A novel two‐dimensional nickel(II) coordination polymer with 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene and azide ligands

The coordination geometry of the Ni^II atom in the title complex, poly[diazidobis[μ‐1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene‐κ²N⁴:N^4′]nickel(II)], [Ni(N₃)₂(C₁₂H₁₂N₆)₂]_n, is a distorted octahedron, in which the Ni^II atom lies on an inversion centre and is coordinated by four N atoms from the triazole rings of two symmetry‐related pairs of 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene (bbtz) ligands and two N atoms from two symmetry‐related monodentate azide ligands. The Ni^II atoms are bridged by four bbtz ligands to form a two‐dimensional (4,4)‐network.     

EPR Spectroscopy of 4, 4′‐Bis(tert‐butyl)‐2, 2′‐bipyridine‐1, 2‐dithiolatocuprates(II) in Host Lattices with Different Coordination Geometries

A series of new heteroleptic MN₂S₂ transition metal complexes with M = Cu²⁺ for EPR measurements and as diamagnetic hosts Ni²⁺, Zn²⁺, and Pd²⁺ were synthesized and characterized. The ligands are N₂ = 4, 4′‐bis(tert‐butyl)‐2, 2′‐bipyridine (tBu₂bpy) and S₂ =1, 2‐dithiooxalate, (dto), 1, 2‐dithiosquarate, (dtsq), maleonitrile‐1, 2‐dithiolate, or 1, 2‐dicyanoethene‐1, 2‐dithiolate, (mnt). The Cu^II complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [Ni^II(tBu₂bpy)(S₂)] or[Pd^II(tBu₂bpy)(S₂)] as well as in tetrahedrally coordinated[Zn^II(tBu₂bpy)(S₂)] host structures to put steric stress on the coordination geometry of the central CuN₂S₂ unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi‐occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [Ni^II(tBu₂bpy)(mnt)], is characterized by X‐ray structure analysis to prove the coordination geometry. The complex crystallizes in a square‐planar coordination mode in the monoclinic space group P2₁/a with Z = 4 and the unit cell parameters a = 10.4508(10) Å, b = 18.266(2) Å, c = 12.6566(12) Å, β = 112.095(7)°. Oxidation and reductions potentials of one of the host complexes, [Ni(tBu₂bpy)(mnt)], were obtained by cyclovoltammetric measurements.     

A comparative study of the packing of two polymorphs of the nickel(II) pincer complex [2,6‐bis(di‐tert‐butylphosphinoyl)‐4‐(3,5‐dinitrobenzoyloxy)phenyl‐κ3P,C1,P′]chloridonickel(II)

Pincer complexes can act as catalysts in organic transformations and have potential applications in materials, medicine and biology. They exhibit robust structures and high thermal stability attributed to the tridentate coordination of the pincer ligands and the strong σ metal–carbon bond. Nickel derivatives of these ligands have shown high catalytic activities in cross‐coupling reactions and other industrially relevant transformations. This work reports the crystal structures of two polymorphs of the title Ni^II POCOP pincer complex, [Ni(C₂₉H₄₁N₂O₈P₂)Cl] or [NiCl{C₆H₂‐4‐[OCOC₆H₄‐3,5‐(NO₂)₂]‐2,6‐(OP^tBu₂)₂}]. Both pincer structures exhibit the Ni^II atom in a distorted square‐planar coordination geometry with the POCOP pincer ligand coordinated in a typical tridentate manner via the two P atoms and one arene C atom via a C—Ni σ bond, giving rise to two five‐membered chelate rings. The coordination sphere of the Ni^II centre is completed by a chloride ligand. The asymmetric units of both polymorphs consist of one molecule of the pincer complex. In the first polymorph, the arene rings are nearly coplanar, with a dihedral angle between the mean planes of 27.9 (1)°, while in the second polymorph, this angle is 82.64 (1)°, which shows that the arene rings are almost perpendicular to one another. The supramolecular structure is directed by the presence of weak C—H…O=X (X = C or N) interactions, forming two‐ and three‐dimensional chain arrangements.     

