R-phenyldicarboxyl (R = H, NO2 and COOH) modular effect on Ni(II) coordination polymers incorporated with a versatile connector 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

Based on the versatile ligand 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4′-Hbpt) (1), a series of coordination compounds [Ni(3,4′-Hbpt)(ip)] (2), [Ni(3,4′-Hbpt)₂(tp)(H₂O)₂] (3), [Ni₂(3,4′-Hbpt)(5-NO₂-ip)₂(H₂O)₄] (4) and [Ni(3,4′-Hbpt)(pm)_0.5(H₂O)₃]·2H₂O (5) have been hydrothermally constructed through R-phenyldicarboxyl (R = H, NO₂ and COOH) intervention effect (ip = isophthalic anion, tp = terephthalic anion, 5-NO₂-ip = 5-NO₂-isophthalic anion, pm = pyromellitic anion). Structural analysis reveals that 3,4′-Hbpt adopts μ-N_py, N_py coordination modes in two typical conformations in these target coordination compounds. In cooperation with the auxiliary ligands benzenedicarboxylate connectors, a variety of Ni(II) coordination networks such as 2-D layer with (4, 4) topology (2) 1-D chain (3), honeycomb (4) and 2-D helical chains (5) have been assembled. Theoretical calculation based on density functional theory (DFT) for ligand (1) is also employed to explicate the stability of the different conformations. Moreover, thermal stability of these crystalline materials is explored by TG-DTG.     

Two new 2D copper(II) complexes constructed from a flexible bis-pyridyl-bis-amide ligand and two aromatic tricarboxylates: syntheses, crystal structures, fluorescence, and electrochemical properties

Two new 2D metal-organic complexes, namely [Cu(3-dpyb)(1,2,4-HBTC)(H₂O)]·H₂O (1) and [Cu₃(3-dpyb)₃(SIP)₂(H₂O)₈]·6H₂O (2) [3-dpyb?=?N,N??-bis(3-pyridinecarboxamide)-1,4-butane, 1,2,4-H₃BTC?=?1,2,4-benzenetricarboxylic acid, H₃SIP?=?5-sulfoisophthalic acid], have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction analyses. Single crystal X-ray analyses reveal that the two Cu(II) complexes show different 2D coordination networks, the 4-connected (4⁴·6²) topology for complex 1 and the (4·6²)₂(4²·6²·8²) topology for complex 2. In the 2D layers of complexes 1 and 2, the 3-dpyb ligands adopt a typical ?? ₂-bridging mode (via ligation of two pyridyl nitrogen atoms), while 1,2,4-HBTC and SIP serve as a linear spacer and a ??V??-like linker, respectively, to connect the adjacent Cu(II) centers. The adjacent 2D layers are extended to 3D supramolecular networks via hydrogen-bonding interactions. The fluorescence properties of both complexes and electrochemical properties of complex 2 have also been investigated. The complex 2 bulk-modified carbon paste electrode (2-CPE) displayed a one-electron redox wave in potential range of 600?C200?mV in 1?M H₂SO₄ aqueous solution, and 2-CPE showed good electrocatalytic activity toward the reduction of nitrite.     

Iron(II) closo-borate complexes with 1,2,4-triazole derivatives: Spin crossover in the iron(II) closo-borate complexes with tris(pyrazol-1-yl)methane

Methods of synthesis of iron(II) complexes containing cluster closo-borate anions—[Fe(Htrz)₃]B₁₀Cl₁₀ (I) (HTrz is 1,2,4-triazole), [Fe(NH₂Trz)₃]B₁₀Cl₁₀ · 2H₂O (II) (NH₂Trz is 4-amino-1,2,4-triazole), [Fe{HC(pz)₃}₂]B₁₀Cl₁₀ (III), [Fe{HC(pz)₃}₂]B₁₀H₁₀ (IV), and [Fe{HC(pz)₃}₂]B₁₂H₁₂ · 2H₂O (V) (HC(pz)₃ is tris(pyrazol-1-yl)methane)—have been developed. The compounds have been studied by the static magnetic susceptibility method (78–500 K) and electronic, IR, and EXAFS spectroscopy. Complexes I and II in the temperature range under consideration remain in the high-spin state. Low-spin complex III shows incomplete spin crossover and decomposes on heating above 440 K. Complexes IV and V are characterized by reversible spin crossover ¹ A ₁ ? ⁵ T ₂ accompanied by thermochromism (the pink ? white color change). The crossover temperature (T _c) for IV and V is 375 and 405 K, respectively.     

