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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)

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 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)

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 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.

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.

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.

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.

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 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 ...

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.

The neodymium complex with hexaazacyclooctadecane ([18]aneN6) has been obtained as a single crystal by the reaction of neodymium nitrate and macrocycle ligand in methanol solution. The crystal structure of the complex [Nd([18]aneN6)(NO3)3] was determined by X-ray diffraction. The neodymium centre is 10-coordinate with the coordination polyhedron being an irregular capped square-antriprism. The absorption spectrum of the complex was measured and the intensities of f−f transitions were analyzed according to the Judd-Ofelt theory.

The synthesis and characterization of lanthanide complexes with bis(phenylsulphinyl)propane (L) are reported. Elemental analyses, molar conductivities, magnetic and spectral (visible, IR) measurements have been used to characterize the complexes. The IR spectral data show that the ligand (L) behaves as a bidentate ligand and coordination is through the oxygen of the sulphoxide moieties.

Unique and unprecedented five-connected lanthanide−bis(sulfinyl) coordination polymers forming an unusual two-dimensional ( , 5) network consisting of 21- and 28-membered macrometallacyclic structural units constructed from a structurally flexible bis(sulfinyl) ligand, meso-1,2-bis(n-propylsulfinyl)ethane (L), and LnIII(NCS)3 (Ln = Nd and Yb) have been reported.

An investigation into the dependence of the framework formation of coordination architectures on ligand spacers and terminal groups was reported based on the self-assembly of AgClO4 and eight structurally related flexible dithioether ligands, RS(CH2)nSR (Lan, R = ethyl group; Lbn, R = benzyl group, n = 1–4). Eight novel metal–organic architectures, [Ag(La1)3/2ClO4]n (1a), [Ag2(La2)2(ClO4)2]2 (2a), [AgLa3ClO4]n (3a), {[Ag(La4)2]ClO4}n (4a), [AgLb1ClO4]2 (1b), [Ag(Lb2)2]ClO4 (2b), {[Ag(Lb3)3/2(ClO4)1/2](ClO4)1/2}n (3b) and [Ag(Lb4)3/2ClO4]n (4b), were synthesized and structurally characterized by X-ray crystallography. Structure diversities were observed for these complexes: 1a forms a 2-D (6,3) net, while 2a is a discrete tetranuclear complex, in which the AgI ion adopts linear and tetrahedral coordination modes, and the S donors in each ligand show monodentate terminal and μ2-S bridging coordination fashions; 3a has a chiral helical chain structure in which two homo-chiral right-handed single helical chains (Ag–La3–)n are bound together through μ2-S donors, and simultaneously gives rise to left-handed helical entity (Ag–S–)n. In 4a, left- and right-handed helical chains formed by the ligands bridging AgI centers are further linked alternately by single-bridging ligands to form a non-chiral 2-D framework. 1b has a dinuclear structure showing obvious ligand-sustained Ag–Ag interaction, while 2b is a mononuclear complex; 3b is a 3-D framework formed by ClO4− linking the 2-D (6,3) framework, which is similar to that of 1a, and 4b has a single, double-bridging chain structure in which 14-membered dinuclear ring units formed through two ligands bridging two AgI ions are further linked by single-bridging ligands. In addition, a systematic structural comparison of these complexes and other reported AgClO4 complexes of analogous dithioether ligands indicates that the ligand spacers and terminal groups take essential roles on the framework formation of the AgI complexes, and this present feasible ways for adjusting the structures of such complexes by modifying the ligand spacers and terminal groups.

The reactions of meso-1,2-bis(ethylsulfinyl)ethane (meso-L) with Ln(ClO(4))(3) [Ln(NO(3))(3) or Ln(NCS)(3)] in MeOH and CHCl(3) gave a series of new lanthanide coordination polymers, [[Ln(micro-meso-L)(rac-L)(2)(CH(3)OH)(2)](ClO(4))(3)](n) [Ln: La (1), Nd (2), Eu (3), Gd (4), Tb (5), Dy (6), and Yb (7)], [Yb(micro-meso-L)(1.5)(NO(3))(3)](n) (8), and [La(micro-meso-L)(2.5)(NCS)(3)](n) (9). All the structures were established by single-crystal X-ray diffraction. Complexes 1-7 are isostructural with infinite single micro-chain structure, in which the L ligands take two kinds of coordination modes: bidentate chelating and bis-monodentate bridging. Six sulfur atoms of the sulfoxide groups around each Ln(III) center adopt alternatively the same R or S configuration in the chain. In addition, the configuration change of partial ligands occurred from the meso to the rac form when reacting with Ln(ClO(4))(3). To our knowledge, this is the first example of disulfoxide complexes with two kinds of coordination modes and three kinds of configurations (R,R, S,S, and R,S) occurring simultaneously in the same complex. 8 exhibits single-double bridging chain structure, in which dinuclear macrometallacycles formed through bridging two Yb(III) by two meso-L ligands are further linked by another meso-L ligand. In 9 each La(III) ion is linked to five other La(III) ions by five meso-L ligands to form a 5-connected 2-D (3/4,5) network containing two types of macrometallacyclic arrays: quadrilateral and triangle grids. The structural differences among 1-7, 8, and 9 show that counteranions play important roles in the framework formation of such coordination polymers. In addition, the luminescent properties of 3 and 5 were also investigated.

