AgI Ions Research Articles

Synthesis and crystal structure of a silver(I) 6-methylmercaptopurine riboside complex.

Silver nitrate reacts with 6-methylmercaptopurine riboside (6-MMPR) in aqueous solution containing methanol and dimethyl sulfoxide at room temperature to give a colourless crystalline complex, namely, bis(6-methylmercaptopurine riboside-κN7)(nitrato-κ2O,O')silver(I) 2.32-hydrate, [Ag(NO3)(C11H14N4O4S)2]·2.32H2O. The crystal structure, determined from synchrotron diffraction data, shows a central AgI ion on a crystallographic twofold rotation axis, coordinated in an almost linear fashion by two 6-MMPR ligands via atom N7 (purine numbering), with the nitrate counter-ion loosely coordinated as a bidentate ligand, forming a discrete molecular complex as an approximate dihydrate. The complex and water molecules are connected in a three-dimensional network by hydrogen bonding.

Cover Feature: Organometallic–Organic Hybrid Assemblies Featuring the Diantimony Complex [Cp2Mo2(CO)4(μ,η2‐Sb2)], AgI Ions and N‐Donor Molecules as Building Blocks (Chem. Eur. J. 35/2023)

The first supramolecular assemblies composed of the organometallic diantimony complex [(Cp)2Mo2(CO)4(μ,η2-Sb2)], AgI ions and various N-donor molecules are presented; the cover feature depicts the synthesis of these organometallic–organic aggregates as a fascinating, yet challenging, adventure. The crossroads in the middle reflects the dependency of the final product's structure and dimensionality (0D, 1D, or even 2D) on N-donor ligand choice and highlights the importance of fine tuning of the reaction conditions. More information can be found in the Research Article by M. Scheer and co-workers (DOI: 10.1002/chem.202300610).

Organometallic-Organic Hybrid Assemblies Featuring the Diantimony Complex [Cp2Mo2(CO)4(μ,η2-Sb2)], Ag(I) Ions and Ndonor Molecules as Building Blocks.

The reactions of the of the organometallic ligand complex [Cp2Mo2(CO)4(μ,η2-Sb2)] (C) with Ag[TEF] ([TEF]‾ = [Al{OC(CF3)3}4]‾) in the presence of a number of di- or polytopic N-donor molecules (1,6,7,12-tetraazaperylene (L1), 2,2'-bipyrimidine (L2), 4,4'-bipyridine (L3), trans-1,2-di(4-pyridyl)ethylene (L4)) and 1,3-di(4-pyridyl)propane (L5), were studied. These reactions lead, depending on the reaction stoichiometry and choice of linker, to the selective formation of dimeric or tetrameric supramolecular coordination complexes as well as 1D and 2D coordination polymers (CPs). The presented compounds are unique examples of supramolecular complexes incorporating both organometallic Sb-donor and organic N-donor molecules as ligands to stabilize metal ions. Moreover, one of the formed compounds, the CP [Ag4(η2:1-C)4(L4)4]n[TEF]4n, represents an exceptional 1D polymer incorporating both N- and Sb-donor ligands as connectors for metal ions.

Inside Cover Picture

The pentagons are charming architectures found abundantly in organisms (such as starfish). The inside cover picture shows the first pentagonal‐prismatic organometallic cylinder obtained from the pentaphenylpyrrole‐bridged pentaimidazolium salt and AgI ions. Photophysical studies showed that the organometallic cylinder not only exhibited enhanced fluorescence emission in dilute solution at room temperature but also showed an improved phosphorescence ratio and maintained a long lifetime (1.39 s) in the solid state at 77 K. The current study is believed to provide important insights into the future design of novel phosphorescent organometallic materials with high efficiency and ultralong lifetime. More details are given in the article by Han et al. on page 1431–1436.image

An Ultralong Low‐Temperature Phosphorescent Pentagonal‐Prismatic Organometallic Cylinder Featuring Pentaphenylpyrrole‐N‐Heterocyclic Carbenes

Comprehensive SummaryA pentagonal‐prismatic cylinder [Ag5(L)2](PF6)5 obtained from the pentaphenylpyrrole‐bridged pentaimidazolium salt H5‐L(PF6)5 and AgI ions was determined by X‐ray diffraction analyses. The target organometallic cylinder not only exhibited enhanced fluorescence emission in dilute solution at room temperature but also showed an improved phosphorescence ratio compared with the free precursor and maintained a long lifetime (1.39 s) in the solid state at 77 K. Furthermore, the experimental results and DFT calculations confirmed that the formation of the organometallic cylinder promoted intersystem crossing. Meanwhile, the frontier orbitals of [Ag5(L)2](PF6)5 showed the main contribution of building block PPP as the luminescence source of [Ag5(L)2](PF6)5 by a modest heavy‐atom effect. These results provide a strategy for constructing enhanced phosphorescent emission and long lifetime organometallic supramolecular phosphorescent materials.

