Ag Separation Research Articles

Bis[μ-1-(2-pyridylmethyl)-1H-benzotriazole]disilver(I) bis(perchlorate)

In the title centrosymmetric binuclear AgI complex, [Ag2(C12H10N4)2](ClO4)2, each AgI center is two-coordinated by one pyridine and one benzotriazole N-donor atom of two inversion-related 1-(2-pyridylmeth­yl)-1H-benzotriazole (L) ligands. This forms a unique box-like cyclic dimer with an intra­molecular Ag⋯Ag separation of 4.479 (2) Å. Inter­molecular C—H⋯O hydrogen-bonding inter­actions, involving uncoordinated ClO4 − ions, link the binuclear units, forming a two-dimensional network parallel to (10).

Synthesis and Structures of Group 11 Metal Triazenide Complexes: Ligand Supported Metallophilic Interactions

A homologous and homoleptic series of stable Group 11 metal triazenide complexes with the general formula [M(L')](n) (M = Cu or Au, n = 2; M = Ag, n = 3) featuring the bulky triazenide ligand N,N'-bis(2,6-di-isopropylphenyl)triazene, L'H, have been prepared by the reaction of Li[L'] with the metal chlorides, CuCl, AgCl, and [(THT)AuCl], respectively, in a 1:1 stoichiometric ratio. The compounds [Cu(2)(L')(2)] and [Au(2)(L')(2)] crystallized as dimers with M...M separations of 2.4458(4) A and 2.6762(4) A, respectively. In comparison, the reaction of AgCl with Li[L'] results in the formation of the tri-silver complex [Ag(3)(L')(3)] with Ag...Ag separations of 3.01184(17) A, 2.95329(17) A, and 2.92745(16) A. Attempts to react the parent triazene system L'H with [Cu(Mes)] resulted in the formation of the novel tri-copper system [Cu(3)(L')(2)(Mes)]. In all cases the molecular structures of the resultant complexes have been unambiguously determined by single crystal X-ray diffraction experiments.

Catena-Poly[[(nitrato-κO,O')silver(I)]-μ(3)-4-pyridone-κO:O:O

In the title complex, [Ag(NO3)(C5H5NO)]n, the AgI atom is coordinated by two O atoms from two different 4-pyridone ligands and two O atoms from one nitrate anion, displaying a nearly planar coordination geometry. The O atoms of two 4-pyridone ligands bridge two symmetrically related AgNO3 units, forming a dimer, with an Ag⋯Ag separation of 3.680 (2) Å. Neighbouring dimers are linked into an infinite chain through weak Ag⋯O inter­actions [2.765 (2) Å], Ag⋯Ag inter­actions [3.1511 (4) Å] and π–π stacking inter­actions [centroid–centroid distance = 3.623 (4) Å]. N—H⋯O and C—H⋯O hydrogen bonds assemble these chains into a three-dimensional network.

Synthesis, spectroscopy and structures of halogen and sulfur-bridged dinuclear silver(I) complexes with N 1-substituted thiophene-2-carbaldehyde thiosemicarbazone

The reactions of silver(I) halides (Cl or Br) with thiophene-2-carbaldehyde N 1-methyl thiosemicarbazone (HttscMe) in the presence of Ph 3P (1:1:1 molar ratio) yield halogen-bridged dimers, [Ag 2(μ-X) 2(η 1-S-HttsMe) 2(PPh 3) 2] (X = Cl, 1; Br, 2). The use of 2,2′-bipyridine in lieu of Ph 3P in the reaction of silver(I) chloride with HttscMe yields the sulfur-bridged dimer, [Ag 2(μ-S-HttscMe) 2(η 1-HttsMe) 2] · 2CHCl 3 3. The substituents have altered the nature of bridge between the two silver atoms. The Ag···Ag separation (3.4867(5) Å) in complex 3 is less than that in the halogen-bridged dimers (3.734(4) Å 1; 3.746(5) Å 2). Unlike PPh 3 the co-ligand 2,2′-bipyridine did not coordinate to the silver center, but was necessary for crystallization in the reaction with the thio-ligand. NMR spectroscopy revealed that the complexes remained unchanged in the solution state (CDCl 3).

