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The postcoordinated interligand-coupling strategy provides a useful and complementary protocol for synthesizing polydentate ligands. Herein, diastereoselective photoreactions of Λ-[Ir(pq)2(d-AA)] (Λ-d) and Λ-[Ir(pq)2(l-AA)] (Λ-l, where pq is 2-phenylquinoline and AA is an amino acid) are reported in the presence of O2 under mild conditions. Diastereomer Λ-d is dehydrogenatively oxidized into an imino acid complex, while diastereomer Λ-l mainly occurs via interligand C-N cross-dehydrogenative coupling between quinoline at the C8 position and AA ligands at room temperature, affording Λ-[Ir(pq)(l-pq-AA)]. Furthermore, the photoreaction of diastereomer Λ-l is temperature-dependent. Mechanistic experiments reveal the ligand-radical intermediates may be involved in the reaction. Density functional theory calculations were used to eluciate the origin of diastereoselectivity and temperature dependence. This will provide a new protocol for the amination of quinoline at the C8 position via the postcoordinated interligand C-N cross-coupling strategy under mild conditions.

Diastereoselective synthesis of bis-cyclometalated Ir(III) stereoisomers Δ/Λ-[Ir(C∧N)2(d-pro)] and Δ/Λ-[Ir(C∧N)2(l-pro)] (where C∧N is 2-phenylpyridine (Hppy), (4,6-difluorophenyl)pyridine (Hdfppy), and 2-phenylquinoline (Hpq) and pro is proline) with dual stereogenic centers at the metal and auxiliary ligand has been developed. The diastereomers Λ-l and Λ-d, and Δ-l and Δ-d exhibit distinguishable photophysical properties in both solution and the solid state. The thermodynamically stable diastereomers Λ-[Ir(ppy)2(l-pro)], Λ-[Ir(dfppy)2(l-pro)], and Λ-[Ir(pq)2(l-pro)] emit a green emission at 524 nm (Φ = 3.5% and τ = 35 ns), a blue-green emission at 480 nm (Φ = 4.5% and τ = 59 ns), and a red emission at 588 nm (Φ = 6.5% and τ = 200 ns) in DCM solution, respectively, which are blue-shifted accompanied by a large quantum yield and long lifetime relative to the corresponding unstable diastereomers Δ-[Ir(ppy)2(l-pro)] at 537 nm (Φ = 2.3% and τ = 29 ns), Δ-[Ir(dfppy)2(l-pro)] at 489 nm (Φ = 2.8% and τ = 43 ns)...

The optically active Ir(III) complex Λ-[Ir(ppy)2(MeCN)2](PF6) (ppy is 2-phenylpyridine) with a chiral-at-metal was first demonstrated to preferentially react with (R)-configuration sulfoxides 2-(alkylsulfinyl)phenol (HLO-R, R = Me, Et, iPr, and Bn) rather than (S)-configuration sulfoxides under thermodynamic equilibrium due to the hydrogen-bonding interaction and the differences in the steric interference, and thus act as a highly efficient enantioreceptor for resolution of sulfoxide enatiomers. Treatment of Λ-[Ir(ppy)2(MeCN)2](PF6) with 2 equiv of rac-HLO-R offered (S)-HLO-R in yields of 46–47% with 97–99% enantiomeric excess (ee) values and Λ-[Ir(ppy)2{(S)-LO-R}] complex in yields of 89–93% with 98% diastereomeric excess (de). The (R)-HLO-R chiral sulfoxides were obtained by the acidolysis of Λ-[Ir(ppy)2{(S)-LO-R}] complexes with trifluoroacetic acid (TFA) in the presence of coordinated solvent MeCN in yields of 45–47% with 98–99% ee values. Moreover, the enantioreceptor Λ-[Ir(ppy)2(MeCN)2](PF6) can be ...

