Structures and Fluorescent Properties of Cadmium(II) Complexes with 1D and 2D Structures Based on Tridentate Benzimidazole Ligands

The cadmium(II) complexes [CdL1(m‐nba)₂] ( 1 ), [CdL1(p‐nba)₂] · C₂H₅OH ( 2 ), [CdL2(p‐nba)₂] · CH₃OH ( 3 ), and [CdL2(p‐nbat)₂] ( 4 ) containing the ligands L1 and L2 [L1 = 2,6‐bis(benzimidazol‐2‐yl)pyridine, L2 = bis(2‐benzimidazolylmethyl)amine] were synthesized and characterized (m‐nba, p‐nba, and p‐nbat are the anions of p‐nitrobenzoic acid, m‐nitrobenzoic acid, and p‐nitrobenzeneacetic acid, respectively). The complexes were investigated by X‐ray single crystal diffraction, elemental analysis as well as IR and fluorescence spectroscopy. Compounds 1 – 3 contain a distorted pentagonal bipyramidal coordination sphere with Cd^II coordinated by two carboxylate ligands in bidentate‐chelating mode, whereas complex 4 exhibits a distorted octahedral arrangement with one carboxylate ligand in bidentate‐chelating and the other in monodentate coordination mode. 1 and 2 form a 1D chain interplayed by hydrogen bonding and strong π–π stacking interactions. 3 and 4 vary from 1D chain into 2D single‐layer and double‐layer networks because of more extensive hydrogen bonding interactions. The complexes show emission maxima in the blue region in the solid state and emission bands are red‐shifted compared to those of the free ligands.     

Syntheses,Crystal Structures,and Magnetic Properties of Two Cobalt Coordination Polymers Constructed From 1,3‐Bis(2,4‐dicarboxyphenyl) Benzene and Bis(imidazole) Linkers

Abstract. The 3D cobalt(II) coordination polymers [Co_1.5(HDDB)(1,4‐bib)_1.5(H₂O)]_n ( 1 ), and {[Co₂(DDB)(1,3‐bib)₂(μ₂‐H₂O)] · H₂O}_n ( 2 ) were assembled by mixed‐ligand synthetic strategy [H₄DDB = 1,3‐bis(2,4‐dicarboxyphenyl) benzene, 1,3‐bib = 1,3‐bis(1H‐imidazol‐4‐yl)benzene, and 1,4‐bib = 1,4‐bis(1H‐imidazol‐4‐yl)benzene]. Their structures were determined by single‐crystal X‐ray diffraction analyses and further characterized by elemental analyses (EA), IR spectroscopy, powder X‐ray diffraction (PXRD), and thermogravimetric (TG) analyses. Single X‐ray diffraction analysis reveals that complex 1 is an interestingly 3D (3,3.6)‐connected (6³)₄(6⁵ · 8⁸ · 10²) net, and complex 2 is an unprecedented dinuclear [Co₂(COO)(μ₂‐H₂O)] SBUs based 3D (3,6)‐connected (3 · 6 · 7)(3² · 4³ · 5⁴ · 6³ · 7 · 8²) net. Additionally, the magnetic properties of 2 were investigated.     

Synthesis,Structures and DFT Studies of Imido‐bridged and (Bis)ligand‐coordinated Titanium Complexes

