SYNTHESIS AND STRUCTURE OF A POLYMERIC 1,3-BENZENEDICARBOXYLATO COMPLEX OF Mn(II) WITH PHENANTHROLINE

Abstract

A novel Mn(II) complex bridged by 1,3-benzenedicarboxylate (BDC) has been synthesized by the diffusion method. The complex crystallizes in space group P2₁/c with a = 8.345(2), b = 10.427(1), c = 18.756(2) Å, β = 100.19(1)°. Each BDC bridges three Mn(II) atoms through two carboxyl groups with different coordination modes to form a complex polymeric chain. The coordination geometry around the Mn(II) atom is seriously distorted from the normal octahedron. Large deviations of the donor atoms out of the coordination planes and unexpected bond angles around Mn(II) and donor O atoms suggest the existence of an electrostatic interaction between Mn(II) and donor atoms in the complex. Close stacking of aromatic rings is observed in the complex, the distance between the neighboring phen planes being 3.2085 Å.     

THE POLYMERIC COMPLEX 1, 10-PHENANTHROLINE-N,N'-(μ-NICOTINATO-N,O)DIAQUACOPPER(II) NITRATE DIHYDRATE

Abstract

The title complex has been prepared and its structure determined by X-ray diffraction methods. The complex crystallizes space group P2₁/a with a = 12.833(3), b = 10.443(2), c = 16.628(2)Å, β = 111.686(9)°. The nicotinate anions bridge adjacent Cu(II) atoms through both the pyridine N atom and the carboxyl O atom to form zigzag polymeric chains along the b axis. The carboxyl group of the nicotinate anion coordinates to the Cu(II) atom as a unidentate. Based on the molecular structure the infrared spectrum is discussed.     

THE POLYMERIC COPPER(II) COMPLEX 1, 10-PHENANTHROLINE -N,N '-(μ-ISONICOTINATO-N,O) MONOAQUACOPPER(II) NITRATE DIHYDRATE

Abstract

The title complex has been prepared and its structure determined by X-ray diffraction. The complex crystallizes in space group C2/c with a = 26.892(5), b = 10.479(4), c = 14.179(2) Å, β = 98.59(2)°. Isonicotinate anions bridge adjacent Cu(II) atoms through the pyridine N atom and the carboxyl O atom to form zigzag polymeric chains along the b axis. The carboxyl group of the isonicotinate anion coordinates to the Cu(II) atom as a unidentate. Based on the molecular structure the infrared spectrum is discussed.     

Synthesis and Crystal Structure of a 1,3-Benzenedicarboxylatomanganese(II) Complex with 2,2-Bipyridine

The title complex has been prepared by the reaction of Mn(2,2'-bipy)Cl 2 with 1,3-benzenedicarboxylate (BDC) in ethanol solution. The complex crystallizes in space group C 2/ c with a =13.847(6), b =15.629(7), c =17.106(6) Å, g =107.90(3)° and z =8. Three BDC and one bipy ligands coordinate to Mn(II) to form a distorted octahedron. Each BDC bridges three Mn(II) atoms to form a polymeric chain. It is notable that although the Mn(II) atom deviates 1.084 Å from the bridging carboxyl plane it still has a normal coordination distance of 2.141(2) Å. This might suggest an electrostatic interaction between Mn(II) and carboxyl O atoms in the title complex. The IR spectrum is discussed, based on the molecular structure.     

Synthesis and Crystal Structure of a Polymeric Benzimidazole Complex of Mn(II) Bridged by Succinate

The title complex has been prepared and its crystal structure determined by X-ray diffraction methods. The Mn (II) complex is seven coordinate with two benzimidazole (bimid)ligands in axial positions and two succinate and one bimid ligands in the equatorial plane. The succinate bridges Mn (II) atoms to form polymeric chains, linked by intermolecular H-bonding. Free bimid molecules occur in the crystal structure; they link Mn (II) complexes with H-bonds involving N atoms. Aromatic stacking between bimid rings is observed, resulting in a gauche confirmation of succinate in the structure. The IR spectrum is assigned based on the crystal structure. The difference of 139cm^-1 between symmetric and asymmetric stretching vibrations of carboxyl groups is in line with seven coordination at the Mn (II) atom.     

Structure of a Polymeric Mn(Ⅱ) Complex Bridged by Benzenetetracarboxylate

The single crystals of the title compound were obtained from a reaction of MnCO3,benzenetetracarboxylic acid (H4BTC)and imidazole in an aqueous solution.The crystal of Mn(II)complex (C28H34Mn2N12O12(4H2O,Mr=912.62) belongs to tricli nic,space group Pī with a=10.036(1),b=10.650(1),c=11.102(1)A,α=114.72(2),β=95.75(1),γ=108.46(2)°,V=984.2(2)A3,Z=1,Dc=1.540 g/cm3,F(000)=472,μ(MoKα)=0.726 mm-1,R=0.0409 and wR=0.1166 for 3909 observed reflections (I>2σ(I)).The crystal consists of the polymeric Mn(II)complex anions and discrete Mn(II) complex cations,both with normal octahedral coordination geometry.Each BTC bridges two Mn(II) atoms to form the anionic polymeric chain,and the cations distribute be-tween the chains and link them through both classic and weak C-H…O H-bonding.     