A three‐dimensional cadmium(II) coordination polymer: poly[[[μ‐4,4′‐(propane‐1,3‐diyl)dipyridine‐κ2N:N](μ‐3,3′‐thiodipropionato‐κ3O,O′:O)cadmium(II)] monohydrate]

In the title coordination polymer, {[Cd(C₆H₈O₄S)(C₁₃H₁₄N₂)]·H₂O}_n, the Cd^II atom displays a distorted octahedral coordination, formed by three carboxylate O atoms and one S atom from three different 3,3′‐thiodipropionate ligands, and two N atoms from two different 4,4′‐(propane‐1,3‐diyl)dipyridine ligands. The Cd^II centres are bridged through carboxylate O atoms of 3,3′‐thiodipropionate ligands and through N atoms of 4,4′‐(propane‐1,3‐diyl)dipyridine ligands to form two different one‐dimensional chains, which intersect to form a two‐dimensional layer. These two‐dimensional layers are linked by S atoms of 3,3′‐thiodipropionate ligands from adjacent layers to form a three‐dimensional network.     

mer‐Di­aqua­bis(1H‐imidazole‐κN3)(orotato‐κ2N3,O4)­nickel(II)

The title mononuclear complex, [Ni(C₅H₂N₂O₄)(C₃H₄N₂)₂(H₂O)₂] or [Ni(HOr)(im)₂(H₂O)₂] (im is imidazole and H₃Or is orotic acid, or 2,6‐dioxo‐1,2,3,6‐tetra­hydro­pyrimidine‐4‐carboxylic acid), has been synthesized and the crystal structure determination is reported. The Ni^II ion in the complex has a distorted octahedral coordination geometry comprised of one deprotonated pyrimidine N atom and the adjacent carboxyl­ate O atom of the orotate ligand, two tertiary imidazole N atoms and two aqua ligands. An extensive three‐dimensional network of OW—H⋯O and N—H⋯O hydrogen bonds, and π–π and π–ring interactions are responsible for crystal stabilization.     

Two Coordination Polymers based on 2‐Ethyl‐1H‐imidazole‐4,5‐dicarboxylic Acid and 1,3‐Bis(4‐pyridyl)propane: Synthesis,Crystal Structures,and Photoluminescent Properties

Two coordination polymers, [Cd(Heidc)(bpp)]_n ( 1 ) and [Zn₃ (eidc)₂(bpp)(H₂O)₂] · 2H₂O}_n ( 2 ) (H₃eidc = 2‐ethyl‐4,5‐imidazole dicarboxylic acid, bpp = 1,3‐bis(4‐pyridyl)propane) were hydrothermally synthesized and characterized by elemental analysis, IR, spectroscopy single‐crystal X‐ray diffraction, and thermogravimetric analyses. Compound 1 features a 2D layer formed by C–H ··· π stacking interactions between adjacent chains, whereas compound 2 shows a 3D (8³)₂(8⁵.10)‐tfc framework constructed of the 2D (6,3) layer. The result demonstrates that the central metal atoms play a key role in governing the coordination motifs. Moreover, solid‐state properties such as thermal stabilities and photoluminescence of 1 and 2 were also investigated.     