Syntheses and structures of five imido‐bridged dinuclear titanium complexes and two (bis)ligand‐coordinated mononuclear titanium complexes are reported. Addition of 1 or 2 equiv. of Schiff base ligand (((1H‐pyrrol‐2‐yl)methylene)amino)‐2,3‐dihydro‐1H‐inden‐2‐ol (H₂L) to Ti(NMe₂)₄ resulted in transamination with 4 equiv. of dimethylamides generating a (bis)ligand‐coordinated complex Ti(L)₂ ( 1 ). Treatment of Ti(NMe₂)₄ with 1 equiv. of ^tBuNH₂ followed by addition of 1 equiv. of H₂L afforded an imido‐bridged complex [Ti(L)(N^tBu)]₂ ( 2 ). 1:1:1:1 reaction of Ti(NMe₂)₄/RNH₂/H₂L/py(or phen) produced imido‐bridgedcomplexes [Ti(L)(NPh)(py)]₂ ( 3 ), [Ti(L)(4‐F‐PhN)(py)]₂·Tol ( 4 ·Tol), [Ti(L)(4‐Cl‐PhN)(py)]₂·Tol·THF ( 5 ·Tol·THF), [Ti(L)(4‐Br‐PhN)(py)]₂·Tol ( 6 ·Tol) and a (bis)ligand‐coordinated complex Ti(L)₂·phen ( 7 ) (py = pyridine, phen = 1,10‐phenanthroline). Attempts to prepare the monomeric titianium imido complexes were unsuccessful. DFT studies show that the assumed compound which contains Ti = N species is less stable than imido‐bridged Ti‐N(R)‐Ti complexes, providing the better understanding of the experimental results.     

Syntheses,Crystal Structures,and Photocatalytic Activities of Three Copper Coordination Polymers Based on Bis(1H‐imidazol‐4‐yl)benzene/3‐(2‐Pyridyl)pyrazole

Three copper(II) coordination polymers (CuCPs), namely, [Cu_0.5(1,4‐bib)(SO₄)_0.5]_n ( 1 ), {[Cu(1,3‐bib)₂(H₂O)] · SO₄ · H₂O}_n ( 2 ), and [Cu(bpz)(SO₄)_0.5]_n ( 3 ), were assembled from the reaction of three N‐donors [1,4‐bib = 1,4‐bis(1H‐imidazol‐4‐yl)benzene, 1,3‐bib = 1,3‐bis(1H‐imidazol‐4‐yl)benzene, and Hbpz = 3‐(2‐pyridyl)pyrazole] with copper sulfate under hydrothermal conditions. Their structures were determined by single‐crystal X‐ray diffraction analyses and further characterized by elemental analyses (EA), IR spectroscopy, powder X‐ray diffraction (PXRD), and thermogravimetric analyses (TGA). Structure analyses reveal that complex 1 is a 3D 6‐connected {4¹² · 6³}‐ pcu net, complex 2 is a fourfold 3D 4‐connected 6⁶‐ dia net, whereas complex 3 is a 1D snake‐like chain, which further expanded into 3D supramolecular architectures with the help of C–H ··· O hydrogen bonds. Moreover, the photocatalytic tests demonstrate that the obtained CuCPs are photocatalysts in the degradation of MB with the efficiency is 86.4 % for 1 , 75.3 % for 2 , and 91.3 % for 3 after 2 h, respectively.     

Synthesis, characterization, structures and cytotoxic activity of palladium(II) and platinum(II) complexes containing bis(2-pyridylmethyl)amine and saccharinate

New palladium(II) and platinum(II) complexes containing bis(2-pyridylmethyl)amine (bpma) and saccharinate (sac), [Pd(bpma)(sac)](sac)·2H₂O (1), [Pt(bpma)(sac)](sac)·2H₂O (2), [Pd(bpma)Cl](sac)·2H₂O (3) and [Pt(bpma)(sac)]Cl·1.5H₂O (4), were synthesized and characterized by elemental analysis, IR, NMR and TG-DTA. A single-crystal X-ray analysis of 3 and 4 proved a distorted square-planar geometry around the metal ions with one tridentate bpma ligand and one Cl or sac monoanion. The [Pd(bpma)Cl]⁺ ions in 3 form dimers by intermolecular N-H?Cl and Pd?Pd interactions. The cations reside in the centers of a hydrogen-bonded honeycomb network formed by the uncoordinated sac ions and the lattice water molecules, while the cations of 4 are connected by N-H?Cl and OW-H?O hydrogen bonds into one-dimensional chains. Cyclic planar tetrameric and trimeric water clusters were observed in 3 and 4, respectively. Cytotoxicity of 1-4 was tested against A549, C6 and CHO cells. Although 2 and 4 have no cytotoxicity, the best results were achieved for 1 and 3. In particular, the cyctotoxic activity of 3 is comparable to cisplatin.     

