Butane Ligands Research Articles

2D Cadmium(II) Coordination Polymer Based on 2,5-Furandicarboxylate and 1,4-Bis(1H-imidazol-1-yl)butane Linkers: Synthesis, Characterization and DFT Studies

As a result of hydrothermal synthesis of 2,5-furandicarboxylate (fdc2−), Cd(II) ion and bis(imidazole) derivative 1,4-bis(1H-imidazole-1-yl)butane (bib) ligand, a novel two-dimensional Cd(II) coordination polymer {[Cd(µ-fdc)(H2O)(µ-bib)]·H2O}n (1) was synthesized. According to the results of single crystal X-ray diffraction analysis, the complex was crystallized in the monoclinic system and in the P21/n space group. In addition, the thermal, luminescence and optical properties of the complex were investigated. The complex emits a maximum at 509 nm and also shows semi-conductor properties according to the solid-state UV–Vis diffuse reflection spectra results. To determine chemical structure, vibrational properties and some chemical properties of complex, theoretical calculations were carried out. All theoretical computations were performed using the DFT method at the B3LYP/LanL2DZ level of theory. The obtained experimental results were in good agreement with theoretical results. To calculate HOMO–LUMO energy values, which provided insights into the material's electronic properties, DFT calculations were used. Detailed information about the local and global chemical activity, as well as the electrophilic and nucleophilic nature of the complex, were also obtained.

Superatomic Ag58 nanoclusters incorporating a [MS4@Ag12]2+ (M = Mo or W) kernel show aggregation-induced emission

In core-shell silver nanoclusters, the control of core structure presents a more formidable challenge compared to that of the shell structure. Here, we report the successful synthesis and characterization of four distinct silver thiolate nanoclusters [MS4@Ag12@Ag46S24(dppb)12] (M = Mo or W), each incorporating a cup-like [MS4@Ag12]2+ kernel. These nanoclusters were meticulously prepared using (NH4)2MoS4 or (NH4)2WS4 as both a template and a controlled source of S2− ions. Remarkably, we have observed a unique configuration within these eight-electron superatomic Ag58 nanoclusters, where the zero-valent Ag atoms reside exclusively within the inner [MS4@Ag12]2+ kernel. This stands in contrast to other superatomic clusters possessing an Ag(0) core. Notably, the introduction of phenyl-containing compounds during the synthesis process induced a transformation in the space group symmetry from C2/c to I4¯. This transformative effect was found to originate from the interplay between adjacent 1,4-bis(diphenylphosphino)butane (dppb) ligands, which facilitated enhanced emission through aggregation-induced intermolecular interactions, specifically C−H···π interactions. Collectively, our findings contribute substantively to the understanding of the intricate relationship between nanocluster structures and their corresponding properties, shedding light on the crucial roles played by templates and diphosphine ligands in this context.

An structural study of nine-membered monometallocycles of Pd(II) and Pt(II) employing the 1,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)butane ligand

Two nine-membered metallocycles of PdII (1) and PtII (2) containing 1,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)butane ligand (L1) have been prepared and their structures were determined by IR, NMR spectroscopy, and by single-crystal X-ray diffraction analysis. The molecular structures of L1 display that the pyrazolyl groups adopt an anti-conformation, while in 1 and 2 a discrete nine-membered monometallic macrocycle is generated by the assembly of one ligand and one metal atom, and the ring adopts a twist-chair-boat conformation. The ligand L1 in complexes 1 and 2 acts as cis-chelating ligand via a κ2 N,N coordination mode by the nitrogen atoms of the pyrazolyl rings. In compounds 1 and 2 the metal center adopts a planar geometry. The molecular structure of 1 and 2 also revealed two intramolecular anagostic interactions M•••Hγ–C(sp3) (M = Pd and Pt) with M•••H distances between 2.689 and 2.780 Å, which are important to stabilize the nine membered ring formed. Considering those two M•••Hγ interactions, the ligand L1 generates a κ4 N,N,H,H coordination mode and the metal centers adopt a trigonal prism geometry. The crystal packing of L1, 1 and 2 displayed supramolecular networks promoted mainly by C–H•••π interactions, which were analyzed by Hirshfeld Surface Analysis