Single crystal X-ray analysis of isomeric 2-(2,4,4-trimethyl-3,4-dihydro-2h-benzo[h]× chromen-2-yl)-1-naphthyl acetate and 3-(2,4,4-trimethyl-3,4-dihydro-2H-benzo[g]× chromen-2-yl)-2-naphthyl acetate

Single crystal X-ray structure characterization of isomeric 2-(2,4,4-trimethyl-3,4-dihydro-2H-benzo[h]chromen-2-yl)-1-naphthyl acetate (1) and 3-(2,4,4-trimethyl-3,4-dihydro-2H-benzo[g]chromen-2-yl)-2-naphthyl acetate (2) is described. Compound 1 crystallizes in the centrosymmetric monoclinic space group P2₁/c with all atoms situated in general positions. Isomeric compound 2 crystallizes in the centrosymmetric triclinic space group P-1 and its structure consists of two crystallographically independent molecules with all atoms located in general positions. In addition to intramolecular C-H??O bonding, 2 is involved in two intermolecular C-H??O interactions resulting in a one-dimensional H-bonded network.     

Copper(II) malonate coordination frameworks with amino-1,2,4-triazole: Crystal structures and magnetic properties of [Cu2(mal)2(datz)2(H2O)]·5H2O and [Cu2(mal)2(atz)2(H2O)]·3H2O

Two new malonato-bridged copper(II) complexes of the composition [Cu₂(mal)₂(datz)₂(H₂O)]·5H₂O (1) and [Cu₂(mal)₂(atz)₂(H₂O)]·3H₂O (2) (mal = malonate, atz = 4-amino-1,2,4-triazole, datz = 3,5-diamino-1,2,4-triazole) are prepared and characterized by X-ray crystal structure determination and magnetic studies. The environment of each copper atom in 1 and 2 has distorted square pyramidal and octahedral geometries. The intrachain copper-copper separation is 6.305 Å and 3.640 Å across the carboxylates and trizolates bridges respectively for complexes 1 and 2. The magnetic properties of 1 and 2 are investigated in the temperature range 2–300 K. The overall antiferromagnetic behavior is observed in both cases.     

Synthesis and properties of ZnII and CdII complexes with chiral N-derivatives of aminoacetic acid based on natural monoterpenes (+)-3-carene and (?)-��-pinene. Crystal structure of coordination polymer [Zn(HL)Cl��2H2O] n

Chiral sodium salts of N-derivatives of aminoacetic acid based on (+)-3-carene (HLNa) and (?)-??-pinene (HLNa) were synthesized. Complexes Zn(HL)Cl (1), Cd(HL)Cl·0.5H₂O (3), Zn(HL??)Cl·0.5H₂O (4), and Cd(HL??)Cl·0.5H₂O (5) were obtained. The single crystals of the coordination polymer [Zn(HL)Cl·2H₂O] _n (2) were grown. According to the X-ray diffraction analysis, the crystal structure of 2 consists of 1D chains built of Zn(HL)Cl and water molecules. The coordination polyhedron ClN₂O₂ is a distorted square pyramid. The HL^? ligand performs the chelating tetradentate-bridging function, and the COO^? group binds two adjacent Zn atoms. The IR spectroscopy data for compounds 1 and 3?C5 indicate the coordination of the COO^?, NOH, and NH functional groups. The excitation and photoluminescence (PLM) spectra of the solid samples of compounds HLNa, HL??Na, 1, and 3?C5 were recorded at room temperature. The compounds exhibit blue PLM. The intensity of PLM of the CdII complexes is higher than that of the ZnII complexes, which is a characteristic feature of PLM of the studied compounds.     