Syntheses,Spectral, Thermal and Structural Characterization of 2‐Phenyl‐2‐(1‐hydroxyiminoethyl)‐1,2,3,4‐tetrahydroquinazoline and Its Novel Nickel(II) Complex

The 2‐phenyl‐2‐(1‐hydroxyiminoethyl)‐1,2,3,4‐tetrahydroquinazoline (HL) and its Ni^II complex have been prepared and characterized by spectral method (FT‐IR, NMR (¹³C and ¹H), UV‐vis.), elemental analysis, magnetic susceptibility and thermal analysis (TG, DTA) techniques. The crystal structures of HL and Ni^II complex were also determined by the single crystal X‐ray diffraction. The HL and Ni^II complex crystallizes in the monoclinic and triclinic, space groups P2₁/c and , respectively. The complex was occurred by the elimination of 1 mole of 2‐aminobenzylamine from the 2 moles of the HL after the ring opening reaction by the Ni^II attack. Crystallographic study reveal that Ni^II atom has a square planer geometry being coordinated by four nitrogen atoms of HL. Two thermal processes of the HL and Ni^II complex can occur in TG and DTA curves.     

(2‐Aminopyrimidine‐κN1)aqua(pyridine‐2,6‐dicarboxylato‐κ3O2,N,O6)copper(II): X‐ray and DFT calculated structure

In the title compound, [Cu(C₇H₃N₂O₄)(C₄H₅N₂)(H₂O)], (I), pyridine‐2,6‐dicarboxylate (pydc²⁻), 2‐aminopyrimidine and aqua ligands coordinate the Cu^II centre through two N atoms, two carboxylate O atoms and one water O atom, respectively, to give a nominally distorted square‐pyramidal coordination geometry, a common arrangement for copper complexes containing the pydc²⁻ ligand. Because of the presence of Cu...X_bridged contacts (X = N or O) between adjacent molecules in the crystal structures of (I) and three analogous previously reported compounds, and the corresponding uncertainty about the effective coordination number of the Cu^II centre, density functional theory (DFT) calculations were used to elucidate the degree of covalency in these contacts. The calculated Wiberg and Mayer bond‐order indices reveal that the Cu...O contact can be considered as a coordination bond, whereas the amine group forming a Cu...N contact is not an effective participant in the coordination environment.     

A one‐dimensional ladder‐like coordination polymer derived from chains formed via hydrogen bonds: catena‐poly­[[aqua­di­pyridine­nickel(II)]‐μ‐2,2′‐di­thio­dibenzoato‐κ3O,O′:O′′]

The title one‐dimensional chain nickel(II)–di­sulfide complex, [Ni(C₁₄H₈O₄S₂)(C₅H₅N)₂(H₂O)]_n, has each Ni^II cation coordinated by two N atoms from two pyridine ligands, three carboxyl­ate O atoms from two different di­thio­dibenzoate ligands and one O atom from a coordinated water mol­ecule, in a distorted octahedral coordination geometry. Each di­thio­dibenzoate ion links two Ni^II cations through its carboxyl­ate O atoms, making the structure polymeric. Hydro­gen‐bond interactions between two shoulder‐to‐shoulder chains lead to the formation of a ladder‐like structure.     

Acetato(N‐phenylpyridine‐2‐carboxamidato‐κ2N,N)(N‐phenylpyridine‐2‐carboxamide‐κ2N1,O)copper(II)

The title complex, [Cu(C₁₂H₉N₂O)(C₂H₃O₂)(C₁₂H₁₀N₂O)], is a neutral Cu^II complex with a primary N₃O₂ coordination sphere. The Cu centre coordinates to both a deprotonated and a neutral molecule of N‐phenylpyridine‐2‐carboxamide and also to an acetate anion. The coordination around the metal centre is asymmetric, the deprotonated ligand providing two N donor atoms [Cu—N = 1.995 (2) and 2.013 (2) Å] and the neutral ligand providing one N and one O donor atom to the coordination environment [Cu—N = 2.042 (2) Å and Cu—O = 2.2557 (19) Å], the fifth donor being an O atom of the acetate ion [Cu—O = 1.9534 (19) Å]. The remaining O atom from the acetate ion can be considered as a weak donor atom [Cu—O = 2.789 (2) Å], conferring to the Cu complex an asymmetric octahedral geometry. The crystal structure is stabilized by intermolecular N—H...O, C—H...O and C—H...π interactions.     