Synthesis, characterization and dye adsorption properties of a 3-fold interpenetrated cobalt(II)-metal organic framework based on (E)-5,5'-(but-2-ene-1,4-diylbis(oxy))diisophthalate and 1,4-bis(imidazole-1-yl)butane ligands

A new 3D cobalt(II)-metal organic framework, [Co2(μ4-L)(μ-bib)2]n(1) was synthesized with solvothermal method by using (E)-5,5'-(but-2-ene-1,4-diylbis(oxy))diisophthalic acid (H4L) and 1,4-bis(1H-imidazole-1-yl)butane (bib) in the presence of cobalt(II) ion. Compound 1 was characterized by elemental analysis, FTIR spectroscopy and single crystal X-ray diffraction (SCXRD) technique. SCXRD analysis result revealed that 1 displayed a 3-fold interpenetrated 3D framework with bbf topology. The dye adsorption ability of 1 towards methylene blue (MB) was assessed with diverse parameters (pH, the compound amount, temperature, contact time and initial MB concentration). Adsorption kinetics and isotherms fitted well with pseudo-second-order kinetic and Langmuir isotherm models. The highest adsorption capacity of compound 1 was 473.57 ​mg ​g−1 ​at pH ​= ​8.0, 20 ​°C. The adsorption ability could be due to the electrostatic interactions between cationic MB and negative charge density on 1 ​at pH ​= ​8.0. Overall, adsorption studies indicated that synthesized compound 1 may be an efficient alternative adsorbent for MB removal from aqueous solutions.

Self-assembly and photocatalytic property of a new inorganic-organic hybrid material based on 1,4-bis(4-pyridylthio)butane

A new hybrid compound consisting of 1,4-bis(4-pyridylthio)butane ([Bpytb]) ligand, namely {[Bpytb]Ag2I3}n (1), has been prepared and characterized by IR spectroscopy, solid UV-visible diffuse reflectance spectrum, X-ray Powder Diffraction (PXRD) and TG. Compound 1 consists of 1D anion chain structure. Crystal system: Monoclinic, Space group: P2/c, a = 4.5092(3), b = 11.1895(9), c = 21.3893(14), α= 90°, β= 92.907(2)°, γ= 90°, V = 1077.82(13) Å3, Z = 2, Dcalc = 2.693 g cm–3. The photocatalytic property of compound 1 was also studied and it exhibits a better degradation effect on organic dye MB.

Mechanistic Investigation on Hydrocyanation of Butadiene: A DFT Study

The nickel-catalyzed addition of Hydrocyanic acid (HCN) to butadiene usually leads to a mixture of the branched 2-methyl-3-butenenitrile (2M3BN) and the linear 3-pentenenitrile (3PN) with a 30:70 ratio by employing mono-dentate phosphites, while a 97% selectivity to 3PN is obtained using a 1,4-bis(diphenyphosphino)butane (dppb) ligand and Ni(COD)2 (1,5-Cyclooctadiene) as catalysts. To explain this phenomenon, a reasonable mechanism of the hydrocyanation, involving the cyano (CN) migration (for 3PN) and the methylallyl rotation (for 2M3BN) pathways, is proposed. The key intermediates and the rate-determining steps in the pathways have been illustrated. The methylallyl rearrangement is the rate-determining step in the formation of 3PN while the reductive elimination governs the reaction to 2M3BN, which is subsequently isomerized to 3PN. Moreover, the opposite changes of the bite angle of the intermediates and transition states explain how the reactions proceed in two different directions.