Synthesis, crystal structures, and luminescence spectra of the coordination compounds of cadmium(II) iodide with hexamethylenetetramine

Coordination compounds [Cd_1.5I₃(HMTA) · H₂O] (I) and [CdI₂(HMTA) · H₂O] (II) are synthesized by the reaction of CdI₂ with hexamethylenetetramine (HMTA, C₆H₁₂N₄) with the 1: 1 ratio in ethanol, and their structures are determined. The crystals of compound I are triclinic, space group P $ \bar 1 $ , a = 8.027(1), b = 9.391(1), c = 10.382(1)?, ?? = 66.64(1)°, ?? = 86.18(1)°, ?? = 73.63(1)°, V = 749.2(1) ?³, ??_calcd = 3.136 g/cm³, Z = 2. The crystals of compound II are triclinic, space group P $ \bar 1 $ , a =7.713(1), b = 8.192(1), c = 12.101(1)?, ?? = 80.32(1)°, ?? = 89.57(1)°, ?? = 7.30(1)°, V = 725.0(1) ?³, ??_calcd = 2.402 g/cm³, Z = 2. Structure I includes two types of cadmium complexes. The Cd(1) atom is coordinated through the octahedral mode by three pairs of the I, N(HMTA), and O(H₂O) atoms. The coordination polyhedron of the Cd(2) atom is a distorted tetrahedron (three I atoms and one N atom). The structure contains infinite strips consisting of tetranuclear cyclic fragments joined by the Cd(1) atoms due to the bridging iodine and nitrogen atoms. In structure II, the Cd atom is coordinated through the tetrahedral mode by two iodide ions and the N(HMTA) and O(H₂O) atoms. The interaction between the complexes occurs due to hydrogen bonds O-H??N to form supramolecular chains along the direction [010]. In each HMTA molecule, one of four nitrogen atoms is a proton acceptor in the hydrogen bonds, one nitrogen atom is coordinated, and two N atoms are terminal. Compound II in the solid state has photoluminescence with maxima at 443, 470, and 518 nm.     

Dinuclear nickel(II) complexes with Schiff base ligands: syntheses, structures and bio-relevant catalytic activities

Three Ni(II) complexes of cresol-based Schiff-base ligands, namely [Ni₂(L¹)(NCS)₃(H₂O)₂], (1) [Ni₂(L²)(CH₃COO)(NCS)₂(H₂O)] (2) and [Ni₂(L³)(NCS)₃] (3), (where L¹ = 2,6-bis(N-ethylpyrrolidineiminomethyl)-4-methylphenolato, L² = 2,6-bis(N-ethylpiperidineiminomethyl)-4-methylphenolato and L³ = 2,6-bis{N-ethyl-N-(3-hydroxypropyl iminomethyl)}-4-methylphenolato), have been synthesized and structurally characterized by X-ray single-crystal diffraction in addition to routine physicochemical techniques. Density functional theory calculations have been performed to understand the nature of the electronic spectra of the complexes. Complexes 1?C3 when reacted with 4-nitrophenyl phosphate in 50:50 acetonitrile?Cwater medium promote the cleavage of the O?CP bond to form p-nitrophenol and smoothly convert 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) either in MeOH or in MeCN medium. Phosphatase- and catecholase-like activities were monitored by UV?Cvis spectrophotometry and the Michaelis?CMenten equation was applied to rationalize all the kinetic parameters. Upon treatment with urea, complexes 1 and 2 give rise to [Ni₂(L¹)(NCS)₂(NCO)(H₂O)₂] (1??) and [Ni₂(L²)(CH₃COO)(NCO)(NCS)(H₂O)] (2??) derivatives, respectively, whereas 3 remains unaltered under same reaction conditions.     