Bis[μ-2-(3-pyridylmethyl)-2H-benzotriazole]bis[nitratosilver(I)

In the title centrosymmetric binuclear AgI complex, [Ag2(NO3)2(C12H10N4)2], each AgI center is coordinated by one pyridine and one benzotriazole N-donor atom of two inversion-related 2-(3-pyridylmeth­yl)-2H-benzotriazole (L) ligands, and an O atom of a coordinated NO3 − anion in a distorted T-shaped geometry. This forms a unique box-like cyclic dimer with an intra­molecular non-bonding Ag⋯Ag separation of 6.327 (2) Å. Weak inter­molecular Ag⋯O(nitrate) inter­actions [2.728 (4) and 2.646 (3) Å] link the binuclear units, forming a two-dimensional network parallel to (100). Inter­molecular C—H⋯O hydrogen-bonding inter­actions, involving the L ligands and the coordinated NO3 − anions, link the sheets, forming a three-dimensional framework.

A Stair‐Shaped Molecular Silver(0) Chain

A Stair‐Shaped Molecular Silver(0) Chain

Bis{μ-3-[3-(2-pyridyl)pyrazol-1-ylmethyl]pyridine}disilver(I) bis(trifluoromethanesulfonate): effect of counter-anions on the self-assembly of coordination complexes

As part of a study on the effect of different counter-anions on the self-assembly of coordination complexes, a new dinuclear Ag(I) complex, [Ag(2)(C(14)H(12)N(4))(2)](CF(3)SO(3))(2), with the 3-[3-(2-pyridyl)pyrazol-1-ylmethyl]pyridine (L) ligand was obtained through the reaction of L with AgCF(3)SO(3). In this complex, each Ag(I) center in the centrosymmetric dinuclear complex cation is coordinated by two pyridine and one pyrazole N-atom donor of two inversion-related L ligands in a trigonal planar geometry. This forms a unique box-like cyclic dimer with an intramolecular nonbonding Ag...Ag separation of 6.379 (7) A. Weak Ag...CF(3)SO(3) and C-H...X (X = O and F) hydrogen-bonding interactions, together with pi-pi stacking interactions, link the complex cations along the [001] and [1\overline{1}0] directions, respectively, generating two different one-dimensional chains and then an overall two-dimensional network of the complex running parallel to the (110) plane. Comparison of the structural differences with previous findings suggests that the presence of different counter-anions plays an important role in the construction of such supramolecular frameworks.

Catena-Poly[silver(I)-μ-pyrazolato-κ2N:N′

The title compound, [Ag(C3H3N2)]n, has an infinite helical chain structure in which each pyrazolate group bridges two AgI atoms related by a 21 axis with an intra­chain Ag⋯Ag separation of 3.3718 (7) Å. Each AgI center is linearly coordinated by two N atoms [N—Ag—N angle = 169.98 (14)°]. The chains are held together by inter­chain Ag⋯Ag inter­actions [3.2547 (6) Å], forming a two-dimensional layer. The X-ray single-crystal diffraction result is consonant with that of the ab initio X-ray powder diffraction reported by Masciocchi, Moret, Cairati, Sironi, Ardizzoia & La Monica [J. Am. Chem. Soc. (1994). 116, 7668–7676], with only minor deviations of structural parameters.

Poly[μ2-(N-hydroxypyridine-2-carboxamidine)-μ2-nitrato-silver(I)

In the title complex, [Ag(NO3)(C6H7N3O)]n or [Ag(NO3)(pyaoxH2)] (pyaoxH2 is N-hydroxy­pyridine-2-carboxamidine), the Ag+ ion is bridged by the pyaoxH2 ligands and nitrate anions, giving rise to a two-dimensional mol­ecular structure. Each pyaoxH2 ligand coordinates to two Ag+ ions using its pyridyl and carboxamidine N atoms, and the OH and the NH2 groups are uncoordinated. Each nitrate anion uses two O atoms to coordinate to two Ag+ ions. The Ag⋯Ag separation via the pyaoxH2 bridge is 2.869 (1) Å, markedly shorter than that of 6.452 (1) Å via the nitrate bridge. The two-dimensional structure is fishscale-like, and can be described as pyaoxH2-bridged Ag2 nodes that are further linked by nitrate anions. Hydrogen bonding between the amidine groups and the nitrate O atoms connects adjacent layers into a three-dimensional network.

Catena-Poly[[silver(I)-μ-1,1′-methylenediimidazole] hexafluoridophosphate

The title compound, {[Ag(C7H8N4)]PF6}n, has a one-dimensional zigzag chain structure. The Ag+ cation and the PF6− anion reside on crystallographic inversion centres. The Ag+ cation is coordinated by the unsubstituted N atoms of two separate 1,1′-methyl­enediimidazole ligands. The closest Ag⋯Ag separation in the same cationic chain is 7.704 (2) A and the dihedral angle between the two imidazole rings in the same ligand is 85.5 (1)°. A two-dimensional layer framework is formed by weak Ag⋯N inter­actions between adjacent chains, with an Ag⋯N distance of 3.472 (2) A.