Anion-directed assembly of three cationic silver(I) coordination polymers with bis(imidazolyl)-based linker: Structural characterization and anion exchange study

Three cationic silver(I) coordination polymers, namely {[Ag2(μ-bib)3](SO3CF3)2·(CH3CN)}n (1), {[Ag(μ-bib)](NO3)·(H2O)}n (2), and {[Ag(μ-bib)]BF4}n (3), have been prepared using flexible bis(imidazolyl)butane (bib) ligand and silver salts of different anions. All compounds are characterized by FT-IR, PXRD, elemental analysis, and single-crystal X-ray diffraction. Compound 1, containing triflate (SO3CF3−) anions, exhibits a two dimensional 63-hcb network with an amazing ABCDEF packing mode of the single hexagonal layers. Compound 2, containing nitrate ions, forms a simple one dimensional wavy chain, while compound 3 with BF4− anions, shows a double helix DNA-shaped structure stabilized by Ag⋯Ag interactions between the two strands. The anions in the structures 1–3 are non-coordinating and participate in weak H-bonding, while imidazolyl rings are involved in π⋯π stacking interactions. Anion exchange experiments in aqueous solution, monitored by FT-IR and PXRD analyses, reveal interesting structural transformations.

Two entangled photoluminescent MOFs of naphthalenedisulfonate and bis(benzimidazole) ligands for selective sensing of Fe3+

Two entangled MOFs based on rigid 1,6-naphthalenedisulfonate (1,6-NDS) mixed with flexible 1,4-bis(benzoimidazol-1-yl)butane (bbimb) ligands, [Zn(1,6-NDS)(bbimb)1.5]·2H2O (1) and [Cd2(1,6-NDS)2(bbimb)3(H2O)4]·2H2O (2), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric and photoluminescent analyses. In 1, the Zn(II) ions are connected by bbimb ligands into a 2D (6,3) brick wall structure with the 1,6-NDS2- as dangling arms threaded into the voids of two adjacent layers up and down, and finally generates a 2D→3D polythreading framework. While the Cd(II) centers in 2 are connected by bbimb ligands into a 3D (10,3)-b network, and four (10,3)-b networks interweave to generate a 4-fold interpenetrating structure. 1 and 2 dispay similar photoluminescence at 343 nm (λex = 302 nm) and 342 nm (λex = 293 nm), respectively. And both MOFs display selective sensing of Fe3+ through the luminescent quenching experiments.

Two-dimensional structure of poly[[[μ2-1,4-bis(pyridin-4-yl)butane]bis(μ4-pentanedioato)dicopper(II)] acetonitrile disolvate

In the title compound, {[Cu2(μ4-C5H6O4)2(μ2-C14H16N2)]·2CH3CN}n, the Cu2dinuclear units are connected by glutartate ligands, forming one-dimensional double chains. These chains, are in turn bridged by 1,4-bis(pyridin-4-yl)butane ligands to form a two-dimensional layer structure parallel to (112). The carboxylate groups of the glutarate ligand bridge two copper(II) ions, forming a paddle-wheel-type Cu2(CO2)4dinuclear secondary building unit. A crystallographic inversion centre is located midway between two CuIIions, with a Cu...Cu distance of 2.639 (3) Å. The coordination geometry of the unique CuIIion is slightly disorted square pyramidal, formed by four equatorial carboxylate O atoms and an axial pyridyl N atom.

Structures and Properties of New Cadmium(II) and Copper(II) Metal–Organic Frameworks Based on Flexible Bridged 1,4-bi(1H-imidazol-1-yl)butane Ligand

Two new metal–organic frameworks (MOFs) based on cadmium(II) ions, 1,2-benzenedicarboxylic acid (BDC), flexible ligand 1,4-bi(1H-imidazol-1-yl)butane (BIIM), coordinated water molecules, [(BIIM)(BDC)(H2O)Cd]3n (1) and copper(II) ions, BIIM, coordinated water, free thiophene-2,5-dicarboxylate (TDC), free water, {[(BIIM)4(H2O)4Cu2]·(TDC)2·(H2O)12}n (2) are prepared and characterized by X-ray diffraction, thermal gravimetric analysis (TGA), infrared (IR) spectrum and the photoluminescence property for complex (1). The X-ray diffraction analysis reveals that the structures of complexes 1 and 2 are 2D structures through the C–H···π stacking interactions (for 1) and the BIIM bridging connections (for 2). The IR spectrum for 1 and 2 are presented in the paper, for 1, the strong peaks at 1399 and 1573 cm−1 are owing to the carboxylic CO2 − symmetry and asymmetry stretching vibrations of BDC. The features of the IR spectrum are consistent with the single crystal structures. The TGA reveal the water is the first lost material from complex, then the ligands removed, and finally the residues of these two complexes are the metal oxide.

