Search

A new disulfoxide-La(III) complex {[La(L)2(DMF)4](ClO4)3} n (1) has been prepared by the reaction of La(ClO4)3 · nH2O and a flexible disulfoxide ligand, 1,6-bis(ethylsulfinyl)hexane (L), and characterized by elemental analysis, IR and single-crystal X-ray diffraction analysis (monoclinic system, space group C2/c, with a = 24.94(2), b = 12.012(8), c = 20.81(1) A, β = 117.57(1)°, V = 5527(6) A3 and Z = 4). The crystal structure consists of polymeric chains of {[La(L)2(DMF)4]3+} n cations and anions. In the cation of 1, each La(III) center is coordinated to eight O atoms from four distinct L ligands and four DMF molecules to give a square antiprism coordination geometry. The adjacent two La(III) ions are linked by two L ligands, which adopt bis-monodentate O-coordination bridging mode to form a double-bridging zigzag chain containing 22-membered macrocycles.

Ten disulfoxide−CuII coordination architectures, {[Cu(meso-Lb1)2(ClO4)](ClO4)}n (1B), [Cu(meso-Lb2)2(ClO4)2]n (2B), [Cu(rac-Lb3)2(ClO4)2]n (3B), {[Cu(meso-Lb3)3](ClO4)2}n (3B‘), [Cu(meso-Lc1)2(ClO4)2]n (1C), [Cu(meso-Lc2)2(ClO4)]2(ClO4)2(CHCl3)2 (2C), {[Cu(meso-Lc3)2(ClO4)](ClO4)}n (3C), [Cu(meso-Ld1)2(ClO4)2]n (1D), {[Cu2(rac-Ld2)4(ClO4)2](ClO4)2(CHCl3)}n (2D), and [Cu(rac-Ld3)2(ClO4)2]n (3D), were obtained by the reaction of Cu(ClO4)2 with nine structurally related flexible disulfoxide ligands, RS(O)(CH2)nS(O)R (n = 2−4; R = −CH2CH3, −CH2CH2CH3, −CH2CH2CH2CH3 for Lbn-1, Lcn-1, and Ldn-1, respectively) in the presence of dehydrating reagent (diethoxyethane) in acetone/chloroform. The X-ray crystal structural analyses of the complexes revealed that all of them display a 2-D network structure, except for 2B and 2C, which display a one-dimensional and a dinuclear cage structure, respectively. All 2-D systems have a (4,4) topological arrangement with different conformations, except for 3B‘, which has a (3,6)...

Four new disulfoxide-LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3·nH2O with meso-1,3-bis(ethylsulfinyl)propane (meso-L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the LaIII ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2–4 have isostructural dinuclear structures, in which the LnIII ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso-configuration, and monodentate coordination with a rac-configuration. The structural differences between 1 and 2–4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Two new coordination polymers, [Eu2(L)3(H2O)2]n 1 and {[Tb2(L)3(H2O)2]·H2O}n 2, (H2L=succinic acid) have been synthesized by the reaction of H2L with nitrate salts of Eu(III) or Tb(III) under hydrothermal conditions. The X-ray diffraction analysis reveals that the two complexes are constructed by L bridging the chains of edge-sharing EuO8(H2O) or TbO8(H2O) polyhedra to form 3D network structure. 1 and 2 possess different topological structures due to the difference in the conformations of L. The solid photoluminescence of 1 and 2 was also investigated in room temperature.

The self-assembly of a flexible disulfoxide ligand, meso-1,2-bis(ethylsulfinyl)ethane (L) with AgClO4 led to the formation of a novel tetra-nuclear complex, {[Ag2(O,O-L)(μ-O-μ-(SO)-L)2(ClO4)]ClO4}2, in which the AgI ions exhibit two kinds of coordination modes: trigonal–bipyramidal and octahedral, and the ligands take bidentate (O,O) chelating and tridentate μ-O-μ-(SO) bridging-chelating coordination modes. Such a ligand coordination mode is unprecedented in the metal-complexes of disulfoxides.