In our efforts to systematically investigate the effects of the linker units of flexible ligands and other factors on the structures of Ag(I) complexes with thioethers, five new flexible pyridyl thioether ligands, bis(2-pyridylthio)methane (L(1)()), 1,3-bis(2-pyridylthio)propane (L(3)()), 1,4-bis(2-pyridylthio)butane (L(4)), 1,5-bis(2-pyridylthio)pentane (L(5)), and 1,6-bis(2-pyridylthio)hexane (L(6)), have been designed and synthesized, and the reactions of these ligands with Ag(I) salts under varied conditions (varying the solvents and counteranions) lead to the formation of eight novel metal-organic coordination architectures from di- and trinuclear species to two-dimensional networks: [Ag(3)(L(1)())(2)(ClO(4))(2)](ClO(4)) (1), [[AgL(3)](ClO(4))]( infinity ) (2), [[Ag(2)(L(4))(2)](ClO(4))(2)(CHCl(3))]( infinity ) (3), [[AgL(4)](ClO(4))(C(3)H(6)O)]( infinity ) (4), [[Ag(2)L(4)](NO(3))(2)]( infinity ) (5), [Ag(2)L(4)()(CF(3)SO(3))(2)]( infinity ) (6), [[AgL(5)](ClO(4))(CHCl(3))](2) (7), and [[AgL(6)()](ClO(4))]( infinity ) (8). All the structures were established by single-crystal X-ray diffraction analysis. The coordination modes of these ligands were found to vary from N,N-bidentate to N,N,S-tridentate to N,N,S,S-tetradentate modes, while the Ag(I) centers adopt two-, three-, or four-coordination geometries with different coordination environments. The structural differences of 1, 2, 3, 7, and 8 indicate that the subtle variations on the spacer units can greatly affect the coordination modes of the terminal pyridylsulfanyl groups and the coordination geometries of Ag(I) ions. The structural differences of 3 and 4 indicate that solvents also have great influence on the structures of Ag(I) complexes, and the differences between 3, 5, and 6 show counteranion effects in polymerization of Ag(I) complexes. The influences of counterions and solvents on the frameworks of these complexes are probably based upon the flexibility of ligands and the wide coordination geometries of Ag(I) ions. The results of this study indicate that the frameworks of the Ag(I) complexes with pyridyl dithioethers could be adjusted by ligand modifications and variations of the complex formation conditions.

The reactions of 1,4-bis(phenylthio)butane (L) with Ag(I) salts in varied conditions (varying the solvents, metal-to-ligand ratios, and counteranions) lead to the formation of four new two-dimensional (2D) coordination polymers with different network structures: [Ag(2)L(3)(ClO(4))(2)](infinity) 1, [Ag(2)L(3)(ClO(4))(2) x CH(3)OH](infinity) 2, [[AgL(2)](ClO(4))](infinity) 3, and [AgLNO(3)](infinity) 4. All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, P-1, a = 11.0253(9) A, b = 11.3455(9) A, c = 11.5231(9) A, alpha = 93.931(2) degrees, beta = 92.689(2) degrees, gamma = 112.9810(10) degrees, Z = 2. 2: triclinic, P-1, a = 11.9147(13) A, b = 16.1534(17) A, c = 16.2259(17) A, alpha = 74.977(2) degrees, beta = 69.030(2) degrees, gamma = 69.986(2) degrees, Z = 2. 3: triclinic, P-1, a = 12.1617(9) A, b = 12.5054(10) A, c = 13.1547(10) A, alpha = 64.3370(10) degrees, beta =85.938 (2) degrees, gamma = 69.3010(10) degrees, Z = 2. 4: monoclinic, P2(1)/c, a = 5.4032(17) A, b = 16.974(6) A, c = 19.489(6) A, beta = 94.234(6) degrees, Z = 4. In all four complexes, each Ag(I) center has a tetracoordination geometry, and the 2D networks consist of fused large macrometallacyclic ring systems. The "hexagonal" 42-membered rings, Ag(6)L(6), observed in 1 and 2 are nearly identical, which could be considered as unique examples of self-sustaining noninterpenetrated frameworks formed with flexible ligands. The repeating rectangular 28-membered macrometallacycle, Ag(4)L(4), is the basis for the network of 3, in which the perchlorate anions occupy the voids to prevent the ring from collapsing. In 4, columns of the fused rectangular 22-membered rings, Ag(4)L(2)(NO(3))(2), are cross-linked through the L ligands to form a unique 2D network consisting of two types of 22-membered repeating units.