Modular Construction,Structures, and Magnetic Properties of Two Manganese Coordination Polymers Based on 3,5‐Bis(2–carboxylphenoxy)benzoic Acid

Two manganese(II) coordination polymers, namely, [Mn_1.5(BCB)(bpy)_1.5(H₂O)]_n ( 1 ), and [Mn(HBCB)(bibp)₂(H₂O)] ( 2 ), were assembled from the mixed ligands of the flexible tripodal ligand of 3,5‐bis(2‐carboxylphenoxy)benzoic acid (H₃BCB) and two rigid N‐donors [bpy = 4,4′‐bipyridine, and bibp = 4,4′‐bis(imidazolyl)biphenyl]. Their structures were determined by single‐crystal X‐ray diffraction analyses and further characterized by elemental analyses (EA), IR spectra, powder X‐ray diffraction (PXRD), and thermogravimetric (TG) analyses. Structural analysis reveals that complex 1 is a 3D (3,4,6)‐connected {5 · 6²}₂{5⁶ · 6⁴ · 7 · 8² · 9²}{6⁴ · 8 · 9} net based on two kinds of inorganic nodes of dinuclear {Mn₂(COO)₂} SBUs and Mn(2) ions. Complex 2 is a hydrogen bonds based 3D supramolecule with 6‐connected {4¹² · 6³}‐ pcu net. Besides, the variable‐temperature susceptibilities of 1 and 2 were investigated.     

Syntheses,Structures, and Catalytic Properties of Two 2D Manganese(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two Mn^II coordination polymers based on the flexible bis(benzimidazole) and dicarboxylic acids, namely, [Mn(L1)(bpdc)(H₂O)_0.5]_n ( 1 ) and [Mn(L2)(Htbi)₂]_n ( 2 ) [L1 = 1,4‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, H₂bpdc = 4,4′‐biphenyldicarboxylic acid, L2 = 1,4‐bis(5,6‐dimethylbenzimidazole)butane, H₂tbi = 5‐tert‐butyl isophthalic acid] were hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, as well as single‐crystal X‐ray diffraction. Both of the complexes crystallize in the triclinic P$\bar{1}$ space group and present distorted octahedral configurations. Complex 1 possesses a 2D binodal (3,5)‐connected 3,5L2 network with the point symbol of (4².6⁷.8)(4².6), whereas 2 features a 2D uninodal 3‐connected hcb topology and the Schläfli symbol is (6³). Complexes 1 and 2 ultimately are extended into 3D supramolecular framework via π–π stacking and O–H ··· O hydrogen bonding interaction, respectively. Moreover, both of the complexes manifest excellent catalytic activities for the degradation of Congo red.     

Syntheses and Structures of Three Copper Coordination Polymers Based on Bis(triazol‐1‐ylmethyl)benzene

Three copper(II) coordination polymers [Cu(mbtz)₂(NCS)₂]_n ( 1 ), [Cu(mbtz)₂Cl₂]_n ( 2 ) and [Cu(mbtz)(btec)_0.5]_n ( 3 ) (mbtz=1,3‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene, btec=1,2,4,5‐benzenetetracarboxylate) were synthesized. In 1 and 2 , two mbtz ligands are wrapped around each other and are held together by Cu(II) atoms to form one‐dimensional double chain. In 3 , each btec ligand connects four Cu(II) atoms through its four carboxylate groups, resulting in a planar two‐dimensional [Cu(btec)_0.5]_n network. The Cu(II) atoms are further coordinated mbtz ligands to fulfil their coordination geometry and construct new [Cu(btec)_0.5(mbtz)]_n network. 2 and 3 further form the three‐dimensional network through the π···π stacking interactions between the mbtz ligands. The thermal stabilities of 1 , 2 and 3 were measured.     

