTBC) with the rate dependent on the ligand and the counterion present.     

Syntheses and structures of four- and five-coordinate bio-related zinc complexes containing dithiolate-diamine ligands

Two new zinc complexes, namely, [{Zn(N₂H₂S₂)}₂] (3) [N₂H₂S₂²⁻ = N,N-bis(2-mercaptophenyl)ethylendiamine (2−)] and [Zn(N₂Me₂S₂)] (4) [N₂Me₂S₂²⁻ = N,N′-dimethyl-N,N′-bis(2-mercaptophenyl)ethylendiamine) (2−)] have been synthesized and structurally characterized by X-ray structure analyses. The structure of 3 consists of a bis(μ-thiolato) binuclear unit, in which each zinc center was found to reside in an N₂S₃ array between square-pyramidal and trigonal-bipyramidal environment. The two zinc centers are bridged by one of the two thiolates of an [N₂S₂] ligand. In the crystal packing, the neighboring binuclear units interact with each other by H-bonding interaction, which extends the binuclear unit into a 3D network. In contrast to 3 complex 4 is mononuclear, where each zinc center now was found to reside in an N₂S₂ distorted tetrahedral environment with a large S-Zn-S bite angle. The relevance of these compounds in biological systems is discussed. Unlike 3, the formation of hydrogen bridges in 4 is no longer possible and instead the molecular packing is determined by π-stacking between the phenyl rings.     

Zinc(II) complexes based on sterically hindered hydrotris(pyrazolyl)borate ligands: Synthesis, reactivity and solid-state structures

The coordination chemistry and reactivity of zinc(II) complexes supported by monoanionic hydrotris(pyrazolyl)borate ligands substituted by 3,3,3-mesityl groups (Tp^Ms) and 3,3,5-mesityl groups (Tp^Ms∗) have been investigated. Salt metathesis of ZnCl₂, ZnEt₂, and Zn(OAc)₂ with Tl[Tp^Ms] or Tl[Tp^Ms∗] cleanly afforded the corresponding compounds Tp^MsZnCl (1), Tp^MsZnEt (2), Tp^Ms∗ZnEt (3), and Tp^MsZnOAc (5). Compound 3 slowly disproportionates in benzene solution to afford the bis(ligand) complex (κ²-Tp^Ms∗)₂Zn (4). Acetate complex 5 as well as Tp^MsZnOCOPh (6) and [Tp^Ms∗ZnOAc]₂ (7) were alternatively prepared by acidolysis of the parent ethyl complexes (2, 3) with the corresponding carboxylic acid. No reaction was observed between 2 and 3 and alcohols (ROH; R = Et, iPr, Bn), while salt metathesis reactions of ZnEt(OR) with Tl[Tp^Ms] led to 2 instead of the desired zinc-alkoxide complex. Compounds 1-7 were characterized by elemental analysis, ¹H and ¹³C NMR spectroscopy, as well as by X-ray diffraction studies for 1, 2, 4, 5 and 7. The former compounds adopt a monomeric structure in the solid state while [Tp^Ms∗ZnOAc]₂ (7) exists as an anti-syn bridged acetate dimer. Complex 4 is four-coordinated, featuring a rare bidentate coordination mode of the Tp^Ms∗ ligands. The results are rationalized in terms of the variable steric constraint around the zinc atom provided by the Tp^Ms and Tp^Ms∗ ligands.     

Synthesis and characterization of nickel and palladium complexes containing hetero-multidentate PNO ligands

Formation of mono- and dinuclear complexes containing ligands stemmed from the condensation of 2,6-diformyl-4-methylphenol derivatives with 2-(diphenylphosphino)aniline (P∼N) was investigated. Condensation of P∼N with 2,6-diformyl-4-methylanisole yielded the desired bis(imine-phosphine) L₃, but provided the cyclized benzoazaphospholium compound with 2,6-diformyl-4-methylphenol. Complexation of L₃ with (COD)PdCl₂ gave the dinuclear complex 4. On the other hand, L₃ underwent the intramolecular cyclization in the presence of (DME)NiCl₂ via the formation of benzoazaphospholium rings. Template condensation of 2,6-diformyl-4-methylphenol with P∼N in the presence of metal ions yielded the mononuclear nickel(II) and palladium(II) complexes, respectively.     

