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Out of all the candidate plasmonic metals, copper has noteworthy optical characteristics and is also economically favourable for use. However, the stability of plasmonic copper nanomaterials against the loss of the plasmonic property is a setback. The present work is on the synthesis of oxidation‐stable copper micro/nanoparticles (CuMps/NPs) at ambient conditions with chosen precursors, antioxidizing agents, polymeric capping agents and chelating ligands. The Surface Plasmon Resonance (SPR) response of the synthesized Cu structures and their morphological analyses are studied. XRD data revealed changes in crystal structure such as crystallite sizes, lattice distortions and dislocation densities as a result of variations in the synthesis conditions. We present from these analyses micro/nanostructures of oxidation‐stable plasmonic Cu. The validation of the aggregation and oxidation stabilities of the different synthesized samples make them a worthy choice for multiple plasmonic applications, along with showing the synthesis protocols as viable approaches for achieving such structures with a markedly increased shelf life. [ABSTRACT FROM AUTHOR]

This study focuses on the cytotoxic activity of ruthenium(II) complexes, denoted as Ru1–8, which exhibit coordination with nitrogen (amine and amide), oxygen, and sulfur donor atoms, coupled with aryl and aliphatic wingtips. Specifically, the complexes were evaluated for their impact on the MCF‐7 breast cancer cell line. A systematic exploration of various parameters, including solubility, donor atom type, metal number, carbon chain length, aromatic ring presence, and molecular weight, was conducted to discern their influence on cytotoxic activity. The investigation involved assessing the cell viability across five concentrations (100, 50, 25, 10, and 5 μM) for five distinct monometallic and three bimetallic ruthenium complexes. Notably, Ru3, characterized by an extended carbon chain length (dodecyl) and favorable oil solubility facilitating cellular membrane penetration, demonstrated particularly promising results with the IC50 value of 1.03 μM. This research underscores the critical role of ligand design in shaping the cytotoxic potential of ruthenium(II) complexes and emphasizes the suitability of the Ru(II) p‐cymene complexes, as demonstrated by their robust activity against breast cancer in this specific investigation. [ABSTRACT FROM AUTHOR]

The study of the liquid–liquid extraction of gadolinium (Gd(III) ion) with a chelating compound, 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP), and the determination of the process parameters are presented by employing two ionic liquids, namely, ([C1Cnim+][Tf2N−], n = 4, 10) and CHCl3, as diluents. Compared to CHCl3, the ionic liquid offers increased distribution ratios in an aqueous medium. A step forward, enhanced solvent extraction, and improved separation upon the addition of ethylene glycol are demonstrated, i.e., a boost of two immiscible organic phases, compared to traditional aqueous solutions. However, this is noticeable when using CHCl3, but unfortunately not with ionic liquid combination, [C1C10im+][Tf2N−]. Several conclusions are given, highlighting the role of the ionic diluent in complexation processes and selectivity with an employment of the chelating agent HP for various metal s-, p-, d-, and f-cations, i.e., nearly 25 metals. A detailed evaluation of the selectivity between these metals was made when changing both the aqueous phase completely with ethylene glycol or partially with glycerol (1:1). Electron paramagnetic resonance (EPR) spectroscopy has been used to study the established chemical species in the obtained organic extracts, such as Gd3+, Fe3+, Cu2+, and Cr3+, with unpaired electrons. [ABSTRACT FROM AUTHOR]

A new sterically bulky chelating bis(alkoxide) ligand 3,3′-([1,1′:4′,1′′-terphenyl]-2,2′′-diyl)bis(2,2,4,4-tetramethylpentan-3-ol), (H2[OO]tBu), was prepared in a two-step process as the dichloromethane monosolvate, C36H50O2·CH2Cl2. The first step is a Suzuki–Miyaura coupling reaction between 2-bromophenylboronic acid and 1,4-diiodobenzene. The resulting 2,2′′-dibromo-1,1′:4′,1′′-terphenyl was reacted with tBuLi and hexamethylacetone to obtain the desired product. The crystal structure of H2[OO]tBu revealed an anti conformation of the [CPh2(OH)] fragments relative to the central phenyl. Furthermore, the hydroxyl groups point away from each other. Likely because of this anti–anti conformation, the attempts to synthesize first-row transition-metal complexes with H2[OO]tBu were not successful.

Present herein is the currently largest catecholato‐based aluminum oxo clusters. By adjusting the amount of auxiliary 3, 5‐dimethylpyrazole ligands, the synthesis of aluminum oxo clusters (AlOCs) (AlOC‐86) to high nuclearity AlOCs (AlOC‐88) were successfully achieved. Such synthetic strategy is applicable to imidazole ligands and new compounds (AlOC‐87 and AlOC‐89) were obtained. Single crystal analysis shows that AlOC‐86 and AlOC‐87 are hexanuclear clusters made up of two edge‐sharing tetrahedral clusters. The nuclearity of compounds AlOC‐88 and AlOC‐89 is doubled and they are S‐shape dodecanuclear AlOCs. The aggregation of such clusters is attributed to the labile sites on the two ends of the hexanuclear clusters. In addition, open aperture (OA) Z‐scan measurements results indicate that these compounds exhibit manifest reverse saturation absorption (RSA) response. [ABSTRACT FROM AUTHOR]