Diantimony Complexes [CpR 2 Mo2 (CO)4 (μ,η2 -Sb2 )] (CpR =C5 H5 , C5 H4 t Bu) as Unexpected Ligands Stabilizing Silver(I)n (n=1-4) Monomers, Dimers and Chains.

Synthesis and reactivity of transition metal compounds bearing "naked" pnictogen atoms is an active research area with remarkable bonding patterns observed in the formed compounds. Within this field, intense investigations on the coordination behavior of complexes possessing Pn and Asn (2≤n≤5) moieties have been conducted. However, studies on heavier analogues have been ignored so far due to arduous challenges related to low yields and moderate air stability. Herein, we present the first in-depth study addressing the reactivity of organometallic complexes containing Sb-donor atoms with several AgI salts. These reactions afforded twelve unprecedented aggregates as monomers, dimers as well as three- and four-membered chains of AgI ions claimed in the literature to be inaccessible. Interatomic distances as well as computational evidence obtained with help of several different methods suggest the presence of Ag⋅⋅⋅Ag interactions in all complexes containing more than one AgI ion.

"Tree"-like Multidentate Ligand-Assisted Synthesis of Polymolybdate-Based Architectures with Multinuclear Metal Clusters: Supercapacitor and Electrochemical Sensing Performances.

In this work, aiming for constructing multinuclear metal cluster-modified polymolybdate-based architectures with novel conformation, the "tree"-like multidentate ligand 5-(3-pyridyl)-1H-tetrazole) (3-ptzH) is introduced into the polymolybdate reaction system. Three new polymolybdate-based architectures with various multinuclear metal clusters, H4[Cu6(μ3-OH)2(3-ptz)6(γ-Mo8O28) (H2O)2]·2H2O (BOHU-1), H2[Ag4(3-ptz)2(Mo8O26)] (BOHU-2), and H4[Cu5(3-ptzH)2(3-ptz)2(MnMo9O32)2(H2O)4] (BOHU-3) (BOHU = Bohai University), have been prepared via the hydrothermal method and structurally characterized. In BOHU-1, a kind of pentanuclear copper cluster unit: [Cu5(μ3-OH)2(3-ptz)6]2+ is formed, which connects to construct a one-dimensional (1D) cluster-based chain. The 1D chains are extended to a two-dimensional (2D) layer via the Cu ions, which are further linked by the 4-connected [γ-Mo8O28]8- anions to build a three-dimensional (3D) framework. In BOHU-2, when a AgI ion was used as the central metal, the 3-ptz adopts different coordination modes to link the Ag ions, forming hexanuclear [Ag6(3-ptz)4]2+ cluster and finally 1D chains. These 1D cluster-based chains are connected by the 6-connected [γ-Mo8O26]4- anions to establish a 2D layer, which is further extended by [Mo8O26]n4n- 1D chains to a 3D framework. For BOHU-3, the chiral [MnMo9O32]6- anions are introduced and coordinated with the Cu ions to build left- and right-handed 1D chains, which are connected via the [Cu3(3-ptz)4]2+ cluster to form a 1D ladder-like chain. The effects of 3-ptz on the formation of multinuclear clusters, as well as the metals and polymolybdates on the multinuclear clusters and final structures of BOHU-1∼3, are discussed. The electrochemical performances of BOHU-1∼3 as electrode materials for supercapacitors and electrochemical sensors are investigated.

Self‐Assembly of a Bis‐NHC Ligand and Coinage Metal Ions: Unprecedented Metal‐Driven Chemistry between the Tri‐ and Tetranuclear Species

AbstractThe discrete multinuclear AgI−NHC complexes [Agn(1)n)](X)n; (n=3 or 4, X=BF4, PF6), synthesized from a bis‐NHC ligand 1 and AgI ions via multiligand self‐assembly, were observed to be in equilibrium between two forms (tri‐ and tetranuclear) in solution on the NMR timescale, which is unprecedented in CNHC‐donor based chemistry. The existence of both the species was confirmed by various studies such as NMR (1H, VT, 2D‐DOSY) and ESI‐MS analysis along with concentration studies. Importantly, replacing AgI with other coinage metals (AuI and CuI) was found to alter the phenomenon entirely: a slow exchange from the tetra‐ to trinuclear species was noticed for the AuI complexes (4 a, b), whereas no such process was detected in case of the CuI complexes (5 a, b).