With the idea of supramolecular hosts encircling monoanions, a series of urea-containing trinuclear cationic copper complexes were designed, prepared and structurally analyzed. Copper(I) acetylides [Cu3(μ-dppm)3(μ3-η1-CCC6H4-4-NHC(O)NHC6H4-4-R)2]+ (dppm = bis(diphenylphosphino)methane; R = NO2 (1), CF3 (2), Cl (3), H (4), tBu (5), and OCH3 (6)) were prepared with F−, BF4−, or NO3− present as the anion. Eight 1-D anion coordination polymers (ACPs), 1·F, 2·F, 3·BF4, 4·F, 5·F, 5·BF4, 5·NO3 and 6·0.5F·0.5BF4, were clearly determined by X-ray diffraction. Diversity in the polymeric architecture is generated by both the choice of R-group used and anion present. 2·F, 3·BF4, 4·F, and 5·F show linear 1-D structures; 5·BF4 and 5·NO3 feature single-stranded helical structures; 1·F and 6·0.5F·0.5BF4 exhibit meso-helical structures. Solid state UV-vis absorption and luminescence properties are also discussed.

Chiral precursors Λ-[Ir(ppy)2(l-pro)] (Λ-L, where ppy is 2-phenylpyridine; pro is proline), Λ-[Ir(ppy)2(MeCN)2](PF6) (Λ-1), Δ-[Ir(ppy)2(d-pro)] (Δ-D), and Δ-[Ir(ppy)2(MeCN)2](PF6) (Δ-1) were synthesized from rac-[(Ir(ppy)2)2Cl2] and l-pro or d-pro by means of the auxiliary ligand strategy with 99% de values. The enantiopure mono complexes Λ/Δ-[Ir(ppy)2(L)](PF6) (L is 2,2'-bipyridine, Λ/Δ-2; L is 2,2'-dipyrimidine (dpm), Λ/Δ-3; L is 2,2'-bibenzimidazole (H2bbim), Λ/Δ-4) with 99% ee values and binuclear complexes ΛΛ/ΔΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (ΛΛ-5 and ΔΔ-5) and ΛΛ/ΔΔ-[(Ir(ppy)2)2(bbim)] (ΛΛ-6 and ΔΔ-6) with 99% de values were synthesized in one step using the corresponding chiral precursors. The absolute configurations at Ir(III) centers of precursor Δ-1, mononuclear Λ-3, and binuclear ΔΔ-6 were confirmed by single-crystal structural analysis and characterized by circular dichroism (CD) spectroscopy. The correlation between the absolute configuration at Ir(III) center and CD spectra was established. The configurations at Ir(III) centers are stable during the reactions, and the chiral precursors can be used for the asymmetric synthesis of enantiomerically pure mono- and polynuclear Ir(III) complexes. Moreover, meso ΛΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (meso-5) and ΛΔ-[(Ir(ppy)2)2(bbim)] (meso-6) were also synthesized using these precursors.

The enantioselective oxidation synthesis of chiral modafinil acid and its analogues with high enantiomeric excess has been developed by means of a chiral-at-metal strategy. Treatment of ruthenium complexes cis-[Ru(bpy)2Cl2] or Δ/Λ-[Ru(bpy)2(MeCN)2](PF6)2 (bpy is 2,2′-bipyridine) with the appropriate prochiral thioether ligands afforded thioether complexes rac-1, Δ/Λ-1, rac-2, Δ/Λ-2, rac-3, and Δ/Λ-3. Diastereoselective oxidation of the thioether complexes in situ produced the corresponding sulfoxide complexes rac-1a, Δ/Λ-1a, rac-2a, Δ/Λ-2a, rac-3a, and Δ/Λ-3a. The configuration at the metal center in each case is stable during the coordination and oxidation reactions, and dictates the chirality of the sulfoxide ligand in the oxidation process. The chiral modafinil acids were obtained with ee values greater than 98 % upon their removal from the corresponding sulfoxide complexes in the presence of TFA/MeCN. Moreover, the chiral ruthenium precursors Δ/Λ-[Ru(bpy)2(MeCN)2](PF6)2 are recyclable and reusable with complete retention of the configurations.

