Two- and three-dimensional silver(I)-organic networks generated from mono- and dicarboxylphenylethynes

Three phenylethynes bearing methyl carboxylate (HL1), monocarboxylate (H(2)L2), and dicarboxylate (H(2)L3) groups were utilized as ligands to synthesize a new class of organometallic silver(I)-ethynide complexes as bifunctional building units to assemble silver(I)-organic networks. X-ray crystallographic studies revealed that in [Ag(2)(L1)(2)·AgNO(3)](∞) (1) (L1= 4-C(2)C(6)H(4)CO(2)CH(3)), one ethynide group interacts with three silver ions to form a complex unit. These units aggregate by sharing silver ions with the other three units to afford a silver column, which are further linked through argentophilic interaction to generate a two-demensional (2D) silver(I) network. In [Ag(2)(L2)·3AgNO(3)·H(2)O](∞) (2) (L2 = 4-CO(2)C(6)H(4)C(2)), the ethynide group coordinates to four silver ions to form a building unit (Ag(4)C(2)C(6)H(4)CO(2)), which interacts through silver(I)-carboxylate coordination bonds to generate a wave-like 2D network and is subsequently connected by nitrate anions as bridging ligands to afford a three-demensional (3D) network. In [Ag(3)(L3)·AgNO(3)](∞) (3) (L3 = 3,5-(CO(2))(2)C(6)H(3)C(2)), the building unit (Ag(4)C(2)C(6)H(3)(CO(2))(2)) aggregates to form a dimer [Ag(8)(L3)(2)] through argentophilic interaction. The dimeric units interact through silver(I)-carboxylate coordination bonds to directly generate a 3D network. The obtained results showed that as a building unit, silver(I)-ethynide complexes bearing carboxylate groups exhibit diverse binding modes, and an increase in the number of carboxylate groups in the silver(I)-ethynide complex unit leads to higher level architectures. In the solid state, all of the complexes (1, 2, and 3) are photoluminescent at room temperature.     

Cyclophosphazenes as nodal ligands in coordination polymers

Herein, we show that cyclotriphosphazenes carrying organo amino side chains, (RNH)6P3N3 [R = n-propyl (1), cyclohexyl (2), benzyl (3)], and (C4H8N)6P3N3 (4) produce supramolecular coordination compounds in conjunction with silver salts by formation of linear N-Ag-N connections via nitrogen centers of the phosphazene ring. Crystalline materials were obtained by layering methanol solutions containing phosphazene ligands with methanol solutions of AgClO4 and AgNO3. The donor ability of the anion and the steric demand of the lipophilic ligand sphere R control the topology of the coordination network: (1)2(AgClO4)3 forms a graphite-type (6,3) network. All three N(ring) atoms of the phosphazene ligand coordinate to silver ions, which, in return, linearly bridge two phosphazene ligands. The phosphazene-Ag(I) arrangement in 1(AgNO3)2 exists of zigzag chains featuring one bridging silver ion and one terminally coordinated silver ion per ligand molecule. The terminally located Ag(I) ions of neighboring chains are bridged by nitrate ions, resulting in a 2D network. Both 2(AgClO4) and 4(AgClO4) contain only one bridging silver ion per phosphazene ligand, which leaves one N(ring) site vacant and gives 1D zigzag chain arrangements. The crystal structures of 3(AgClO4)2 and 3(AgNO3)2 resemble that of 1(AgNO3)2, but show additional Ag-pi(aryl) interactions between the terminally arranged silver ions and benzyl groups. Treatment of 3 with a methanol solution containing both AgNO3 and AgClO4 leads to the heteroanion derivative 3(AgNO3)(AgClO4). Phosphazene ligands 1-3 have the ability to undergo hydrogen bonding to anions via the six NH groups, and the coordination polymers containing these ligands feature dense networks of NH...O bonds.     

