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The reaction of hot (~95 °C) aqueous solutions of Tl2CO3 with solid HL (HL = NC-C(=N-OH)-R is a cyanoxime, and R is an electron-withdrawing group; 37 ligands are known up-to-date) leads to crystalline yellow/orange TlL. Similarly, the reaction between AgNO3 and ML (M = K+, Na+; L = anion of the monodeprotonated cyanoxime) this time at room temperat...
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... this work we summarize up-to-date results of our studies of coordination polymers based on cyanoximes-a new class of small organic molecules that exhibit properties of excellent anionic ligands that bind a variety of metal ions [4][5][6][7][8][9]. The relationship between different subclasses of oximes and their precursors is shown in Figure 1. Within the last decade we developed three routes of the Meyer reaction [10] that afford cyanoximes in yields above 60% (Figure 2), with the route 3 using gaseous methylnitrite being the most successful in preparation of different aryl-ligands [11] (Electronic Supporting Information: ESI 1). ...
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... formation of a double-stranded, -ladder-type‖ 1D coordination polymer is the most common way of building the structure, we examined this topological motif in detail. A typical organization of such a motif consists of a centrosymmetric dimer (Figure 11(A)), with its Tl 2 O 2 units fused together by additional, longer auxiliary third contact with the oxygen atom of the neighboring dimer to form a -ladder‖ (Figure 11(B)). This double-stranded zigzag chains form infinite columns that represent a 1D coordination polymer in which individual columns have no chemical bonding between them in the lattice (Figure 11(C)), but are instead connected by means of the van-der-Waals forces. ...
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... formation of a double-stranded, -ladder-type‖ 1D coordination polymer is the most common way of building the structure, we examined this topological motif in detail. A typical organization of such a motif consists of a centrosymmetric dimer (Figure 11(A)), with its Tl 2 O 2 units fused together by additional, longer auxiliary third contact with the oxygen atom of the neighboring dimer to form a -ladder‖ (Figure 11(B)). This double-stranded zigzag chains form infinite columns that represent a 1D coordination polymer in which individual columns have no chemical bonding between them in the lattice (Figure 11(C)), but are instead connected by means of the van-der-Waals forces. ...
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... typical organization of such a motif consists of a centrosymmetric dimer (Figure 11(A)), with its Tl 2 O 2 units fused together by additional, longer auxiliary third contact with the oxygen atom of the neighboring dimer to form a -ladder‖ (Figure 11(B)). This double-stranded zigzag chains form infinite columns that represent a 1D coordination polymer in which individual columns have no chemical bonding between them in the lattice (Figure 11(C)), but are instead connected by means of the van-der-Waals forces. There are two rhombs 1 and 2 in this -ladder‖ motif, which are different both by Tl---Tl, Tl---O distances, and by the bend angle ( Figure 12). ...
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... double-stranded zigzag chains form infinite columns that represent a 1D coordination polymer in which individual columns have no chemical bonding between them in the lattice (Figure 11(C)), but are instead connected by means of the van-der-Waals forces. There are two rhombs 1 and 2 in this -ladder‖ motif, which are different both by Tl---Tl, Tl---O distances, and by the bend angle ( Figure 12). Details of the geometry of such topology for these polymers are summarized in Table 3. ...
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... are typical of argentophilic interactions ranging from 2.9 to 3.3 Å and are well documented in the literature [53]. The most important motif in crystal structures of Ag(I)-cyanoximates is a formation of complex 2D layered polymers with only one exception of well-defined 3D network in the case of Ag(CCO) [19] ( Figure 13). Organization of very elegant, and yet completely different 2D coordination polymers in the structures of Ag(ACO), Ag(BCO), Ag(DCO), Ag(ECO) and Ag(PiCO) is shown in Figures 14-18 respectively. ...
