Crystal Structure and Luminescent Properties of Diverse Cadmium(II) Coordination Polymers Based on A Semirigid Multicarboxylate Ligand

Four Cd^II metal coordination polymers, namely, [Cd(HL)(H₂O)₃]_n ( 1 ), [Cd(HL)(4,4′‐bpy)]_n · nH₂O ( 2 ), [Cd₃(L)₂(2,2′‐bpy)₃(H₂O)₃]_n · 2nH₂O ( 3 ), and [Cd₃(L)₂(phen)₂(H₂O)]_n · 2.5nH₂O ( 4 ) [H₃L = 3‐(3‐carboxyphenoxy) phthalic acid, 4,4′‐bpy = 4,4′‐bipyridine, 2,2′‐bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline], were synthesized and structurally characterized by X‐ray diffraction, elemental analysis, and IR spectroscopy. Single‐crystal X‐ray analyses reveal that complexes 1 – 3 have different one‐dimensional (1D) chain structures including zigzag chain, ladder chain, and helical chain, whereas complex 4 shows a 0D trinuclear motif. These low‐dimensional complexes are further extended to 3D supramolecular networks by intermolecular π–π interactions and hydrogen bonds. The ligand H₃L exhibits five coordination modes: μ₁‐η²‐chelating/μ₁‐η²‐chelating, μ₁‐η²‐chelating/μ₁‐η²‐chelating/μ₁‐η²‐chelating, μ₁‐η²‐chelating/μ₁‐η²‐chelating/μ₁‐η¹‐bridging, μ₁‐η²‐chelating/μ₂‐η²‐bridging/μ₂‐η¹:η¹‐bridging, and μ₂‐η²‐chelating:η¹‐bridging/μ₂‐η²‐chelating:η¹‐bridging/μ₁‐η¹‐bridging. Moreover, the photoluminescent properties of complexes 1 – 4 were studied in the solid‐state at room temperature.     

Synthesis and Single Crystal Structure of a New Dinuclear Copper(II) Complex of 1,5-Bis(8-oxaquinoline)-3-methylpentane

A new flexible ligand, 1,5-bis(8-oxaquinoline)-3-methylpentane (C5MeOQ), was synthesized and used in the preparation of the new dinuclear copper(II) complex 1: [Cu₂(μ-OMe)₂(μ-C5MeOQ)(NO₃)₂]. Single crystal X-ray analysis revealed that complex 1 contains dinuclear Cu(II) units with bridging methoxo groups. The ligand, C5MeOQ, takes on a bent conformation in order to connect to and complete the square planar coordination environment of both copper centers; and one of the two Cu(II) centers adopts a distorted square planar configuration as a result of the ligand conformation. The magnetic properties of complex 1 were investigated by variable-temperature magnetic susceptibility measurements in the 100–300 K range. Interestingly, the susceptibility data for complex 1 reveals that the compound is diamagnetic, suggesting the presence of very strong antiferromagnetic coupling interactions between the adjacent Cu(II) centers.     

Syntheses,Structures, and Properties of Two Coordination Compounds of Pb(II) and Cd(II) with Quinoline‐8‐oxy‐acetate Acid

Quinoline‐8‐oxy‐acetate acid (8‐qoacH) reacts with M(II) (M=Pb and Cd) to give rise to two coordination complexes [Pb(8‐qoac)₂] ( 1 ) and [Cd(8‐qoac)(bdc)_0.5(H₂O)₂] ( 2 ) under hydrothermal conditions. They are characterized by single‐crystal X‐ray diffraction, IR, elemental, thermal analyses and luminescent analysis. The Pb metal centers connect the 8‐qoac anions to form a 1D linear chain in 1 . In 2 , two symmetrical [Cd(8‐qoac)(H₂O)₂] are bridged by a 1,4‐bdc^2? to generate a coordination unit [Cd(8‐qoac)(bdc)_0.5(H₂O)₂], and all the units are further connected to a 2D supramolecular layer‐like structure via hydrogen bonds. TG analyses indicate that 1 exhibits higher thermostability than 2 . Fluorescence spectrum of compound 2 in solid state shows strong fluorescence property.     