A new dithioether silver(I) complex, {[Ag(L)1.5]NO3}n (1) has been prepared by the reaction of AgNO3 with 1,3-bis(benzylthio)propane (L) in methanol/chloroform. The structure was characterized by single-crystal X-ray diffraction analysis: rhombohedral system, space group R −3c, with a =b = 15.651(7), c = 39.26(4) A, V = 8328(1) A3, and Z = 6. The crystal structure consists of [Ag(L)1.5]+ cations and NO3− anions. In 1, each silver(I) center is coordinated equivalently to three sulfur donors from three different ligands to give a trigonal-planar coordination geometry. Each L links two adjacent silver(I) centers in bis-monodentate bridging mode to form a 2D (6,3) network sheet. Furthermore, these 2D sheets are linked by the weak coordination interactions between nitrate ions and silver(I) atoms to form a 3D brick-wall framework.

A new trisulfoxide ligand, 1,3,5-tris(ethylsulfinyl)-2,4,6-trimethylbenzene (L), was designed and synthesized, and treated with Ln(NO3)3 or Ln(ClO4)3 to produce three coordination polymers: [Ln(L)(MeOH)(NO3)3]n [where Ln = LaIII (1); NdIII (2)] and {[La(L)(DMF)5](ClO4)3}n (3). Solid-state structures of all three complexes were determined by single-crystal X-ray diffraction. The three complexes have 1D helical-chain structures and complexes 1 and 2 are isostructural. To the best of our knowledge, these coordination polymers are the first examples of (trisulfoxide)metal complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Two novel dimeric palladium(II) complexes with flexible pyridyl dithioether bridging ligands, [Pd(L1)Cl2]2 (1) and [Pd(L2)Cl2] (2), where L1=1,3-bis(2-pyridylthio)propane and L2=1,3-bis(4-pyridylthio)propane, have been synthesized and structurally characterized by X-ray diffraction analyses. In both complexes, each PdII center is four-coordinated in the trans-form by two chloride anions and two nitrogen donors from two distinct ligands. Complex 1 exhibits a unique 20-membered metallomacrocyclic structure with twisted conformation, while 2 shows a dinuclear 28-membered metallomacrocycle with planar conformation. In addition, there are weak C-H Cl or C-H S hydrogen bonding interactions in both complexes, resulting in different 3-D supramolecular architectures.

In our efforts to systematically investigate the influences of terminal groups, ligand spacers, and counteranions on the framework formations of the AgI complexes with thioether ligands, four structurally related flexible N-containing heterocyclic thioethers, bis(benzothiazol-2-ylsulfanyl)methane (L1), 1,3-bis(benzothiazol-2-ylsulfanyl)propane (L2), 1,4-bis(benzothiazol-2-ylsulfanyl)butane (L3) and 1,5-bis(benzothiazol-2-ylsulfanyl)pentane (L4), and seven new AgI complexes of these ligands, [AgL1(NO3)]∞ 1, {[AgL1](ClO4)(H2O)}2 2, {[AgL2(NO3)](CHCl3)}2 3, {[AgL3](ClO4)}∞ 4, {[AgL3](BF4)}∞ 5, {[AgL4(NO3)]CHCl3}2 6, and {[AgL4(ClO4)]2}∞ 7, have been synthesized and characterized. The crystal structures of these complexes show that all the other complexes except 4 and 5 form ligand-supported dinuclear clusters, and in 1 and 7 the dinuclear cluster units are further linked by anions to form 1D chains, and complexes 4 and 5 exhibit 1D zigzag chain structures. Furthermore, these ligands coordinate to AgI ions in...