A series of mixed–ligand lanthanide complexes, Ln(Pip)3(iPrOH)x (x = 2 for Ln(III) = La, Ce–Nd, Sm–Eu and x = 1 for Ln(III) = Gd–Lu; HPip is 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide, the carbacylamidophosphate (CAPh) ligand), has been synthesized and identified. Using indirect techniques (FT-IR, 1H, 31P-NMR, and absorption spectroscopy) and the X-ray diffraction method (for europium complex) it was found that three Pip-ligands are coordinated to lanthanide(III) ions in a bidentate chelate manner via oxygen atoms of the carbonyl and phosphoryl groups. The oxygen atoms of 2-propanol molecules complete the coordination number of Ln(III) ions to eight (for Ln from La to Eu) or seven (for Ln from Gd to Lu). The europium complex Eu(Pip)3(iPrOH)2 crystallizes in the Рī space group. The {EuO8} polyhedron has a triangular dodecahedron (TDD-8) conformation and exists in a form of a t1t2p2+MC isomer. The luminescent properties of Eu(Pip)3(iPrOH)2 polycrystalline samples were investigated at 300, 77, and 4.2 K. [ABSTRACT FROM AUTHOR]

This review article highlights the synthetic design of various pyrrole‐based acyclic, tripodal, macrocyclic, and macrobicyclic Mannich bases and their applications, mainly as anion receptors. By varying the amine‐types and molar proportions of reagents, a range of value‐added Mannich bases are obtained. Herein, the synthesis and properties of several azacalixpyrroles, azacalixdipyrrolylmethanes, and azacryptands are discussed. Emphasis is also given to the applications of pyrrole‐based Mannich bases in the construction of some chelating ligands as one of the steps in multistep organic syntheses. In addition, the use of Mannich products as ligands for synthesizing metal complexes is also described. More importantly, the establishment of Mannich reactions as an alternative approach for traditionally used Schiff's base or aldehyde/ketone‐condensation reactions is delineated. [ABSTRACT FROM AUTHOR]

Attempts to stabilise a TmII metal centre with the bulky β-diketiminate ligand HC[C(Me)=N(DIPP)]2 (BDI) failed (DIPP, 2,6-diisopropylphenyl). Reaction of TmI2 and 2 equiv. (BDI)K gave the TmIII complex (BDI)(BDI-H)Tm (1) in which (BDI-H)2− is a doubly deprotonated ligand. However, following the same route, (BDI)2Sm (2) was isolated in 48% crystalline yield. Complex 2 is highly soluble in aromatic solvents or alkanes and was reacted with various reagents like phenazine, PhSSPh, O2, NO, cuminil and fluorenone. This led to isolation and structural characterisation of the following SmIII complexes: [(BDI)2Sm]2(μ-phenazine) (3), [(BDI)Sm(SPh)(μ-SPh)]2 (4), (BDI)(BDI-H)Sm (5a), (BDI)2Sm(OC13H8) (6) and (BDI)2Sm(NO2) (7). The rich redox reactivity of (BDI)2Sm (2) and its very high solubility in apolar solvents like hexane make it an attractive reducing agent in synthesis. The structure and synthesis of a low-valent β-diketiminate SmII complex are reported and its redox reactivity with various reagents was investigated. With a rich redox reactivity, the SmII complex is an easy-to-prepare, attractive reducing agent that is soluble in apolar organic solvents. [ABSTRACT FROM AUTHOR]

Attempts to stabilise a TmII metal centre with the bulky β-diketiminate ligand HC[C(Me)=N(DIPP)]2 (BDI) failed (DIPP, 2,6-diisopropylphenyl). Reaction of TmI2 and 2 equiv. (BDI)K gave the TmIII complex (BDI)(BDI-H)Tm (1) in which (BDI-H)2− is a doubly deprotonated ligand. However, following the same route, (BDI)2Sm (2) was isolated in 48% crystalline yield. Complex 2 is highly soluble in aromatic solvents or alkanes and was reacted with various reagents like phenazine, PhSSPh, O2, NO, cuminil and fluorenone. This led to isolation and structural characterisation of the following SmIII complexes: [(BDI)2Sm]2(μ-phenazine) (3), [(BDI)Sm(SPh)(μ-SPh)]2 (4), (BDI)(BDI-H)Sm (5a), (BDI)2Sm(OC13H8) (6) and (BDI)2Sm(NO2) (7). The rich redox reactivity of (BDI)2Sm (2) and its very high solubility in apolar solvents like hexane make it an attractive reducing agent in synthesis. The structure and synthesis of a low-valent β-diketiminate SmII complex are reported and its redox reactivity with various reagents was investigated. With a rich redox reactivity, the SmII complex is an easy-to-prepare, attractive reducing agent that is soluble in apolar organic solvents. [ABSTRACT FROM AUTHOR]

The study of the liquid–liquid extraction of gadolinium (Gd(III) ion) with a chelating compound, 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP), and the determination of the process parameters are presented by employing two ionic liquids, namely, ([C1Cnim+][Tf2N−], n = 4, 10) and CHCl3, as diluents. Compared to CHCl3, the ionic liquid offers increased distribution ratios in an aqueous medium. A step forward, enhanced solvent extraction, and improved separation upon the addition of ethylene glycol are demonstrated, i.e., a boost of two immiscible organic phases, compared to traditional aqueous solutions. However, this is noticeable when using CHCl3, but unfortunately not with ionic liquid combination, [C1C10im+][Tf2N−]. Several conclusions are given, highlighting the role of the ionic diluent in complexation processes and selectivity with an employment of the chelating agent HP for various metal s-, p-, d-, and f-cations, i.e., nearly 25 metals. A detailed evaluation of the selectivity between these metals was made when changing both the aqueous phase completely with ethylene glycol or partially with glycerol (1:1). Electron paramagnetic resonance (EPR) spectroscopy has been used to study the established chemical species in the obtained organic extracts, such as Gd3+, Fe3+, Cu2+, and Cr3+, with unpaired electrons.

