Nickel(II), Cadmium(II), and Copper(II) Complexes Based on Ditopic Terpyridine Derivative Ligand: Syntheses,Crystal Structures,and Luminescent Properties

Three complexes with the ditopic ligand 4′‐[4‐(quinolin‐8‐yloxymethyl)phenyl]‐2,2′:6′,2′′‐terpyridine (abbreviated as L ), [Ni(L)₂](CH₃COO)₂ ( 1 ), [Cd(L)₂](ClO₄)₂ ( 2 ), and [Cu₂(L)₂](ClO₄)₄ · 4DMF ( 3 ), were synthesized and characterized by elemental analysis, IR spectroscopy, and structurally analyzed by X‐ray single‐crystal diffraction. Interestingly, in complexes 1 and 2 , two ligands adopt a tridentate chelating pattern where the oxaquinoline group is non‐coordinated and coordinate with one M^II ion (M = Ni for 1 , M = Cd for 2 ) to form a mononuclear unit. In complex 3 , two ligands bridge two Cu^II ions by pyridyl N atoms, ethereal O atoms, and quinolyl N atoms in a head‐to‐tail mode to generate a dinuclear [Cu₂L₂] unit. Moreover, extended 1D and 2D supramolecular architectures are further constructed in 1 – 3 by multiple secondary interactions such as aromatic stacking and hydrogen bonding. Notably, the structural diversity of complexes 1 – 3 can be properly assigned to the central metal ions that have distinct coordination preferences. In addition, luminescent properties of the ligand and complex 2 were also investigated.     

Cadmium(II) Complexes with a Bulky Anthracene‐based Carboxylate Ligand: Syntheses,Crystal Structures,and Luminescent Properties

To explore the coordination possibilities of anthracene‐based ligands, three cadmium(ιι) complexes with anthracene‐9‐carboxylate ( L ) and relevant auxiliary chelating or bridging ligands were synthesized and characterized: Cd₂( L )₄(2bpy)₂(μ‐H₂O) ( 1 ), Cd₂( L )₄(phen)₂(μ‐H₂O) ( 2 ), and {[Cd₃( L )₆(4bpy)]}_∞ ( 3 ) (2bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, and 4bpy = 4,4′‐bipyridine). Structural analyses show that complexes 1 and 2 both take dinuclear structures by incorporating the chelating 2bpy or phen ligand, which are further interlinked by intermolecular hydrogen‐bonding, π ··· π stacking, and/or C–H ··· π supramolecular interactions to generate higher‐dimensional supramolecular frameworks. Complex 3 has a one‐dimensional (1D) ribbon‐like structure, which is further assembled into a two‐dimensional (2D) layer, and a three‐dimensional (3D) framework by the co‐effects of interchain C–H ··· O hydrogen‐bonding and C–H ··· π supramolecular interactions. Moreover, the luminescent properties of these complexes were further investigated in detail.     

Syntheses,Crystal Structures,and Properties of Metal(II) Coordination Polymers based on Flexible Ligand 1,3‐Bis(4‐phenoxy)benzenedicarboxylic Acid and Bis(benzimidazole)

Three new coordination polymers, [Zn(PBDC)(bbbm)_0.5]_n ( 1 ), [Co(PBDC)(bbbm)]_n ( 2 ), and [Cd(PBDC)(bbbm)]_n ( 3 ) were prepared via hydrothermal reactions of different metal(II) nitrates with flexible 1,3‐bis(4‐phenoxy)benzenedicarboxylic acid (H₂L) and 1,1‐(1,4‐butanediyl)bis(benzimidazole) ligand. All these complexes were fully characterized by elemental analysis, FT‐IR, thermogravimetric analysis (TGA), powder X‐ray diffraction, and single‐crystal X‐ray diffraction. Structure analyses revealed that complex 1 has a 2D→2D twofold interpenetrating framework simplified by a 4‐connected sql net with point symbol (4⁴.6²), whereas complexes 2 and 3 are isostructural and exhibit a 2D→2D twofold interpenetrating framework rationalized as a three‐connected hcb net with point symbol (6³). Complexes 1 – 3 further expand to 3D supramolecular structures through non‐covalent C–H ··· O interactions. Additionally, the luminescent and magnetic properties of some of these complexes were studied. Complex 3 presents ideal photoluminescent behavior, whereas complex 2 shows antiferromagnetic coupling between the central Co^II ions, suggesting its latent application in magnetic material.     