Anion dependent structures of luminescent silver(i) complexes

The reaction of AgX, where X = trifluoroacetate (CF(3)CO(2)(-), tfa), nitrate (NO(3)(-)), trifluoromethanesulfonate (triflate, CF(3)SO(3)(-), OTf), hexafluorophosphate (PF(6)(-)), or perchlorate (ClO(4)(-)), with 2,2',3' '-tripyridylamine (tpa) yields five novel silver(I) complexes, which have been structurally characterized. The five complexes have the same 1:1 stoichiometry of Ag/tpa but exhibit different modes of coordination, depending upon the counterion present in the compound. Compound 1, [Ag(tpa)(tfa)](n)(), forms a 1D coordination polymer of [Ag(tpa)(tfa)](2) dimer units linked through bridging tfa counterions. Compound 2, [Ag(tpa)(CH(3)CN)(NO(3))](n), forms a zigzag chain 1D coordination polymer exclusively through Ag-N bonds. In compounds 1 and 2, each tpa ligand is bound to two Ag(I) ions via a 2-py and a 3-py group. Compound 3, [Ag(tpa)(OTf)](n), forms a ribbonlike 1D coordination polymer, in which each tpa ligand binds to three different silver centers via all three pyridyl groups, and the counterion remains coordinated to the Ag(I) center. Compounds 4, [Ag(tpa)(CH(3)CN)](n)(PF(6))(n), and 5, [Ag(tpa)(CH(3)CN)](n)() (ClO(4))(n), display ribbonlike structures resembling that of 3, except that the counterions are not coordinated. All complexes are luminescent in acetonitrile solution, with emission maxima in the near-UV region (lambda(max) = 366, 368, 367, 367, and 368 nm for 1-5, respectively). At 77 K, the emission maxima are red-shifted to lambda(max) = 452, 453, 450, 450, and 454 nm for 1-5, respectively.     

Assembly of discrete,one-, two-, and three-dimensional silver(I) supramolecular complexes containing encapsulated acetylide dianion with nitrogen-donor spacers

The first successful attempt to construct supramolecular entities via incorporation of bifunctional exodentate ligands into the silver acetylide system is reported. Coordination assembly with nitrogen-donor spacers led to the formation of five distinct supramolecular complexes, namely [(Ag(2)C(2))(AgCF(3)CO(2))(4)(pyz)(2)](n) (1), [(Ag(2)C(2))(2)(AgCF(3)CO(2))(10)(CF(3)CO(2))(4)(DabcoH)(4)(H(2)O)(1.5)].H(2)O (2), [(Ag(2)C(2))(AgCF(3)CO(2))(4)(CF(3)CO(2))(bpaH)](n)() (3), [(Ag(2)C(2))(AgCF(3)CO(2))(8)(bpa)(4)](n) (4), and [(Ag(2)C(2))(2)(AgCF(3)CO(2))(10)(bppz)(2)(H(2)O)](n) (5) (pyz = pyrazine; Dabco = 1,4-diazabicyclo[2.2.2]octane; bpa = 1,2-bis(4-pyridyl)ethane; bppz = 2,3-bis(2-pyridyl)pyrazine). Complex 1 is a three-dimensional framework composed of silver columns cross-linked by pyrazine bridges, whereas 2 contains a discrete supermolecule whose core is a Ag(14) double cage that is completely surrounded by trifluoroacetate, aqua, and terminal monoprotonated Dabco ligands. Complex 3 has a branched-tree architecture with one terminal of the bpa ligand attached to the silver backbone and the other exposed and protonated. In 4, neutral decanuclear [(Ag(2)C(2))(AgCF(3)CO(2))(8)] units are interlinked by bpa spacers adopting both gauche and anti conformations to generate a layer structure. Another two-dimensional network was formed with bppz serving as an angular bridging ligand in 5, in which the building unit is a silver quadruple cage containing 24 silver atoms.     