To investigate the influences of ligand spacers of flexible bis(thioether) bridging ligands on the framework formations of their complexes, six new AgI coordination compounds with a series of structurally related bis(tert-butylthio)alkane ligands, Ln = (CH3)3CS-(CH2)n-SC(CH3)3 where n = 1−6, [(AgL1)ClO4]n (1), {[Ag(L2)1.5]ClO4}n (2), [(AgL3)ClO4]2 (3), {[Ag(L4)1.5]ClO4}n (4), [(AgL5)ClO4]2 (5), and {[Ag(L6)1.5]ClO4}n (6), have been synthesized and structurally characterized by elemental analysis, IR, 1H NMR spectra, and X-ray crystallography. In 1, the AgI centers are linked by bridging L1 to form a one-dimensional (1-D) zigzag chain, and complex 2 has an extended two-dimensional (2-D) (6,3) topologic array with hexagonal 30-membered macrometallacycles. Complexes 3 and 5 show similar discrete dinuclear structures. Complexes 4 and 6 consist of single-double bridging chains in which dinuclear macrometallacycles are further linked by single bridging L ligands. The differences among these structures indicate ...

A new flexible disulfoxide ligand 1,6-bis(benzylsulfinyl)hexane (L), which is a mixture of the meso and rac isomers, was treated with CuII or CdII nitrate and obtained dimeric complex [Cu2(L)3(H2O)2(NO3)4] 2 or [Cd2(L)3(H2O)2(NO3)4] 3. In the reacting system the crystals of meso isomer 1 of L together with 2 or 3 were obtained. 2 and 3 have similar molecular structures. In the neutral dimer, three ligands present two kinds of coordination models: monodentate and bis-monodentate. The neutral dimeric units in 2 and 3 are linked by hydrogen bonds to yield a chain structure. Crystal structures of all three compounds were determined by single-crystal X-ray diffraction methods. Crystal data for 1: monoclinic, space group Cc, a=41.95(2), b=5.132(2), c=8.660(4) A, β=94.898(9)°, V=1857.7(15) A3, Z=4, final refinement (I>2σ(I)): R1=0.0659, wR2=0.1415. Crystal data for 2: triclinic, space group P–1, a=9.242(4), b=9.539(4), c=21.042(9) A, α=83.888(9), β=87.971(8), γ=74.177(9)°, V=1774.6(13) A3, Z=2, final refinement (I>2σ(I)): R1=0.0577, wR2=0.0954. Crystal data for 3: triclinic, space group P–1, a=9.203(4), b=9.831(3), c=20.860(7) A, α=84.313(6), β=86.432(7), γ=74.188(6)°, V=1805.9(11) A3, Z=2, final refinement (I>2σ(I)): R1=0.0548, wR2=0.1192.

Two silver(I) coordination architectures with the flexible ligand 1,6-bis(phenylthio)hexane (L) have been synthesized and their crystal structures determined by X-ray diffraction analysis. Different frameworks were observed in the two complexes due to variation of the counter anions. The dinuclear complex [Ag(L)(ClO4)]2 (1) has a cage structure with the perchlorate anions coordinated to the two silver(I) ions in a rare η2 bridging mode. However, in the complex [Ag(L)(NO3)]n (2) there is a 2D network with monatomic bridging nitrate anions. The results show the great influence of counter anions on building metal–organic supramolecular structures. In addition, the different conformations of the flexible ligand L in the frameworks of 1 and 2 indicate its ready adaptability to various coordination environments.

The reactions of a series of nitrogen-containing heterocyclic thioether ligands, 2,2′-[methylenebis(thio)]bis(pyrimidine) (L1), 2,2′-[1,2-ethanediylbis(thio)]bis(pyrimidine) (L2), 2,2′-[methylenebis(thio)]bis[5-methyl-1,3,4-thiadiazole] (L3) and 2,2′-[1,2-ethanediylbis(thio)]bis[5-methyl-1,3,4-thiadiazole] (L4), with silver(I) nitrate or silver(I) perchlorate salt led to the formation of five new metal–organic supramolecular architectures from dinuclear to three-dimensional structures. All the structures were determined by single-crystal X-ray diffraction analysis. In the crystal structures of the five complexes, a variety of coordination modes of AgI have been observed, probably due to the variation of the chain length of the linker unit or the terminal groups as well as the counter anions, which indicates that the nature of the ligands is a determining factor in controlling the structural topologies of such metal–organic supramolecular architectures. Geometrical effects seem to be more important than electronic effects in these systems, leading the AgI centre to prefer to coordinate to N donors first rather than S donors despite AgI being a ‘soft’ metal.