The reactions of square-planar Pt(II) complexes bearing NHC-based chelating ligands with pyrazole derivatives gave monopyrazole adducts regioselectively. [Display omitted] • Ligand substitution reactions of Pt(II) complexes bearing N^C and C^C chelating ligands were examined. • NMR spectra of the reaction mixtures indicated that the reaction afforded the major isomers in a regioselective manner. • The molecular structures of the major products were confirmed using single crystal X-ray analysis. • The regioselectivity of the reaction followed the trend of the trans effect of the chelating ligands. The regioselectivity of the ligand substitution reaction of square-planar Pt(II) complexes with chelating ligands pyridyl-NHC (Py-NHC), phenyl-NHC (Ph-NHC), and phenyl-pyridine (ppy, Ph-Py) was studied. The reaction of the dichlorido Pt(II) complex bearing these chelating ligands in the presence of pyrazole (pz) ligands afforded mono-pyrazole adducts [PtCl(ChL)(pz)] n+ (n = 0 and 1; ChL=chelating ligand (Py-NHC, Ph-NHC, Ph-py)). The structures of the PtCl(pz) complexes with the Py-NHC, Ph-NHC, and Ph-Py chelating ligands were confirmed by X-ray crystallographic analysis. The regioselectivity of the ligand substitution reaction between the pyrazole moieties and chloride ions can be controlled by the strength of the trans effect of the chelating ligands. Based on the structures of the products, a clear trend of Py < NHC < Ph was observed in the trans effect of the chelating ligands. This finding provides a rational synthetic procedure for asymmetric Pt(II) complexes with chelating ligands in a stepwise manner. [ABSTRACT FROM AUTHOR]

Biosorbents are the alternatives for the removal of heavy metals because they are cheaper and more effective. This is attributed to the metallic elements interactions with the functional groups on the surface of the adsorbent. Additionally, the surface of biosorbents can further be improved by pretreatment and modification leading to the formation of functional derivatives onto the cellulose backbone. In this study pine cone powder was pretreated using Fenton reagent and modified by grafting with acrylic acid in order to enhance structural characteristics of the material. Grafting of acrylic acid onto Fenton treated pine cone powder was achieved by a free radical procedure in which ceric ammonium nitrate (CAN) was used as an initiator. Furthermore, a new poly (hydroxamic acid) ligand was synthesized from the poly(acrylic acid) grafted pine cone powder for heavy metal ions removal from aqueous media. The observed FTIR bands that shifted from 1727 cm−1 shifted to 1616 cm−1 confirmed that ester functional groups were converted to hydroxamic acid groups, which was further confirmed by elemental analysis results. The poly (hydroxamic acid) ligand was further characterized by TGA/DTA, XRD, SEM-EDS techniques. The TGA/DTA results revealed that the poly(acrylic acid) grafted pine cone powder had better thermal stability. The XRD spectra revealed that the structure of pine cone powder is composed mainly of crystalline cellulose. The SEM results indicated that the grafted pine cone powder showed a smooth surface, which is an indication that the acrylic acid was coated on the surface of the Fenton treated pine cone powder. It further revealed a coarse surface the poly (hydroxamic acid) ligand confirming the conversion of the carboxyl group to hydroxamic acid group. The linear Langmuir isotherm plot gave an R2 values of 0.9997 for Cu (II), 0.9961 Fe (II) biosorption while Freundlich isotherm plot R2 values were 0.9581 for Cu(II) and 0.9671 Fe (II) biosorption. These results demonstrate that the Freundlich isotherm was not a good fit to describe the process of adsorbed metal ions and their equilibrium concentration in solution. The theoretical values qe (mg g−1) of the pseudo second order model compared with those for the pseudo first order kinetic model agree with the experimental value qe (mg g−1). Therefore, these results confirm the chemisorption of Cu (II) and Fe (II) onto poly (hydroxamic acid) ligand.

ABSTRACT: Metal-chelating ligands such as nitrilotriacetic acid (NTA) bind to polyhistidine-tagged (His-tagged) proteins. Lipids conjugated to NTA are widely used to decorate the surface of liposomes with proteins in cell biology applications. Multivalent NTA ligands such as tris-nitrilotriacetic acid (TrisNTA) display higher affinities than the monovalent NTA when co-assembled with phospholipids and cholesterol in liposomes. However, there is a limited number of available lipids conjugated to NTA and only few are commercially available. Additionally, their activity diminishes during storage or upon exposure to air. Here we report a library of five amphiphilic Janus dendrimers conjugated to NTA (JD-NTA) and three to TrisNTA (JD-TrisNTA). Both JD-NTA and JD-TrisNTA are indefinitely stable at room temperature in air and preliminary results demonstrate that they co-assemble with phospholipids and cholesterol into liposomes, with Janus dendrimers into dendrimersomes, and with block copolymers into polymersomes. The resulting hybrid liposomes co-assembled with JD-NTA display up to thirty-fold higher activity towards His-tagged fluorescent proteins when compared to lipid-NTAs. Hybrid liposomes co-assembled with JD-TrisNTA exhibit even higher binding affinity to His-tagged proteins and can function at much lower ligand concentration in hybrid liposomes than those containing JD-NTA. These preliminary results demonstrate the power of modular synthesis of JD-NTA or JD-TrisNTA to provide highly efficient new tools for biological reconstitution and synthetic cell biology as well as for nanomedicine.