Influences of changes in multitopic tris(pyrazolyl)methane ligand topology on silver(I) supramolecular structures

The reactions between silver tetrafluoroborate and the ligands 1,2,4,5-C(6)H(2)[CH(2)OCH(2)C(pz)(3)](4) (L1, pz = pyrazolyl ring), o-C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2) (L2), and m-C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2) (L3) yield coordination polymers of the formula (C(6)H(6)(-)(n)[CH(2)OCH(2)C(pz)(3)](n)(AgBF4)(m))( infinity ) (n = 4, m = 2, 1; n = 2, ortho substitution, m = 1, 2; meta substitution, m = 2, 3). In the solid state, L2 molecules dimerize by a pair of C-H.pi interactions, forming an arrangement that resembles the tetratopic ligand L1. In the solid-state structure of 1, each silver atom is kappa(2)-bonded to two tris(pyrazolyl)methane units from different ligands with the overall structure a polymer made up from 32-atom macrocyclic rings formed by bonding tris(pyrazolyl)methane groups from nonadjacent positions on the central arene rings to the same two silver atoms. In 2, each silver is bonded to two tris(pyrazolyl)methane units in the same kappa(2)-kappa(2) fashion as with 1, forming a polymer chain. The chains are organized into dimeric units by strong face-to-face pi-pi stacking between the central arene rings making bitopic L2 act as half of tetratopic L1. The chains in both structures are organized by weak C-H.F hydrogen bonds and pi-pi stacking interactions into very similar 3D supramolecular architectures. The structure of 3 contains three types of silvers with the overall 3D supramolecular sinusoidal structure comprised of 32-atom macrocycles. Infrared studies confirm the importance of the noncovalent interactions. Calculations at the DFT (B3LYP/6-31G) level of theory have been carried out on L2 and also support C-H.pi interactions. Electrospray mass spectral data collected from acetone or acetonitrile show the presence of aggregated species such as [(L)Ag(2)(BF(4))](+) and [(L)Ag(2)](2+), despite the fact that (1)H NMR spectra of all compounds show that acetonitrile completely displaces the ligand whereas acetone does not.     

Homochiral and heterochiral coordination polymers and networks of silver(I)

The self-assembly of racemic and enantiopure binaphthylbis(amidopyridyl) ligands 1,1'-C(20)H(12){NHC(O)-4-C(5)H(4)N}(2), 1, and 1,1'-C(20)H(12){NHC(O)-3-C(5)H(4)N}(2), 2, with silver(I) salts (AgX; X = CF(3)CO(2), CF(3)SO(3), NO(3)) to form extended metal-containing arrays is described. It is shown that the self-assembly with racemic ligands can lead to homochiral or heterochiral polymers, through self-recognition or self-discrimination of the ligand units. The primary polymeric materials adopt helical conformations (secondary structure), and they undergo further self-assembly to form sheets or networks (tertiary structure). These secondary and tertiary structures are controlled through secondary bonding interactions between pairs of silver(I) centers, between silver cations and counteranions, or through hydrogen bonding involving amide NH groups. The self-assembly of the enantiopure ligand R-1 with silver trifluoroacetate gave a remarkable three-dimensional chiral, knitted network composed of polymer chains in four different supramolecular isomeric forms.     

Systematic Investigation of Silver–Carbon Bonding in Coordination Frameworks with Aryl Ligands That Contain Ethynyl and Ethenyl Substituents

Single‐crystal X‐ray diffraction of a series of ten crystalline silver(I)–trifluoroacetate complexes that contained designed ligands, each of which was composed of an aromatic system that was functionalized with terminal and internal ethynyl groups and a vinyl substituent, provided detailed information on the influence of ligand disposition and orientation, coordination preferences, and the co‐existence of different types of silver(I)–carbon bonding interactions (silver–ethynide, silver–ethynyl, silver–ethenyl, and silver–aromatic) on the construction of coordination networks that were consolidated by argentophilic and weak inter/intramolecular interactions. The complex Ag L10? 6 AgCF₃CO₂ ? H₂O ? MeOH ( HL10 =1‐{[4‐(prop‐2‐ynyloxy)‐3‐vinylphenyl]ethynyl}naphthalene) is the first reported example that exhibits all four kinds of silver(I)–carbon bonding interactions in the solid state.     