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... most important motif in crystal structures of Ag(I)-cyanoximates is a formation of complex 2D layered polymers with only one exception of well-defined 3D network in the case of Ag(CCO) [19] ( Figure 13). Organization of very elegant, and yet completely different 2D coordination polymers in the structures of Ag(ACO), Ag(BCO), Ag(DCO), Ag(ECO) and Ag(PiCO) is shown in Figures 14-18 respectively. In all these cases 2D sheets of different complexity and composition are connected into the framework either by means of extensive H-bonding like in the structure of Ag(ACO) [20] (Figure 14), or by means of van-der-Waals interactions C-H---H-C (aromatic) between phenyl groups b a a c in the structure of Ag(BCO) [54] (Figure 15), or via C-H---H-C (aliphatic) interactions between ethoxy-and t-butyl-groups in structures of Ag(ECO) and Ag(PiCO) [21] (Figures 17, 18 respectively). ...
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... of very elegant, and yet completely different 2D coordination polymers in the structures of Ag(ACO), Ag(BCO), Ag(DCO), Ag(ECO) and Ag(PiCO) is shown in Figures 14-18 respectively. In all these cases 2D sheets of different complexity and composition are connected into the framework either by means of extensive H-bonding like in the structure of Ag(ACO) [20] (Figure 14), or by means of van-der-Waals interactions C-H---H-C (aromatic) between phenyl groups b a a c in the structure of Ag(BCO) [54] (Figure 15), or via C-H---H-C (aliphatic) interactions between ethoxy-and t-butyl-groups in structures of Ag(ECO) and Ag(PiCO) [21] (Figures 17, 18 respectively). An interesting case of electrostatic interlayer attractions between oxygen atoms of the nitroso-group and hydrogen atoms of methyl groups of the anion was determined in the structure of Ag(DCO) [21] ( Figure 16). ...
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... of very elegant, and yet completely different 2D coordination polymers in the structures of Ag(ACO), Ag(BCO), Ag(DCO), Ag(ECO) and Ag(PiCO) is shown in Figures 14-18 respectively. In all these cases 2D sheets of different complexity and composition are connected into the framework either by means of extensive H-bonding like in the structure of Ag(ACO) [20] (Figure 14), or by means of van-der-Waals interactions C-H---H-C (aromatic) between phenyl groups b a a c in the structure of Ag(BCO) [54] (Figure 15), or via C-H---H-C (aliphatic) interactions between ethoxy-and t-butyl-groups in structures of Ag(ECO) and Ag(PiCO) [21] (Figures 17, 18 respectively). An interesting case of electrostatic interlayer attractions between oxygen atoms of the nitroso-group and hydrogen atoms of methyl groups of the anion was determined in the structure of Ag(DCO) [21] ( Figure 16). ...
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... of very elegant, and yet completely different 2D coordination polymers in the structures of Ag(ACO), Ag(BCO), Ag(DCO), Ag(ECO) and Ag(PiCO) is shown in Figures 14-18 respectively. In all these cases 2D sheets of different complexity and composition are connected into the framework either by means of extensive H-bonding like in the structure of Ag(ACO) [20] (Figure 14), or by means of van-der-Waals interactions C-H---H-C (aromatic) between phenyl groups b a a c in the structure of Ag(BCO) [54] (Figure 15), or via C-H---H-C (aliphatic) interactions between ethoxy-and t-butyl-groups in structures of Ag(ECO) and Ag(PiCO) [21] (Figures 17, 18 respectively). An interesting case of electrostatic interlayer attractions between oxygen atoms of the nitroso-group and hydrogen atoms of methyl groups of the anion was determined in the structure of Ag(DCO) [21] ( Figure 16). ...