Treatment of cis-[Ru(bpy)2Cl2]⋅2 H2O or Δ/Λ-[Ru(bpy)2(py)2]2+ (bpy=2,2′-bipyridine, py=pyridine) with the prochiral thioether ligands 2-alkylthiobenzoic acid (HOSR) produces the corresponding thioether complexes rac-[Ru(bpy)2(OSR)](PF6) (R=Me (rac-1), iPr (rac-2), 2-benzylthiobenzonate (Bn) (rac-3)) and Δ/Λ-[Ru(bpy)2(OSR)](PF6) (R=Me (Δ-1/Λ-1), iPr (Δ-2/Λ-2), Bn (Δ-3/Λ-3)) with retention of the configurations at chiral metal centers. In situ oxidation of the thioether complexes by meta-chloroperoxybenzoic acid provides the corresponding sulfoxide complexes rac-[Ru(bpy)2(OSOR)](PF6) (OSOR is 2-alkylsulfinylbenzonate, R=Me (rac-1 a), iPr (rac-2 a), Bn (rac-3 a)), Δ-[Ru(bpy)2{(R)-OSOR}](PF6) (R=Me (Δ-1 a), iPr (Δ-2 a), Bn (Δ-3 a)), and Λ-[Ru(bpy)2{(S)-OSOR}](PF6) (R=Me (Λ-1 a), iPr (Λ-2 a), Bn (Λ-3 a)) in yields of 95 % with 98 % ee values. The absolute configurations at the metal centers and sulfur atoms were determined by means of X-ray crystallography. The results indicate that the configurations of the metal centers are retained and have the function of controlling sulfoxide chirality during the oxidation process. The Δ metal-centered configuration enantioselectively generates an R-configuration sulfoxide, and the Λ configuration enantioselectively forms an S-configuration sulfoxide in the course of the in situ oxidation reaction, thereby resulting in a predetermined chirality of the sulfoxide ligands. The predetermined chirality of sulfoxides (S)-HOSOR and (R)-HOSOR were obtained by the treatments of the corresponding sulfoxide complexes Δ-[Ru(bpy)2{(R)-OSOR}](PF6) and Λ-[Ru(bpy)2{(S)-OSOR}](PF6) with trifluoroacetic acid in yields of 90 % with 83.5–92.9 % ee values.

Six new complexes [Zn2(L1)4]·2H2O·DMF (1), [Zn2(L2)4]3·13H2O (2), [Zn1.5(L3)3]2 (3), Zn(L4)2·2H2O (4), Zn(L5)2·2CHCl3 (5), and [Zn(L6)2]2 (6) (where HL1 = 1-(4-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL2 = 1-(4-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione, HL3 = 1-(4-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione, HL4 = 1-(3-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL5 = 1-(3-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione and HL6 = 1-(3-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione) have been synthesized by the reaction of the bifunctional ligands and Zn(II) salts under similar experimental conditions. Structural analyses show that the ligands act as a tridentate and bind to two Zn(II) ions as a two-connected linker, generating a variety of geometries from discrete binuclear [2 + 2] metallomacrocycles (3 and 6) to a one-dimensional looped-chain coordination polymer (4) and two-dimensional (4,4) network (5) as well as three-dimensional frameworks with lvt (1) and NbO (2) topologies. The results demonstrate that ...

Seven complexes based on the ligands 4,6-bis(4-pyridyl)-1,3,5-triazin-2-ol (4-HOBPT) and 4,6-bis(3-pyridyl)-1,3,5-triazin-2-ol (3-HOBPT), namely, [Fe(4-OBPT)2(H2O)2]·6H2O (2), M(4-OBPT)(INA)(H2O) (M = Co(II) (3a), Fe(II) (3b), Zn(II) (3c), HINA = isonicotinic acid), [Co(3-OBPT)2(H2O)2]·H2O (4), and [M(3-OBPT)(NA)(H2O)]·0.5CH3OH (M = Co(II) (5a), Ni(II) (5b), HNA = nicotinic acid), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The thermal stability and coordination model of the ligands are extremely dependent on the reaction temperature and the presence of metal ions. In the range of 90−120 °C, unique complexes 2 and 4 were obtained and the ligands are a N,O-bimonodentate coordination model. At 130 °C, complexes 3 and 5 were afforded in yields of 12−48% depending on the metal ions, in which both of the ligands act as a N,N,O-trimonodentate triangular ligand and the INA and NA anions are generated in situ by hydrolysis of the corresponding parents...