The syntheses, characterization, structures, and properties of a series of LnIII coordination polymers with a flexible bis(sulfinyl) ligand, 1,4-bis(phenylsulfinyl)butane (L), are reported. Unique noninterpenetrated two-dimensional (4,4) nets are formed in these complexes. The coordination number of the LnIII ions across the whole LnIII series remains unchanged, and all the complexes of this series are isomorphous and isostructural. The perchlorate anions may set as a template in the formation of these unique square arrays, and the counteranions may be a key factor in controlling the structures of such complexes.

The crystal structure of the title complex, [Ni(C(6)H(14)N(2))(2)]Br(2), consists of discrete [Ni(C(6)H(14)N(2))(2)](2+) cations and bromide counter-anions. The Ni(II) ion is at the center of symmetry and is four-coordinated by four nitrogen donors of the mesocyclic ligand 1,5-diazacyclooctane (DACO) [Ni-N 1.935 (2)-1.937 (2) A]. The coordination geometry of Ni(II) can be considered as square planar and both DACO ligands take the boat-chair conformation. The bromide anions are hydrogen bonded with the nitrogen donors of the ligands to form a macrocycle-like ring system.

The title compound, C9H20O4S2, has been obtained as an unexpected product when attempting to prepare a zinc(II) complex with the di­sulfoxide ligand 1,5-bis­(ethyl­sulfinyl)­pentane. The average S—C and S=O bond lengths are 1.781 (3) and 1.436 (2) A, respectively. The two O—S—O angles [118.0 (1) and 117.2 (1)°] are nearly equivalent, with an average value of 117.6 (1)°. The molecular skeleton is almost fully extended in the crystalline state.

The crystal structure of the title compound, [CoCl-(C16H26N6)]ClO4, consists of discrete [CoCl­(C16­H26N6)]+ cations and perchlorate anions. The five-coordinate CoII atom has four nitro­gen donors from the new mesocyclic ligand 1,5-bis(1-methyl-1H-­imidazol-2-ylmethyl)-1,5-di­aza­cyclo­octane [Co—N 2.046 (3)–2.214 (4) A], and a chloride anion at the apical site [Co—Cl 2.3184 (13) A]. The coordination geometry of the complex is essentially square pyramidal. The mesocyclic ligand takes a boat–chair configuration and the two imidazole pendants are not coplanar. The dihedral angle between the two imidazole planes is 15.97°. An H atom from the 1,5-diaza­cyclo­octane group effectively blocks the axial coordination site opposite the Cl ligand.

The present paper reports our sequential efforts to investigate the structures and properties of flexible disulfoxide–lanthanide complexes. Combining our reported results, on the basis of changing synthesis conditions and using a co-ligand, six new complexes, [Ln(meso-L)4](ClO4)3(H2O) n (n = 0.5, Ln = Eu (1), Gd (2); n = 0, Ln = Tb (3)) and [Ln(meso-L)2(phen)2](ClO4)3(CHCl3)2 (Ln = Eu (4), Gd (5), and Tb (6)) (herein, L = 1,2-bis(ethylsulfinyl)ethane, phen = 1,10-phenanthroline) were synthesized, and their structures were characterized by IR spectroscopy, elemental analysis, and X-ray single-crystal diffraction. The dependence of the formation of 1–3 on the solvents used and reaction ratios in the preparation was confirmed. Complexes 1–3 are isomorphous ionic complexes, and the coordination cation is chiral and has a mononuclear structure, in which the LnIII atom is eight-coordinated by four L ligands. Complexes 4–6 are also isomorphous mononuclear ionic complexes, and in each complex cation, the central LnIII atom is eight-coordinated by two L ligands and two phen molecules. In 1–6, all the L ligands exhibit the meso configuration and bis-monodentate chelating coordination mode. Further, the absorption and luminescent spectra of L, phen and complexes 4–6 in solution were investigated at room temperature. The absorption spectra show that only a very slight shift of the absorption band occurred for the ligands L and phen when coordinating to metal ions, being consistent with their origin. The photoluminescence of 4 and 6 exhibits the usual metal-centred emission spectra arising from ligand-to-metal energy transfer and the emission of π → π* transitions from the phen ligand; the latter is also seen in the emission spectrum of 5.