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... all these cases 2D sheets of different complexity and composition are connected into the framework either by means of extensive H-bonding like in the structure of Ag(ACO) [20] (Figure 14), or by means of van-der-Waals interactions C-H---H-C (aromatic) between phenyl groups b a a c in the structure of Ag(BCO) [54] (Figure 15), or via C-H---H-C (aliphatic) interactions between ethoxy-and t-butyl-groups in structures of Ag(ECO) and Ag(PiCO) [21] (Figures 17, 18 respectively). An interesting case of electrostatic interlayer attractions between oxygen atoms of the nitroso-group and hydrogen atoms of methyl groups of the anion was determined in the structure of Ag(DCO) [21] ( Figure 16). Figure 15. ...
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... interesting case of electrostatic interlayer attractions between oxygen atoms of the nitroso-group and hydrogen atoms of methyl groups of the anion was determined in the structure of Ag(DCO) [21] ( Figure 16). Figure 15. Organization of layered 2D structure of Ag(BCO): view of two unit cells along b showing polymeric motif (A), and ab diagonal view of two unit cells (B). ...
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... latter must be normally obeyed during work with common light-sensitive silver(I) compounds. Despite being very stable towards visible light, solid powders of AgL being exposed to the UV-light develop contrast and sharp images (Figure 19; ESI 22). A detailed investigation of the irreversible color change and samples darkening revealed that it occurs only on the surface of solid samples with the rest of the bulk sample left intact [19][20][21]. ...
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... measurements were carried out within some time intervals, at room temperature, and at normal pressure of the above gases. Typical results presented in Figure 21 and indicate certain trend in observed emissions quench with acetylene, nitrous oxide and sulfur dioxide being electron rich and the most responsive molecules [19,20]. The most interesting feature of these coordination polymers is in their developed sensitization: the initial solid AgL are not visible light sensitive, but being exposed to these gases of industrial importance become sensitized and rapidly, within minutes, irreversibly change color and darken. ...
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A width and shape of resistive transition as well as thermal uctuations of the thallium based superconductors were analyzed theoretically. The applied magnetic eld widens the resistive transition according to the following formula: ∆T = CH m + ∆T0. The exponent m uctuates around 2/3 and depends on vortex structure and strength of the pinning force....
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... In this work, we expanded the utility of the metathesis reaction in dry organic solvents with Tl(I) cyanoximates (Scheme 1) and applied it to synthesize a series of Sb(V) compounds. These compounds were prepared practically quantitatively in warm aqueous solutions using Tl 2 CO 3 as the source for the heavy-metal cation [16,34,35] (Scheme 2B). Thus, we showed that the use of Tl(I) salts is equally useful and convenient when desired Ag-salts for other cyanoximates are either not obtainable or difficult to handle because of their high light sensitivity and thermal instability. ...
A series of the eight novel organoantimony(V) cyanoximates of Sb(C6H5)4L composition was synthesized using the high-yield heterogeneous metathesis reaction between solid AgL (or TlL) and Sb(C6H5)4Br in CH3CN at room temperature. Cyanoximes L were specially selected from a large group of 48 known compounds of this subclass of oximes on the basis of their water solubility and history of prior biological activity. The synthesized compounds are well soluble in organic solvents and were studied using a variety of conventional spectroscopic and physical methods. The crystal structures of all reported organometallic compounds were determined and revealed the formation of the distorted trigonal bipyramidal environment of the Sb atom and monodentate axial binding of acido-ligands via the O atom of the oxime group. The compounds are thermally stable in the solid state and in solution molecular compounds. For the first time, this specially designed series of organoantimony(V) compounds is investigated as potential non-antibiotic antimicrobial agents against three bacterial and two fungal human pathogens known for their increasing antimicrobial resistance. Bacterial pathogens included Gram-negative Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus. Fungal pathogens included Cryptococcus neoformans and Candida albicans. The cyanoximates alone showed no antimicrobial impact, and the incorporation of the SbPh4 group enabled the antimicrobial effect. Overall, the new antimony compounds showed a strong potential as both broad- and narrow-spectrum antimicrobials against selected bacterial and fundal pathogens and provide insights for further synthetic modifications of the compounds to increase their activities.