Ru(II)/diphenylphosphine/pyridine-6-thiolate complexes induce S-180 cell apoptosis through intrinsic mitochondrial pathway involving inhibition of Bcl-2 and p53/Bax activation.

The aim of this work was the synthesis, characterization, and cytotoxicity evaluation of three new Ru(II) complexes with a general formula [Ru(Spy)(bipy)(P-P)]PF6 [Spy=pyridine-6-thiolate; bipy=2,2'-bipyridine; P-P=1,2-bis(diphenylphosphine)ethane (1); 1,3-bis(diphenylphosphine) propane (2); and 1,1'-bis(diphenylphosphino)ferrocene] (4). Complex (3) with the 1,4-bis(diphenylphosphine)butane ligand, already known from the literature, was also synthesized, to be better studied here. The cytotoxicities of the complexes toward two kinds of cancerous cells (K562 and S-180 cells) were evaluated and compared to normal cells (L-929 and PBMC) by MTT assay. The complex [Ru(Spy)(bipy)(dppb)]PF6 (3) was selected to study both the cellular and molecular mechanisms underlying its promising anticancer action in S-180 cells. The results obtained from this study indicated that complex (3) induces cell cycle arrest in the G0/G1 phase in S-180 cells associated with a decrease in the number of cells in S phase. After 24 and 48h of exposure to complex (3), the cell viability decreased when compared to the negative control. Complex (3) does not appear to be involved in the DNA damage, but induced changes in the mitochondrial membrane potential in S-180 cells. Furthermore, there was also an increase in the gene expression of Bax, Caspase 9, and Tp53. According to our results, complex (3) induces cell apoptosis through p53/Bax-dependent intrinsic pathway and suppresses the expression of active antiapoptotic Bcl-2 protein.

Structural, spectral and magnetic properties of Ni(ii), Co(ii) and Cd(ii) compounds with imidazole derivatives and silanethiolate ligands

A series of new metal heteroleptic complexes have been obtained in simple reactions of 1-(3-aminopropyl)-imidazole (api) and 1,4-bis(imidazol-1-yl)-butane (bbi) ligands with metal silanethiolates or acetylacetonates. The obtained complexes are the coordination polymers [Ni{SSi(tBuO)3}2(μ-api)]n1, [Co{SSi(tBuO)3}2(μ-api)]n2, [Cd{SSi(tBuO)3}2(μ-api)·2CH3OH]n3, [Cd{SSi(tBuO)3}2(μ-bbi)·CHCl3]n4 and the dimer [Co{SSi(tBuO)3}2(μ-bbi)·3CH3OH]25. Another coordination polymer with the formula [Ni(acac)2(μ-bbi)·9CHCl3]n6 was obtained in the reaction of Ni(acac)2 with (tBuO)3SiSH (TBST) and bbi; however, the silanethiolate residue didn't coordinate to the metallic center as intended. The molecular structures of 1–6 were determined by single-crystal X-ray diffraction. Compounds 1–5 were additionally characterized by thermogravimetry (TGA) and powder X-ray diffraction. The emission spectra of the Cd complexes 3 and 4 were recorded in the solid state at ambient temperature, whereas 1, 2 and 5 were subjected to magnetic studies. Variable-temperature magnetic measurements of the polycrystalline sample 1 suggest the presence of weak intra-chain magnetic interactions between the nickel(II) ions. Magnetic studies of 2 and 5 show their paramagnetic behavior. For sample 1 as well as samples 2 and 5, a noticeable influence of single-ion magnetic anisotropy on their magnetic behavior has been revealed.