Catena-Poly[silver(I)-μ-2-phenylimidazolato-κ2N:N′

The asymmetric unit of the title compound, [Ag(C9H7N2)]n, contains two independent AgI ions and two 2-phenyl­imidazolate (L) ligands. Each AgI centre is linearly coordinated by two N atoms [Ag—N 2.092 (3)–2.097 (3) Å]. Ligands L bridge AgI ions into polymeric chains parallel to the c axis, with Ag⋯Ag separations of 6.232 (2) and 6.254 (2) Å. No inter­actions between the Ag centres from neighbouring chains are observed.

Spin-Crossover Behavior in Cyanide-Bridged Iron(II)−Silver(I) Bimetallic 2D Hofmann-like Metal−Organic Frameworks

Two new series of compounds formulated {Fe(3-Xpyridine)2[Ag(CN)2]2} (X = F (1), Cl (2), Br (3), I (4)) and {Fe(3-Xpyridine)2[Ag(CN)2][Ag(3-Xpyridine)(CN)2]}.3-Xpy (X = Br (5), I (6)) have been synthesized and characterized. The six compounds are made up of stacking of slightly corrugated two-dimensional coordination polymers defined by sharing {Fe4[Ag(CN)2]4}n motifs. The stacking is different for the two families. In compounds 1-4 the layers are organized by pairs displaying argentophilic interactions; the Ag...Ag distance was found to be in the interval 3.0-3.3 A, while the Ag...Ag separation between two consecutive layers belonging to different pairs was found to be around 6 A. Compounds 5 and 6 are isostructural with a crystal packing defined by an almost homogeneous distribution of layers separated by around 8.3 A (referred to the Fe...Fe interlayer distance). Between the layers an uncoordinated 3-Xpyridine molecule is included. Another 3-Xpyridine molecule, which remains in the plane defined by the {Fe4[Ag(CN)2]4}n windows, coordinates one silver atom. Both series display quite different properties; at 300 K, 1-4 are pale-yellow and display similar distorted [FeN6] octahedron cores characteristic of the iron(II) ion in the high-spin state. 1 and 2 undergo a two-step (T(1)1/2 = 96 K and T(2)1/2 = 162 K) and a 50% spin transition (T1/2 = 106 K), respectively. Compounds 3 and 4 are high-spin compounds at ambient pressure. 5 and 6 are deep red in color at 300 K and undergo spin-crossover behavior at significantly higher temperatures T1/2 = 306 and 261 K, respectively.

Catena-Poly[[(acetonitrile-κN)silver(I)]-di-μ-trifluoromethanesulfonato-κ4O:O′-[(acetonitrile-κN)silver(I)]-μ-tetraphenyldiphosphine-κ2P:P′

The silver(I)-based title polymer, [Ag2(CF3SO3)2(C28H26N2P2)]n, has been synthesized and structurally characterized. The compound shows the formation of a centrosymmetric eight-membered Ag/O/S/O/Ag/O/S/O ring situated around an inversion center, with the AgI ions bridged by two trifluoro­methane­sulfonate ions in a staggered conformation. The rings are then linked by tetra­phenyl­diphosphine ligands into a one-dimensional polymer. The rings have an Ag⋯Ag separation of 5.419 (5) Å and are linked by a 2.2206 (15) Å P—P bond. All AgI ions have pseudo-tetra­hedral geometry, with a coordination environment consisting of two O atoms from two symmetry-related trifluoro­methane­sulfonate ions, a P atom from a phosphine ligand and an N atom from an acetonitrile ligand.