Silver(I) coordination chemistry of 2,6-diarylpyrazines. Pi-stacking,anion coordination,and steric control

The silver(I) coordination chemistry of 2,6-diarylpyrazines is reported. Discrete coordination complexes and two-dimensional coordination networks were characterized. The substitution pattern on the pendant aryl groups controlled the type of coordination chemistry involved. Thus, o-methyl-substituted aryl groups held the aryl groups orthogonal to the central pyrazine ring, opening the "hindered" nitrogen atoms to complexation, and polymeric networks were characterized. In the absence of the o-methyl groups, discrete coordination complexes were characterized. Thus, a dimeric 2:1 ligand-silver(I) complex was isolated and characterized on reaction of 2,6-bis(3',5'-dimethylphenyl)pyrazine with silver(I) trifluoroacetate in acetonitrile solvent, while a 2:2 complex was isolated from dichloromethane solvent. Two trifluoroacetate ligands bridge two silver cations in both complexes. Reaction of the same pyrazine ligand with silver(I) tetrafluoroborate yielded a discrete 2:1 complex. A 2:1 complex was isolated on reaction of 2,6-diphenylpyrazine with silver(I) nitrate. These complexes were interlinked by weakly coordinating nitrate anions to form interwoven one-dimensional ribbons. Two-dimensional networks were obtained on reaction of silver(I) trifluoroacetate with either 2,6-bis(2',6'-dimethylphenyl)pyrazine or 2-(2',6'-dimethylphenyl)-6-(3',5'-dimethylphenyl)pyrazine. The networks comprised pyrazine-silver(I) strands cross-linked with complex bridged silver(I) trifluoroacetates.     

Silver supramolecule catalyzed multicomponent reactions under mild conditions

A novel supramolecular complex [Ag(L)(NO(3))] (1) was synthesized by reaction of the oxazoline-containing ligand 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (L) with silver(I) nitrate and its structure was determined by single-crystal X-ray diffraction. Structurally speaking, the one-dimensional (1D) zigzag chains of 1, in which the Ag(I) is three-coordinated with distorted trigonal-planar coordination geometry, are linked together by the hydrogen bonding interactions to form a three-dimensional (3D) supramolecular structure. It was found that the silver supramolecule 1 catalyzes the three-component coupling reactions of aldehyde, alkyne, and amine in the air at room temperature to generate propargylic amines with high efficiency. No additional co-catalyst or activator is required. A variety of aldehydes and amines were used to demonstrate the versatility of the reaction.     

catena‐Poly[[silver(I)‐μ‐[(E)‐1,2‐bis(2‐pyridyl)ethylene‐N:N′]] nitrate]

In the title complex, {[Ag(C₁₂H₁₀N₂)]NO₃}_n, the Ag atom, which is in a linear AgN₂ geometry, is surrounded by two trans‐related N atoms of two bpe ligands [Ag—N = 2.173 (3) and 2.176 (3) Å; bpe is trans‐1,2‐bis(2‐pyridyl)­ethyl­ene]. The bpe ligands bridge neighbouring Ag atoms to form zigzag polymeric chains in the lattice. These adjacent one‐dimensional zigzag chains are extended into a three‐dimensional supramolecular array by strong interchain π?π interactions between the pyridyl rings of adjacent chains.     

Assembly of silver(I)-organic networks from flexible supramolecular synthons with pendant ethynide arms attached to a naphthyl skeleton

Five new ligands bearing terminal ethynide moieties attached via pendant arms to a naphthyl skeleton have been used in the synthesis of eight silver(I) complexes. In these compounds, the invariable appearance of the mu 4 and mu 5 ligation modes of the ethynide moiety reaffirms the general utility of the silver-ethynide supramolecular synthons R-CC supersetAg n and Ag n subsetCC-R-CC supersetAg n ( n = 4, 5) in coordination network assembly, even when the R group is conformationally flexible. Besides the silver-ethynyl and silver-aromatic interactions, several unconventional intermolecular interactions (argentophilicity, anion-pi, C-H...pi, and CN...pi) also make their appearance.     