Two Manganese(II) Complexes with a Bulky Fluorene‐Based Carboxylate Ligand: Syntheses,Crystal Structures,and Luminescent Properties

To explore the coordination possibilities of fluorene‐based ligands, two manganese(II) complexes with the ligand 9,9‐dibutyl‐9H‐fluorene‐2,7‐carboxylate ( L ) were synthesized and characterized: [Mn₂( L )₂(DMF)₃]_∞ ( 1 ) and [Mn₂( L )₂(DMF)]_∞ ( 2 ). X‐ray single‐crystal diffraction analyses show that complex 1 has a two‐dimensional (2D) (4,4) structure, whereas complex 2 consits of a three‐dimensional (3D) (4,5)‐connected topology framework. The results indicate that the steric bulk of the fluorene ring in H₂ L plays an important role in the formations of 1 and 2 . Additional pyridine‐based ligands govern the formation of the final frameworks of 2 . Moreover, the luminescent properties of these complexes were briefly investigated.     

N,N′‐Bis(Salicylidene)‐1,2‐Cyclohexanediamine Lanthanide(III) Coordination Polymers: Syntheses,Crystal Structures,and Luminescence Properties

The salen‐type ligand H₂L [H₂L = N,N′‐bis(salicylidene)‐1,2‐cyclohexanediamine] was utilized for the synthesis of two lanthanide(III) coordination polymers [LnH₂L(NO₃)₃MeOH]_n [Ln = Eu ( 1 ) and Ln = Lu ( 2 )]. The single‐crystal X‐ray diffraction analyses of 1 and 2 revealed that they are isomorphous and exhibit one‐dimension neutral structure, in which H₂L effectively functions as a bridging ligand and give rise to a chain‐like polymer. The luminescent properties of polymers in solid state and in solution were investigated and 1 exhibits typical red luminescence of Eu^III ions in solid state and dichloromethane solution and 2 emits the ligand‐centered blue luminescence. The energy transfer mechanisms in these luminescent lanthanide polymers were described through calculation of the lowest triplet level of ligand H₂L.     

Syntheses,Structures, and Properties of Copper(II), Cobalt(II), and Cadmium(II) Complexes with Flexible Multicarboxylate Ligand

Three new coordination polymers, namely, [CuL_0.5] ( 1 ), [Co(H₂L)(H₂O)₂][H₂O] ( 2 ), and [(CdCl)_0.5Cd_0.25(H₂L)_0.5] ( 3 ) were synthesized under hydrothermal conditions from the corresponding Cu^II, Co^II, and Cd^II salts with a multidentate ligand of 2,2′,2′′,2′′′‐[2,3,5,6‐tetramethyl‐1,4‐phenylenebis(methylenenitrilo)]tetraacetic acid (H₄L). The complexes were characterized by single‐crystal X‐ray diffraction, IR, thermogravimetric, and elemental analyses. Complex 1 crystallizes in the orthorhombic space group Pbca and has a three‐dimensional architecture with infinite two‐dimensional networks linked together by weak Cu–O interactions. Complex 2 crystallizes in the monoclinic space group P2(1) and displays a 2D network. Complex 3 crystallizes in the tetragonal space group P4(2)/ncm and exhibits an infinite 3D architecture that has unusual [Cd₂(CO₂)₄Cl₂] dinuclear paddle‐wheel units and [Cd(CO₂)₄] dodecahedron units. The results showed that the coordination arrangement of central metal atoms and the conformation and coordination mode of organic ligands play an important role in determining the structure of the complexes. The luminescence property of complex 3 was studied in the solid state at room temperature.     