One-pot microwave-assisted solvent-free synthesis,theoretical and experimental studies on barrier rotation of C–N bond of N-alkenyl-1,2,3-triazoles

The reactions on benzotriazoles continue to happen to reach interesting varieties of their derivatives. This study reports a fast one-pot microwave-assisted solvent-free synthesis of N-alkenyl-1,2,3-benzotriazole (3, 5, and 7) and 1-(2-Alkyloxycarbonyl-vinyl)-1H-[1–3] triazole-4-carboxylic acid methyl ester (8 and 9) derivatives by nucleophilic addition reactions of 1,2,3-benzotriazole (C₆H₅N₃) (1) and 1H-[1–3] triazole-4-carboxylic acid methyl ester (C₄H₄N₃O₂) (1′) with R-propiolates (R = Me, Et; 2 & 4) and phenylacetylene 6 in good yields. The values of activation energy for rotation around C–N bond in the synthesized N-alkenyl-1,2,3-triazole compounds were studied by DFT-B3LYP/6-31G* method.     

3-(diallylamino)propanenitrile ((C3H5)2NC2H4CN, L) π-complexes with copper(I) ionic salts. Syntheses and crystal structures of compounds [Cu(H+L)ClO4]ClO4 · H2O, [Cu(H+L)BF4]BF4 · H2O, and [Cu(H+L)(H2O)]SiF6 · H2O

Qualitative single crystals of ??-complexes Cu(H⁺L)(ClO₄)]ClO₄ · H₂O (I), Cu(H⁺L)(BF₄)]BF₄ · H₂O (II), and [Cu(H⁺L)(H₂O)]SiF₆ · H₂O (III) are synthesized from solutions of 3-(diallylamino)propanenitrile (L) in propanol, ethanol, and methanol-water acidified with the corresponding acid to pH 3.5?C5 and from the copper(II) salts (Cu(ClO₄)₂ · 6H₂O, Cu(BF₄)₂ · 6H₂O, and CuSiF₆ · 4H₂O) using the alternating-current electrochemical method on copper wire electrodes. The crystal structures of the complexes are determined. All compounds crystallize in the monoclinic crystal system: complexes I and II are isostructural, space group P2₁/n, Z = 4. For compound III, space group P2₁/c, Z = 8. Unit cell parameters: for I a =7.8153(3), b = 16.7824(7), c = 12.4426(5) ?, ?? = 93.410(2)°, V = 1629.1(1) ?³; for II, a = 7.6755(4), b = 16.7119(7), c = 12.3784(6) ?, ?? = 94.354(2)°, V = 1583.2(1); and for III a = 9.826(2), b = 24.009(3), c = 12.061(2) ?, ?? = 91.820(6)°, V = 2843.9(7) ?³. The trigonal pyramidal coordination of the copper atom in complexes I-III is formed by two C=C bonds of the allyl groups of H⁺L, the nitrile N atom of the adjacent cation of the ligand, and the O or F atom of the ClO ₄ ^? or BF ₄ ^? anions. In structure III, the apical position of the pyramid is occupied by the O atom of the water molecule, since the SiF ₆ ^2? anion is considerably remote from the copper(I) atom. However, this anion is bound to the organic cation by hydrogen bonds F??H (2.05?C2.51 ?).     

Syntheses, characterization and crystal structures of new mono- and bis-Schiff base compounds derived from 1,2,4-triazine and the silver(I) complexes containing mono-Schiff base ligands

Some new Schiff bases, (Z)-4-amino-3-((E)-(R-methoxybenzylidene)hydrazono)-6-methyl-3,4-dihydro-1,2,4-triazin-5(2H)-one (R?=?2 (L2), R?=?3 (L3) and R?=?4 (L4)), were synthesized by the condensation reactions of 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5(4H)-one (L1) and corresponding methoxybenzaldehyde in a molar ratio 1:1.5 in high yields. The reaction of L2 and L4 with an excess amount of the corresponding aldehydes gave the unsymmetrical bis-Schiff bases (E)-3-((E)-(R-methoxybenzylidene)hydrazono)-4-((E)-R-methoxybenzylideneamino)-6-methyl-3,4-dihydro-1,2,4-triazin-5(2H)-one (R?=?2 (L22) and R?=?4 (L44)), respectively. Furthermore, the reaction of L2?CL4 with silver(I) nitrate in a molar ratio 2:1 led to the silver(I)-complexes with the general formula [Ag(Lx)₂]NO₃ (Lx?=?L2 (2), L3 (3) and L4 (4)). All synthesized Schiff base compounds and complexes were characterized by a combination of IR-, ¹H-NMR spectroscopy, mass spectrometry and elemental analyses. In addition, the structures of L2, L4·CH₃CN, L22·CH₃OH and L44·CH₃OH and complexes 2 and 4 were determined by X-ray diffraction studies.     