A new sterically bulky chelating bis(alkoxide) ligand 3,30-([1,10:40,100-terphenyl]- 2,200-diyl)bis(2,2,4,4-tetramethylpentan-3-ol), (H2[OO]tBu), was prepared in a two-step process as the dichloromethane monosolvate, C36H50O2°CH2Cl2. The first step is a Suzuki-Miyaura coupling reaction between 2-bromophenylboronic acid and 1,4-diiodobenzene. The resulting 2,200-dibromo-1,10:40,100-terphenyl was reacted with tBuLi and hexamethylacetone to obtain the desired product. The crystal structure of H2[OO]tBu revealed an anti conformation of the [CPh2(OH)] fragments relative to the central phenyl. Furthermore, the hydroxyl groups point away from each other. Likely because of this anti-anti conformation, the attempts to synthesize first-row transition-metal complexes with H2[OO]tBu were not successful. [ABSTRACT FROM AUTHOR]

The title compound, [Ni(C4H5N4O2)2(H2O)2]·2H2O, represents the first transition metal complex of the novel chelating triazole ligand, 2-(5-amino-1H-1,2,4-triazol-3-yl)acetic acid (ATAA), to be structurally characterized. In the mol-ecule of the title complex, the nickel(II) cation is located on an inversion centre and is coordinated by two water mol-ecules in axial positions and two O and two N atoms from two trans-oriented chelating anions of the deprotonated ATAA ligand, forming a slightly distorted octa-hedron. The trans angles of the octa-hedron are all 180° due to the inversion symmetry of the mol-ecule. The cis-angles are in the range 87.25 (8)-92.75 (8)°. The six-membered chelate ring adopts a slightly twisted boat conformation with puckering parameters Q = 0.542 (2) Å, Θ = 88.5 (2) and ϕ = 15.4 (3)°. The mol-ecular conformation is stabilized by intra-molecular N-H⋯O hydrogen bonds between the amino group and the chelating carboxyl-ate O atom of two trans-oriented ligands. In the crystal, the complex mol-ecules and lattice water mol-ecules are linked into a three-dimensional framework by an extensive network of N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds.

The title compound, [Ni(C4H5N4O2)2(H2O)2]·2H2O, represents the first transition metal complex of the novel chelating triazole ligand, 2-(5-amino-1H-1,2,4-triazol-3-yl)acetic acid (ATAA), to be structurally characterized. In the mol-ecule of the title complex, the nickel(II) cation is located on an inversion centre and is coordinated by two water mol-ecules in axial positions and two O and two N atoms from two trans-oriented chelating anions of the deprotonated ATAA ligand, forming a slightly distorted octa-hedron. The trans angles of the octa-hedron are all 180° due to the inversion symmetry of the mol-ecule. The cis-angles are in the range 87.25 (8)-92.75 (8)°. The six-membered chelate ring adopts a slightly twisted boat conformation with puckering parameters Q = 0.542 (2) Å, Θ = 88.5 (2) and ϕ = 15.4 (3)°. The mol-ecular conformation is stabilized by intra-molecular N-H⋯O hydrogen bonds between the amino group and the chelating carboxyl-ate O atom of two trans-oriented ligands. In the crystal, the complex mol-ecules and lattice water mol-ecules are linked into a three-dimensional framework by an extensive network of N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds.

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Biomass is an abundant and environmentally friendly source for materials that can be used in a multitude of applications in the effort to replace petrochemicals. Furfural and malonic acid are biomass-sourced platforms that can be utilized in the synthesis of biobased compounds; rctt-3,4-di-2-furanyl-1,2-cyclobutanedicarboxylic acid (CBDA-2) is one such compound. In this study, CBDA-2 has been introduced into metal-organic materials chemistry as a semi-rigid polytopic ligand. This compound has been utilized as a polytopic ligand in the formation of two different 2D coordination polymers with Cu2+ and Co2+ as the metal centers via a conventional solution method. Both complexes have been characterized by X-ray crystal structure determination and showed visual thermochromic behaviors. This study demonstrates that CBDA-2 is a promising green building block in coordination chemistry. [ABSTRACT FROM AUTHOR]

The structure of the title compound, C24H26S2, an example of a pincer ligand with an SCS-chelation motif, illustrates the steric effects of the methyl groups in the thiophenyl rings at the 2- and 6-positions, forcing a dissimilar spatial orientation of the thiophenyl rings relative to the central aryl group [dihedral angles = 33.58 (7) and 40.49 (7)°]. In the crystal, weak S...S contacts [3.4009 (7) Å] link the molecules into inversion dimers.

Building upon previous work, the chemistry of [(η6‐p‐cymene)Ru{P(OMe)2OR}Cl2], (R=H or Me) has been extended with [H2B(mbz)2]− (mbz=2‐mercaptobenzothiazolyl) using different Ru precursors and borate ligands. As a result, a series of 1,3‐N,S‐chelated ruthenium borate complexes, for example, [(κ2‐N,S‐L)PR3Ru{κ3‐H,S,S'−H2B(L)2}], (2 a–d and 2 a'–d'; R=Ph, Cy, OMe or OPh and L=C5H4NS or C7H4NS2) and [Ru{κ3‐H,S,S'‐H2B(L)2}2], (3: L=C5H4NS, 3': L=C7H4NS2) were isolated upon treatment of [(η6‐p‐cymene)RuCl2PR3], 1 a–d (R=Ph, Cy, OMe or OPh) with [H2B(mp)2]− or [H2B(mbz)2]− ligands (mp=2‐mercaptopyridyl). All the Ru borate complexes, 2 a–d and 2 a'–d' are stabilized by phosphine/phosphite and hemilabile N,S‐chelating ligands. Treatment of these Ru borate species, 2 a'–c' with various terminal alkynes yielded two different types of five‐membered ruthenacycle species, namely [PR3{C7H4S2‐(E)‐N‐C=CH(R')}Ru{κ3‐H,S,S'−H2B(L)2}], (4–4'; R=Ph and R'=CO2Me or C6H4NO2; L=C7H4NS2) and [PR3{C7H4NS‐(E)‐S‐C=CH(R')}Ru{κ3‐H,S,S'−H2B(L)2}], (5–5', 6 and 7; R=Ph, Cy or OMe and R'=CO2Me or C6H4NO2; L=C7H4NS2). All these five‐membered ruthenacycle species contain an exocyclic C=C moiety, presumably formed by the insertion of a terminal alkyne into the Ru−N and Ru−S bonds. The new species have been characterized spectroscopically and the structures were further confirmed by single‐crystal X‐ray diffraction analysis. Theoretical studies and chemical‐bonding analyses established that charge transfer occurs from phosphorus to ruthenium center following the trend PCy3