A Novel AgI -DNA Rod Comprising a One-Dimensional Array of 11 Silver Ions within a Double Helical Structure.

DNA/RNA duplexes containing metal-ion-mediated base pairs (metallo-base pairs) have potential applications in developing nucleic acid-based nanodevices and genetic code expansion. Many metallo-base pairs are formed within duplexes stabilized by Watson-Crick base pairs. Recently, the crystal structure of an AgI -DNA nanowire with an uninterrupted one-dimensional silver array was determined. Here, we present a new DNA helical wire, the "AgI -DNA rod", containing an uninterrupted array of 11 AgI ions. The AgI -DNA rod consisted of only C-AgI -C, G-AgI -G, G-AgI -5-bromouracil (Br U), and Br U-AgI -Br U metallo base pairs, with no Watson-Crick pairs. The AgI -DNA rods were connected by non-canonical G-G pairs in crystals. Notably, data from our absorbance, circular dichroism, nuclear magnetic resonance, and mass spectrometry analyses suggested that the AgI -DNA rods formed in solution, as well as within crystals.

A Novel AgI‐DNA Rod Comprising a One‐Dimensional Array of 11 Silver Ions within a Double Helical Structure

AbstractDNA/RNA duplexes containing metal‐ion‐mediated base pairs (metallo‐base pairs) have potential applications in developing nucleic acid‐based nanodevices and genetic code expansion. Many metallo‐base pairs are formed within duplexes stabilized by Watson–Crick base pairs. Recently, the crystal structure of an AgI‐DNA nanowire with an uninterrupted one‐dimensional silver array was determined. Here, we present a new DNA helical wire, the “AgI‐DNA rod”, containing an uninterrupted array of 11 AgI ions. The AgI‐DNA rod consisted of only C‐AgI‐C, G‐AgI‐G, G‐AgI‐5‐bromouracil (BrU), and BrU‐AgI‐BrU metallo base pairs, with no Watson–Crick pairs. The AgI‐DNA rods were connected by non‐canonical G–G pairs in crystals. Notably, data from our absorbance, circular dichroism, nuclear magnetic resonance, and mass spectrometry analyses suggested that the AgI‐DNA rods formed in solution, as well as within crystals.

Synthesis and Metallation of Unsymmetric Tetrakisimidazolium Macrocycles

AbstractThe synthesis of the unsymmetric macrocyclic tetrakismidazolium salts H4‐4(PF6)4and H4‐5(PF6)4featuring a 2,6‐pyridinylene‐ and a 2‐bromo‐1,3‐xylylene‐bridged bisimidazolium unit is described. Reaction of macrocycle H4‐4(PF6)4with Ag2O yields the tetranuclear complex [6](PF6)4composed of four AgIions sandwiched in between two tetra‐NHC ligands. The 2,6‐pyridinylene‐bridged bisimidazolium moiety of the macrocycles can be site‐selectively deprotonated and metallated with RuIIor RhIto give the pincer complexes [8](PF6)3‐[11](PF6)3. Introduction of a second metal in these complexes by deprotonation/metallation and oxidative addition to the 2‐bromo‐1,3‐xylylene‐bridged bisimidazolium moiety of the macrocycles proved not possible.

Three Keggin POMs-based coordination polymers constructed by linear N-heterocyclic ligand for proton conduction, photocatalytic activity and magnetic property

POMs-based coordination polymers are promising materials for their potential application in the fields of proton conduction, catalysis and magnetism. Three new coordination polymers namely, {[Co2(bib)3(H2O)2(H4W12O40)]·7H2O}n (1), {[Zn3(bib)8(H3ZnW12O40)2]·12H2O}n (2) and {[Ag5(bib)5(H3W12O40)]·5H2O}n (3) were synthesized under hydrothermal conditions based on linear nitrogen heterocyclic ligand 1,4-bis(1-imidazolyl)benzene (bib). In compound 1, CoII ions are linked with [H4W12O40]4– anions to form a planar network and can be simplified as kgd topology, which are further linked with bib ligands to form a 3D framework. Zn2 ions of compound 2 alternately connect with bib ligands and [H3ZnW12O40]3– anions to form 1D chain structure, while Zn1 ion forms isolated unit with three bib ligands and one [H3ZnW12O40]3– anion, and a 3D framework is finally constructed through π … π stacking interactions. In compound 3, the 3D structure is constructed from a number of 1D chains formed by AgI ions and bib ligands in different directions through π … π stacking interaction and Ag⋯O weak connection. The proton conductivity of 1–3 are 2.03 ​× ​10−5, 1.04 ​× ​10−6 and 1.87 ​× ​10−4 ​S ​cm−1 at 98% RH and 358 ​K, respectively. In addition, compounds 1–3 exhibit photocatalytic degradation capacity towards RhB and compound 1 displays antiferromagnetic behavior.