A new dithioether palladium(II) complex {Pd[PhS(CH 2 ) 5 SPh]Cl 2 } n ( 1 ) has been prepared by the reaction of PdCl 2 and bis(phenylthio)pentane [PhS(CH 2 ) 5 SPh, bptf] in acetonitrile/chloroform (1:1), and structurally characterized by X-ray crystallography. It crystallized in orthorhombic system, space group Pbcn , with a =9.744(3), b =14.452(4), c =27.393(8) A, and Z =8. There are two palladium(II) ions in the same structure unit and each is coordinated by two chloride anions and two sulfur atoms of two distinct ligands in trans positions, forming a rhombic planar geometry. The flexible bptf ligand acts as bridge to link palladium(II) ions to form a coordination polymer with one-dimensional chain structure.

A series of novel silver-thioether metal-organic supramolecular architectures forming different frameworks are constructed by the direct reactions of Ag I perchlorate with a series of di- or trithioether ligands which are closely related in structure. In the crystal structures of the four complexes, a variety of coordination modes of the Ag I centers due to the conformation freedom or steric hindrance have been observed, indicating that the nature of the ligands is a determining factor in controlling the structural topology of the metal-organic supramolecular architectures.

Two new platinum(II) complexes with dithioether ligands, cis-[Pt(L1)Cl2] (1) and cis-[Pt(L2)Cl2]2 (2), where L1=1,3-bis(phenylthio)propane and L2=1,5-bis(n-propylthio)pentane, have been synthesized and structurally characterized by X-ray diffraction analyses. In 1, the Pt(II) center is four-coordinated and forms a six-membered chelated ring with L1, while 2 exhibits a unique di-nuclear structure containing a 16-membered metallomacrocyles with chair-shaped conformation, in which each Pt(II) center is coordinated by two chloride anions and two sulfur-donors from two L2 ligands.

Two NiII complexes of 1,5-diazacyclooctane (DACO), [Ni(DACO)2]Br2 (I) and [Ni(DACO)2]Br·ClO4 (II) have been newly synthesized and characterized. Single crystal X-ray diffraction analysis of DACO and both NiII complexes reveals that DACO takes boat/chair conformation in the solid state and its NiII complexes. In complex I, NiII ion is at the center of symmetry, which is four-coordinated by nitrogen donors of DACO. However, in complex II, an unexpected coordination mode of [M(DACO)2]2+ (M=CuII and NiII) was found, in which two DACO ligands are related to each other by a mirror plane and the coordination sphere of NiII is a distorted planar geometry. Furthermore, complexes I and II form quite different packing patterns (macrocycle or chain) through hydrogen bonds, which may be a key role to stabilize the crystals. The results of theoretical calculation indicate that complex I has thermodynamic stability, while II has chemical stability. Therefore, both of them have the probability to be obtained from different reaction processes or conditions.

Two novel diazamesocyclic ligands based on l,5-diazacyclooctane (DACO) and functionalized with additional pyridyl donor groups, namely 1,5-bis(2-pyridylmethyl)-1,5-diazacyclooctane (L1) and 1-(2-pyridylmethyl)-1,5-diazacyclooctane (L2), have been synthesized and characterized, as have their CuII complexes. Crystal structure analyses revealed that with Cu(ClO4)2L1 forms a five-coordinate mononuclear complex [CuIIL1Cl]ClO4 (1), whereas L2 forms a µ-Cl−-bridged dinuclear complex [CuII(L2)Cl]2(ClO4)2 (2). Furthermore, it has been found that the apical chloride anion of 1 may be easily exchanged by azide anion, forming the mononuclear complex [CuIIL1(N3)]ClO4 (3). There is a notable difference between 3 and 1 in that 3 forms a quasi-two-dimensional network through intermolecular C−H···O hydrogen bonds and π−π stacking interactions. Each CuII center in the three complexes is pentacoordinated in a distorted square-pyramidal environment and the DACO ring of each ligand adopts a boat-chair configuration in all the complexes. In the mononuclear complexes 1 and 3, the Cl− or N3− anions occupy the apical sites, whereas in the dinuclear complex 2 the two bridging Cl− anions occupy both axial positions as well as one equatorial position, leading to an intramolecular Cu···Cu separation of 3.396 A. Variable-temperature magnetic susceptibility measurements on 2 in the range 4−300 K indicate a weak intramolecular ferromagnetic coupling between adjacent CuII centers with 2J = 2.28 cm−1; the magneto-structural correlations are discussed in detail. The solution behavior of the complexes has been further studied by UV/vis and ESR techniques.