Crystal Structure and Magnetic Exchange in the Single Chloride‐Bridged Copper(II) Chain Compound [CuCl2(TzHy)] [TzHy = (4,5‐dihydro‐1,3‐thiazol‐2‐yl)hydrazine]

The copper complex [CuCl₂(TzHy)] has been synthesized and its crystal structure determined. The coordination complex contains polymeric [CuCl₂(TzHy)]_n chains in which the units are linked by μ‐chloro bridges. The chains run along the crystallographic c axis. The geometry around the copper(II) is best described as distorted square pyramidal. The equatorial positions are occupied by Cl(1) and Cl(2) ligands and one thiazolinic nitrogen atom and another hydrazinic nitrogen atom, from TzHy ligand. The axial position is occupied by the Cl(2b) ligand. The magnetic susceptibility measurements in the temperature range 4 – 290 K show a weak antiferromagnetic intrachain interactions (J = ?8.6 cm^?1).     

SYNTHESIS AND CRYSTAL STRUCTURE OF A MANGANESE(II) COMPLEX,Mn(phen)2(phcoo)2 2HzO

Abstract

The title complex has been prepared by the reaction of Mn(phcoo)2 with phen in EtOH/H₂O solution (where phcoo = the anion of benzoic acid, phen= 1,10-phenanthroline). The crystal structure has been determined by X-ray diffraction. The complex molecule has distorted octahedron geometry. Carboxyl O atoms coordinate to Mn(II) from unidentate ligands with a cis-configuration. Two uncoordinated O atoms of benzoate anions locate on the one side of the coordination plane so that there is free space on the other side of the plane; such a spatial arrangement may promote the attack of a water molecule at the manganese atom in the oxygen evolution process in photosystem II.     

Synthesis and Crystal Structure of an Azido-Bridged Cadmium(II) Dimer [L2Cd2(μ-N3)2(N3)2] (L=1,4,7-Triazacyclononane)

A new dinuclear Cd(II) complex, [L₂Cd₂(μ-N₃)₂(N₃)₂], containing two end-on bridging azide ligands, two monodentate N₃ ligands and 1,4,7-triazacyclononane as the capping ligand, has been synthesized and its structure determined by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/c with a=8.467(3), b=14.359(5), c=10.115(4)Å, β=95.026(6)° and z=4. The cadmium(II) centre is six-coordinate with distorted octahedral geometry, bonded to three N atoms of the 1,4,7-triazacyclononane, two nitrogen atoms of μ-azide bridges and one nitrogen atom of a monodentate azide ligand. Neighboring Cd(II) atoms are linked by the double end-on azide bridges.     

A POLYMERIC COMPLEX OF MANGANESE(II) AZIDE CONTAINING ALTERNATE END-ON AND END-TO-END BRIDGING AZIDO LIGANDS Synthesis,Structural, Spectroscopic and Thermal Study of [Mn(N3)2 (Ethyl Nicotinate)2]n

Abstract

A mixed ligand 1:2 manganese(II) azido complex of ethyl nicotinate has been synthesized and characterized by spectroscopic and crystallographic methods. The structure consists of a two-dimensional manganese-azido compound with each manganese atom in a trans octahedral environment, bonded to four azido ligands [Mn?N = from 2.199(4) Å to 2.231(3) Å] and two axial ethyl nicotinate ligands [Mn-N = 2.285(3) and 2.308(3) Å]. Two azido ligands are coordinated end-on between the manganese atoms giving planar and centrosymmetric Mn₂N₂ units. Each Mn₂N₂ unit is linked to four neighboring Mn₂N₂ units by means of four end-to-end azido bridges. The IR and Raman spectra correlate with the structure of the complex. The vibrational bands are compared with those of the free ligand. The EPR spectra of polycrystalline powder and solutions of the complex are measured at room temperature and discussed. The thermal decomposition of the complex was investigated derivatographically under nitrogen.     