• Unsymmetric 1,3-bis(diphosphino)propane ligands synthesized. • Modular approach provides efficient access to ligand libraries. • Synthesis allows fine tuning of steric and electronic ligand properties. Methods to synthesize diphosphines with different substituents on the two phosphorus centers are limited, particularly for the synthesis of unsymmetric bis(dialkylphosphine) ligands. Herein is reported a modular and high-yielding synthesis of borane-protected unsymmetric 1,3-bis(diphosphino)propanes containing either two dialkylphosphine moieties or one dialkylphosphine and one diphenylphosphine group. The method relies on sequential phosphine substitution on 1,3-dibromopropane. The borane-protected diphosphines are readily converted to bis(phosphonium salts), which serve as convenient preligands. Palladium(II) complexes of di- tert -butyl(3-(dicyclohexylphosphino)propyl)phosphine (tBuCyPP), di- tert -butyl(3-(diisobutylphosphino)propyl)phosphine (tBuiBuPP), and diisobutyl((3-(dicyclohexylphosphino)propyl)phosphine (CyiBuPP) have been prepared. The tBuiBuPP and CyiBuPP complexes have been structurally characterized and their structural properties compared to symmetric (1,3-diphosphinopropane)palladium dichloride structures. [Display omitted] [ABSTRACT FROM AUTHOR]

The title compound [Co(C22H26N4O4)]PF6, commonly known as [Co(bpcd)]PF6, where bpcd2− is derived from the historical ligand name N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N′-diacetate, crystallized by slow evaporation of a saturated acetonitrile solution in air. The cation of the hexafluoridophosphate salt has the CoIII atom in a distorted octahedral coordination geometry provided by an N4O2 donor atom set. The acetate groups, which are oriented trans with respect to each other, exhibit monodentate coordination whereas the pyridyl N atoms are coordinating in a cis configuration. The geometry of the cation is compared to the geometries of other diamino diacetate complexes with CoIII.

The title compound, [Ni(C4H5N4O2)2(H2O)2]·2H2O, represents the first transition metal complex of the novel chelating triazole ligand, 2-(5-amino-1H-1,2,4-triazol-3-yl)acetic acid (ATAA), to be structurally characterized. In the molecule of the title complex, the nickel(II) cation is located on an inversion centre and is coordinated by two water molecules in axial positions and two O and two N atoms from two trans-oriented chelating anions of the deprotonated ATAA ligand, forming a slightly distorted octahedron. The trans angles of the octahedron are all 180° due to the inversion symmetry of the molecule. The cis-angles are in the range 87.25 (8)–92.75 (8)°. The six-membered chelate ring adopts a slightly twisted boat conformation with puckering parameters Q = 0.542 (2) Å, Θ = 88.5 (2) and ϕ = 15.4 (3)°. The molecular conformation is stabilized by intramolecular N—H...O hydrogen bonds between the amino group and the chelating carboxylate O atom of two trans-oriented ligands. In the crystal, the complex molecules and lattice water molecules are linked into a three-dimensional framework by an extensive network of N—H...O, O—H...O and O—H...N hydrogen bonds.

Abstract Here we report the synthesis of aminoborane HN(BCy 2 ) (C 6 H 3 -2,6-Me 2 ) ( 1 ) (Cy = cyclohexyl), that was successfully deprotonated and its lithium salt {LiN(BCy 2 ) (C 6 H 3 -2,6-Me 2 )} 2 ( 2 ) has been characterised. The borylamide ligand -N(BCy 2 ) (C 6 H 3 -2,6-Me 2 ) was used for the preparation of N→Sn coordinated stannylene [2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ]Sn [N(BCy 2 ) (C 6 H 3 -2,6-Me 2 )] ( 3 ) and two coordinate tetrylenes {E [N(BCy 2 ) (C 6 H 3 -2,6-Me 2 )] 2 } (E = Sn ( 4 ), Pb ( 5 )). Experimental and theoretical studies suggested σ character of E-N bonds without additional N(p)→E(p) donation as the result of the preference of N(p)→B(p) donation in 4 and 5. DFT studies on 4 and 5 also reveal theirs HOMO to exhibit E lone pair character and theirs LUMO to include p-orbital character located on metal atoms E. Graphical abstract The aminoborane HN(BCy 2 )(C 6 H 3 -2,6-Me 2 ) (Cy = cyclohexyl) was prepared and used for synthesis of two coordinate tetrylenes {E[N(BCy 2 ) (C 6 H 3 -2,6-Me 2 )] 2 } (E = Sn ( 4 ), Pb ( 5 )). Frontier orbitals analysis of 4 and 5 showed Sn/Pb lone pair associated with the HOMO and the LUMO with substantial p-orbital character located on metal atoms. Experimental and theoretical studies suggest that amidoborane -N(BCy 2 )(C 6 H 3 -2,6-Me 2 ) may protect sufficiently the empty p orbital located on the central E atoms similarly to bulky amido ligands, but it deviates in the character of N-E bonds. Image 1 Highlights • We stabilized aminoborane HN(BCy 2 )(C 6 H 3 -2,6-Me 2 ). • The borylamide ligand is suitable for preparation of two coordinate tetrylenes. • DFT studies reveal theirs LUMO to include p-orbital character located on metal atoms. [ABSTRACT FROM AUTHOR]