Cadmium(II) Complexes with Mixed cis‐Epoxysuccinate and 2,2′‐Bipyridyl‐Like Ligands: Syntheses,Crystal Structures,and Luminescent Properties

Two new Cd^II complexes, [Cd( ces )(phen)]_∞ ( 1 ) and {[Cd( ces )(bpy)(H₂O)](H₂O)}₂ ( 2 ), were prepared by slow solvent evaporation methods from mixtures of cis‐epoxysuccinic acid and Cd(ClO₄)₂ · 6H₂O in the presence of phen or bpy co‐ligand ( ces = cis‐epoxysuccinate, phen = 1,10‐phenanthroline, and bpy = 2,2′‐bipyridine). Single‐crystal X‐ray diffraction analyses show that complex 1 has a one‐dimensional (1D) helical chain that is further assembled into a two‐dimensional (2D) sheet, and then an overall three‐dimensional (3D) network by the interchain C–H ··· O hydrogen bonds. Complex 2 features a dinuclear structure, which is further interlinked into a 3D supramolecular network by the co‐effects of intermolecular C–H ··· O and C–H ··· π hydrogen bonds as well as π ··· π stacking interactions. The structural differences between 1 and 2 are attributable to the intervention of different 2,2′‐bipyridyl‐like co‐ligands. Moreover, 1 and 2 exhibit intense solid‐state luminescence at room temperature, which mainly originates from the intraligand π→π* transitions of aromatic co‐ligands.     

Syntheses,Structures, and Luminescent Properties of two Cadmium(II) Entangled Frameworks Based on 5‐Bromoisophthalic Acid and Bipyridyl Ligands

Two cadmium(II) entangled frameworks, Cd(BIPA)(bpe)_1.5 ( 1 ) and Cd(BIPA)(bpp)(H₂O) ( 2 ), were prepared by hydrothermal reactions based on rigid 5‐bromoisophthalic acid (H₂BIPA) and two flexible bipyridyl ligands 1, 2‐bis(4‐pyridyl)ethane (bpe) and 1, 3‐bis(4‐pyridyl)propane (bpp). The complexes were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction. Complex 1 is a rare example of a polycatenated array of 1D nanotubes, whereas complex 2 exhibits a three‐dimensional twofold interpenetrating diamondoid network. The analysis results reveal that the flexibility of the bipyridyl ligands plays a significant role in the structure of the final products. Moreover, the luminescent properties of the complexes were investigated.     

Solvothermal Syntheses,Crystal Structures,and Luminescent Properties of Two New Cadmium(II) Coordination Polymers Based on Rigid / Flexible Dicarboxylate and N,N′‐Bis(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide

In order to investigate the effect of the organic ligands on the structures of coordination polymers, two new cadmium(II) coordination polymers based on the different dicarboxylate ligands, namely [Cd₂(bpdc)₂(DPNDI)₂] · 3H₂O · NMF ( 1 ) and [Cd(obb)(DPNDI)] ( 2 ) [H₂bpdc = biphenyl‐4,4′‐dicarboxylate, H₂obb = 4,4′‐oxybis(benzoic acid), DPNDI = N,N′‐bis(4‐pyridyl)‐1,4,5,8‐naphthalene tetracarboxydiimide, and NMF = N‐methylformamide), were synthesized under solvothermal condition and further characterized. Complex 1 shows a twofold interpenetrated pcu topology. Complex 2 possesses a two‐dimensional (2D) layer structure with –ABCD– stacking sequence. Furthermore, the luminescent properties of complexes 1 and 2 are investigated.     