Heterometallic coordination polymers incorporating dipyrrin based heteroleptic copper and cobalt complexes: to Ag-π or not?

Using ligands based on either an acetylacetonate or a dipyrrin moiety appended with pyridyl groups, a series of novel heteroleptic copper(II) and cobalt(III) complexes combining both chelate units such as (acacpy(2))Cu(dpm-py) and (acacpy(2))Co(dpm-py)(2) (acacpy(2) = 1,3-bis(4-pyridyl)-1,3-propanedionate; dpm-py = 5-(4-pyridyl)dipyrrin) have been prepared and fully characterized. These two complexes were obtained upon reaction of dpm-py with the (acacpy(2))M homoleptic species (M = Cu(II), Co(II)). In the solid state, the (acacpy(2))Cu(dpm-py) complex behaves as a self-complementary metallatecton and leads to the formation of a 1D coordination polymer (CP) through the coordination of a peripheral pyridyl group to the copper centre. Contrastingly, the octahedral (acacpy(2))Co(dpm-py)(2) complex featuring a coordinatively saturated Co(III) centre crystallizes as an isolated mononuclear species. In order to generate heterometallic CPs, both complexes have been used as metallatectons upon their combination with different silver(I) salts. Upon reaction of (acacpy(2))Cu(dpm-py) with Ag(BF(4)) or Ag(TfO), 2- and 3-D heterometallic networks were obtained, respectively. In both cases, sheet type arrangements resulting from the binding of Ag(+) cations by three peripheral pyridyl groups were observed. These 2D sheets are further interconnected through Ag-π interactions with the pyrrolic rings. Under the same conditions, the combination of (acacpy(2))Co(dpm-py)(2) with Ag(TfO) leads to two networks differing by their connectivity patterns and dimensionality. Interestingly, whereas no Ag-π interactions were observed for the 2D network, a combination of coordination bonding with the pyridyl moieties and Ag-π interactions was detected for the 1D architecture.     

New bis-, tris- and tetrakis(pyrazolyl)borate ligands with 3-pyridyl and 4-pyridyl substituents: synthesis and coordination chemistry

The new ligands dihydrobis[3-(4-pyridyl)pyrazol-1-yl]borate [Bp(4py)]-, hydrotris[3-(4-pyridyl)pyrazol-1-yl]borate [Tp(4py)]-, tetrakis[3-(4-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]-, dihydrobis[3-(3-pyridyl)pyrazol-1-yl]borate [Bp(3py)]-, hydrotris[3-(3-pyridyl)pyrazol-1-yl]borate [Tp(3py)]- and tetrakis[3-(3-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]- are derivatives of the well known bis-, tris- and tetrakis-(pyrazolyl)borate cores, bearing 4-pyridyl or 3-pyridyl substituents attached to the pyrazolyl C3 positions. These pyridyl groups cannot chelate to the metal ions in the poly(pyrazolyl) cavity but are externally directed. Structural studies on a range of metal complexes show how, in many cases, coordination of these pendant pyridyl groups to the M(pyrazolyl)n core of an adjacent metal complex fragment results in formation of coordination oligomers or polymeric networks. [Tl(Bp(3py))], [Tl(Bp(4py))] and [Tl(Tp(4py))] form one-dimensional polymeric chains via coordination of one of their pendant pyridyl units to the Tl(I) centre of an adjacent complex fragment; in contrast, in [Tl(Tp(3py))] coordination of all three pendant pyridyl units to separate Tl(I) neighbours results in formation of a two-dimensional polymeric sheet. In [Tl(Tkp(3py))] and [Tl(Tkp(4py))] the Tl(I) is coordinated by two or three of the four pyrazolyl arms, respectively; bridging interactions of pendant 4-pyridyl groups with adjacent Tl(I) centres result in a two-dimensional sheet forming in each case. In Ag(Tkp(4py)) each Ag(I) ion is coordinated by two pyrazolyl rings, and two bridging pyridyl ligands from other complex units, resulting in a one-dimensional chain consisting of pairs of cross-linked zigzag chains. In contrast to these polymeric coordination networks, the structures of [Cu(Tp(4py))] and [(Tp(3py))Cd(CH3CO2)] are dimers, with a pendant pyridyl residue from the first metal centre attaching to a vacant coordination site on the second, and vice versa; these dimers are stabilised by pi-stacking interactions between sections of the two ligands. [Ni(Tp(3py))2] is monomeric, with an octahedral coordination geometry arising from two tris(pyrazolyl)borate chelates; the array of pendant 3-pyridyl groups is involved only in intramolecular hydrogen-bonding. [(Tp(4py))Re(CO)3] is also monomeric, with a facial arrangement of three pyrazolyl ligands and three carbonyls, with the pendant 4-pyridyl groups not further coordinated. [(Tp(2py))Re(CO)3], based on the related ligand hydrotris[3-(2-pyridyl)pyrazol-1-yl]borate, has a similar fac-(CO)3(pyrazolyl)3 coordination geometry.     