Three dinuclear lanthanide complexes of flexible disulfoxide ligand meso-1,2-bis(ethylsulfinyl)ethane (L), [Ln2(L)2(μ-L)(tpy)4](ClO4)6(CHCl3)4 (Ln = Eu 1, Gd 2) and [Tb2(L)4(μ-L)(tpy)2](ClO4)6(CHCl3) 3 with 2,2′:6′,2′′-terpyridine (tpy) as co-ligand were synthesized and structurally characterized. In 1 and 2, the metal centre is nine-coordinated to two tpy and one-and-a-half L ligands, whereas in 3 it coordinates with one tpy and two-and-a-half L, which may be attributed to the influence of the lanthanide contraction. In such complexes the disulfoxide ligands perform two kinds of coordination modes, bridging and chelating, indicating their flexibility in the formation of such complexes.

Five novel Cd(II) coordination polymers with three structurally related flexible disulfoxide ligands, {[Cd(L1)3](ClO4)2}n (1), {[Cd(L2)3](ClO4)2(CHCl3)}n (2), [Cd(L2)(NO3)2(H2O)]n (3), [Cd2(L3)2(NO3)4]n (4) and {[Cd(L3)3](ClO4)2}n (5), where L1 = 1,3-bis(phenylsulfinyl)propane, L2 = 1,4-bis(phenylsulfinyl)butane and L3 = 1,4-bis(ethylsulfinyl)butane, were synthesized and structurally determined by X-ray diffraction. Complex 1 has a 2D layer structure, in which part of the L1 ligands bridge the Cd(II) ions to form double-bridging chains and the other part of ligands link such chains to form a 2D framework. Complexes 2 and 5 are isomorphous, showing unusual 2D (3,6) network structures containing triangular grids. Complex 3 adopts a 2D (4,4) network formed by L2 linking the NO3− bridged (Cd–O–N–O–)n 1D zigzag chains. By contrast, 4 is a 1D chain, in which two Cd(II) centers are bridged by μ2-O of sulfoxide groups to form a dinuclear unit, and L3 ligands link such dinuclear units to form a 1D double-bridging chain. The structural differences among such complexes show that the ligand nature and counter anions have important influences on the complex structures, which may provide a rational method for controlling the framework formation in metal–organic coordination polymers.

Five representative lanthanide coordination compounds with a disulfoxide ligand [L = 1,4-bis(phenylsulfinyl)butane], [Ln(L)4](ClO4)3 (Ln = La, 1; Eu, 2; Gd, 3; Tb, 4; Yb, 5), have been synthesized and structurally characterized by single-crystal X-ray diffraction. These compounds have isostructural mononuclear structures, in which the ligand L coordinates to the metal ions through O donors in chelating coordination mode. The luminescence studies of 2 and 4 in the solid state and solution exhibit the usual metal-centred emission spectra arising from ligand-to-metal energy transfer, and their intensity and lifetimes are increased compared to those of previously reported analogous complexes {[Ln(L)2(DMF)4](ClO4)3·nH2O}∝ (Ln = Eu, n = 4, 6; Ln = Tb, n = 3, 7). The stability of these complexes in solution was also investigated.

Two CuII complexes, [Cu2(α-L)Cl4·H2O (1) and Cu2(β-L)Cl4(2) [α-L and β-L = meso- and rac-PhS(O)(CH2)2S(O)Ph, respectively], were synthesized and characterized by elemental analysis, i.r. spectra and molar conductances. In each case, the CuII ion bonds to the 557-01 moiety through oxygen, and may be bridged by the ligand (α-L or β-L). From magnetic moment measurements at room temperature and variable temperature magnetic susceptibilities, we suggest that complexes (1) and (2) exhibit weak ferromagnetic behaviour.

The first AgI complex with a flexible meso-bis(sulfinyl) ligand forming a unique two-dimensional, 36-membered macrometallacyclic molecular square array is reported.