Structure and Magnetic Properties of Mononuclear Copper(II) Complexes with 2,2‐Bipyrimidine, 2,3‐Bis(2‐pyridyl)pyrazine,and 4‐Terpyridone Based Ligands

Four new complexes of [Cu(bpm)(ox)(H₂O)] ( 1 ), [Cu(tpd)(dca)(H₂O)] ( 2 ), [Cu(bppz)(N₃)₂] ( 3 ), and [Cu(bpm)₂(μ_1,3‐N₃)(N₃)] ( 4 ) (bpm = 2,2′‐bipyrimidine, bppz = 2,3‐bis(2‐pyridyl)pyrazine, tpd = 4‐terpyridone, dca = dicyanamide, ox = oxalate) have been prepared and characterized by X‐ray single‐crystal analysis and variable‐temperature magnetic measurements. Compounds 1–4 are essentially mononuclear Cu(II) complexes. However, in complex 1 , Cu(II) it was found that intermolecular hydrogen bonding through between H₂O and ox formed 1‐D chain structure. In complex 2 it was found that the hydrogen bonding between H₂O and tpd of the next molecule led to for a binuclear Cu(II) complex. In complex 3 , two nitrogen atoms, one of the pyridyl group of bppz and one of N₃^? ligands, are weakly coordinated to neighbor Cu(II) ion thus leading to formation of a 1‐D chain structure. In complex 4 , one nitrogen atom of terminated N₃^? is weakly coordinated to the neighbor Cu(II) site to form a 1‐D polymeric structure. The magnetic susceptibility measurements indicate that complex 1 and 4 exhibit a weak antiferromagnetic interaction whereas a ferromagnetic coupling has been established for complexes 2 and 3 .     

Syntheses,Structures, and Luminescent Properties of Two Cadmium(II) Coordination Compounds based on a Sulfonate Functionalized Terpyridine Ligand

The coordination compounds [Cd(TBDS)(H₂O)₂]_n ( 1 ) and Cd(TBDS)(bpy)₂(H₂O) · 3H₂O ( 2 ) {H₂TBDS = 4‐([4,2′:6′,4′′‐terpyridine]‐4′‐yl)benzene‐1,3‐disulfonic acid, bpy = 2,2′‐bipyridine} were synthesized under hydrothermal conditions. Single crystal X‐ray diffraction analyses revealed that compound 1 is a twofold interpenetrating 3D framework with 4‐connected dia topology, whereas compound 2 is a mononuclear compound, which packed with each other via hydrogen‐bonding interactions to construct a three‐dimensional supramolecular structure, and contained unusual meso‐helical chains. Additionally, the luminescence properties and thermal stabilities of 1 and 2 were investigated.     

Synthesis,Crystal Structures,and Luminescent Properties of Two Complexes based on 5‐tert‐Butylisophthalic Acid and 1, 2‐Bis(4‐pyridyl) Ethane

Abstract. Two coordination polymers, namely, [Zn(bpe)_0.5(Htbip)(tbip)_0.5] · H₂O ( 1 ) and [Cd(bpe)_0.5(tbip)] ( 2 ) [H₂tbip = 5‐tert‐butylisophthalic acid and bpe = 1, 2‐ bis(4‐pyridyl) ethane] were synthesized through hydrothermal reactions. Single‐crystal X‐ray diffraction analysis reveals that complex 1 presents a three‐dimensional (3D) six‐connected uninodal structure with the type of topology of svi‐x/I4/mcm → Ibam, whereas complex 2 holds a 2D 4⁴‐sql layer structure. Moreover, the photoluminescent properties of the complexes at room temperature were investigated.     

Syntheses,Structures, and Magnetism of Trinuclear Zn2Ln Complexes with 2,6‐Dipicolinoylbis(N,N‐diethylthiourea)

The bifunctional ligand 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H₂L) readily reacts with mixtures of Zn(CH₃COO)₂ and LnCl₃ in MeOH at ambient temperature with formation of trinuclear heterobimetallic complexes [Zn₂Ln(L)₂(OAc)₃] ( 1a – 1f ) (Ln = Ce, Nd, Sm, Gd, Dy, Er). The X‐ray single‐crystal diffraction and structural studies of the complexes revealed their isostructural nature, in which two doubly‐charged ligands {L^2–} bind two Zn²⁺ ions with the terminal acylthiourea sites and one Ln³⁺ ion with the central 2,6‐pyridinedicarboxamide site. In the complexes, the coordination numbers of Ln^III and Zn^II ions are 9 and 5, respectively. Magnetic properties of the complexes were studied by temperature‐dependent dc magnetic measurements. The observed μ_eff values at room temperature are all closed to the calculated values. Fitting χ_M and M data of [Zn₂Gd(L)₂(OAc)₃] ( 1d ) shows a g_iso value of 1.94.     