Copper(II) complexes with three diazamesocyclic ligands based on l,5-diazacyclooctane (DACO) bearing additional imidazole or phenol functional donor groups, 1,5-bis(imidazol-4-ylmethyl)- (L111), 1-(imidazol-4-ylmethyl)- (L222), and 1-(2-hydroxybenzyl)-1,5-diazacyclooctane (HL333), have been newly synthesized and characterized, and their structures determined by X-ray diffraction analyses. It has been revealed that with Cu(ClO4)2·6H2O L111 forms a mononuclear complex [CuL111Cl]ClO4·H2O 1, L222 forms a μ-Cl− bridged binuclear complex [CuL222Cl]2[ClO4]22, whereas HL333 forms a phenoxo-bridged binuclear complex [CuL33(H2O)]2[ClO4]23. Each CuII in the three complexes is five-coordinated in a distorted square-pyramidal environment. For the mononuclear complex 1 the Cl− anion is at the apical site, whereas for the μ-Cl−-bridged binuclear complex 2 the two bridging Cl− anions occupy both the axial and one equatorial position with Cu–Cl–Cu angle 88.81(5)° and intramolecular Cu ⋯ Cu separation 3.494(8) A. In the phenoxo-bridged binuclear complex 3 the Cu–O–Cu bridging angle is 100.80(12)° and the intramolecular Cu ⋯ Cu distance is 3.0324(9) A. Variable-temperature magnetic susceptibility measurements on the two binuclear complexes 2 and 3 in the range 4.2–300 K indicate a quite different magnetic intramolecular coupling between the binuclear copper(II) centers, from a weak ferromagnetic to a very strong antiferromagnetic coupling, with 2J = 1.16 (for 2) vs. −574 cm−1 (for 3), and the magneto-structural correlations are discussed in detail. The solution behaviors of the complexes have been further studied by UV/Vis and ESR techniques.

The formation of two unique μ-phenoxo-bridged nickel(II) complexes with l,5-diazacyclooctane (DACO) ligands functionalized by additional phenol donor pendants has been achieved and the complexes have been characterized by IR, elemental analyses, conductivity, thermal analysis, and UV-Vis techniques. Single-crystal X-ray diffraction analyses reveal that HL111 forms a phenoxo-bridged binuclear complex (in the presence of N3− anions) [NiL111(N3)]2·0.5H2O 1, H22L22 a phenoxo-bridged edge-sharing linear trinuclear complex [Ni3(L22)2(C2H5OH)2Cl2] 2, where HL111 = 1-(2-hydroxybenzyl)-1,5-diazacyclooctane and H22L22 = 1,5-bis(2-hydroxybenzyl)-1,5-diazacyclooctane. In 1 the two NiII are in five-coordinated distorted square-pyramidal environments with a intramolecular Ni ⋯ Ni distance of 3.1232(13) A. However in 2 the two terminal NiII are in nearly ideal square-pyramidal coordination environments and the central NiII takes an octahedral configuration by axial coordination of two ethanol molecules, the adjacent intramolecular Ni ⋯ Ni distance being 3.132(2) A. Such a trinuclear nickel(II) complex with square-pyramidal/octahedral/square-pyramidal coordination is unprecedented. These results also indicate that the coordination chemistry of the nickel(II) complexes with DACO ligands can be controlled by altering the pendant donors. Variable-temperature magnetic data show that both complexes display modest intramolecular antiferromagnetic coupling between adjacent nickel(II) centers, which is unusual for such linear trinuclear nickel(II) complexes. The magneto-structural correlation has been investigated for both complexes, and a rough correlation between the exchange coupling and the Ni–O–Ni angle of phenoxo-bridged binuclear nickel(II) complexes obtained and discussed. p