Syntheses and crystal structures of oxovanadium(V) complexes derived from N′-[1-(2-hydroxynaphthyl)ethylidene]-4-nitrobenzohydrazide and 2-hydroxy-N′-[1-(2-hydroxynaphthyl)ethylidene]benzohydrazide

Reactions of bis(acetylacetonato)oxovanadium(IV) with N??-[1-(2-hydroxynaphthyl)ethylidene]-4-nitrobenzohydrazide (H₂HNB) and 2-hydroxy-N??-[1-(2-hydroxynaphthyl)ethylidene]benzohydrazide (H₂HHB), respectively, product two oxovanadium(V) species with the formulas [VO(OMe)(HNB)]₂ (I) and [VO(OMe)(HHB)] (II). The complexes I and II have been characterized by elemental analysis, IR spectra, and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n, a = 8.208(2), b = 14.528(3), c = 16.418(3) ?, ?? = 97.887(3)°, V = 1939.3(7) ?³, Z = 2. The crystal of II is triclinic: space group P $P\bar 1$ a = 8.334(2), b = 10.236(2), c = 11.337(2) ?, ?? = 80.91(3)°, ?? = 75.41(3)°, ?? = 75.63(3)°, V = 902.0(3) ?³, Z = 2. Complex I is a methoxide-bridged dimeric oxovanadium(V) complex, and complex II is a mononuclear oxovanadium(V) complex. The V atom in I is in an octahedral coordination, and that in II is in a square pyramidal coordination.     

Syntheses,crystal structures,and magnetic properties of three one-dimensional metal–nitroxide complexes linked by 1,4-cyclohexanedicarboxylate ligands

Three one-dimensional metal–nitroxide complexes [Cu(NIT4Py)₂(1,4-chdc)] _n (1), {[Cu(IM4Py)₂(1,4-chdc)(H₂O)]·H₂O} _n (2) and {[Zn(IM4Py)₂(1,4-chdc)(H₂O)₂]·H₂O} _n (3) (NIT4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, IM4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 1,4-chdc = 1,4-cyclohexanedicarboxylate anion) have been synthesized and characterized structurally as well as magnetically. All three complexes crystallize in neutral one-dimensional chains in which the nitroxide–metal–nitroxide units are linked by linear 1,4-cyclohexanedicarboxylate anions. The 1,4-chdc ligands only present the e,e-trans-configuration in these complexes, although there are both cis- and trans-isomers in the free ligand. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the copper atoms and nitroxide radicals.     

Self-assembly of two 1D tube-like metal-organic networks based on flexible bis(benzimidazole) ligand and 5-nitroisophthalate

Two new polymeric networks, [Co(pbbm)(nip)] · H₂O (1) and [Ni(pbbm)(nip) · (H₂O)] (2) (pbbm = 1,1-(1,3-propanediyl)bis-1H-benzimidazole, H₂nip = 5-nitroisophthalic acid) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 is an interesting one-dimensional (1D) tube-like chain utilizing [Co₂(pbbm)₂] metallocycle as subunit. Complex 2 is also an interesting 1D tube-like chain based on [Ni₂(pbbm)₂] loop subunit. In the title complexes, the ??-?? stacking and H-bonding interactions extend the 1D tube into 3D supramolecular framework, respectively. The structural differences between the title complexes indicate the importance of metal ions for the creation of molecular architectures. Furthermore, the luminescent properties of 1 and 2 were investigated.     