4-硝基邻苯二硫酚金属镍配合物的合成、结构和性质

合成了4-硝基邻苯二硫酚配体及相应金属镍配合物，(Bu₄N)₂[Ni(nbdt)₂] (1)和(Bu₄N)[Ni(nbdt)₂] (2)(nbdt=4-硝基邻苯二硫酚阴离子), 并通过X-射线单晶结构测定、循环伏安、ESR谱、紫外可见吸收光谱和变温磁化率实验对其结构和性质进行了表征。这两个化合物均为略有变形的平面四方型配合物。配合物2是由配合物1通过I₂氧化制备。配合物2含有一个未成对电子，磁性研究表明由于分子间的自旋耦合使它表现为反铁磁性。     

The Syntheses,Structures, and Magnetic Properties of Four 2D Lanthanide(III)‐naphthalenedicarboxylic Complexes

Four Ln‐NDC coordination polymers [Ln(NDC)(HNDC)(H₂O)] (Ln = La ( 1 ), Pr ( 2 ), Nd ( 3 ), Sm ( 4 ), H₂NDC = 1,4‐naphthalenedicarboxylic acid) were hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single‐crystal X‐ray diffraction. Compounds 1 – 4 are isomorphous, and their structures display a layer constructed from a Ln‐organic chain and NDC^2– ligand, in which the H₂NDC ligands adopt two different acidity‐dependent types and coordination modes: HNDC^1– with μ‐η¹:η¹ and NDC^2– with μ‐η¹:η²:η¹:η². The 3D supramolecular networks of 1 – 4 are mainly controlled by hydrogen bonds interactions. The magnetic susceptibilities of complexes 2 – 4 reveal overall antiferromagnetic interactions between the Ln^III ions. In addition, thermogravimetric analysis of compound 2 is described.     

Syntheses,Crystal Structures,and Magnetic Properties of Two Mononuclear Nickel‐Nitronyl Nitroxide Radical Compounds

Two nickel(II) complexes were synthesized and structurally as well as magnetically characterized by using two positional isomeric nitronyl nitroxide radical ligands and H₃cda as co‐ligand: [Ni(NIToPy)(cda)]H₂O · CH₃OH ( 1 ) and [Ni(IM4Py)₂(cda)H₂O] ( 2 ) [NIToPy = 2‐(3′‐pyridinyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide; IM4Py = 2‐(4′‐pyridinyl)‐4,4,5,5‐tetramethylimidazoline‐l‐oxyl; H₃cda = 4‐hydroxypyridine‐2,6‐dicarboxylic acid]. Single‐crystal structures analyses show that both complexes have similar mononuclear structures, in which the central Ni^II ions are hexacoordinated with a distorted octahedral arrangement. The magnetic properties of 1 and 2 were studied, and antiferromagnetic interactions between Ni^II ion and radicals are observed.     

Crystal Structure and Magnetic Properties of Copper(II) and Nickel(II) Binuclear Complexes with Bisacylhydrazones Based on 2,6‐Diformyl‐4‐methylphenol

The series of binuclear Cu(II) and Ni(II) complexes with an asymmetrical exchange fragment based on 2,6‐diformyl‐4‐methylphenol bishydrazone has been synthesized for the first time. The compositions and structures of both ligands and its complexes have been established with the data of IR, ¹H NMR, and extended X‐ray absorption fine structure (EXAFS) spectroscopical studies as well as magnetic measurements. The structure of [Ni₂L₃(μ‐Pz)] · 2CH₃OH (L = triply deprotonated form of bishydrazone, Pz = pyrazol) was confirmed by X‐ray crystallographic analysis. In this complex, the coordination environment of two nickel ions is quite different, one nickel atom is square‐planar and the other is distorted octahedral coordinated. The values of exchange parameter calculated in terms of HDVV theory have been compared with the features of an asymmetrical exchange fragment's electronic and geometrical structure.     