Adept representatives of light, middle and heavy rare earths metals, the trivalent lanthanoids La, Eu, and Lu were selected for synergistic solvent extraction by using an ionic liquid, 1-methyl-1,3-butylimidazolium-bis(trifluoromethanesulfonyl)imide. The process was carried out with mixtures of a chelating extractant (HL), 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one (HPMMBP) and two novel synthesized compounds. The latter consisted of unsymmetrical NH-urea fragments attached to a p -cresol scaffold (S 1 and S 2 ). To elucidate the mechanistic aspects of the extraction process and reveal the nature of the formed metal species in the organic ionic phase, the slope analysis of the extraction data was deduced and compared the results of solution chemistry. From this, the effects caused by CHON based molecular synergistic agents on the extraction-separation efficiency of the aforementioned rare earth elements were investigated. Furthermore, the synergistic enhancement and separation factors between lanthanoid metals were also evaluated. Finally, testing was carried out for the applicability of these new enforced ligands for the competitive removal of rare earth ions from leach solution containing various s- and d-cations. [ABSTRACT FROM AUTHOR]

Low-spin manganese (II) complexes [Mn II (H 2 slox) (bipy)] (1), [Mn II (H 2 slox) (phen)] (2), [Mn II (H 2 slox) (phen)].1.5.H 2 O (2a), [Mn II (H 2 nph) (bipy)].H 2 O (3) and [Mn II (H 2 nph) (phen)].H 2 O (4) were synthesized from oxaloyldihydrazones in methanolic-water medium. The stoichiometry of the complexes was established by analytical, molecular weight and thermoanalytical data. Based on the data obtained from molar conductance, UV–visible, Infrared spectral, magnetic moment and electron paramagnetic resonance spectroscopic studies, the structures of the complexes have been established. From molar conductance it is suggested that all the complexes are non-electrolyte in DMF medium. The complex (2a) is monomeric in nature whereas the complexes (1) to (4) are dimeric based on the molecular weight data. The effective magnetic moment of complexes (1) to (4) show metal-metal interaction while complex (2a) has no metal-metal interaction. The complexes (1)–(4) show two quasi-reversible metal centred electron transfer reaction involving Mn II /Mn I /Mn 0 redox reactions in DMF medium. [ABSTRACT FROM AUTHOR]

The new o -hydroxy N 3 O 2 -donor Schiff base ( H 2 L ) was synthesized and characterized using FITR and UV–Vis spectroscopies, X-ray diffraction analysis, thermogravimetric methods and computational studies. In the solid state intramolecular proton transfer from the phenolic oxygen to the imino nitrogen atom is observed. The resulting compound occurs as a mixture of phenol-imine and zwitterionic forms. The temperature does not affect significantly the shift of equilibrium from the phenol-imine tautomer to the zwitterion form. In solution the H 2 L exists mainly in the phenol-imine tautomeric form but in more polar solvents stabilization of the more polar keto-amine form is also observed. The reaction of H 2 L with Cu II ion at the stoichiometric metal:ligand 2:1 ratio results in formation of cyclic, tetranuclear complex where the coordination geometry around each metal centres is distorted square pyramid. [ABSTRACT FROM AUTHOR]

Functionalized nanofibers made by electrospinning technique. [...]

The new N 2 O 3 -donor pentadentate Schiff base (C 29 H 26 N 2 O 3 ) was synthesized and characterized by different techniques. The single crystal X-ray analysis confirmed that in the solid state one half of the molecule contains the phenol-imine form while in the other one the proton of phenol group is moved towards the azomethine group creating the zwitterionic form. In solution, the studied Schiff base exists mainly in the phenol-imine tautomer but in more polar solvents (MeOH or EtOH) stabilization of the more polar keto-amine form is also observed. The effect of polar protic solvents (methanol and ethanol) on synthesis of Ni II complexes with the Schiff base was studied. The synthesis of compounds was performed at the stoichiometric metal:ligand 1:1 and 2:1 ratio. This allowed to obtain four different nickel(II) complexes. The products were characterized using FITR spectroscopy, X-ray diffraction analysis and thermogravimetric methods. When equimolar amounts of reagents were used in both solvents, the mononuclear complexes were formed, [Ni(C 29 H 24 N 2 O 3 )]·(CH 3 OH)(H 2 O) 0.25 ( 1a ) and [Ni(C 29 H 24 N 2 O 3 )]·H 2 O ( 2a ). In both compounds Ni II ions have distorted square planar geometry formed by N 2 O 2 -core of Schiff base ligand. Increasing the concentration of metal ions in the synthesis, it was possible to obtain tetranuclear ([Ni 4 (C 29 H 24 N 2 O 3 ) 2 (CH 3 COO) 2 (CH 3 OH) 3.65 (H 2 O) 0.35 ]·(CH 3 OH) 7 ( 1b )) and hexanuclear ([Ni 6 (C 29 H 24 N 2 O 3 ) 2 (C 16 H 17 N 2 O 2 ) 2 (CH 3 COO) 2 ]·(C 2 H 5 OH) ( 2b )) complexes. In crystal 1b the Ni II ions have octahedral geometry whereas in complex 2b the metal centres are four- and six-coordinate. [ABSTRACT FROM AUTHOR]

A series of Ni/SBA-15 (AM) catalysts were prepared by chelating ligand assisted impregnation method. The results showed that the chelating ligand played a positive promoting role for CH 4 dry reforming with CO 2 over Ni/SBA-15. The electron-pair donor atoms and the high viscosity of chelating agent could inhibit the aggregation of nickel species and contribute to the well-dispersed Ni particles with size of <6 nm. Compared to the Ni/SBA-15 (CM) prepared by conventional impregnation, all the Ni/SBA-15 (AM) exhibited superior catalytic performance, especially the catalyst assisted by ethylenediamine possessed stable activity and the least amount of carbon deposition. [ABSTRACT FROM AUTHOR]