An unusual chain cadmium(II) coordination polymer: catena‐poly[[(2,2′‐bipyridyl‐κ2N,N′)cadmium(II)]‐di‐μ‐chlorido‐[(2,2′‐bipyridyl‐κ2N,N′)cadmium(II)]‐di‐μ‐thiocyanato‐κ2N:S;κ2S:N]

The title complex, [CdCl(NCS)(C₁₀H₈N₂)]_n, represents an unusual Cd^II coordination polymer constructed by two types of anionic bridges and 2,2′‐bipyridyl (bipy) terminal ligands. These two types of bridges are arranged around inversion centers. The distorted octahedral coordination of the Cd^II center is provided by two chloride ions, one N‐ and one S‐donor atom from two thiocyanate ions, and a pair of N atoms from the chelating bipy ligand. Interestingly, adjacent Cd^II ions are interconnected alternately by paired chloride [Cd...Cd = 3.916 (1) Å] and thiocyanate bridges [Cd...Cd = 5.936 (1) Å] to generate an infinite one‐dimensional coordination chain. Furthermore, weak interchain C—H...S interactions between the bipy components and thiocyanate ions lead to the formation of a layered supramolecular structure.     

The two‐dimensional coordination polymer poly[diaqua(μ2‐1H‐imidazo[4,5‐f][1,10]phenanthroline)‐μ4‐sulfato‐μ3‐sulfato‐dicadmium(II)]

In the title coordination polymer, [Cd₂(SO₄)₂(C₁₃H₈N₄)(H₂O)₂]_n, there are two crystallographically independent Cd^II centres with different coordination geometries. The first Cd^II centre is hexacoordinated by four O atoms of four sulfate ligands, one water O atom and one N atom of a 1H‐imidazo[4,5‐f][1,10]phenanthroline (IP) ligand, giving a distorted octahedral coordination environment. The second Cd^II centre is heptacoordinated by four O atoms of three sulfate ligands, one water O atom and two N atoms of one chelating IP ligand, resulting in a distorted monocapped anti‐trigonal prismatic geometry. The symmetry‐independent Cd^II ions are bridged in an alternating fashion by sulfate ligands, forming one‐dimensional ladder‐like chains which are connected through the IP ligands to form two‐dimensional layers. These two‐dimensional layers are linked by interlayer hydrogen bonds, leading to the formation of a three‐dimensional supramolecular network.     

[Cu(bpp)2(bpdc)(H2O)2]×2H2O and [Cu(bpp)2](tdc)×7.5H2O的合成、晶体结构和热稳定性

在室温下, 由Cu(NO3)2 、1,3 -二（4 -吡啶基）丙烷(bpp)、4,4 ’ -联苯二甲酸(H2bpdc)和2,5-噻吩二甲酸(H2tdc)制备出两种新型铜( II)配位聚合物[Cu(bpp)2(bpdc)(H2O)2]n·2nH2O, 1 和[Cu(bpp)2]n·n(tdc) 7.5nH2O, 2。两个配位聚合物均为一维线型结构,铜原子均采取变形的八面体结构,在轴线方向上的两个水分子与铜原子存在较弱的配位作用。在配合物1中,两个bpdc羧酸根离子与铜原子配位,而2中的tdc羧酸离子没有与铜原子键合,只是作为反离子平衡电荷。在两个产物中, 配体bpp具有不同的构象。热重分析表明配合物1与2分别在110°C和160°C以下是稳定的。     

A New Polymer of Mixed‐Anions Complex [Pb(phen)(O2CCH3)(O2NO)]n (phen = 1,10‐phenanthroline)

The single crystal X‐ray data of a mixed anions complex of Pb^II with 1,10‐Phenantroline, [Pb(phen)(O₂CCH₃)‐ (O₂NO)], shows the complex to be polymeric as a result of acetate ligand bridging. The Pb atom has an asymmetrical eightfold coordination of two nitrogen atoms of the 1,10‐phenanthroline ligand and six oxygen atoms of the nitrate and acetate anions. The arrangement of the 1,10‐phenantroline ligand, acetate and nitrate anions suggest a gap in the coordination around the Pb^II ion, occupied possibly by a stereoactive lone pair of electrons on lead(II) where the coordination around the lead atoms is hemidirected. There is a π‐π stacking interaction between the parallel aromatic rings of an adjacent chain in the compound which might help to increase the ‘gap' in the coordination around the Pb^II ion.     