Redox Properties of Copper(I) Complex Bearing 4,7-Diphenyl-2,9-dimethyl-1,10-phenanthroline and 1,4-Bis(diphenylphosphino)butane Ligands and Effects of Light in the Presence of Chloroform

Abstract We have examined emission and redox properties of a copper(I) complex bearing a phenanthroline type ligand and the 1,4-bis(diphenylphosphino)butane ligand. Changes in the absorption spectra upon electrolysis and light irradiation in the presence of chloroform indicate the formation of bis(diimine)copper(I) complexes.

Crystal structure of bis-[μ-1,4-bis-(di-phenyl-phos-phan-yl)butane-κ2P:P']bis-[(3,4,7,8-tetra-methyl-1,10-phenanthroline-κ2N,N')copper(I)] bis-(hexa-fluorido-phosphate) di-chloro-methane disolvate.

The dication of the title compound, [Cu2(C28H28P2)2(C16H16N2)2](PF6)2·2CH2Cl2, has crystallographically imposed inversion symmetry. The copper(I) cation is coordinated in a distorted tetra-hedral geometry by two N atoms of a chelating 3,4,7,8-tetra-methyl-1,10-phenanthroline ligand and two P atoms of two bridging 1,4-bis-(di-phenyl-phosphan-yl)butane ligands, forming a 14-membered ring. An intra-molecular π-π inter-action stabilizes the conformation of the dication. In the crystal, dications are linked by π-π inter-actions involving adjacent phenanthroline rings, forming chains running parallel to [111]. Weak C-H⋯F hydrogen inter-actions are also observed.

Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution

A Z-selective rhodium-catalyzed hydrothiolation of 1,3-disubstituted allenes and subsequent oxidation towards the corresponding allylic sulfones is described. Using the bidentate 1,4-bis(diphenylphosphino)butane (dppb) ligand, Z/E-selectivities up to >99:1 were obtained. The highly atom-economic desymmetrization reaction tolerates functionalized aromatic and aliphatic thiols. Additionally, a variety of symmetric internal allenes, as well as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities. Starting from chiral but racemic 1,3-disubstituted allenes a dynamic kinetic resolution (DKR) could be achieved by applying (S,S)-Me-DuPhos as the chiral ligand. The desired Z-allylic sulfones were obtained in high yields and enantioselectivities up to 96 % ee.

Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution

AbstractA Z‐selective rhodium‐catalyzed hydrothiolation of 1,3‐disubstituted allenes and subsequent oxidation towards the corresponding allylic sulfones is described. Using the bidentate 1,4‐bis(diphenylphosphino)butane (dppb) ligand, Z/E‐selectivities up to >99:1 were obtained. The highly atom‐economic desymmetrization reaction tolerates functionalized aromatic and aliphatic thiols. Additionally, a variety of symmetric internal allenes, as well as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities. Starting from chiral but racemic 1,3‐disubstituted allenes a dynamic kinetic resolution (DKR) could be achieved by applying (S,S)‐Me‐DuPhos as the chiral ligand. The desired Z‐allylic sulfones were obtained in high yields and enantioselectivities up to 96 % ee.

1,4-Bis(imidazole)butane ligand and strontium(ii) directed 1-D chains based on basket-type molybdophosphates and transition metal (TM) linkers

Five unclassical heteropoly blues, (H2bib)3[{TMII(H2O)2}{Sr⊂P6Mo2VMo16VIO73}]·nH2O (TM = Fe (1), Co (2), Ni (3), Cu (4), Zn (5)); bib = 1,4-bis(imidazole)butane), have been hydrothermally synthesized and fully characterized. Compounds 1–5 are based on the basket-shaped [Sr⊂P6Mo2VMo16VIO73]8− (abbreviated as {P6Mo18O73}) units, which consist of a vacant Dawson-type “basket body” {P2Mo14} unit and a “handle”-like {P4Mo4} fragment encasing a Sr2+ cation in the central cage. All the compounds exhibit isostructural 1-D zigzag chains linked by a {TM(H2O)2} unit, which are observed for the first time as 1-D basket-like assemblies connected by a TM linker. The optical band gaps of 1–5 show that they are semiconductor materials and potential photocatalysts. Compound 2 as a representative catalyst exhibits a universal highly efficient degradation ability for typical dyes MB, MO, and RhB under UV light and bifunctional electrocatalytic behavior for oxidation of AA and reduction of NO2−.