The Fe2+ and Co2+ complexes with a hepta-dentate ligand, 1-methyl-4,7,10-tris(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L), have been synthesized and their crystal structures determined by X-ray diffraction analyses. The two complexes have been found to have different coordination modes. The Fe2+ complex (I) is seven-coordinated with the four cyclen (cyclen=1,4,7,10-tetraazacyclododecane) nitrogen donors and all three pendant pyridine nitrogens, adopting a mono-capped distorted octahedral coordination geometry. To our knowledge, this is the first example of a structurally characterized seven-coordinated Fe2+ complex formed with only one N7 donor set ligand. Whereas the Co2+ complex (II) of L is a normal six-coordination with four cyclen nitrogen donors and two pendant pyridines to give a distorted octahedron in which one pendant pyridine nitrogen remains uncoordinated.

Two novel homobinuclear lanthanide(III) complexes with isonicotinoyl hydrazone ligand [Ho2(L)3(H2O)](NO3)2·(OH)·3.5H2O (I) and [Lu2(L)3](OH)3 (II) (where HL=N,N′-diisonicotinoyl-2-hydroxy-5-methylisophthalaldehyde dihydrazone) have been synthesized and characterized by infrared spectra, elemental analyses, thermal analyses and UV–Vis techniques. The crystal structures of both complexes have been determined by X-ray diffraction analysis. In complex I, the two intramolecular holmium(III) centers have different coordination environments with nine and ten coordination numbers, respectively; however, in complex II, both lutetium(III) centers have the same structure with nine coordination number. In both complexes, the lanthanide(III) ions are intramolecularly bridged by three phenolic oxygen atoms forming a dimeric complex with Ho⋯Ho distance of 3.5398(7) and Lu⋯Lu distance of 3.3960(9) A, respectively. L acts as a pentadentate ligand with keto-form coordination in both complexes as indicated by the results of crystal structures and infrared spectral analysis.

Two new MnII complexes with polydentate macrocyclic polyamine ligands functionalized with pyridyl donor pendants, 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L1) and 1-methly-4,7,10-tris(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L2), have been synthesized and their structures determined by X-ray diffraction analysis. In [MnL1](ClO4)2 (I), the MnII central ion is eight-coordinated with all the eight donor nitrogens of L1 (including four pendant pyridyl nitrogens and four tertiary amines of cyclen) to form a distorted square-prism coordination geometry, and in [MnL2](ClO4)2 (II), the MII central ion is seven-coordinated (distorted monocapped octahedral geometry) with all the seven nitrogen donor atoms of L2 (including three pendant pyridyl nitrogens and four tertiary amines of cyclen) comprising the donor set. The solution chemistry of the two MnII complexes has been further studied by cyclic voltammetry (CV), UV–Vis and ESR spectral techniques.