Novel three-dimensional coordination polymer of 2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethanoic acid with silver(I) tetra-fluoro-borate.

An AgI-based coordination polymer (CP), namely, poly[[[μ3-2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethano-ate-κ4 N:N':O,O']silver(I)] tetra-fluoro-borate], {[Ag(C9H16N3O2P)]BF4} n , was synthesized in an aqueous solution of zwitterionic 2-(1,3,5-tri-aza-7-phospho-niatri-cyclo-[3.3.1.13,7]decan-7-yl)ethan-o-ate (L) and AgBF4 with exclusion of light at room temperature. The colourless and light-insensitive CP crystallized in the monoclinic space group Cc. The asymmetric unit consists of an AgI cation, the zwitterionic L ligand and a BF4 - counter-ion. Each AgI ion is coordinated by two carboxyl-ate oxygen atoms in a chelating coordination mode, as well as one of the nitro-gen atoms of two neighbouring L ligands. The crystal structure of the CP was classified as a unique three-dimensional arrangement. The CP was also characterized in aqueous solutions by multinuclear NMR and HRMS spectroscopies and elemental analysis.

Versatile Coordination of AgI and CuI Ions towards cyclo-As5 Ligands.

The reactions of the cyclo‐As5 complex [Cp*Fe(η5‐As5)] (B) with the AgI and CuI salts of the weakly coordinating anion (WCA) [FAl{OC6F10(C6F5)}3]− ([FAl]−) are studied. These reactions allow the synthesis of the mononuclear complexes [M(η5 : η2‐B)2][FAl] (M=Ag (1), Cu (2)) when a ratio of B/M(FAl) 2 : 1 is used. Compound 1 shows an unusual disorder of the central AgI cation between two π‐coordinating cyclo‐As5 ligands, which is absent in 2 pointing to a weak interaction of the Ag center towards the cyclo‐As5 ligands in B. When the ratio of B/Ag(FAl) is changed to 3 : 1 or 1 : 1, the respective coordination compounds [Ag(η2‐B)3][FAl] (3) and [Ag2(η2 : η2‐B)2][FAl]2 (4) are accessible. The coordination modes of the cyclo‐As5 units in 1, 3 and 4 are all different, reflecting the adaptive coordination behavior of B towards AgI ions. The optimized geometries in the gas phase of 1–4 are determined by DFT calculations to support the bonding situation observed in their solid‐state structures.

A study on the secondary structure of the metalloregulatory protein CueR: effect of pH, metal ions and DNA.

The response of CueR towards environmental changes in solution was investigated. CueR is a bacterial metal ion selective transcriptional metalloregulator protein, which controls the concentration of copper ions in the cell. Although several articles have been devoted to the discussion of the structural and functional features of this protein, CueR has not previously been extensively characterized in solution. Here, we studied the effect of change in pH, temperature, and the presence of specific or non-specific binding partners on the secondary structure of CueR with circular dichroism (CD) spectroscopy. A rather peculiar reversible pH-dependent secondary structure transformation was observed, elucidated and supplemented with pKa estimation by PROPKA and CpHMD simulations suggesting an important role of His(76) and His(94) in this process. CD experiments revealed that the presence of DNA prevents this structural switch, suggesting that DNA locks CueR in the α-helical-rich form. In contrast to the non-cognate metal ions HgII, CdII and ZnII, the presence of the cognate AgI ion affects the secondary structure of CueR, most probably by stabilizing the metal ion and DNA-binding domains of the protein.

Crystallographic Structure of Novel Types of AgI -Mediated Base Pairs in Non-canonical DNA Duplex Containing 2'-O,4'-C-Methylene Bridged Nucleic Acids.

Metal-mediated base pairs have widespread applications, such as in DNA-metal nanodevices and sensors. Here, we focused on their sugar conformation in duplexes and observed the crystallographic structure of the non-canonical DNA/DNA duplex containing 2'-O,4'-C-methylene bridged nucleic acid in the presence of AgI ions. The X-ray crystallographic structure was successfully obtained at a resolution of 1.5 Å. A novel type of AgI -mediated base pair between the N1 positions of anti-conformation of adenines in the duplex was observed. In the central non-canonical region, a hexad nucleobase structure containing AgI -mediated base pairs between the N7 positions of guanines was formed. A highly bent non-canonical structure was formed at the origin of AgI -mediated base pairs in the central region. The bent duplex structure induced by the addition of AgI ions might become a powerful tool for dynamic structural changes in DNA nanotechnology applications.