Three Novel 1‐H‐Benzimidazole‐5‐Carboxylate‐Based Nickel(II)/Cobalt(II) Coordination Polymers: Synthesis,Crystal Structures,Luminescent, and Magnetic Properties

Three 1H‐benzimidazole‐5‐carboxylate (Hbic^–)‐based coordination polymers, {[Ni(H₂O)(Hbic)₂] · 2H₂O}_n ( 1 ), {[Ni(H₂O)₂(Hbic)₂] · 3H₂O}_n ( 2 ), and {[Co₂(H₂O)₄(Hbic)₄] · 4DMF · 3H₂O}_n ( 3 ) were obtained by reactions of the ligand H₂bic and Ni^II or Co^II salts in the presence of different structure directing molecules. They were structurally characterized by single‐crystal X‐ray diffraction, IR spectra, elemental analysis, thermal stability, luminescent, and magnetic measurements. Structural analysis suggests that the three polymers exhibit a 2D (4, 4) layer for 1 and 1D linear double chains for both 2 and 3 due to the variable binding modes and the specific spatial orientation of the Hbic^– ligand towards the different paramagnetic metal ions, which were further aggregated into different 3D supramolecular architectures by popular hydrogen‐bonding interactions. Weak and comparable antiferromagnetic couplings mediating by Hbic^– bridge are observed between the neighboring spin carriers for 2 and 3 , respectively. Additionally, complexes 1 – 3 also display different luminescence emissions at room temperature due to the ligand‐to‐metal charge transfer.     

Syntheses,Crystal Structures,and Photophysical Properties of Heteronuclear Zinc(II)/Cadmium(II)‐Lanthanide(III) Coordination Complexes based on Benzoic Acid

The heteronuclear d‐f coordination complexes [Er₂Zn₂(C₆H₅COO)₁₀(phen)₂] (1), [Ho₂Zn₂(C₆H₅COO)₁₀(phen)₂] ( 2 ), [Pr₃Zn₆(C₆H₅COO)₂₁(phen)₃] ( 3 ), [ErCd(C₆H₅COO)₅(phen)·H₂O] ( 4 ), [Ho₂Cd₃(C₆H₅COO)₁₂(phen)₂] ( 5 ), [EuCd₂(C₆H₅COO)₇(phen)₂] ( 6 ) (C₆H₅COOH = benzoic acid;phen = 1,10‐phenanthroline) were synthesized by hydrothermal methods, and their structures were studied by single‐crystal X‐ray diffraction. Complexes 1 , 2 , 4 , and 5 crystallize in the triclinic space group P$\bar{1}$ and complexes 3 and 6 in the monoclinic space group C2/c. The room temperature IR, UV/Vis/NIR absorption, and emission spectra of the six complexes were determined and assigned. In the visible and NIR regions, the emission spectra of complexes show characteristic bands of corresponding Ln^III ions, which are attributed to the sensitization from the d block (Zn/Cd‐ligand section) and ligands. In comparison with isolated Ln^III ions, the NIR emission bands of complexes 1 – 5 exhibit shifting, broadening and splitting, which are also present in their UV/Vis/NIR absorption spectra. Thus, the two spectra of complexes can evidence each other.     

Two Zinc(II) Coordination Polymers Based on the Ligand 1, 4‐Bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene: Syntheses,Crystal Structures and Properties

Two coordination polymers (CPs), {[Zn₂(BMB)(5‐AIPA)₂] · 2H₂O}_n( 1 ) and [Zn(BMB)(5‐NIPA)]_n( 2 ) {BMB = 1, 4‐bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene, 5‐AIPA = 5‐aminoisophthalic acid, 5‐NIPA = 5‐nitroisophthalic acid}, were synthesized under hydrothermal conditions. Compound 1 displays a 2D double‐layer structure, which is packed into a 3D supramolecule by interlayer hydrogen bonds and π–π stacking interactions. Compound 2 displays a threefold interpenetrating 3D network, which is composed of left‐handed helical chains and two types of meso‐helical chains along different directions.