CRYSTAL STRUCTURE AND PROPERTIES OF A COPPER(II) COMPLEX OF AN 18-MEMBERED MACROCYCLIC LIGAND WITH N,N' -DICARBOXYLIC ACID ARMS

Abstract

CuL 5H₂O (H₂L = 1, 15-diaza-3, 4; 12, 13-dibenzo-5, 8, 11 -trioxacyclo-octadecane-N,N′-diacetic acid) crystallized from water. Its crystal structure was determined by X-ray diffraction analysis and refined in space group Pnma, a = 20.1784(11), b = 15.8745(9), c = 8.9266(5)Å, V = 2859.4(3)ų, Z = 4, ?(MOKα) = 0.71073, R_W . = 0.0294 for 1822 observed reflection [I > 2[sgrave](I)]. The copper atom is surrounded by two nitrogen atoms, two oxygen atoms from the carboxyl groups in the ligand and one oxygen atom from a coordinated water to form a distorted square pyramidal arrangement. The three ether oxygen atoms in the cycle have no contact with the copper ion.

The stability constant for the 1 :1 complex of copper(II) and protonation constants for the ligand have been determined by potentiometric titration in water (I = 0.1, KNO₃) at 25°C. Electronic spectra, conductivity measurements, thermal analysis, and the EPR of the complex are discussed in terms of the crystal structure.     

DIRECT SYNTHESIS OF LEAD(II) COMPLEXES WITH TRIETHANOLAMINE USING LEAD(II) OXIDE AS STARTING MATERIAL

Abstract

A number of lead(II) complexes containing triethanolamine (L) is reported. The compounds were identified and characterized by chemical analyses and IR investigations. The crystal structure of bis(triethanolamine)lead(II) acetate was determined by X-ray crystallographic analysis. The compound crystallizes in space group C2/c with a = 10.373(2), b = 16.079(2), c = 13.707(3) Å, β = 99.36(2)°, V = 2255.7 ų, Z = 4, d(calculated) = 1.84 g cm^?3. The structure was refined by least-squares methods to a final value of the R of 0.025 for 3185 reflections with I > 3σ(I). The complex consists of eight coordinated [PbL₂]²⁺ cations and two CH₃COO^? anions joined together by hydrogen bonds between the oxygen atoms of the carboxyl groups and the hydroxyl hydrogens of ligands. The lead atom lies on a two-fold rotation axis and the structure of the coordination polyhedron is a distorted trigonododecahedron.     

Synthesis and structural characterization of a new polymeric zinc(II) complex with thiophene-2-carboxylic acid

A new polymeric zinc(II) complex with thiophene-2-carboxylic acid (α-tpc) of composition [Zn₂(C₂₀H₁₂O₈S₄)] _n was obtained and structurally characterized by X-ray diffraction, thermal analysis, nuclear magnetic resonance (NMR), and infrared spectroscopies. Upfield shift in the ¹H-NMR spectrum is explained by the crystalline structure, which shows the thiophene rings overlapping each other in parallel pairs. The compound crystallizes in the monoclinic system, space group P2₁/c, with a = 9.7074(4) Å, b = 13.5227(3) Å, c = 18.9735(7) Å, β = 95.797(10)°, and Z = 4. Three α-tpc groups bridge between two Zn(II) ions through oxygens and the fourth one bridges between one of these ions and the third one, symmetry related by a twofold screw axis. This arrangement gives rise to infinite chains along the crystallographic a direction. The metal atoms display an approximate tetrahedral configuration. The complex is insoluble in water, ethanol, and acetone, but soluble in dimethyl sulfoxide.     

Synthesis and Crystal Structure of BIS(Imidazole)(µ-Succinato) Manganese(II)

The title complex was prepared by reaction of succinatomanganese(II) with imidazole in water-ethanol. The complex crystallizes in orthorhombic space group Pna 2 1 with a = 7.9990(15), b = 14.8690(15), c = 11.028(2) Å. The metal assumes a distorted octahedral coordination. In the crystal, each succinate dianion bridges three Mn(II) atoms to form a polymer with a layered structure.     

DTPA-BpABA与锰配合物的结构表征和弛豫研究

X-ray single crystal analysis of a new paramagnetic manganese（Ⅱ） complex with DTPA-BpABA （a DTPAbisamide derivative）, Mn（DTPA-BpABA）·4H2O, shows that four oxygen atoms and three nitrogen atoms from the ligand coordinate to Mn（Ⅱ） cation, forming a seven-coordinate distorted pentagonal bipyramid polyhedron. In the crystal, the carboxyl groups and the nitrogen atoms extensively form hydrogen bonds with the lattice water molecules, building a 3D-network. The relaxometric study indicates that the R1 value of the paramagnetic manganese（Ⅱ）complex is 5.12 mmol·L·s^-1. The higher R1 value means that this complex may find an application in magnetic resonance imaging （MRI） technique.     