Influence of the counter anion and steric hindrance of pyrazolyl and imidazolyl flexible ligands on the structure of zinc-based coordination polymers

Treatments of flexible 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd), 1,4-bis(imidazolyl)butane (bib) and 1,4-bis(2-methylimidazolyl)butane (bmib) ligands with zinc salts at room temperature, resulted in the formation of four novel metal–organic coordination architectures: [ZnI2(μ-bbd)]n (1), [Zn(NCS)2(μ-bbd)]n (2), {[Zn(μ-bib)2](ClO4)2·(Et2O)0.5·(H2O)0.25}n (3) and {[Zn(μ-bmib)2](ClO4)2·(H2O)4}n (4). X-ray crystallographic analyses show different 1D and 3D polymeric structures for compounds 1–4 due to the variation of the counter anions, solvent, steric hindrance and position of donating atoms in the structure of flexible ligands. In 1 and 2, one-dimensional (1D) zig-zag polymeric chains are formed via metal centers and μ-bbd ligands. Complex 3 shows a 3-fold interpenetrated 3D architecture with 103-ths network topology. In contrast to 3, in the structure of 4 neighboring Zn(II) ions are interconnected by a double-bridging μ-bmib ligands to form an infinite 1D polymeric double chain. The conformations of the flexible ligands were analyzed in detail.

1,4-Bis(di-phenyl-phosphan-yl)butane-κ(2) P,P']di-bromido-palladium(II).

In the title complex, [PdBr2(C28H28P2)], the PdII ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis­(di­phenyl­phosphan­yl)butane ligand and two Br− anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294 (7) Å], making dihedral angles of 66.3 (2), 87.2 (2), 68.8 (2) and 86.8 (2)°. The butyl­ene chain is in a gauche conformation, with a C—C—C—C torsion angle of 57.0 (8)°. Inter­molecular C—H⋯Br hydrogen bonds link the complex mol­ecules into supra­molecular layers in the ab plane. Weak π–π inter­actions, both intra- and inter­molecular [shortest inter-centroid distance = 4.598 (5) Å], are also noted in the three-dimensional architecture.

The influence of ClO4− and PF6− anions and the steric hindrance of flexible bis-imidazole ligands on the formation and structures of iron(II) coordination polymers

Treatments of the flexible 1,4-bis(imidazolyl)butane (bib) ligand with Fe(II) salts in a mixture of ethanol and water (1:1) as a solvent at room temperature resulted in the formation of two novel coordination polymers, {[Fe(bib)3](ClO4)2}n (1) and {[Fe(bib)3](PF6)2}n (2), with two distinctly different network structures due to the variation of the ClO4− and PF6− moieties in these compounds. Their infrared spectra, X-ray powder diffraction (XRPD), elemental and thermal analyses were also investigated in detail. The results of the X-ray analyses demonstrate that in these structures, the iron(II) ion lies on an inversion center and adopts an FeN6 octahedral geometry. Each μ2-bib serves as a bridging ligand connecting two adjacent iron(II) ions. In the structure of 1, six μ2-bib ligands are simultaneously coordinated to one central iron(II) ion to form an open 3D 2-fold interpenetrating framework with an α-polonium (pcu) topology, while 2 has an open 3D network with an acs [point symbol (49.66)] structure. The structure of [bibMeH](PF6) [bibMe=1,4-bis(2-methylimidazolyl)butane] (3) has also been studied by X-ray crystallography as an unexpected product in an attempt to synthesize the {[Fe(bibMe)3]2+}n cation with the PF6− anion.