The effect of different solvents on synthesis and recrystallization of Ni 2+ complex with the tetradentate Schiff base was studied. The polar protic (MeOH and EtOH) and aprotic (ACN, DMF and THF) solvents have been used. The synthesis and recrystallization from these solvents allow obtaining seven different solvates or solvent free compounds. The products were characterized using UV–vis and FITR spectroscopy, X-ray diffraction analysis and thermogravimetry. Only in the case of DMF, the synthesis and recrystallization lead to formation of the same compound. The remaining pairs of complexes differ in their composition or/and structure. In almost all compounds the coordination environment around Ni 2+ centre consists of two nitrogen and two oxygen atoms of Schiff bases ligand which forms the distorted square planar geometry. The compound synthesised form THF shows significant paramagnetism which suggests that the coordination geometry around metal centre is a distorted octahedral. [ABSTRACT FROM AUTHOR]

This paper studied the efficiency of another series of advanced oxidation processes involving the use of a chelating ligand, combined with a transition metal forming the transition metal complexes to produce reactive radicals. Previous reports using this H2O2/pyridine/Cu(II) system focused only on the decolorization of a single synthetic dye wastewater. In practice, real dye wastes contain mixture of dyes. Therefore, in this study, we combined two classes of most widely used dyes namely the reactive dye (RD) and disperse dye (DD) in three different ratios of (RD: DD) = (0.25:0.75), (0.50:0.50), and (0.75:0.25) to obtain a better idea of the trend in the treatment efficiency of this system. Experimental results are assessed in terms of percentage chemical oxygen demand (COD) reduction, decolourisation, and the amount of sludge produced. Optimal concentrations were obtained using statistical design of experiment. At optimal concentrations, for (RD:DD) = (0.25:0.75), (0.50:0.50), and (0.75:0.25), the percentage of COD reduction was recorded at 87%, 86% and 81%, respectively, decolourization at 97%, 98% and 96%, respectively while sludge produced was 185 mg/L, 125 mg/L, and 210 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Screening of optimal chelating ligands which not only have high capacities to enhance plant uptake of mercury (Hg) from soil but also can decrease bioavailable Hg concentration in soil is necessary to establish a viable chemically-assisted phytoextraction. Therefore, Brassica juncea was exposed to historically Hg-contaminated soil (total Hg, 90 mg kg −1 ) to investigate the efficiency of seven chelating agents [ammonium thiosulphate, sodium thiosulphate, ammonium sulfate, ammonium chloride, sodium nitrate, ethylenediaminetetraacetic acid (EDTA), and sodium sulfite] at enhancing Hg phytoextraction; the leaching of bioavailable Hg caused by these chelating agents was also investigated. The Hg concentration in control (treated with double-distilled water) plant tissues was below 1 mg kg −1 . The remarkably higher Hg concentration was found in plants receiving ammonium thiosulphate and sodium sulfite treatments. The bioaccumulation factors and translocation factors of ammonium thiosulphate and sodium sulfite treatments were significantly higher than those of the other treatments. The more efficient uptake of Hg by plants upon treatment with ammonium thiosulphate and sodium sulfite compared to the other treatments might be explained by the formation of special Hg-thiosulphate complexes that could be preferentially taken up by the roots and transported in plant tissues. The application of sulfite significantly increased bioavailable Hg concentration in soil compared with that in initial soil and control soil, whereas ammonium thiosulphate significantly decreased bioavailable Hg concentration. The apparent decrease of bioavailable Hg in ammonium thiosulphate-treated soil compared with that in sodium sulfite-treated soil might be attributable to the unstable Hg-thiosulphate complexes formed between thiosulphate and Hg; they could react to produce less bioavailable Hg in the soil. The results of this study indicate that ammonium thiosulphate may be an optimal chelating ligand for phytoextraction due to its great potential to enhance Hg accumulation in plants while decreasing bioavailable Hg concentration in the soil. [ABSTRACT FROM AUTHOR]

• a cationic 1,2-bis-imidazolylbenzene bearing a η6-coordinated (η5-Cp)Fe+ moiety was synthesized. • this precursor was successfully methylated twice resulting in the formation of a tricationic 1,2-bis-imidazolylideneylbenzene. • in-situ deprotonation of this compound and treatment with palladiumdichloride gave the first chelating bis-NHC-complex with a cationic backbone. • structural characterization of this complex by X-ray structure analysis. We here present the synthesis of a novel chelating N -heterocyclic carbene (NHC) ligand with the two NHC moieties bound to a cationic (η5-cyclopentadienyl)(η6-arene)iron(II) center and its coordination to palladium(II). Spectroscopic and spectrometric characterization, together with X-ray structural analyses, proves the molecular structure of these new organometallic compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

The reaction of HSiCl 3 with 2-[N-(2,6-diisopropylphenyl)iminomethyl]indolyl lithium (DippIMIndLi) provided disubstituted (DippAMInd)(DippIMInd)SiCl ( 2 ), where one imino moiety of DippIMInd ligand was reduced to amino group by Si-H fragment. In contract the reaction of HSiCl 3 with 2-[N-(2,6-diisopropylphenyl)iminomethyl]phenyl lithium (DippIMPhLi) provided stable CH N → Si coordinated silane (DippIMPh)SiHCl 2 ( 3 ). Heating of the toluene solution of 3 provided the hydrosilylated compound (DippAMPh)SiCl 2 ( 4 ). It has been demonstrated that the rate of CH N imino group reduction strongly depends on type of the anionic ligand. [ABSTRACT FROM AUTHOR]

Monodisperse maghemite nanoparticles, templated in novel, well-defined pyrazole-containing norbornene-based block copolymers, provided a superparamagnetic nanocomposite with high saturation magnetization at room temperature under an applied magnetic field. The synthesis of the polymer nanocomposites and physical, morphological, and magnetic chracaterization of the nanocomposites are reported. Micelle-encapsulated superparamagnetic nanocomposites were generated for dispersal in aqueous medium. Their stability in water in the presence of a magnetic field was investigated as was their morphology and cell viability, strongly suggesting the potential of these superparamagnetic polymer-based nanocomposites in certain biomedical imaging and associated applications.