5-(3,4-dichlorophenyl)-3-{[4-(2-pyridyl)piperazine-1-yl]methyl}-1,3,4-oxadiazole-2(3H)-one: Synthesis, characterization, X-ray and DFT structures

5-(3,4-Dichlorophenyl)-3-{[4-(2-pyridyl)piperazine-1-yl)]methyl}-1,3,4-oxadiazole-2(3H)-one C₁₈H₁₇Cl₂N₅O₂ (3) is synthesized and characterized by IR, ¹H NMR, ¹³C NMR, elemental analyses, single-crystal X-ray diffraction, and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). All data obtained from the spectral studies support the structural properties of 3. The molecules are linked principally by C-H??O hydrogen bonds involving carbonyl atoms and carboxylate O atoms, forming R ₂ ² (16) and R ₄ ² (20) rings that link to give a one-dimensional network of molecules. An extensive two-dimensional network of C-H??O hydrogen bonds and ?С??? interactions are responsible for crystal stabilization.     

First MnIII complexes with tetradentate (N2O2) Schiff bases and tricyanomethanide: synthesis,crystal structure,and magnetic properties

The first Mn^III complexes with Schiff bases and tricyanomethanide-anion were synthesized: [Mn(salen)C(CN)₃(H₂O)] (1), [Mn(5-Brsalen)C(CN)₃(H₂O)] (2), [Mn(salpn)C(CN)₃(H₂O)] (3), [Mn(3-MeOsalen)C(CN)₃(H₂O)] (4), [Mn(5-Brsalen)(MeOH)(H₂O)][C(CN)₃] (5), and [Mn(3-MeOsalpn)(H₂O)₂][C(CN)₃] (6), where SalenH₂ is N,N′-bis(salicylidene)ethylenediamine, 5-BrsalenH₂ is N,N′-bis(5-bromosalicylidene)ethylenediamine, SalpnH₂ is N,N′-bis-(salicylidene)-1,3-diaminopropane, 3-MeOsalenH₂ is N,N′-bis(3-methoxysalicylidene)-ethylenediamine, 3-MeOsalpnH₂ — N,N′-bis(3-methoxysalicylidene)-1,3-diaminopropane. The tricyanomethanide anion in complexes 1–4 acts as a the terminal ligand, whereas in complexes 5 and 6 tricyanomethanide is not coordinated by Mn^III and acts as an out-of-sphere counterion. The structures of complexes 1–4 are characterized by the formation of dimers due to hydrogen bonds between the water molecules and oxygen atoms of the Schiff bases. The Mn...Mn distances inside the dimers are 4.69–5.41 Å. Complex 6 has a zigzag chain structure consisting of the [Mn(3-MeOsalpn)(H₂O)₂]⁺ cations bound by double bridging aqua ligands. The study of the magnetic properties of complexes 1, 3, 4, and 6 showed the existence of antiferromagnetic interactions between the Mn^III ions through the system of hydrogen bonds.     

π-Complexes of copper(I) halides with 3-(allylamino)-(C3H5NHC2H4CN, Apn) and 3-(diallylamino)-((C3H5)2NC2H4CN, Dapn)-propanenitrile. syntheses and crystal structures of compounds [CuCl(Apn)], [(H+Apn)Cu2Cl3], [(H+Dapn)CuCl2], and [(H+Dapn)CuBr2]

The ??-complexes [CuCl(C₃H₅NHC₂H₄CN)] (I), [(C₃H₅NH₂C₂H₄CN)Cu₂Cl₃] (II), [((C₃H₅)₂NHC₂H₄CN)CuCl₂] (III), and [((C₃H₅)₂NHC₂H₄CN)CuBr₂] (IV) are obtained as single crystals by the ac electrochemical synthesis on copper wire electrodes from ethanolic solutions of 3-(allylamino)propanenitrile, 3-(diallylamino)propanenitrile, and CuX₂ (X = Cl, Br). Their crystal structures are determined. The crystals of compounds I, III, and IV are monoclinic, space group P2₁/c, Z = 4. The crystals of compound II are triclinic, space group P $\bar 1$ , Z = 2. The unit cell parameters are a = 11.125(4), b = 8.769(4), c = 8.570(4) ?, ?? = 90.94(4)°, V = 835.9(6) ?³ (I); a = 6.2566(4), b = 7.5975(6), c = 11.1251(8) ?, ?? = 90.896(6)°, ?? = 92.827(5)°, ?? = 94.340(5)°, V = 526.57(7) ?³ (II); a = 11.656(4), b = 6.992(4), c = 14.681(5) ?, ?? = 100.89(4)°, V = 1174.9(9) ?³ (III); a =11.845(4), b = 7.282(4), c=14.855(5) ?, ?? = 100.37(4)°, V = 1260.4(9) ?³ (IV). The coordination mode of the Cu(I) atom in complex I includes two halogen atoms, the C=C bond, and the secondary amine N atom. The coordination environment in isostructural crystals of complexes III and IV is formed by the C=C bond and three halogen atoms as in complex II.     