... The latter include growth-regulating [37,38] and antimicrobial [39][40][41] properties. We initiated synthesis and characterization of structures and properties of the new family of silver cyanoximates (reviewed in Reference [42]) and performed a preliminary assessment of their antimicrobial activity [43], followed by their further detailed characterization [44]. In the most recent work, we obtained two previously unknown AgL (L = 2-oximino-2-cyano-N-morpholylacetamide, MCO-and 2-oximino-2cyano-N-piperidineacetamide, PiPCO-), which were added to the list of visible light and heat stable, poorly water soluble antimicrobial compounds [45]. ...
... Our objectives were to: antimicrobial [39][40][41] properties. We initiated synthesis and characterization of structures and properties of the new family of silver cyanoximates (reviewed in Reference [42]) and performed a preliminary assessment of their antimicrobial activity [43], followed by their further detailed characterization [44]. In the most recent work, we obtained two previously unknown AgL (L = 2oximino-2-cyano-N-morpholylacetamide, MCO-and 2-oximino-2cyano-N-piperidineacetamide, PiPCO-), which were added to the list of visible light and heat stable, poorly water soluble antimicrobial compounds [45]. ...
... Preparation of twelve Silver(I) complexes of 1:1 composition that include cyanoxime anions was accomplished using a modified straightforward one-pot two steps reaction [42][43][44]47,48]. Thus, the deprotonated cyanoxime, obtained upon the addition of K 2 CO 3 to the HL (Scheme 1) forming bright-yellow solution in water, received an aqueous solution of AgNO 3 , which was added dropwise at room temperature and intense stirring: (a) 2 HL + K 2 CO 3 = 2 KL + H 2 O + CO 2 ↑ and (b) KL + ...
Biofilms are surface-associated microbial communities known for their increased resistance to antimicrobials and host factors. This resistance introduces a critical clinical challenge, particularly in cases associated with implants increasing the predisposition for bacterial infections. Preventing such infections requires the development of novel antimicrobials or compounds that enhance bactericidal effect of currently available antibiotics. We have synthesized and characterized twelve novel silver(I) cyanoximates designated as Ag(ACO), Ag(BCO), Ag(CCO), Ag(ECO), Ag(PiCO), Ag(PICO) (yellow and red polymorphs), Ag(BIHCO), Ag(BIMCO), Ag(BOCO), Ag(BTCO), Ag(MCO) and Ag(PiPCO). The compounds exhibit a remarkable resistance to high intensity visible light, UV radiation and heat and have poor solubility in water. All these compounds can be well incorporated into the light-curable acrylate polymeric composites that are currently used as dental fillers or adhesives of indwelling medical devices. A range of dry weight % from 0.5 to 5.0 of the compounds was tested in this study. To study the potential of these compounds in preventing planktonic and biofilm growth of bacteria, we selected two human pathogens (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and Gram-positive environmental isolate Bacillus aryabhattai. Both planktonic and biofilm growth was abolished completely in the presence of 0.5% to 5% of the compounds. The most efficient inhibition was shown by Ag(PiCO), Ag(BIHCO) and Ag(BTCO). The inhibition of biofilm growth by Ag(PiCO)-yellow was confirmed by scanning electron microscopy (SEM). Application of Ag(BTCO) and Ag(PiCO)-red in combination with tobramycin, the antibiotic commonly used to treat P. aeruginosa infections, showed a significant synergistic effect. Finally, the inhibitory effect lasted for at least 120 h in P. aeruginosa and 36 h in S. aureus and B. aryabhattai. Overall, several silver(I) cyanoximates complexes efficiently prevent biofilm development of both Gram-negative and Gram-positive bacteria and present a particularly significant potential for applications against P. aeruginosa infections.