The complexes [Pd(phen)(aa)]Cl·3H2O, where phen is 1,10-phenanthroline and as is the anion of glycine (gly), DL-alanine (ala), DL-serine (ser) or DL-asparagine (asn), were synthesized and characterized by spectroscopies. The NMR signals were assigned completely on the basis of the double irradiation, 1H-1 H COSY and 1H-13C COSY techniques. In the 1H NMR spectra of phen in the complexes, the signals of 2-H and 9-H show upfield shifts 0.8–1 ppm, while the signals of 4-H and 3-H show downfield shifts or almost no shift, as compared to the free phen ligand, and the signal of 4-H appears in the lowest field. The signals of ring B which is trans to the carboxyl group show significant upfield shirts as compared to those of ring A. The probable structures were described on the basis of a metal-non-bonded hydrogen interaction, trans effect and ligand-ligand interaction. There may exist three conformation isomers in the [Pd(phen)(asn)]Cl·3H2O complex at room temperature. The preferred conformation isomer is about 75% in terms of the relative peak areas in the α-CH part of the spectra.

We describe the first observation of the quantitative and rapid synthesis ofa (10,3)-b three-dimensional hydrogen bonded network {[Ru(H 2 biim) 3 ](TMA)}·5H 2 O(1·H 2 O)(H 2 biim = 2,2'-biimidazole; H3TMA = trimesic acid) via a "liquid-assisted" solid-state reaction approach. The reaction occurs within minutes of grinding together [Ru(H 2 biim) 3 ](PF 6 ) 2 and Na 2 HTMA with a few drops of H 2 O 2 as an oxidant and solvent, concomitant with a color change from yellow (Ru(II) ion) to blue-green (Ru(III) ion). The characterization of the solid-state product was achieved by a combination of a single crystal obtained via seeding and powder diffraction experiments. To compare with the solid-state reaction, similar reactions were also carried out in an EtOH solution. Two complexes {[Ru(H 2 biim) 3 ](TMA)}·10H 2 O(2·H 2 O) and [Ru(H 2 biim) 3 ](HTMA) (3) were isolated in the presence of a polypyridine base, such as 2,2-dipyridylamine or 2,2':6',2"-terpyridine or 1,10-phenanthroline. Complex 2 is a (6,3) honeycomb two-dimensional hydrogen-bonded network. Complexes 1 and 2 are topological isomers. The formation of multiple robust hydrogen bonds between [Ru(H 2 biim) 3 ] 3+ and TMA may trigger the proton transfer from H 2 biim to TMA, then electron transfer, resulting in Ru(III) status. This may provide an effective approach for the generation of high status metal complexes via supramolecular interactions. Importantly, our experiments suggest that solution crystallization may at times offer more product diversity than grinding.

Five different cobalt complexes were synthesized by the combination of the multidentate ligand 2,2′-bibenzimidazole (H2bbim) and the coordination plasticity of cobalt ion in the presence of 4-cyanopyridine under hydrothermal conditions using temperature as the only independent variable. The structural features of theses complexes, which ranged from zero-dimensional (0D) in [Co(Hbbim)3]·3H2O (1) and [Co(ina)2(H2O)4] (5) to two-dimensional (2D) layer in {[Co4(Hbbim)4(bbim)2]·2H2O}n (2) or three-dimensional (3D) networks in [Co2(Hbbim)(bbim)2(H2O)]n (3) and [Co5(Hbbim)(bbim)3(ina)2(μ3-OH)]n (4), were extremely dependent on the reaction temperature. At 130 °C, discrete 1 was the unique product. However, 4 was the main product when the reaction temperatures were set in the range of 160−200 °C. 2 and 3 yielded at 140 °C as main products. In spite of the structural diversity of this system, crystallographic studies reveal that the H2bbim ligand typically displays tridentate (Hbbim−) and/or tetradentate (bbim2−) ...

Six complexes containing the 2,2′-biimidazole-like ligand and chloride, namely, trans-[Ni(H2biim)2(H2O)2]Cl2 (1), trans-[Co1.5(H2biim)3(H2O)3]Cl3 (2), [Zn(H2biim)2Cl]Cl (3), [Ni2(H2bbim)4(bbim)]Cl2 (4), [Co(H2bbim)3]Cl2·2H2O (5), and [Zn2(Hbbim)2(bbim)0.5Cl] (6) (where H2biim = 2,2′-biimidazole, H2bbim = 2,2′-bibenzimidazole) have been synthesized by the reactions of the H2biim or H2bbim ligand with the metal chloride salts. The structures of the complexes were determined by single-crystal X-ray diffraction analyses, and the results revealed that the distances of N···Cl varied from 3.10 to 3.29 A and the angles of N−H···Cl varied from 148 to 169°, O···Cl varied from 3.09 to 3.16 A, O−H···Cl varied from 151 to 178°, C···Cl varied from 3.49 to 3.69 A, and C−H···Cl varied from 122 to 167°. The chloride may act as a multi hydrogen bonded acceptor varying from 3 to 6, resulting in an important collective contribution to cohesion. The data observed in this study seem to suggest that a variety of X−H···Cl (X = N...