Synthesis, a case of isostructural packing, and antimicrobial activity of silver(I)quinoxaline nitrate, silver(I)(2,5-dimethylpyrazine) nitrate and two related silver aminopyridine compounds

The synthesis and low temperature crystal structures of [Ag(quinoxaline)]n(NO3)n, 1, [Ag(2,5-dimethylpyrazine)(NO3)]n, 2 and [Ag4(3-aminopyridine)4(NO3)4]n 3 are presented. The quinoxaline compound forms a 1D coordination polymer with the characteristic linear 2-coordination figure of silver(I), the N-Ag-N angle being 164.2(1) degrees, and only weak silver-nitrate interactions. In addition there is an interaction giving pairs of parallel chains as the main structural theme. The 2,5-dimethylpyrazine compound has approximately trigonal-planar coordination, also binding one nitrate at the relatively short Ag-O distances 2.444(3) angstroms and 2.484(3) angstroms, respectively, for the two crystallographically different silver atoms. This also results in a 1D coordination polymer that, despite the large differences in the Ag(I) coordination environment, is isostructural with 1. [Ag4(3-aminopyridine)4(NO3)4]n 3 forms a 2D coordination polymer by bridging nitrate ions. The antimicrobial activity of 1-3, and also of [Ag3(2-aminopyridine)4](NO3)3, 4 was screened for 13 different pathogens and substantial activity was shown for 1 against Escherichia coli and Pseudomonas aeruginosa (MIC 4 microg cm(-3)) and somewhat lower activity was registered against Sarcina lutea and Salmonella typhi for 1, Bordetella bronchiseptica for 2, Salmonella typhi and Pseudomonas aeruginosa for 3, and Escherichia coli and Shigella sonnie for 3 (MIC 8 microg cm(-3)). Only low activity was shown against the yeast Candida albicans for 1, 2 and 4 whereas no activity against this pathogen was registered for 3.     

N,N'-双(苯甲酰丙酮)-1,4-丁二胺席夫碱银(I)配合物的合成及其晶体结构

以苯甲酰丙酮与1,4-丁二胺经缩合反应制得一个新的席夫碱配体——N,N'-双(苯甲酰丙酮)-1,4-丁二胺(L);L与硝酸银经配位反应合成了配合物[Ag_2(L)(NO_3)_2]_n(1),其结构经1H NMR,13C NMR,FT-IR,元素分析和X-射线单晶衍射表征。晶体结构解析表明:1(CCDC∶1 434 692)属单斜晶系,空间群P21/c,晶胞参数a=0.997 81(5)nm,b=0.778 36(4)nm,c=1.704 13(8)nm,β=106.637 0(10),V=1.261 85(11)nm3,Z=2,Dc=1.884 g·cm~(-3),R1=0.020 8,wR_2=0.054 4。1中每个银离子为扭曲四面体的配位构型,分别和相邻配体的γ-碳原子,氧原子及两个NO_3~-的氧原子配位;每个配体作为四齿配体,分别用两端的γ-碳原子,氧原子和四个银离子配位形成1D链结构,1D通过NO_3~-与银离子配位扩展形成3D网状结构。热稳定性研究结果表明:L和1的初始分解温度分别为300℃和200℃。     