Synthesis,Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)2(H2O)].NaNO3

Transition metal complexes of arginine (using Co(II), Ni(II), Cu(II) and Zn(II) cations separately) were synthesized and characterized by FTIR, TG/DTA‐DrTG, UV‐Vis spectroscopy and elemental analysis methods. Cu(II)‐Arg complex crystals was found suitable for x‐ray diffraction studies. It was contained, one mole Cu^II and Na⁺ ions, two arginate ligands, one coordinated aqua ligand and one solvent NO₃^? group in the asymmetric unit. The principle coordination sites of metal atom have been occupied by two N atoms of arginate ligands, two carboxylate O atoms, while the apical site was occupied by one O atom for Cu^II cation and two O atoms for Co^II, Ni^II, Zn^II atoms of aqua ligands. Although Cu^II ion adopts a square pyramidal geometry of the structure. Co^II, Ni^II, Zn^II cations have octahedral due to coordination number of these metals. Neighbouring chains were linked together to form a three‐dimensional network via hydrogen‐bonding between coordinated water molecule, amino atoms and O atoms of the bridging carboxylate groups. Cu^II complex was crystallized in the monoclinic space group P2₁, a = 8.4407(5) Å, b = 12.0976(5) Å, c = 10.2448(6) Å, V = 1041.03(10) ų, Z = 2. Structures of the other metal complexes were similar to CuII complex, because of their spectroscopic studies have in agreement with each other. Copper complex has shown DNA like helix chain structure. Lastly, anti‐bacterial, anti‐microbial and anti‐fungal biological activities of complexes were investigated.     

Bis(5‐aminotetrazole‐1‐acetato‐κO)tetraaquacobalt(II) and catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato‐κ3N4:O,O′)]

The Co^II atom in bis(5‐aminotetrazole‐1‐acetato)tetraaquacobalt(II), [Co(C₃H₄N₅O₂)₂(H₂O)₄], (I), is octahedrally coordinated by six O atoms from two 5‐aminotetrazole‐1‐acetate (atza) ligands and four water molecules. The molecule has a crystallographic centre of symmetry located at the Co^II atom. The molecules of (I) are interlinked by hydrogen‐bond interactions, forming a two‐dimensional supramolecular network structure in the ac plane. The Cd^II atom in catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato], [Cd(C₃H₄N₅O₂)₂]_n, (II), lies on a twofold axis and is coordinated by two N atoms and four O atoms from four atza ligands to form a distorted octahedral coordination environment. The Cd^II centres are connected through tridentate atza bridging ligands to form a two‐dimensional layered structure extending along the ab plane, which is further linked into a three‐dimensional structure through hydrogen‐bond interactions.     

Synthesis,Crystal Structure,and Electrochemical Behaviour of an Azido μ‐bridged Ni2+ Complex

A homo‐dinuclear Ni^II complex was prepared from 2, 6‐bis(3, 5‐dimethylpyrazolyl)pyridine (Me₄‐bpp) and azide ions in nonaqueous media. It was characterized by single crystal X‐ray structural analysis, IR spectroscopy, and elemental analysis. In addition, the electrochemical properties of the compound were determined with cyclic voltammetry in DMF. The title compound crystallizes in the P2₁/n monoclinic space group, with unit cell parameters a = 8.978(1), b = 12.459(1), c = 17.764(1) Å, ß =100.603(3)°, V = 1953.0(3) ų, Z = 2. The Ni²⁺ ion has a distorted octahedral environment involving three nitrogen atoms of the Me₄‐bpp ligand, two nitrogen atoms from the bridged azide group, and one nitrogen atom from the terminal azide group. The Ni···Ni distance is 3.273(5) Å.     