The reaction of 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)benzene (bib) ligand with silver(I) nitrate in a 1:1 molar ratio generated a [2 + 2] metallocyclic complex [Ag2(bib)2](NO3)2 · 2H2O, in which bib ligand displayed in cis configuration. When the additional competing ligands/counterions, such as oxlate salt, 1,2-diaminoethene (en), 1,3-diaminopropane (pn), NO 2 - and VO 3 - were introduced, respectively, to the above-mentioned reaction solution, ring-open polymerization of sliver(I) complexes {[Ag(bib)]NO3 · H2O}n (1), {[Ag(bib)2]X}n ( X = NO 3 - (2), ClO 4 - (3)), {[Ag2(bib)2(NO2)](NO2) · 19/8H2O}n (4) and {[Ag2(bib)2](V4O12)0.5 · 3H2O · 2MeCN}n (5) were generated. In compounds 1, 4 and 5, bib ligand adopts trans configuration and twists around the Ag–Ag axis, giving rise to single-stranded helical structure with short adjacent Ag⋯Ag distances of 3.56, 3.56, 3.50 and 3.63 A, respectively. Compounds 2 and 3 are 1D coordination polymers fusing the [2 + 2] metallocycle [Ag2(bib)2]2+, in which bib ligand exhibits in cis configuration and the metallocycles have longer Ag⋯Ag distances of 8.52 A in 2 and 8.61 A in 3 along with the strong intracyclicπ–π interactions between phenyl groups. Cis and trans configurations of bib coexist in solution and crystallize in complexes 1 and 2 in the solid state in the presence of en or pn. The solution of 1 and 2 can be converted into 3 via the addition of the bulky ClO 4 - counter anion or into 4 through introduction of the competing ligand/conuterion NO 2 - .

Two manganese(II) coordination polymers, [Mn2(bpt)(pa)2(N3)]n [1; Hpa = picolinic acid, Hbpt = 3,5-bis(2-pyridyl)-4H1,2,4-triazole] and [Mn3(ina)2(pa)2(N3)2]n (2; Hina = isonicotinic acid), have been synthesized by solvothermal treatment, in which the ligands bpt and pa were generated in situ by cyclocondensation and hydrolysis of 2-pyridylamidrazone, respectively. In 1, each binuclear subunit [Mn2(bpt)(N3)] bridged by bpt and N3 – ligands is interlinked to four adjacent subunits via four tridentate pa ligands into a diamondoid 3D network, which shows spin-canting magnetism arising from

Four dimeric and polymeric coordination compounds [Zn 2 (bimb) 2 (pdc) 2 ]·6H 2 O ( 1 ), [Cd 2 (bimb) 2 (tp) 2 ]·H 2 O ( 2 ), [Cd(bimb)(ada)] ( 3 ) and [Co(bimb)(ada)] ( 4 ) (bimb, 4,4′-bis(imidazol-1-ylmethyl)biphenyl; pdc, pyridine-2,6-dicarboxylate; tp, terephthalate and ada, adipate) have been synthesized under hydrothermal conditions. Complex 1 is a discrete dinuclear metallomacrocycle featuring a 34-membered ring, in which the flexible bimb ligand acts as syn -conformation. While complexes 2 – 4 are 3D network structures connected by bimb and dicarboxylate ligands, the bimb ligand displays anti -confromation.