Trinuclear Silver(I) Complexes of Fluorinated Pyrazolates

Silver pyrazolates [[3-(CF3)Pz]Ag]3, [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(Ph)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 have been synthesized by treatment of the corresponding pyrazole with a slight molar excess of silver(I) oxide. This economical and convenient route gives silver pyrazolates in high (>80%) yields. X-ray crystal structures of [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 show that these molecules have trinuclear structures with essentially planar to highly distorted Ag3N6 metallacycles. [[3-(CF3),5-(CH3)Pz]Ag]3 forms extended columns via intertrimer argentophilic contacts (the closest Ag...Ag separation between the neighboring trimers are 3.355 and 3.426 A). The trinuclear [[3-(CF3),5-(But)Pz]Ag]3 units crystallize in pairs, basically forming "dimers of trimers", with the six silver atom core of the adjacent trimers adopting a chair conformation. However, in these dimers of trimers, even the shortest intertrimer Ag...Ag distance (3.480 A) is slightly longer than the van der Waals contact of silver (3.44 A). [[3-(C3F7),5-(But)Pz]Ag]3, which has two bulky groups on each pyrazolyl ring, shows no close intertrimer Ag...Ag contacts (closest intertrimer Ag...Ag distance = 5.376 A). The Ag-N bond distances and the intratrimer Ag...Ag separations of the silver pyrazolates do not show much variation. However, their N-Ag-N angles are sensitive to the nature (especially, the size) of substituents on the pyrazolyl rings. The pi-acidic [[3,5-(CF3)2Pz]Ag]3 and [[3-(C3F7),5-(But)Pz]Ag]3 form adducts with the pi-base toluene. X-ray data show that they adopt extended columnar structures of the type [[Ag3]2.[toluene]]infinity and [[Ag3]'.[toluene]]infinity ([[3,5-(CF3)2Pz]Ag]3 = [Ag3],[[3-(C3F7),5-(But)Pz]Ag]3 = [Ag3]'), in which toluene interleaves and makes face-to-face contacts with [[3-(C3F7),5-(But)Pz]Ag]3 or dimers of [[3,5-(CF3)2Pz]Ag]3.

Di-μ-iodo-bis[pyridine(tri-p-tolylphosphine)silver(I)

The title compound, [Ag2I2(C5H5N)2(C21H21P)2], has Ci mol­ecular symmetry. Each Ag atom is surrounded by a phosphine ligand, a pyridine ligand and two iodide anions in a distorted tetra­hedral coordination. The Ag⋯Ag separation in the binuclear species is 3.1130 (18) A. The Ag—P distance is 2.4489 (12) A, the Ag—N distance is 2.392 (3) A, and the Ag—I distances are 2.8402 (14) and 2.8644 (8) A.

Bis[μ-3,3′-dimethyl-3,3′-methylenebis(2,3-dihydro-1H-imidazole)]disilver(I)(Ag—Ag) dichloride hemihydrate

In the title compound, [Ag2(C9H12N4)2]Cl2·0.5H2O, each AgI atom is coordinated by two C atoms of two heterocyclic carbene ligands, displaying a nearly linear geometry. The Ag—Ag separation is quite long, indicating a very weak metal–metal interaction.

Synthesis and structural characterization of a coordination polymer of silver(I) with saccharinate and nicotinamide

A silver(I)-saccharinato (sac) complex with nicotinamide (nia), [Ag(sac)(nia)] n has been synthesized and characterized by elemental analysis, IR spectroscopy, DTA-TG analyses and single crystal X-ray diffractometry. The complex crystallizes in monoclinic space group P21/n with unit cell parameters of a=7.0258(4) A, b=24.3784(10) A, c=8.4301(5) A, β=109.407(5)°, V=1361.85(13) A3 and Z=4. [Ag(sac)(nia)] n contains [Ag(sac)(nia)] units, which are doubly bridged by both nia and sac ligands, leading to a linear one-dimensional polymeric chains running along the a axis. The silver(I) ion has a highly distorted AgN2O2 tetrahedral geometry and the coordination polymer exhibits relatively short intra-chain ligand supported Ag···Ag separations of 3.1593(4) A. The one-dimensional chains are crosslinked by N–H···O hydrogen bonds and aromatic π(sac)···π(nia) stacking interactions to generate a two-dimensional layer structure. IR spectra and thermal analysis data are in agreement with the crystal structure.

Metal complexes from 1,1′-di(pyrazinyl)ferrocene: coordination polymers and bridged diferrocenes