Polymeric (3‐amino‐2‐chloropyridine)nitratosilver(I)

In the title compound {alternative name: poly­[silver(I)‐μ‐(3‐­amino‐2‐chloro­pyridine)‐μ‐nitr­ato]}, [Ag(NO₃)(C₅H₅ClN₂)]_n the Ag^I atom is in an irregular AgN₂O₃ geometry, surrounded by one pyridyl N atom [Ag—N 2.283 (5) Å], one amine N atom [Ag—N 2.364 (6) Å] and three O atoms from different nitrate ions [Ag—O 2.510 (6)–2.707 (6) Å]. The Ag ions are bridged by the 3‐amino‐2‐chloro­pyridine ligands into helical chains. Adjacent uniform chiral chains are further interlinked through the NO₃ bridges into an interesting two‐dimensional coordination network in the solid.     

New family of silver(I) complexes based on hydroxyl and carboxyl groups decorated arenesulfonic acid: syntheses, structures, and luminescent properties

Self-assembly of silver(I) salts and three ortho-hydroxyl and carboxyl groups decorated arenesulfonic acids affords the formation of nine silver(I)-sulfonates, (NH(4))·[Ag(HL1)(NH(3))(H(2)O)] (1), {(NH(4))·[Ag(3)(HL1)(2)(NH(3))(H(2)O)]}(n) (2), [Ag(2)(HL1)(H(2)O)(2)](n) (3), [Ag(2)(HL2)(NH(3))(2)]·H(2)O (4), [Ag(H(2)L2)(H(2)O)](n) (5), [Ag(2)(HL2)](n) (6), [Ag(3)(L3)(NH(3))(3)](n) (7), [Ag(2)(HL3)](n) (8), and [Ag(6)(L3)(2)(H(2)O)(3)](n) (9) (H(3)L1 = 2-hydroxyl-3-carboxyl-5-bromobenzenesulfonic acid, H(3)L2 = 2-hydroxyl-4-carboxylbenzenesulfonic acid, H(3)L3 = 2-hydroxyl-5-carboxylbenzenesulfonic acid), which are characterized by elemental analysis, IR, TGA, PL, and single-crystal X-ray diffraction. Complex 1 is 3-D supramolecular network extended by [Ag(HL1)(NH(3))(H(2)O)](-) anions and NH(4)(+) cations. Complex 2 exhibits 3-D host-guest framework which encapsulates ammonium cations as guests. Complex 3 presents 2-D layer structure constructed from 1-D tape of sulfonate-bridged Ag1 dimers linked by [(Ag2)(2)(COO)(2)] binuclear units. Complex 4 exhibits 3-D hydrogen-bonding host-guest network which encapsulates water molecules as guests. Complex 5 shows 3-D hybrid framework constructed from organic linker bridged 1-D Ag-O-S chains while complex 6 is 3-D pillared layered framework with the inorganic substructure constructing from the Ag2 polyhedral chains interlinked by Ag1 dimers and sulfonate tetrahedra. The hybrid 3-D framework of complex 7 is formed by L3(-) trianions bridging short trisilver(I) sticks and silver(I) chains. Complex 8 also presents 3-D pillared layered framework, and the inorganic layer substructure is formed by the sulfonate tetrahedrons bridging [(Ag1O(4))(2)(Ag2O(5))(2)](∞) motifs. Complex 9 represents the first silver-based metal-polyhedral framework containing four kinds of coordination spheres with low coordination numbers. The structural diversities and evolutions can be attributed to the synthetic methods, different ligands and coordination modes of the three functional groups, that is, sulfonate, hydroxyl and carboxyl groups. The luminescent properties of the nine complexes have also been investigated at room temperature, especially, complex 1 presents excellent blue luminescence and can sensitize Tb(III) ion to exhibit characteristic green emission.     