Synthesis and Structure of Copper(II) Nitrate Complexes with 2, 6‐Bis(pyrazolyl)pyridine

Three mononuclear copper(II) complexes of copper nitrate with 2, 6‐bis(pyrazol‐1‐yl)pyridine ( bPzPy ) and 2, 6‐bis(3′,5′‐dimethylpyrazol‐1‐yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO₃)₂] ( 1 ), [Cu(bPzPy)(H₂O)(NO₃)₂] ( 2 ) and [Cu(bdmPzPy)(NO₃)₂] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X‐ray structure analysis of complexes 1 and 2 revealed a five‐coordinate copper atom in 1 , whereas 2 contains a six‐coordinate (4+2) Cu^II ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D‐chains in a zipper‐like motif.     

Synthesis,IR Spectra,Thermal Analysis and Crystal Structures of Bis(saccharinato)mercury(II) Complexes with 2–Aminomethylpyridine and 2–Aminoethylpyridine

Two bis(saccharinato) (sac) complexes of mercury(II) with 2–aminomethylpyridine (ampy) and 2–aminoethylpyridine (aepy) were synthesized and characterized by means of elemental analysis, FT–IR spectroscopy and thermal analysis and single crystal X–ray diffraction. trans–[Hg(sac)₂(ampy)₂] ( 1 ) crystallizes in the monoclinic space group P2₁/c [a = 10.8274(4), b = 16.4903(6), c = 7.7889(3) Å; β = 99.500(1)°] and [Hg(sac)₂(aepy)] ( 2 ) also crystallizes monoclinic in space group P2₁/n [a = 9.0423(4), b = 14.0594(6), c = 18.0146(8) Å; ß = 98.806(1)°]. Both 1 and 2 consist of neutral monomeric units. The mercury(II) ion in 1 lies on an inversion centre and exhibit distorted octahedral coordination by two sac anions and two ampy ligands, whereas the mercury(II) ion in 2 is tetrahedrally coordinated by an aepy and two sac ligands. The sac ligands in both complexes are N–coordinated, while the ampy and aepy ligands act as a bidentate ligand forming two symmetrically chelate rings around the mercury(II) ion.     

Two Novel 3D Copper Phthalate Coordination Complexes Incorporating Isomeric Flexible Bis(pyridylformyl)piperazine Ligands

Two novel metal‐organic coordination complexes [Cu(3‐bpfp)(pht)(H₂O)] · 2H₂O ( 1 ) and [Cu₃(4‐bpfp)(pht)₂(OH)₂] · 2H₂O ( 2 ) were hydrothermally synthesized by self‐assembly of phthalic acid (H₂pht), flexible bis(pyridylformyl)piperazine ligands [3‐bpfp = bis(3‐pyridylformyl)piperazine, 4‐bpfp = bis(4‐pyridylformyl)piperazine], and copper chloride. Single crystal X‐ray diffraction analysis revealed that the adjacent Cu^II ions are connected by pht showing different coordination modes [a bis(monodentate) coordination mode for 1 and a monodentate‐bidentate coordination mode for 2 ] to form 1D Cu‐pht‐Cu chains in 1 and 2D Cu‐pht layers in 2 . In compound 1 , a twofold interpenetrated CdSO₄‐like topology is formed by connection of 3‐bpfp. Using the isomeric ligand 4‐bpfp instead of 3‐bpfp resulted in the formation of 2 , which displays a novel 3, 4, 4, 4‐connected tetranodal 3D coordination polymeric framework. The ligand 3‐bpfp adopts a μ₂‐bridging coordination mode in 1 (by ligation of the pyridyl nitrogen atoms), whereas the ligand 4‐bpfp adopts a μ₄‐bridging coordination mode (by ligation of pyridyl nitrogen and carbonyl oxygen atoms) in 2 . Moreover, the electrochemical properties of carbon paste electrodes bulk modified with the two copper complexes were studied.     