We report the synthesis and structural, spectroscopic and magnetic properties of new 1D coordination polymeric complex {[Cu(μ-l-Arg)2]SO4⋅1.5H2O}n (1) that contains asymmetric μ−O,O’ carboxylic bridge linking distorted square-pyramidal [Cu(μ-l-Arg)2]²⁺ coordination units. In 1D, the syn−anti−μ²−η¹:η¹zigzag polymer conformation, the adjacent Cu(II) ions are distanced by 5.707 Å, and the subsequent Cu∙∙∙Cu proximity in 1D-coordination chain equals 6.978 Å. Detailed interpretation of IR and Raman spectra of l-arginine and 1 was performed. The principal components of the g tensor determined from EPR experiments (gx = 2.059, gy = 2.075, gz = 2.228) indicate nearly axial symmetry of Cu(II) coordination sphere and correspond to the unpaired electron occupying the dx2–y2 orbital. The single broad band at 16,200 cm–1, characteristic of d−d transition, is assigned to the dominant dublet-dublet ²B1g(dx2–y2)→ ²Eg(dyz≈dxz) transition. Magnetic susceptibility measurements have revealed ferromagnetic coupling between the Cu(II) ions within the 1D-coordination chain, while the intermolecular coupling is antiferromagnetic.
Graphical Abstract
Five new Tl(I) coordination compounds based on aryl monocyanoximes, such as phenylcyanoxime - HPhCO, 1, 2-fluorophenylcyanoxime - H(2F-PhCO, 2, 3-fluorophenylcyanoxime – H(3F-PhCO), 3, of TlL composition, and aryl biscyanoximes, such as 1,3-cyanoxime (benzene) - H2(1,3-BCO, 4 and 1,4-cyanoxime (benzene) -H2(1,4-BCO), 5 of Tl2L stoichiometry were synthesized and characterized using spectroscopic methods, thermal stability studies, and X-ray analysis. All obtained complexes represent coordination polymers of different complexity, ranging in dimensionality from 1D in Tl(2F-PhCO) to 3D in Tl2(1,3-BCO). The most interesting feature of all synthesized complexes is the formation of Tl2O2 rhombs: non planar and non-centrosymmetric in Tl(PhCO), and planar and centrosymmetric in the other three compounds. These rhombi are interconnected, forming zigzag and ladder-type polymers in which very short thallophilic Tl---Tl distances were observed. Thus, in the structure of Tl2(1,3-BCO) the closest distance between metal centers was found to be 3.670 Å. This is the second shortest on-record intermetallic contact in non-organometallic and non-cluster, but Werner type complexes, and is close to that in metallic thallium: 3.456 Å. In all five new coordination polymers the central atom has a stereo-active 6s² lone pair that significantly distorts the shape of the coordination polyhedron of Tl(I). The first time, Tl−O vibrations in Tl2O2 rhombs were observed in Raman spectra of the obtained complexes. Thermal analysis studies evidenced stability of all complexes, but Tl(PhCO), to ∼200°C. The Tl2(1,3-BCO) compound demonstrates properties of the high energy compound, and violently exothermically decomposes at ∼255°C with the release of a significant amount of kinetic energy. The final product of anaerobic decomposition of all studied Tl-cyanoximates is metallic thallium sponge.
During the last three decades, considerable research effort has been dedicated to a new class of organic ligands – cyanoximes – which have the general formula NC-C(=NOH)-R, where R is an electron-withdrawing group. The presence of the CN-group makes cyanoximes ~10,000 more acidic, and better ligands than other known conventional monoximes and dioximes. Also, in numerous cases, this group provides extra nitrogen donor atoms to support the formation of bridges between metal centres in obtained coordination polymers. With 36 different R groups, the most abundant is the family of mono-cyanoximes, followed by 7 bis-cyanoximes which include aromatic and aliphatic spacers, and lately, tris-cyanoxime representing a ‘tripod’. The total number of obtained and characterized compounds is 44. These simple, low molecular weight molecules represent a series of new excellent ampolydentate ligands – ‘molecular Lego’, or building blocks – for coordination and organometallic chemistry. Un-complexed ligands, their alkali metal salts, and metal complexes, show a large spectrum of biological activity, ranging from growth regulation in plants, and antimicrobial, to a significant in vitro and in vivo cytotoxicity against human cancers. Currently, there are more than three hundred cyanoximes-based complexes, synthesized and studied using a variety of different spectroscopic methods and X-ray analysis. In this review, the preparation and stereochemistry of cyanoximes ligands, their structures and properties, as well as the most interesting coordination compounds with a broad spectrum of practical applications, are summarized.