A novel two‐dimensional CdII coordination polymer: poly[aqua[μ4‐2‐(4‐carboxylatobenzoyl)benzoato]cadmium(II)]

The title Cd^II coordination framework, [Cd(C₁₅H₈O₅)(H₂O)]_n or [Cd(bpdc)(H₂O)]_n [H₂bpdc is 2‐(4‐carboxybenzoyl)benzoic acid], has been prepared and characterized using IR spectroscopy, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. Each Cd^II centre is six‐coordinated by two O atoms from one 2‐(4‐carboxylatobenzoyl)benzoate (bpdc²⁻) ligand in chelating mode, three O‐donor atoms from three other bpdc²⁻ anions and one O atom from a coordinated water molecule in an octahedral coordination environment. Two crystallographically equivalent Cd^II cations are bridged by one O atom of the 2‐carboxylate group of one bpdc²⁻ ligand and by both O atoms of the 4‐carboxylate group of a second bpdc²⁻ ligand to form a binuclear [(Cd)₂(O)(OCO)] secondary building unit. Adjacent secondary building units are interlinked to form a one‐dimensional [Cd(OCO)₂]_n chain. The bpdc²⁻ ligands link these rod‐shaped chains to give rise to a complex two‐dimensional [Cd(bpdc)]_n framework with a 4,4‐connected binodal net topology of point symbol {4³.6².8}. The compound exhibits a strong fluorescence emission and typical ferroelectric behaviour in the solid state at room temperature.     

Poly[(μ2‐aqua‐κ2O:O)(μ3‐azido‐κ3N1:N1:N3)(μ2‐isonicotinato‐κ2O:O′)lead(II)]

In the title compound, [Pb(C₆H₄NO₂)(N₃)(H₂O)]_n, the Pb ion is seven‐coordinated by three N atoms from three azide ligands, two O atoms from two isonicotinate (inic) ligands and two O atoms from two coordinated water molecules, forming a distorted monocapped triangular prismatic coordination geometry. Each azide ligand bridges three Pb^II ions in a μ_1,1,3 coordination mode to form a two‐dimensional three‐connected 6³ topology network extending in the bc plane. The carboxylate group of the inic unit and the aqua ligand act as coligands to bridge Pb^II ions. Adjacent two‐dimensional layers are connected by hydrogen‐bonding interactions between the isonicotinate N atom and the water molecule, resulting in an extended three‐dimensional network. The title complex is the first reported coordination polymer involving a p‐block metal, an azide and a carboxylate.     

A two‐dimensional cadmium(II) coordination polymer based on 5‐(pyridin‐4‐yl)isophthalic acid: poly[[tetraaquabis[μ3‐5‐(pyridin‐4‐yl)isophthalato]dicadmium(II)] pentahydrate]

The title Cd^II compound, {[Cd₂(C₁₃H₇NO₄)₂(H₂O)₄]·5H₂O}_n, was synthesized by the hydrothermal reaction of Cd(NO₃)₂·4H₂O and 5‐(pyridin‐4‐yl)isophthalic acid (H₂L). The asymmetric unit contains two crystallographically independent Cd^II cations, two deprotonated L²⁻ ligands, four coordinated water molecules and five isolated water molecules. One of the Cd^II cations adopts a six‐coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. The second Cd^II cation adopts a seven‐coordinate pentagonal–bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. Each L²⁻ ligand bridges three Cd^II cations and, likewise, each Cd^II cation connects to three L²⁻ ligands, giving rise to a two‐dimensional graphite‐like 6³ layer structure. These two‐dimensional layers are further linked by O—H...O hydrogen‐bonding interactions to form a three‐dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.