A series of new diazamesocyclic ligands based on a diazamesocycle, 1,5-diazacyclooctane (DACO), functionalized by additional donor groups--1,5-bis(N-1-methylimidazol-2-ylmethyl)-1,5- diazacyclooctane (L1), 1-(2-hydroxybenzyl)-1,5-diazacyclooctane (HL2), 1,5-bis(2-hydroxybenzyl)-1,5-diazacyclooctane (H2L3), and 1-(N-1-methylimidazol-2-ylmethyl)-1,5-diazacyclooctane (L4)--and their Cu(II) complexes have been synthesized and characterized. Single-crystal X-ray diffraction analysis of the four Cu(II) complexes revealed that L1 forms a five-coordinate mononuclear complex, HL2 a N3- mu-bridged binuclear complex, H2L3 an oxygen mu-bridged trinuclear complex, and L4 a one-dimensional zigzag coordination polymeric complex with Cu(II). [CuL1ClO4](ClO4) (I): a = 12.194(2) A, b = 13.351(3) A, c = 14.473(3) A, beta = 107.10(3) degrees, Z = 4. [CuL2(N3)]2 (II): a = 8.1864(6) A, b = 18.141(2) A, c = 9.3307(7) A, beta = 103.662(6) degrees, Z = 2. [Cu3(L3)2Cl2] (III): a = 10.7296(13) A, b = 13.7707(17) A, c = 13.5523(17) A, beta = 106.350(3) degrees, Z = 2. ([CuL4Cl]2ClO4) infinity (IV): a = 7.279(1) A, b = 23.695(5) A, c = 19.308(4) A, beta = 100.28(3) degrees, Z = 8. All four complexes crystallize in the monoclinic crystal system with the P2(1)/c space group, and each Cu(II) center coordinated with DACO is pentacoordinated with a distorted square-pyramidal or trigonal-bipyrimidal coordination environment. In complex IV, the binuclear cation unit [CuL4Cl]2(2+) constitutes the fundamental building block of an infinite alternating zigzag chain structure, and the binuclear unit contains two types of geometries around the Cu(II) centers: the Cu(1) center is a distorted square-pyramidal environment, while the Cu(2) is a distorted trigonal-bipyramidal coordination environment. To the best of our knowledge, this is the first Cu(II) complex of a diazamesocyclic ligand with an infinite polymeric structure. The magnetic properties of complexes II, III, and IV have been investigated by variable-temperature magnetic susceptibility measurements in the solid state. The obtained parameters are 2J = 2.06 cm-1 (II), -345.56 cm-1 (III), and -2.60 cm-1 (IV), which differ greatly from ferromagnetic to weak and strong antiferromagnetic coupling. These results unequivocally indicate that the nature of the pendant arms is a key factor governing the structure and properties of the complexes; therefore, the coordination modes and properties of the metal complexes of a diazamesocycle can be controlled by altering the pendant donors on it. Magneto-structural correlation has been precisely analyzed, and the solution properties of these complexes have also been described.

The potential octadentate ligand, 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L), gives iron(II) and cobalt(II) complexes of general formula [ML](ClO4)2·nH2O (n=1 or 0.5). The crystal and molecular structures of the complexes have been determined by single-crystal X-ray analysis. The complex [FeL](ClO4)2·H2O can be considered as octacoordinated with two semicoordinated bonds. The complex [CoL](ClO4)4·0.5H2O is six-coordinated with approximate octahedral geometry.

The diprotonated perchlorate salt of a new 1,5-diazacyclooctane (DACO) mesocycle functionalized by two imidazole pendants, N,N′-bis(1-methylimidazole-2-methyl)-1,5-diazacyclo-octane (C16H28N6Cl2O8), has been synthesized and the structure determined by X-ray diffraction analysis. The title compound crystallizes in the monoclinic system, space group P21/c with a = 11.964(2), b = 13.251(3), c = 14.741(3) A, β = 106.00(3)°, Mr = 503.34, V = 2246(1) A3, Z = 4. The crystal structure of the title compound reveals that the DACO ring is also folded up into the “chair/boat” configuration, which is consistent with the configuration in most of the transition metal complexes of DACO and its derivatives. The two imidazole pendants of the compound are in cis position with a dihedral angle of 16.0(4)°.