Synthesis, characterizations and crystal structures of antimony(III) complexes with nitrogen-containing ligands

Six antimony adducts with N-donor neutral ligands (1,10-phenanthroline, 4,4′-bipyridine) have been obtained following the reaction of antimony halides with phenanthroline and 4,4′-bipyridine. By changing the solvent and stoichiometry, we obtained six different complexes, Sb(phen)Cl₃ (1), Sb(phen)Br₃ (2), Sb₂(phen)₄Br₈ (3) and Sb(bpy)Cl₃ (4), Sb(bpy)₂Cl₃ (5), Sb(bpyH · bpyH₂)Br₆ (6) (where phen = 1,10-phenanthroline, bpy = 4,4′-bipyridine). All the complexes have been characterized via elemental analysis, FT-IR and NMR (¹H, ¹³C) spectroscopy. The crystal structures of complexes 2, 3 and 6 have been determined by X-ray single crystal diffraction.The structural analysis show that the coordination sphere around antimony atom in complex 2 is a distorted square pyramid, coordinated by three bromine atoms and two nitrogen atoms from phen. In complex 3, the central antimony atom is six-coordinated through four bromine atoms and two nitrogen atoms forming a distorted octahedral geometry. Besides that, there are also uncoordinated 1,10-phenanthroline bonded by hydrogen bonds and π-π stacking interactions, which is rarely observed in previous reports. The crystal structure of complex 6 consists of bpyH · bpyH₂ trications and hexabromoantimonate trianions. The antimony atom in the anion has a distorted octahedral environment. Additionally, all complexes present a 3D framework built up by N-H?Br, C-H?Br and C-H?Cl weak hydrogen bonds interactions.     

Synthesis and characterization of binuclear rhenium(I) complexes containing bifunctional ligands

The ligand exchange reaction of the anionic binuclear rhenium complexes (R = H (1), or Me (2)) has been studied with the bifunctional ligands 2-aminophenol (3), 4-hydroxypyridine (4), 3-hydroxybenzoic acid (5), and 3-pyridylcarbinol (6). The reactivity the pendant pyridyl group of 6 was studied in reactions with the Lewis acids ZnCl₂ (7), and AgPF₆ (8). Crystal structure determinations for several of these derivatives have been carried out which reveal both discrete and polymeric complexes upon addition of the Lewis base.     

Synthesis and characterization of phosphorescent iridium complexes containing trifluoromethyl-substituted phenyl pyridine based ligands

Several iridium complexes containing trifluoromethyl-substituted phenyl pyridine based ligands have been synthesized and characterized to try to investigate the effect of trifluoromethyl group and its position on physical properties. The complexes have the general structure of (C-N)₂Ir(LX), where the C-N are 2-phenylpyridine (ppy), 2-(3,5-bis-trifluoromethylphenyl)pyridine (fmppy), 2-(3,5-bis-trifluoromethylphenyl)-4-methylpyridine (fmpmpy), 2-(3,5-bis-trifluoromethylphenyl)-5-trifluoromethylpyridine (tfmppy) and the LX are 2-picolinic acid (pic) and acetylacetonate (acac). The (tfmppy)₂Ir(pic) was characterized using X-ray crystallography. The absorption, emission, and thermostability of the complexes were systematically investigated. Introduction of CF₃ substituents into 2-phenylpyridine in (ppy)₂Ir(pic) lead to some decrease in the sublimation temperature, which is more suitable to devices fabrication. The experimental results revealed that the emissive colors of these complexes could be finely tuned by suitable incorporation of trifluoromethyl substituents on the 2-phenylpyridine ligand, obtaining bright green-blue emission λ_max values from 471 to 489 nm in CH₂Cl₂ solution at room temperature, with high solution quantum efficiencies ranging from 0.37 to 1.89 relative to Ir(ppy)₃.     