Syntheses, crystal structures, and characterization of four homochiral coordination polymers based on two chiral reduced Schiff base ligands

Four homochiral coordination polymers incorporating two chiral reduced Schiff base ligands, namely, [Cu(L¹)(H₂O)]·H₂O (1), [Zn₂(L²)₂] (2), [Co(L²)(H₂O)] (3), and [Ni(L²)(H₂O)] (4) (H₂L¹ = N-(4-carboxyl)benzyl-l-alanine, H₂L² = N-(4-carboxyl)benzyl-l-leucine) have been obtained by hydrothermal methods and characterized by physico-chemical and spectroscopic methods. X-ray crystallographic analysis reveals that complex 1 exhibits a chain structure with 1D channels. Complexes 2–4 all are 3D network structures with 1D channels in which the isobutyl group of the ligand points toward to the channel. Complex 2 displays strong photoluminescent emission in the purple region.     

Zero-, one- and two-dimensional bis-triazole-bis-amide-based copper(II) complexes tuned by polycarboxylates with different protonation degrees: assembly, structures and properties

Three bis-triazole-bis-amide-based copper(II) complexes with different dimensionality, [Cu(dtcd)₂ (1,3-HBDC)₂]·2H₂O (1), [Cu(dtcd) (1,3,5-H₂BTC)₂]·2H₂O (2) and [Cu₄(μ ₃-OH)₂(dtcd)₂(SIP)₂]·4H₂O (3) (dtcd = N,N′-di(4H-1,2,4-triazole) cyclohexane-1,4-dicarboxamide, 1,3-H₂BDC = 1,3-benzenedicarboxylic acid, 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid, NaH₂SIP = sodium 5-sulfoisophthalate), have been synthesized under different pH values and structurally characterized. Complex 1 exhibits a zero-dimensional mononuclear structure with one carboxyl group of 1,3-HBDC coordinating to copper(II), while the other carboxyl group is protonated. In complex 2, the Cu^II ions are bridged by the dtcd ligands forming a one-dimensional chain, in which only one carboxyl group of 1,3,5-H₂BTC coordinates with the metal, while the others are protonated. Complex 3 possesses a two-dimensional network based on tetranuclear Cu₄ clusters supported by the dtcd and nonprotonated SIP ligands. The various structures clearly indicate that the pH and polycarboxylates have a great influence on the dimensionality and structures of 1–3. The luminescence properties of 1–3 and magnetic properties of 3 were investigated.     

Syntheses,topological networks and properties of four complexes based on 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole ligand

Reactions of metal acetates with 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole (3-abpt) and co-ligands gave rise to four new complexes, namely [Zn₂(3-abpt)(beta)(DMF) (H₂O)₂]_n·nH₂O (1), [Zn(3-abpt)(ip)]_n·3nH₂O (2), [Zn(3-abpt)(ip)(H₂O)₂]_n·2nH₂O (3), and [Cu₂(3-abpt)₂(C₆H₅COO)₄(H₂O)₂]_n·2nH₂O (4) (ip = isophthalate, beta = 1,2,4,5-benzenetetracarboxylate). Compound 1 is a 3D coordination polymer with uncommon 3,4-connected (6².8)₂(6².8².10²) network. Compounds 2–4 are all 1D coordination polymers, which exhibit diversity structures. Compound 2 is a tubular-like chain, 3 is a ring-like network, and 4 is a zigzag chain. Their thermal stabilities and the photoluminescence of 1 have also been investigated.