A new binucleating macrocylic polyamine ligand based on 1,5,9-triazacyclododecane ([12]aneN 3 ), 2,6-bis(1,5,9-triazacyclododecan-9-ylmethyl) benzoate (L), has been synthesized from a selectively Boc protected [12]aneN 3 precursor and 2,6-bis(bromomethyl) benzoate. L can form a stable binuclear complex with Cu(II) in aqueous solution and the complex has been characterized by X-ray crystallography. The intramolecular binuclear Cu(II) centers are bridged by a μ-carboxyl group on L and separated by 5.947 A. Both of the Cu(II) centers are coordinated by three amine nitrogens of [12]aneN 3 subunit and one oxygen of the carboxyl group, as well as one azide anion, and each Cu(II) center is in a distorted square-pyramid environment. To our knowledge, this is the first binuclear Cu(II) complex formed with a bis([12]aneN 3 ) ligand. Variable temperature magnetic susceptibility studies indicate that there exists intramolecular antiferromagnetic coupling (−2 J =71.4 cm −1 ) between the two unpaired electrons of the two Cu(II) ions in complex I .

A binuclear Mn(II) complex of the formula [Mn2(H2pfhmp)Cl2]Cl·3H2O (1) and a mononuclear Mn(II) complex. [Mn(SIH)Cl]·H2O (2), (H3pfhmp = N, N'-diisonicotinoyl-2-hydroxy-5-methyl-isophthalaldehyde dihydrazone and SIH2 = salicylaldhyde-isonicotinoyl hydrazone) have been prepared and characterized by IR, UV. ESR and magnetic susceptibility measurements. The magnetic investigations (4-300K) of complex (1) reveal weak antiferromagnetic spin exchange with J = - 0.46 cm−1. The investigations of catalyzed oxidations of cyclohexane indicate that the Mn(II) complexes (1) and (2) are effective catalysts.

A series of new dinuclear lanthanide complexes with a macrocyclic tetramine ligand containing 4-pyridyl pendants has been synthesized by the reaction of 1,4,7,10-tetrakis-(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L) and lanthanide nitrates (where Ln = Ce, Nd, Eu, Gd, Tb, Ho, Yb). The complexes have the general formula [Ln2(L)(NO3)4](NO3)2. L acts as an octadentate donor ligand to bond two lanthanide(III) ions in these complexes. The electronic and steric requirements of the lanthanide ion appear to be fully satisfied by coordination of the two nitrogens of the macrocyclic ring, the two nitrogens of the pyridyl pendants of L, and the oxygens of two bidentate chelating nitrate ions. The coordination number of the metal ions is therefore 8. The electronic spectra of the Nd and Ho complexes in the visible region have been analyzed, and the spectral parameters (β, b1/2, δ, ωλ) have been calculated and discussed. The emission spectra of the Eu and Tb complexes show strong luminescence, and the ...

Two new macrocyclic dioxotetraamines 4-(pyridin-2-ylmethyl)-1,4,7,10-tetraazacyclotridecane-11,13-dione (H2L1) and 4,7-bis(pyridin-2-ylmethyl)-1,4,7,10-tetraazacyclotridecane-11,13-dione (H2L2) have been synthesized and characterized. The solution behaviors of their copper(II) complexes have been studied with ESR, UV/VIS and cyclic voltammetric techniques. Reaction of H2L2 with Cu(O2CMe)2 in methanol solution yielded a doubly deprotonated dioxotetraamine copper(II) complex, [CuL2]·6H2O, the structure of which has been determined by X-ray diffraction analysis. The Cu atom is five-co-ordinated by four basal nitrogens and one pendant pyridine nitrogen, forming a distorted square pyramid in which N(21) of the pendant pyridine nitrogen is at the apical site. The Cu–N(21) bond distance [2.203(7) A] is longer than the basal average Cu–N bond length [1.985(4) A] due to the Jahn–Teller effect.

The title complex, [NiL](ClO4)2 was synthesized by the reaction of Nickel(II) perchlorate and the new macrocycle ligand, 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane (L) in ethanol solution. The crystal and molecular structure of this complex has been determined by single-crystal X-ray diffraction. The complex consists of [NiL]2+ cation and two perchlorate anions. Within the [NiL]2+ cation, the potential octadentate ligand is using its 4 nitrogen atoms of the macrocycle and 2 pyridine nitrogens to coordinate with the central nickel(II), while the other two pyridine nitrogens remained uncoordinated. The central nickel(II) ion is in a distorted-octahedral coordination environment and in high-spin state.