Synthesis and Crystal Structure of a Cadmium Coordination Polymer with Dicyanamide and 1,2-Bis（1,2,4-triazol- 1-yl）ethane

The new cadmium(II) coordination polymer [Cd(bte)2(dca)2]n 1 (bte = 1,2-bis(1,2,4- triazol-1-yl)ethane, dca = dicyanamide) was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 8.7148(15), b = 8.6142(17), c = 15.204(3) A, β = 92.100(10)o, V = 1140.6(4) A3, Z = 2, Mr = 572.87, Dc = 1.668 g/cm3, F(000) = 572, μ = 1.004 mm-1, the final R = 0.0654 and wR = 0.1429 for 1737 observed reflections (I > 2σ(I)). The cadmium atom is coordinated equatorially by four nitrogen atoms from four bte ligands and axially by two nitrogen atoms from two dca anions to adopt a distorted octahedral geometry. Each bte molecule bridges two cadmium(II) atoms. Two strands of bte molecules are wrapped around each other, and held together by cadmium(II) atoms. 1 Forms a double chain structure containing eighteen-membered Cd2(bte)2 rings.     

Synthesis and Crystal Structure of a Three-dimensional Coordination Polymer {[Cd(cda)_2]·2CH_3OH}_n Generated from Cadmium(II) and Carbamyldicyanomethanide Anion Bridging Ligand

1 INTRODUCTION The polynitrile-ligands, such as TCNE, TCNB, TCNQ, TCNP, tcm, dca and so on, are of ideal multi-functional bridging ligands. Many complexes with poly-nitriles as bridging ligands and uncoor- dinated ligand (electron acceptors) display dist…     

Synthesis and Crystal Structure of Blue Luminescent Cadmium(II) Coordination Networks with 4,4′-Bis(imidazol-1-ylmethyl)biphenyl from Different Solvent Systems

Two supramolecular complexes, [Cd(bimb)²Cl²] (1) and [Cd(bimb)(DMF)Cl²]·DMF (2) [bimb=4,4′-bis(imidazol-1-ylmethyl)biphenyl], were synthesized by reactions of CdCl²·2.5H²O with bimb ligand in ethanol and N,N′-dimethylformamide (DMF), respectively, and their structures were determined by X-ray crystallography. Complex 1 is an infinite 2D grid network bridged by bimb ligands, and the 2D sheets were further linked by C–H ?Cl hydrogen bonds to form a polycatenated 3D framework. Complex 2 has dicadmium(II) di-μ-chloride units which are connected by bimb bridging ligands to form an infinite non-interpenetrating 2D network. The results provide a nice example of the solvent system exerting a great effect on the construction of supramolecular frameworks.     

A New Dinuclear Copper (II) Complex of a Bis‐macrocyclic Ligand: Synthesis,Characterization, Crystal Structure and Magnetic Properties

A new dinuclear Cu(II) complex, [Cu₂L(N₃)₂](ClO₄)₁.₅ (OH)_4.5 · 2H₂O 0.5C₂H₅OH (1), of a bis‐macrocyclic ligand, 2,6‐bis(l,4,7,10‐tetraazacyclododecan‐10‐ylmethyl)‐methoxybenzene (L), has been synthesized, characterized and structurally determined by X‐ray diffraction analysis. Complex 1 crystallizes in orthorhombic crystal system, Pca2(l) space group with a = 1.5371(3), b = 1.6641(3), c = 3.0950(6) nm, V = 7.917(3) nm³, F_w = 904.62, Z=8, D_c= 1.529 g/cm³ and final R = 0.0568, wR = 0.1406 for 10410 observed reflections with I≥2σ (I). Both Cu(II) centers in the structure are coordinated by four nitrogen atoms of 1,4,7, 10‐tetraazacyclododecane (cyclen) and a nitrogen donor of the axial azide anion. Each Cu(II) center is in a square‐pyramidal coordination environment, and the intra‐and nearest inter‐molecular Cu? Cu nonbonding distances are 0.9855 and 0.7298 nm, respectively. Variable temperature magnetic susceptibility measurements in the range of 4.2–300 K indicate mat there exists weak intra‐ and inter‐molecular antiferromagnetic coupling between the Cu(II) centers with 27= ?4.2 cm^?1 and Θ = ?0.47 K.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes with the 2, 2′‐Diamino‐4, 4′‐bithiazole (DABTZ) Ligand — Syntheses and X‐Ray Crystal Structure of [Hg(DABTZ)(SCN)2]