A EuIII‐MOF with Bis(2‐carboxyethyl)isocyanurate for Luminescence Sensing of Fe3+ and SCN– Ions

The water‐stable 3D lanthanide‐organic framework (Ln‐MOF) {[Eu(bci)(H₂O)] · 2H₂O}_n ( 1 ) [H₂bci = bis(2‐carboxyethyl)isocyanurate] was synthesized under hydrothermal conditions. Compound 1 ‐ Eu exhibits a 3D open‐framework connected by Eu–(μ‐O)₂–Eu chains and bci ligands. Meanwhile, 1 ‐ Eu exhibits highly efficient luminescent sensing for environmentally relevant Fe³⁺ and SCN^– ions through luminescence quenching. These results indicated that it could be utilized as a multi‐responsive luminescence sensor.     

Dimeric and polymeric silver(I) saccharinato complexes of two bis(pyridine) ligands: Synthesis,structural, spectroscopic,fluorescent and thermal properties

The reaction of silver(I) with 1,2-bis[1-(pyridin-2-yl)ethylidene]hydrazine (bpeh) and N,N-bis(pyridin-2-ylmethyl)amine (bpma) in the presence of Na(sac) (sac = saccharinate) yielded [Ag₂(sac)₂(bpeh)] (1) and [Ag(sac)(bpma)]_n (2) with conformational chirality. Both complexes have been characterized by elemental analysis, IR, thermal analysis and X-ray single crystal diffraction. Complex 1 displays a binuclear composition, in which each silver(I) ion is bound to one monodentate sac ligand and one of the bidentate pyridylimino groups of the bpeh ligand in a distorted trigonal coordination geometry. Complex 2 is a one-dimensional helical polymer, in which silver(I) centers are bridged by tridentate bpma ligands, and each silver(I) ion is coordinated in a distorted tetrahedral geometry by one monodentate sac ligand, a bidentate pyridylamine group of one bpma ligand, and a py group of another bpma ligand. Weak intermolecular C–H?O hydrogen bonds and C–H?π interactions lead to assembly of 1 and 2 into three-dimensional supramolecular frameworks. Spectral and thermal analysis data for 1 and 2 are in agreement with the crystal structures. In addition, both complexes in the solid state display intraligand π–π∗ fluorescence.     

Coordination Frameworks based on 3,5‐Bis(imidazole‐1‐yl)­pyridine and Aromatic Dicarboxylate Ligands: Synthesis,Crystal Structures,and Photoluminescent Properties

Three metal coordination polymers [Zn(bdc)(L)(H₂O)]_n ( 1 ), [Co(pta)(L)(H₂O)₂]_n ( 2 ), and [Cd(tda)(L)(H₂O)]_n ( 3 ) [H₂bdc = 1,2‐benzene dicarboxylate acid, H₂pta = terephthalic acid, H₂tda = 2,5‐thiophenedicarboxylic acid, L = 3,5‐bis(imidazole‐1‐yl)pyridine] were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X‐ray powder diffraction, and X‐ray single crystal diffraction. Complex 1 shows a three‐dimensional (3D) structure with cco topology with the symbol 6⁵ · 8, whereas complex 2 features a 3D structure with cds topology with the symbol 6⁵ · 8. Complex 3 has a 2D network constructed by the cadmium atoms bridged through the ligands tda and L. Their X‐ray powder diffraction patterns were compared with the simulated ones. Moreover, their luminescent properties were investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the 3D networks.     