Iridium and rhodium complexes containing dichalcogenoimidodiphosphinato ligands

Treatment of [MCl(CO)(PPh₃)₂] with K[N(R₂PQ)₂] afforded [M{N(Ph₂PQ)₂}(CO)(PPh₃)] (M = Ir, Rh; Q = S, Se). The IR C=O stretching frequencies for [M(CO)(PPh₃){N(Ph₂PQ)₂}] were found to decrease in the order S > Se. Treatment of [M(COD)Cl]₂ with K[N(Ph₂PQ)₂] afforded [M(COD){N(Ph₂PQ)₂}] (COD = 1,5-cyclooctadiene; M = Ir, Rh; Q = S, Se). Treatment of [Ir(ol)₂Cl] with afforded (ol = cyclooctene COE, C₂H₄; Q = S, Se). Oxidative addition of [Ir(CO)(PPh₃){N(Ph₂PS)₂}] and [Ir(COD){N(Ph₂PS)₂}] with HCl afforded [Ir(H)(Cl)(CO)(PPh₃){N(Ph₂PS)₂}] and trans-[Ir(H)(Cl)(COD){N(Ph₂PS)₂}], respectively. Oxidative addition of [Ir(CO)(PPh₃){N(Ph₂PS)₂}] with MeI afforded [Ir(Me)(I)(CO)(PPh₃){N(Ph₂PS)₂}]. Treatment of [Ir(COE)₂Cl]₂ with K[N(R₂PO)₂] afforded [Ir(COE)₂{N(Ph₂PO)₂}] that reacted with MeOTf (OTf = triflate) to give [Ir{N(Ph₂PO)₂}(COE)₂(Me)(OTf)]. The crystal structures of [Ir(CO)(PPh₃){N(Ph₂PS)₂}], [M(COD){N(Ph₂PS)₂}] (M = Ir, Rh), (ol = COE, C₂H₄), trans-[Ir(H)(Cl)(COD){N(Ph₂PS)₂}], and [Ir(COE)₂{N(Ph₂PO)₂}] have been determined.     

Syntheses, characterization, and reactivity of copper complexes with tridentate N-donor ligands

The reaction of dioxygen with the copper(I) complex of the tridentate ligand 1,1,4,7,7-pentamethyldiethylenetriamine (Me₅dien) has been investigated using low-temperature stopped-flow techniques. The formation of a bis(μ-oxo)copper(III) complex as a reactive intermediate could be detected spectroscopically at low temperatures and a quantitative kinetic analysis was performed for this system. Crystal structures of the copper(II) complexes [(Me-bpa)Cu(Cl)₂] (1), [{(Me-bpa)Cu(Cl)(ClO₄)}₂] (2), [{(MeL)Cu(Cl)(ClO₄)}₂] (3), and [(MeL)Cu(NCS)₂] (4) (Me-bpa = N-methyl-[bis(2-pyridyl)methyl]amine; MeL = N-methyl-[(2-pyridyl)ethyl(2-pyridyl)methyl]amine) are reported.     

Synthesis, structures and magnetic properties of nicotinato-copper(II) complexes with polybenzimidazole and polyamine ligands

Four novel nicotinato-copper(II) complexes containing polybenzimidazole and polyamine ligands were synthesized with formula [Cu₂(bbma)₂(nic)₂](ClO₄)₂·CH₃OH·0.5H₂O (1), [Cu₂(dien)₂(nic)₂](ClO₄)₂·2CH₃OH (2), [Cu(ntb)(nic)]ClO₄·H₂O (3) and [Cu(tren)(nic)]BPh₄·CH₃OH·H₂O (4), in which bbma is bis(benzimidazol-2-yl-methyl)amine, dien is diethylenetriamine, ntb is tris(2-benzimidazolylmethyl)amine, tren is tris(2-aminoethyl)amine and nic is nicotinate anion. All of the complexes were characterized by elemental analysis, IR and X-ray diffraction analysis. Complexes 1 and 2 contain centrosymmetric dinuclear entity with the two Cu(II) atoms bridged by two nicotinate anions in an anti-parallel mode. The Cu···Cu separation is 7.109 Å for 1 and 6.979 Å for 2. Complexes 3 and 4 are mononuclear with nicotinate coordinated to Cu(II) ion by the carboxylate O atom in 3 and the pyridine N atom in 4. All of the complexes exhibit abundant hydrogen bonds to form 1D chain for 1, 3, 4 and 2D network for 2. Magnetic susceptibility measurements over the 2-300 K range reveal very weak ferromagnetic interaction between the two Cu(II) ions in 1 and antiferromagnetic interaction in 2 mediated by nicotinate ligand, with J value to be 0.15 and −0.19 cm⁻¹, respectively.     

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.