Synthesis,Characterization and Crystal Structure of （2,2′—Bipyridine）（μ—maleato）copper（Ⅱ）Dihydrate

The title polymeric complex [Cu(C₄H₂O₄)(C₁₀H₈N₂)]_n·2nH₂O was prepared and its crystal structure was determined by X‐ray diffraction methods. The crystal belongs to space group P2₁/c with cell dimensions of a = 1.0104(1), b = 1.9952(2), c = 0.7357(2) nm, β= 98.38(2)° and Z = 4. The complex forms zig‐zag chains along crystallographic axis c via Cu—O (carboxyl) bond in the apical direction. Each repeated unit consists of a square pyramidal Cu(II) centre with one maleate dianion and one 2,2′‐bipyridine forming a basal plane. Adjacent chains link to each other by H‐bonding between carboxyl groups and crystalline water. The distance of 0.3482 nm between parallel bipyridine rings shows a π‐π stacking interaction. The title complex was also characterized by IR, UV and ESR spectra.     

A helical polymeric complex,tris(benzimidazole)nickel(II) (μ-maleato)

The title polymeric complex [Ni(C₇H₆N₂)₃(C₄H₂O₄)] _n has been prepared and its crystal structure determined by single-crystal X-ray diffraction methods. The complex is orthorhombic, space group P2₁2₁2₁ with a?=?9.320(1), b?=?12.015(1), c?=?20.964(2)?Å. Three benzimidazole (bzim) and two maleate dianions coordinate to the Ni(II) atom with distorted octahedral geometry. Maleate dianions bridge neighbouring Ni(II) atoms through terminal carboxyl groups, one in monodentate and the other in chelate mode, to form polymeric molecular chains extending along the a axis. The structure is chiral, the Flack index of 0.002(10) suggesting that the helical polymeric chain is right-handed. Both intra-helical and inter-helical N–H···O hydrogen bonding occurs between bzim and carboxyl groups of maleate. The partially overlapped arrangement of nearly parallel bzim rings suggests the existence of π–π stacking in the crystal.     

Synthesis, crystal structure, and fluorescence property of a thiocyanato-bridged polymeric cadmium(II) complex derived from (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine

A new thiocyanato-bridged polymeric cadmium(II) complex with the Schiff base ligand (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine (L) derived from 2-acetylpyridine and 2-aminomethylpyridine has been prepared and characterized by elemental analyses, IR spectrum, and single crystal X-ray crystallographic determination. The complex crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 8.904(2), b = 12.041(2), c = 15.550(3) Å, β = 92.354(2)°, V = 1665.7(5) ų, Z = 4, R ₁ = 0.0523, and wR ₂ = 0.1274. The Schiff base ligand coordinates to the Cd atom through the three N atoms. The Cd atom of the complex is heptacoordinated by the Schiff base ligand in a tridentate fashion, one nitrate ligand in a bidentate fashion, and one N and one S atoms from two thiocyanate ligands. The overall coordination is pseudopentagonal bipyramidal geometry. The fluorescence property of the complex was investigated.     

SYNTHESIS AND STRUCTURES OF DICHLOROTETRAKIS-(PHENYLTHIOUREA) CADMIUM(II) AND CATENA-BIS(THIOCYANATE) BIS(PHENYLTHIOUREA)CADMIUM(II)

Abstract

Two new cadmium(II) complexes with phenylthiourea (PTU), namely Cd(PTU)₄Cl₂ (1) and [Cd₂(NCS)₂(μ₂-SCN)₂(PTU)₂(μ₂-PTU)₂] _n (2), have been prepared and characterized structurally by X-ray diffaction. Complex 1 crystallizes in the monoclinic space group C2/c, with a = 27.057(13), b = 8.108(3), c = 16.751(8) Å, β = 114.46°, V = 3345(3) ų, Z = 4. Complex 2 crystallizes in the triclinic space group P-1, with a = 9.336(3), b = 14.686(5), c = 16.911(5) Å, α = 71.36(2), β = 84.31(2), γ = 72.470(10)°, V = 2095.0(12) ų Z = 4. The structural analysis shows that each metal atom in both the mononuclear complex 1 and polynuclear complex 2 is octahedrally coordinated by four sulfur atoms and two chloro ligands or two nitrogen atoms from the thiocyanate groups, respectively. The PTU ligand can serve as either a monodentate ligand or a μ₂-bridging ligand upon coordination to a metal atom.     

Synthesis and crystal structure of polymeric aqua (2,2′-bipyridine)(μ-isonicotinato)copper(II) nitrate dihydrate

The title complex has been prepared and its crystal structure determined by X-ray diffraction methods. The complex crystallizes in the monoclinic space group P2₁/c. Cu(II) assumes a square pyramidal coordination geometry, formed by two isonicotinate anions, a bipyridine ligand and a coordinated water molecule. Each isonicotinate bridges two Cu atoms through pyridine-N and carboxyl-O atoms, respectively, to form zigzag polymeric chains. Between the polymeric chains, aromatic stacking and hydrogen bonding are observed.