Multinuclear Silver Ethynide Supramolecular Synthons for the Construction of Coordination Networks

The invariant appearance of the μ₈ coordination mode for the C₄^2? dianion in its silver(I) complexes, with four silver(I) atoms attached to each terminal ethynide moiety, implies that the Ag₄?C?C? C?C?Ag₄ species may be considered as a new type of supramolecular synthon for the construction of 1D, 2D, and 3D coordination polymers. This Focus Review covers recent results on the synthesis and structural characterization of silver(I) arylethynide and alkylethynide complexes, which established the existence and utility of analogous polynuclear supramolecular synthons R? C?C?Ag_n (R=aryl or alkyl; n=4, 5) and Ag_n?C₂? R? C₂?Ag_n (R=p‐, m‐, o‐C₆H₄; n=4, 5). The interplay of silver–ethynide bonding, which can be classified into σ, π, and mixed (σ,π) types, with argentophilicity, π–π stacking, and other weak interactions highlights the complexity and challenge in building coordination networks of silver ethynide complexes.     

One-dimensional coordination polymers incorporating silver(I) perfluorocarboxylate cuboctahedral clusters and the bis(methylthio)methane ligand

Two topologically comparable complexes, [Ag6(CF3CO2)3(L1-Me)3(SCH3)3]infinity (1) and [Ag6(CF3CF2CO2)3(L1-Me)2(SCH3)3(H2O)]infinity (2), were prepared and characterized by single-crystal diffractometry. The structures consist of Ag12S6 clusters linked by bis(methylthio)methane ligands, L1-Me, thus forming 1D coordination polymers. The 12 Ag atoms of the cluster are situated at the corners of a distorted cuboctahedron. The sulfur atoms of the six mu4-SCH3 entities occupy a position approximately 0.8 A above the center of each of the square faces of the polyhedron. The cleavage of the C-S bond of some of the ligands occurs during the syntheses, producing the -SCH3 anions. The coordination of the silver atoms varies from 5 to 7. The Ag...Ag contacts range from 2.9250(5) to 3.3615(6) A and from 2.961(1) to 3.380(1) A for 1 and 2, respectively. A polymeric ribbon is obtained when four ligands link a given cluster to two others. The chains of 1, held only by van der Waals forces, pack in a hexagonal manner. The two water molecules in 2 (Ag-OH2 = 2.385(7) A) are coordinated to silver atoms of the cluster. They are also strongly hydrogen bonded to the oxygen atoms of two pentafluoropropionate groups, one within the cluster (O...O = 2.741(1) A), the other in an adjacent chain (O...O = 2.818(1) A). The chains, thus H bonded to one another, generate a 2D coordination network.     

Titanium-based molecular squares and rectangles: syntheses by self-assembly reactions of titanocene fragments and aromatic N-heterocycles

This paper reports on the potential of titanium compounds as building blocks for supramolecular polygons. Self-assembly reactions of low-valent titanocene units and N-heterocyclic bridging ligands lead to novel titanium-based supramolecular squares. Pyrazine (3), 4,4'-bipyridine (4), and tetrazine (5) were used as bridging ligands, and the acetylene complexes [Cp2Ti{eta2-C2(SiMe3)2}] (1) and [(tBuCp)2Ti{eta2-C2(SiMe3)2}] (2) as sources of titanocene fragments. Molecular rectangles can be synthesized by stepwise reduction of the titanocene dichlorides [Cp(2)TiCl2] and [(tBuCp)2TiCl2] and consecutive coordination of two different bridging ligands. The resulting complexes are the first examples of molecular rectangles containing bent metallocene corner units. Single-crystal X-ray analyses of the tetranuclear compounds revealed the geometric properties of the molecular polygons in the solid state. Comparison of bond lengths and angles in coordinated and free ligands reveals the reduced state of the bridging ligand in the low-valent titanium compounds. The syntheses and properties of these novel, highly air- and moisture-sensitive compounds are discussed.