Study of the Interaction of Bis(4‐pyridylthio)methane with Copper(II) Chloride and Bromide

The new ligand bis(4‐pyridylthio)methane (4‐bpytm) ( 1 ) and its complexes [CuX₂(4‐bpytm)] and [CuX₂(4‐bpytm)₂] (X = Cl and Br) ( 2 – 5 ) have been prepared and characterized by elemental analysis, IR‐Raman, UV/Vis spectroscopy. The structures of (4‐bpytm) ( 1 ), [CuCl₂(4‐bpytm)₂] ( 3 ) and [CuBr₂(4‐bpytm)₂] ( 4 ) were determined by single‐crystal X‐ray diffraction analysis. X‐ray analysis of the 1:2 derivatives reveals that the copper atom has a distorted (4 + 2) octahedral environment. The copper atom is coordinated by four nitrogen atoms from four bridging 4‐bpytm ligands and two halogen atoms. The axial Cu–N bonds are considerably longer than the equatorial Cu–N bonds owing to JahñTeller distortion. CuX₂ units are linked to each other through bridging 4‐bpytm ligands to form a 2D interpenetrated coordination polymer. The structural parameters of the 4‐bpytm ligand in these complexes were compared with those of the free ligand.     

Synthesis,Structures, and Photocatalytic Properties of Zinc(II) and Cobalt(II) Supramolecular Complexes Constructed with Flexible Bis(thiabendazole) and Dicarboxylate Linkers

Three coordination complexes, namely, [Zn(btbp)(3‐npa)]_n ( 1 ), [Co(btbh)(3‐npa)]_n ( 2 ), and {[Co(btbb)(5‐nipa)(H₂O)] · H₂O}_n ( 3 ) (btbp = 1,3‐bis(thiabendazole)propane, btbh = 1,6‐bis(thiabendazole)hexane, btbb = 1,4‐bis(thiabendazole)butane, 3‐H₂npa = 3‐nitrophthalic acid and 5‐H₂nipa = 5‐nitroisophthalic acid) were synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single‐crystal X‐ray diffraction. Complex 1 features a fascinating meso‐helical chain, which is further extended into a 2D supramolecular framework involving π ··· π stacking interactions. Complexes 2 and 3 show dinuclear structures. Complex 2 is further connected through C–H ··· O hydrogen bonding interactions to afford a 2D supramolecular layer, whereas complex 3 is further extended to a rare 2‐nodal (3,4)‐connected supramolecular sheet with a point symbol of {3.4².5.6.7}₂{3.8²} by O–H ··· O hydrogen bonding interactions. The electrochemical behaviors of the two cobalt complexes 2 and 3 were reported. Moreover, the luminescent properties for 1 and the photocatalytic properties for the complexes were investigated.     

Synthesis,Structure and Magnetic Properties of Two Cobalt(II) Dicyanamide (dca) Complexes with Heterocyclic Nitrogen Donors Tetra(2‐pyridyl)pyrazine (tppz) and 2,4,6‐Tri(2‐pyridyl)‐1,3,5‐triazine (tptz): [Co2(tppz)(dca)4]·CH3CN and [Co(tptz)(dca)(H2O)](dca)

Two new transition metal dicyanamide complexes [Co₂(tppz)(dca)₄]·CH₃CN ( 1 ) [tppz=tetra(2‐pyridyl)pyrazine, dca=dicyanamide] and [Co(tptz)(dca)(H₂O)](dca) ( 2 ) [tptz=2,4,6‐tri(2‐pyridyl)‐1,3,5‐triazine] were synthesized and characterized by single crystal X‐ray diffraction analysis. In 1 each cobalt(II) atom is coordinated to three dca anions and one tppz molecule to form a distorted octahedral geometry, the neigbour two cobalt(II) atoms are bridged by one tppz ligand to form a dimer, then the cobalt(II) atoms in each dimer are joined together to form a ladder chain structure. In 2 the coordination geometry around the central metal is also distorted octahedral, each cobalt(II) atom is coordinated by two dca anions, one tptz molecule and one water ligand to form a cationic part, and the cationic part is linked with the free dca anions via the electrostatic attraction to give an infinite chain structure. Magnetic susceptibility measurement in the range of 2–300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 (T>29 K, (=?9.78 K, C=4.92 cm³·K·mol^?1) and ferromagnetic couplings in 2 (T>150 K, (=7.97 K, C=2.59 cm³·K·mol^?1) respectively.     