Reaction of the ligand 2, 2′‐diamino‐4, 4′‐bithiazole (DABTZ) with Zn(ClO₄)₂, CdCl₂, and Hg(SCN)₂ gives complexes with composition [Zn(DABTZ)₂](ClO₄)₂, [Cd(DABTZ)₂Cl₂], and [Hg(DABTZ)(SCN)₂]. The complexes were characterized by elemental analyses and infrared spectroscopy. The crystal structure of the [Hg(DABTZ)(SCN)₂] was determined by X‐ray crystallography. The complex is built up of a monomeric Hg(SCN)₂ unit with one 2, 2′‐diamino‐4, 4′‐bithiazole ligand coordinated to the Hg atom via the two N atoms giving rise to a five‐member chelate ring in a distorted tetrahedral environment. There is π‐π stacking interaction between the parallel aromatic rings belonging to adjacent chain as planar species in which the mean molecular planes are close to parallel and separated by a distance of ～ 3.5Å, close to that of the planes in graphite. The coordinated 2, 2′‐diamino‐4, 4′‐bithiazole molecule is involved in hydrogen bonding acting as hydrogen‐bond donors with N atoms from the SCN ligand as potential hydrogen‐bond acceptors. The hydrogen bonding yields infinite chains parallel to the crystallographic vectors a and b. Each molecule is bonded to three neighbours. Both amine H atoms are hydrogen bonded to N atoms.     

Synthesis,Crystal Structure,and Luminescence of Cadmium(II) and Silver(I) Coordination Polymers Based on 1,3-Bis(1,2,4-triazol-1-yl)adamantane

Coordination polymers with a new rigid ligand 1,3-bis(1,2,4-triazol-1-yl)adamantane (L) were prepared by its reaction with cadmium(II) or silver(I) nitrates. Crystal structure of the coordination polymers was determined using single-crystal X-ray diffraction analysis. Silver formed two-dimensional coordination polymer [Ag(L)NO₃]_n, in which metal ions are linked by 1,3-bis(1,2,4-triazol-1-yl)adamantane ligands, coordinated by nitrogen atoms at positions 2 and 4 of 1,2,4-triazole rings. Layers of the coordination polymer consist of rare 18- and 30-membered {Ag₂L₂} and {Ag₄L₄} metallocycles. Cadmium(II) nitrate formed two kinds of one-dimensional coordination polymers depending on the metal-to-ligand ratio used in the synthesis. Coordination polymer [Cd(L)₂(NO₃)₂]_n was obtained in case of a 1:2 M:L ratio, while for M:L = 2:1 product {[Cd(L)(NO₃)₂(CH₃OH)]·0.5CH₃OH}_n was isolated. All coordination polymers demonstrated ligand-centered emission near 450 nm upon excitation at 370 nm.     

Synthesis,Crystal Structure and Characterization of a New Coordination Polymer from the Self-assembly of CoCl_2 Salt and Flexible Ligand 1,3-Bis（4-pyridyl）propane

A new 1D coordination polymer [Co(bpp)3Cl2(H2O)2]n 1 (bpp = 1,3-bis(4-pyridyl)-propane) was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Ibca with a = 16.569(9),b = 17.240(10),c = 27.087(16) ,V = 7738(8) 3,Z = 8,Dc = 1.306 g/cm3,Mr = 760.65,λ(MoKa) = 0.71073 ,μ = 0.623 mm1,F(000) = 3192,the final R = 0.0678 and wR = 0.2011. The Co(II) atom is coordinated in a slightly distorted octahedral CoN4Cl2 geometry by two Cl atoms in the axial positions,four N atoms from the two bridging bpp ligands and two pendant bpp ligands. The CoN4Cl2 octahedra are connected by the bridging bpp ligands to form a 1D neutral coordination polymer chain. The chains are linked by face-to-face π-π interactions between adjacent pendant bpp ligands to give rise to a 3D supramolecular architecture. The photoluminescent investigation indicates that the emission of 1 is attributed to ligand-centered emission. The variable-temperature magnetic susceptibility measurement shows weak antiferromagnetic behavior in the complex.     

Synthesis,Structure, and Properties of Cadmium(II) Centered Chiral Coordination Polymer based on (R)‐6‐(1‐Carboxyethoxy)‐2‐naphthoic Acid

A cadmium chiral coordination polymer, formulated as [Cd(R‐cna)]_n ( 1 ‐D) was constructed under hydrothermal method. Single‐crystal X‐ray diffraction analysis indicated that 1 ‐D exhibited a 2D layered structure with a point symbol of (4⁷ · 6³). 1 ‐D was further characterized by infrared spectra, powder X‐ray diffraction (PXRD), elemental analysis, thermogravimetric analysis (TGA), and circular dichroism spectra (CD). The second‐harmonic generation (SHG) property was investigated. It was also found that the luminescence of 1 ‐D can be quenched by iron ions and trinitrotoluene, indicating its potential application as luminescence sensing material.     