Reaction of 2-hydroxyimino-4,4-dimethyl-3-oxo-pentanenitrile (HPiCO, pivaloyl-cyanoxime) with zinc sulfate in an aqueous solution results in [Zn(PiCO){H(PiCO)2}(H2O)] (I) and tetranuclear Zn complex [Zn4(μ³−OH)2(PiCO)6(H2O)4] (II). Because of the structural flexibility and multidentate propensity of the pivaloyl-cyanoxime, the complexes may act as a structural model of naturally occurring Zn-containing enzymes. Compound I exhibits efficient catalytic performance for transesterification reaction of various esters in ethanol under mild reaction conditions, classifying it as green catalysis.
Thallium(I) and thallium(III) - cyclohexylpiperazinedithiocarbamates have been prepared with the same donor environment for the first time and analyzed by electronic, IR, 1H, 13C NMR spectral, CV and single crystal X-ray structural analysis. Solvothermal decomposion of the dithiocarbamates yielded nanoTl4S3 and were characterized. Bond parameters from single crystal X-ray structures have been used in Continuous Symmetry Measure and Bond Valence Sum analysis of the compounds to establish the octahedral geometry and formal oxidation numbers of thallium. [Tl(chpzdtc)]2 (1) shows extensive non covalent interactions and the hemidirected TlS2CSTl core is of distorted square pyramidal geometry with the stereo chemically active lone pair of thallium(I) occupying a vertex of the square pyramid. This is the first report which identifies the 4f7/2 and 4f5/2 electron binding energies of Tl(I) and Tl(III) dithiocarbamates unambiguously and the effect of Tl…C interaction on XPS binding energies. [Tl(chpzdtc)3] (2), the trivalent analogue as a contrast is a typical holodirected TlS6 distorted octahedral core with no significant supramolecular interactions. Mean Tl-S bond distances in (1) and (2) are 2.985(7) and 2.6789(19) Å respectively which clearly supports the higher ease of solvothermal decomposition of (1) to nano Tl4S3 than (2). A strong correlation exists between the bond strengths of Tl–S, the thioureide C–N and the ease of formation of Tl4S3 from the two dithiocarbamates (1) and (2).
Clinical experience shows that the effective concentrations of a total oligodynamic Ag+ in vivo must assure the target tissue load of from 1 ppm to 10 ppm, namely required a picoscalar Ag+ content, that is from 10(-6)M to 10(-5)M in solution. We present an analysis of the interaction mechanisms between Ag+ and BSA molecule in solution, at constant BSA: Ag stoichiometry, by time-dependent UV-Vis absorbance recording. Time evolution of the effect of bonded Ag+ at BSA sites has two steeps: first one of binding to protein molecule and second one of competitive Ag-Ag specific interaction that favorises metallic clustered formations with size stabilized by the double layer potential generated by anions protein adsorption on the Ag seeds surface. Finally, the solution contains some Ag nanoparticles as core-shell type, Ag-BSA capped layer. Ag clusters formation is favorized by the Ag excess delivered by the UV photodegradation of the Ag complexes. The bioactivity is substituted by toxicity for a critical size of initial Ag clusters, that essentially depends on the Ag+ concentration in solution. The large size seeds is not assimilated with biological medium.