Ferrocene-based ligands 1,1'-di(pyrazinyl)ferrocene (L1) and 1,1'-di(2-pyrimidinyl)ferrocene (L2) were synthesized and copper and silver complexes were obtained from L1. Coordination polymers [{Cu(2)(PhCOO)(4)}(L1)](n) (1), [{Cu(2)(C(5)H(11)COO)(4)}(L1)](n) (2), and [{Cu(2)(OAc)(4)}(L1)](n).0.5n[Cu(2)(OAc)(4)(H(2)O)(2)].1.5nCH(3)CN (3) resulted from the reaction with the corresponding copper carboxylates. In all three complexes, L1 links the dinuclear copper carboxylate units to form one-dimensional step-like chains. In 2, these chains are further linked by [Cu(2)(OAc)(4)(H(2)O)(2)] dinuclear units via hydrogen bonding to form sheet structures. The reaction of L1 with copper(I) iodide resulted in a multinuclear complex [(CuI)(4)(L1)(2)].(L1) (4), which contains a [(CuI)(4)(L1)(2)] diferrocene unit with a step-like (CuI)(4) core. Reactions of L1 with silver(I) salts resulted in silver-bridged diferrocenes [Ag(2)(L1)(2)]X(2) (X = ClO(4) (5a, b), NO(3) (6a-c) and PF(6) (7)), some of which incorporate aromatic solvents into their crystal lattices. The intramolecular Ag...Ag separations in these metallamacrocycles (3.211-3.430 A) depended upon the counter-anions and on the coordination mode of the silver ions. In all of these coordination complexes, L1adopts a synperiplanar eclipsed conformation and acts as a bidentate ligand, with only the 5-nitrogen of each pyrazine ring involved in coordination.

Disilver(I) Rectangular-Shaped Metallacycles: X-ray Crystal Structure and Dynamic Behavior in Solution

Reaction of the ditopic semirigid ligand 1,2-bis(imidazolylmethyl)benzene (1,2-bImb) or the flexible ligand 1,4-bis(2-benzimidazolyl)butane (C4BIm) with AgX (X = ClO4-, BF4-, CF3CO2-) afforded five new complexes, namely, [Ag2(1,2-bImb)2](ClO4)2 (1), [Ag2(1,2-bImb)2](BF4)2 (2), [Ag2(1,2-bImb)2](CF3CO2)2.2CH3OH (3.2CH3OH), [Ag2(C4BIm)2](ClO4)2.2DMF (4.2DMF), and [Ag2(C4BIm)2](CF3CO2)2.2H2O (5.2H2O), all of which contain a centrosymmetric, rectangular-shaped cationic disilver(I) metallacycle [Ag2(L)2]2+. In 1-3, a pair of 1,2-bImb ligands takes on the syn conformation to connect two Ag(I) ions to give a compressed rectangle with a transannular Ag...Ag separation of 3.27-3.36 angstroms, whereas in 4 and 5, the pair of planar C4BIm ligands acts in the cis conformation to connect two Ag(I) ions to yield a normal rectangle with a transannular Ag...Ag separation of 7.67-7.91 angstroms. The anions form Ag...O or Ag...F weak interactions in 1-3 and O-H...O or N-H...O hydrogen bonds in 4 and 5 in crystal packing but exhibit no significant influence on the formation of the disilver(I) macrocycles. The solution structure and dynamic behavior of the complexes studied by electrospray ionization mass spectrometry, 1H NMR, and variable-temperature NMR indicated that the dynamic equilibrium between the [Ag2(L)2]2+ cation and the open-ring oligomers or other potential species occurs via solvent-assisted dissociative exchange. The metal-ligand exchange barrier was estimated to be 54.5 kJ mol(-1).

Silver(I) Saccharinato Complexes with Ethylenediamine andN,N-Dimethylethylenediamine - [Ag2(sac)2(en)(H2O)]n and [Ag2(sac)2(dmen)2

Two new silver(I)-saccharinato (sac) complexes with ethylenediamine (en) and N,N-dimethylethylenediamine (dmen) were synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single crystal X-ray diffraction. The [Ag2(sac)2(en)(H2O)]n complex, 1, is a coordination polymer in which[Ag(sac)2(H2O)]− and [Ag(en)2]+ ions are bridged by one of the sac ligands and Ag–Ag bonds [2.9920(3) A], resulting in [Ag2(sac)2(en)(H2O)] building blocks which are also linked into one-dimensional helical chains by bridging en ligands. Each silver(I) atom is three-coordinate with a distorted T–shaped coordination of AgN2O. The individual chains of 1 are further stacked by π–π; interactions, OW–H···O and N–H···O hydrogen bonds to form a three–dimensional supramolecular framework. The [Ag2(sac)2(en)2] complex, 2, has two molecules in its asymmetric unit, and each dimer is formed by bridging of two monomeric [Ag(sac)(dmen)] units by Ag–Ag bonds. The silver(I) atoms exhibit a distorted T–shaped coordination of AgN3 with an N–bonded sac and bidentate dmen ligands. The Ag···Ag separations in the pair of dimers are 3.2725(9) and 3.3127(9) A. The dimeric molecules of 2 are connected to one-dimensional hydrogen bonded chains by N–H···O hydrogen bonds.