Consecutive Silver(I) Ion Incorporation into Oligonucleotides containing Cytosine-Cytosine Mispairs.

Invited for this month's cover is the group of Prof. Heinz-Bernhard Kraatz from the University of Toronto, Canada. The cover picture shows the consecutive incorporation of AgI ions into a DNA duplex containing adjacent C-C mispairs. Read the full text of the article at 10.1002/cplu.202000607.

Silver(I) Coordination in Silver(I)-Mediated Homo Base Pairs of 6-Pyrazolylpurine in DNA Duplexes Involves the Watson-Crick Edge.

DNA duplexes comprising 6‐(1H‐pyrazol‐1‐yl)‐9H‐purine (6PP), 1‐deaza‐6PP (1D6PP), 7‐deaza‐6PP (7D6PP) and 1,7‐dideaza‐6PP (1,7D6PP) 2′‐deoxyribonucleosides, respectively, were investigated towards their ability to form metal‐mediated base pairs in the presence of AgI. In 6PP and 7D6PP, the AgI ion can coordinate to the nucleobase via the endocyclic N1 nitrogen atom, that is, via the Watson–Crick edge. In contrast, this nitrogen atom is not available in 1D6PP and 1,7D6PP, so that in 1D6PP an AgI coordination is only possible via the Hoogsteen edge (N7). Reference duplexes with either adenine:adenine mispairs or canonical adenine:thymine base pairs were used to investigate the impact of the pyrazolyl moiety on the AgI‐binding properties. To determine the thermal and structural duplex stabilities in the absence or presence of AgI, all duplexes were examined by UV and circular dichroism spectroscopic studies. These investigations shed light on the question of whether N1‐ or N7‐coordination is preferred in purine‐based metal‐mediated base pairs.

Nucleation of Tiny Silver Nanoparticles by Using a Tetrafacial Organic Molecular Barrel: Potential Use in Visible-Light-Triggered Photocatalysis.

Coordination-driven self-assembly of discrete molecular architectures of diverse shapes and sizes has been well studied in the last three decades. Use of dynamic imine bonds for designing analogous metal-free architectures has become a growing challenge recently. This article reports an organic molecular barrel (OB4R ) as a potential template for nucleation and stabilization of very tiny (<1.5 nm) Ag nanoparticles (AgNPs). Imine bond condensation of a rigid tetra-aldehyde with a flexible diamine followed by imine-bond reduction yielded the discrete tetragonal organic barrel (OB4R ). The presence of a molecular pocket ornamented with eight diamine moieties gives the potential for encapsulation of silver(I). The organic barrel was finally used as a molecular vessel for the controlled nucleation of silver nanoparticles (AgNPs) with fine size tuning through binding of AgI ions in the confined space of the barrel followed by reduction. Transmission electron microscopy (TEM) analysis of the Ag0 @OB4R composite revealed that the mean particle size is 1.44±0.16 nm. The composite material has approximately 52 wt % silver loading. The barrel-supported ultrafine AgNPs [Ag0 @OB4R ] are found to be an efficient photocatalyst for facile Ullmann-type aryl-amination coupling of haloarenes at ambient temperature without using any additives. The catalyst was stable for several cycles of reuse without any agglomeration. The new composite Ag0 @OB4R represents the first example of discrete organic barrel-supported AgNPs employed as a photocatalyst in Ullmann-type coupling reactions at room temperature.

Consecutive Silver(I) Ion Incorporation into Oligonucleotides containing Cytosine-Cytosine Mispairs.

Herein, the consecutive incorporation of AgI ion into the dsDNA containing adjacent C-C mispairs is demonstrated. The melting temperature (Tm ) was 8 ° C higher for DNA containing three C-C mispairs upon the addition of three AgI ions as compared to the AgI -free DNA, and no Tm was obtained in the presence of excess AgI ion, indicating a stable bridging of C-AgI -C upon the incorporation of the stoichiometric amount of AgI per C-C mispair. The circular dichroism (CD) spectra of the dsDNA showed a negative peak at ∼270 nm in the presence of excess AgI , implying that significant structural changes and a potential aggregation of DNA occurred. Subsequently, the AgI -mediated DNA strands are immobilized on Au surfaces. Their electrochemical properties are monitored using CV, EIS and SECM showing increased overpotentials and charge-transfer resistances, and decreased the rate constant in the presence of an excess of AgI , respectively. These results are further supported by the XPS and sulfide-Au reductive desorption measurements.