A series of four C,N-chelated diorganotin(IV) compounds, namely (LCN)2Sn(OCH2CH2O) (1), [LCNBuSn(OCH2CH2O)]2 (2), (LCN)2Sn (1,2-(O) 2-3,5-tBu2C6H2)(3) and [LCNBuSn(1,2-(O)2-3,5-tBu2C6H2)]2(4) (LCN =2-(Me2NCH2)C6H4), one zinc species, namely LNOZnEt (5) (LNO = [2-(MeO)C6H4]NC(Me)=C(H)C(Me)=O), and one magnesium complex, namely [LNNMg] 6 (6), (LNN = [2-(Me2NCH2)C6H4] N),were used as catalysts for the synthesis of poly(ethylene terephthalate) (PET) fromdimethyl terephthalate and ethylene glycol. Prepared PET samples were primarily characterized using the size exclusion chromatography technique. The highest numberaverage molar mass of prepared PET samples reached 10.7 kg mol-1. Novel dimeric compound 2 was structurally characterized using both multinuclear NMR spectroscopy and X-ray diffraction analysis. In addition, an alternative synthesis of 1 is described. [ABSTRACT FROM AUTHOR]

Anion receptor, Chelating ligand, Condensation, Mannich reaction, Pyrrole-based Keywords: Anion receptor; Chelating ligand; Condensation; Mannich reaction; Pyrrole-based EN Anion receptor Chelating ligand Condensation Mannich reaction Pyrrole-based 1 1 1 09/16/22 20220913 NES 220913 B The Cover Feature b illustrates the Mannich reaction as an alternative approach for the synthetic development of structurally diverse pyrrole-based acyclic, tripodal, macrocyclic, and macrobicyclic molecules, which are useful as anion receptors, chelating ligands, and as precursors for further reactions. Cover Feature: Mannich Reaction: An Alternative Synthetic Approach for Various Pyrrole-Based Anion Receptors and Chelating Ligands (Eur. J. Org. [Extracted from the article]

The reaction of mesitylamine (2,4,6-Me 3 C 6 H 2 NH 2 ) with two equivalents of imidoylchloride, ArN C(Cl)Me (Ar = 2,4,6-Me 3 C 6 H 2 or 2,6- i Pr 2 C 6 H 3 ) in the presence of Et 3 N yields neutral [N,N′] chelating ligands, [2,4,6-Me 3 C 6 H 2 N{C(Me)N(2,4,6-Me 3 C 6 H 2 )} 2 ] ( L 1 ) and a pair of ligand isomers; symmetrical [2,4,6-Me 3 C 6 H 2 N{C(Me)N(2,6- i Pr 2 C 6 H 3 )} 2 ] ( L 2a ) & unsymmetrical [2,6- i Pr 2 C 6 H 3 NC(Me)N(2,6- i Pr 2 C 6 H 3 )C(Me)N(2,4,6-Me 3 C 6 H 2 )] ( L 2b ). An exclusive synthesis of the unsymmetrical isomer L 2b has also been optimized by the reaction of a preformed amidine (2,6- i Pr 2 C 6 H 3 )NH{C(Me) N(2,6- i Pr 2 C 6 H 3 )} with the mesityl imidoylchloride. The three ligands have been thoroughly characterized by spectroscopic and X-ray diffraction methods (for L 2a and L 2b ). The reaction of equimolar quantities of L 1 with CoCl 2 ·6H 2 O, NiBr 2 · x H 2 O, Cu(NO 3 ) 2 ·3H 2 O yields the corresponding mononuclear complexes, L 1 ·CoCl 2 ( 1 ), L 1 ·NiBr 2 ( 2 ) and L 1 ·Cu(NO 3 ) 2 ( 3 ). Similarly, reaction of unsymmetrical ligand isomer L 2b with CoCl 2 ·6H 2 O, NiBr 2 · x H 2 O, or CuCl 2 affords the complexes L 2b ·CoCl 2 ( 4 ), L 2b ·NiBr 2 ( 5 ) and L 2b ·CuCl 2 ( 6 ), respectively. The solid state structures of complexes 1 – 6 have been investigated by single crystal X-ray structural analysis. [ABSTRACT FROM AUTHOR]

Acylhydrazones are very versatile ligands and their coordination properties can be easily tuned, giving rise to metal complexes with different nuclearities. In the last few years, we have been looking for new pharmacophores able to coordinate simultaneously two metal ions, because many enzymes have two metal ions in the active site and their coordination can be a successful strategy to inhibit the activity of the metalloenzyme. As a part of this ongoing research, we synthesized the acylhydrazone H 2 L and its complexes with Mg(II), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Their characterization, both in solution – also by means of potentiometric studies – and in the solid state, evidenced the ability of the o -vanillin hydrazone scaffold to give rise to different types of metal complexes, depending on the metal and the reaction conditions. Furthermore, we evaluated both the free ligand and its metal complexes in in vitro studies against a panel of diverse DNA- and RNA-viruses. In particular, the Mg(II), Mn(II), Ni(II) and Zn(II) complexes had EC 50 values in the low micromolar range, with a pronounced activity against vaccinia virus. [ABSTRACT FROM AUTHOR]

The synthesis of the compounds [L 1 Cd(μ-I)] 2 ( 1 ), L 2 Cd(μ-I) 2 ·Li(THF) 2 ( 2 ), and [L 3 ·CdI 2 ] ( 3 ) with L 1 = {2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ) − }, L 2 = {2,6-[(CH 3 )C N(C 6 H 3 -2′,6′- i Pr 2 )] 2 C 6 H 3 } − and L 3 = {2-[(CH 3 )C N(C 6 H 3 -2,6- i Pr 2 )]-6-(CH 3 O)}C 5 H 3 N) is reported. The compounds were characterized by elemental analyses, 1 H and 13 C NMR spectroscopy, and single crystal X-ray diffractions analyses [ABSTRACT FROM AUTHOR]