Syntheses and Characterization of Zinc,Cadmium, and Mercury(II) Complexes with N‐(2‐pyridyl)carbonylaniline (L), X‐ray Crystal Structure of [Hg(L)(SCN)2]

The reaction of N‐(2‐pyridyl)carbonylaniline (L) with Zn(NO₃)₂, CdCl₂, and Hg(SCN)₂ gives the following complexes: [Zn(L)₂](NO₃)₂, [Cd(L)₂Cl₂], and [Hg(L)(SCN)₂]. The new complexes were characterized by elemental analyses and IR‐, ¹H‐, ¹³C‐NMR spectroscopy. The crystal structure of the [Hg(L)(SCN)₂] was determined by single crystal X‐ray analysis. The monomeric complex is built up of a Hg(SCN)₂ unit with one N‐(2‐pyridyl)carbonylaniline (L) ligand coordinated to the Hg atom via the ring pyridinic nitrogen atom and the carbonyl oxygen atom forming a five‐membered chelate ring. The Hg atom has a distorted tetrahedral environment. There is π‐π stacking interaction between the parallel aromatic rings belonging to adjacent chain as planar species in which the mean molecular planes are close to parallel and separated by a distance of ～ 3.5Å, close to that of the planes in graphite. The coordinated N‐(2‐pyridyl)carbonylaniline (L) molecule is involved in hydrogen bonding acting as hydrogen‐bond donors with S and N atoms from SCN^— ligand as potential hydrogen‐bond acceptors. There is a shortest intermolecular contacts between the S and N atoms. The hydrogen bonding and shortest intermolecular contacts between the S and N atoms yields infinite chains parallel to the crystallographic vector c. Each molecule is bonded to two neighbors.     

Synthesis,Crystal Structures,and Properties of Copper(II), Zinc(II), and Cadmium(II) Coordination Polymers Based on 5‐Nitro‐isophthalate and 1,2‐(2‐Pyridyl)‐1,2,4‐triazole

Three coordination polymers, namely {[Cu(5‐nipa)(L²²)](H₂O)₂}_n ( 1 ), [Zn(5‐nipa)(L²²)(H₂O)]_n ( 2 ), and {[Cd₂(5‐nipa)₂(L²²)(H₂O)₃](H₂O)_3.6}_n ( 3 ), were prepared under similar synthetic method based on 1,2‐(2‐pyridyl)‐1,2,4‐triazole (L²²) and ancillary ligand 5‐nitro‐isophthalic acid (5‐H₂nipa) with Cu^II, Zn^II, and Cd^II perchlorate, respectively. All the complexes were characterized by IR spectroscopy, elemental analysis, and powder X‐ray diffraction (PXRD) patterns. Single‐crystal X‐ray diffraction indicates that complexes 1 and 2 show similar 1D chain structures, whereas complex 3 exhibits the 2D coordination network with hcb topology. The central metal atoms show distinct coordination arrangements ranging from distorted square‐pyramid for Cu^II in 1 , octahedron for Zn^II in 2 , to pentagonal‐bipyramid for Cd^II in 3 . The L²² ligand adopts the same (η³,μ₂) coordination fashion in complexes 1 – 3 , while the carboxyl groups of co‐ligand 5‐nipa^2– adopt monodentate fashion in 1 and 2 and bidentate chelating mode in 3 . These results indicate that the choice of metal ions exerts a significant influence on governing the target complexes. Furthermore, thermal stabilities of complexes 1 – 3 and photoluminescent properties of 2 and 3 were also studied in the solid state.     

Synthesis,Crystal Structure and Photoluminescence Property of Zinc(II), Cadmium(II), and Lead(II) Complexes with Bidentate Ligand: 1‐(1‐Imidazolyl)‐4‐(imidazol‐1‐ylmethyl)benzene (IIMB)

Assembly of bidentate ligand 1‐(1‐imidazolyl)‐4‐(imidazol‐1‐ylmethyl)benzene (IIMB) with varied metal salts of Zn^II, Cd^II and Pb^II provide three new complexes, [Zn(IIMB)₂](ClO₄)₂·2H₂O ( 1 ), [Cd(IIMB)₂(SCN)₂] ( 2 ) and [Pb(IIMB)₂(SCN)](SCN) ( 3 ). Single crystal X‐ray diffraction studies revealed that complexes 1 and 2 display a similar one‐dimensional double stranded chain structure, while complex 3 is a slight distorted rhombohedral grid network with (4,4) topology. The results indicate that the coordination geometry of the metal ion and the counter anion have great impact on the structure of the complexes. In addition, the photoluminescence properties of ligand IIMB and complexes 1 – 3 were studied in the solid state at room temperature.