An Aqua‐Bridged Helical‐Chain Copper(II)‐Saccharinato Polymer Linked into a Two‐Dimensional Supramolecular Framework

A new assembly [Cu₂(sac)₂(μ‐dmea)₂(μ‐H₂O)]_n (sac = saccharinate and Hdmea = 2‐dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of dinuclear modules of [Cu₂(sac)₂(dmea)₂]. The sac ligand is N‐coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra‐dimer Cu···Cu separation of 3.0229(7) Å. The dimeric units are bridged by aqua ligands to generate a one‐dimensional water‐bridged helical chain, in which the copper(II) ions exhibit a distorted square‐pyramidal CuN₂O₃ coordination. The Cu–Cu distance in the chain separated by the bridging aqua ligands is 5.297Å. The polymeric chains are further linked by π(sac)···π(sac) and C–H···π(sac) interactions into a two‐dimensional supramolecular network.     

Hydrothermal Synthesis,Crystal Structures,and Catalytic Properties of Three Coordination Polymers Containing ­Flexible Bis(benzimidazole) and Dicarboxylate Ligands

Three metal‐organic coordination polymers, namely {[Cd(L1)(1,2‐chdc)] · 2H₂O}_n ( 1 ), {[Ni(L2)(1,2‐chdc)] · H₂O}_n ( 2 ), and [Cd(L2)(npht)]_n ( 3 ) [L1 = 1,2‐bis(2‐methylbenzimidazol‐1‐ylmethyl)benzene, L2 = 1,2‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, 1,2‐H₂chdc = 1,2‐cyclohexanedicarboxylic acid, H₂npht = 3‐nitrophthalic acid] were synthesized under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction methods, IR spectroscopy, TGA, and elemental analysis. In compound 1 , two 1,2‐chdc^2– ligands connect two neighboring Cd atoms to form a dinuclear [Cd₂(1,2‐chdc)₂] subunit, which is further linked by L1 ligands to construct a 1D ladder‐like chain. Compound 2 exhibits a 2D (4,4) coordination network with {4⁴.6²} topology, whilst compound 3 shows a 1D helical chain structure. The fluorescence, UV/Vis diffuse reflection spectra, and catalytic properties of complexes 1 – 3 for the degradation of the congo red azo dye in a Fenton‐like process are investigated.     

Bis(saccharinato)copper(II) complexes with 2-aminomethylpyridine and 2-aminoethylpyridine: Syntheses,crystal structures,spectral and thermal characterizations of trans-[Cu(sac)2(ampy)2] and [Cu(sac)2(aepy)(H2O)] (ampy = 2-aminomethylpyridine and aepy = 2-aminoethylpyridine)

Two bis(saccharinato)copper(II) complexes with 2-aminomethylpyridine (ampy) and 2-aminoethylpyridine (aepy) have been prepared and characterized by elemental analyses, IR and electronic spectroscopy, magnetic measurements and single-crystal X-ray diffraction. The copper(II) ion in trans-[Cu(sac)₂(ampy)₂] has ?1 site symmetry and is octahedrally coordinated by two neutral ampy and two anionic sac ligands, whereas the copper(II) ion in [Cu(sac)₂(aepy)(H₂O)] is five-coordinate with a distorted square-pyramidal coordination geometry. Both ampy and aepy behave as bidentate (N,N′) chelating ligands, while the saccharinate anion (sac) in the title complexes is N-coordinated. IR spectra of both complexes display typical absorption bands of bidentate aminopyridines and N-bonded sac ligands. Thermal decomposition behavior of the complexes is described in detail.