The preparation of chiral 2-(alkylsulfinyl)phenol compounds by enantioselective coordination-oxidation of the thioether ruthenium complexes with a chiral-at-metal strategy has been developed. The enantiomerically pure sulfoxide complexes Δ-[Ru(bpy)2{(R)-LO-R}](PF6) (bpy is 2,2'-bipyridine, HLO-R is 2-(alkylsulfinyl)phenol, R = Me (Δ-1a), Et (Δ-2a), iPr (Δ-3a), Bn (Δ-4a), and Nap (Δ-5a)) and Λ-[Ru(bpy)2{(S)-LO-R}](PF6) (R = Me (Λ-1a), Et (Λ-2a), iPr (Λ-3a), Bn (Λ-4a), and Nap (Λ-5a)) have been synthesized by the reaction of Δ-[Ru(bpy)2(py)2](2+) or Λ-[Ru(bpy)2(py)2](2+) with the prochiral thioether ligands 2-(alkylthio)phenol (HL-R), followed by enantioselective oxidation with m-CPBA as oxidant. The X-ray crystallography was used to verify the stereochemistry of ruthenium complexes and sulfur atoms. The configurations of the ruthenium complexes are stable during the coordination and oxidation reactions. Moreover, the chiral sulfoxide ligands are enantioselectively generated by controlling of the configuration of ruthenium centers in the course of oxidation reaction. That is, the Λ configuration at the ruthenium center generates the S sulfoxide ligand; on the contrary, the Δ configuration of the ruthenium complex originates the R sulfoxide ligand. Acidolysis of Λ-[Ru(bpy)2{(R)-LO-R}](PF6) and Δ-[Ru(bpy)2{(S)-LO-R}](PF6) complexes in the presence of TFA-MeCN afforded the chiral ligands (R)-HLO-R and (S)-HLO-R in 96-99% ee values, respectively. Importantly, the chiral ruthenium complexes can be recycled as Δ/Λ-[Ru(bpy)2(MeCN)2](PF6)2 and reused in a next reaction cycle with complete retention of the configurations at ruthenium centers.

Four new complexes [Cd4(bpa)2(MeCO2)8]·9H2O (1), {[Cd4(bpa)4(suc)2(H2O)4](suc)2·17H2O}n (2), {[Cd2(bpa)2(glu)2]·9H2O}n (3), and {[Cd2(bpa)2(adi)2]·11H2O}n (4) (where bpa = N,N‘-bis(picolinamide)azine, H2suc = succinic acid, H2glu = glutaric acid, and H2adi = adipic acid) have been synthesized by the reactions of the bpa ligand and different Cd(II) carboxylates in similar conditions. Their structures consist of double-stranded helical [Cd2(bpa)2] structural units and various carboxylates. Each of the [Cd2(bpa)2] structural units in 1 is capped at its both ends by acetate-chelated Cd(II) fragments through acetate bridges into discrete tetranuclear species, which are self-assembled into two-dimensional (2D) hydrogen-bonded sheets with cavities. The 2D hydrogen-bonded sheets in 1 are threaded by one-dimensional (1D) water tapes featuring (H2O)4 clusters to generate an unprecedented three-dimensional (3D) hydrogen-bonded polypseudo-rotaxane architecture. The [Cd2(bpa)2] structural units as secondary building b...

The new complex [Cd2(bpa)2Cl4]·6 H2O [bpa = N,N'-bis(picolinamide)azine] has been synthesized in which each bpa ligand is twisted into a spiral-like conformation and the two CdII ions are ligated by two bpa ligands to form a double-stranded binuclear helicate. Unprecedented water chains featuring cyclic water tetramers composed of three independent water molecules are trapped by [Cd2(bpa)2Cl4] double helicates by hydrogen bonds. The binuclear chiral helicates are interlinked into homochiral layers by hydrogen bonds with the water tapes. The layers are alternately stacked in a heterochiral fashion to yield the final racemic structure. The complex shows an endotherm at 65.7 °C in the DSC due to loss of water molecules, giving an enthalpy value of 47 kJ mol–1 per water molecule. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Two new coordination polymers [Cd(tdc)(bpy)(H2O)]n (1) and [Cd(tdc)(phen)]n (2) (H2tdc = thiophene-2,5-dicarboxylic acid, bpy = 2,2′-bipyridine and phen = 1,10-phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X-ray single-crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) A, V = 7044(6) A3, Z = 16; 2 in the monoclinic space group P21/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) A, β = 105.01(1)°, V = 1548.8(2) A3, Z = 4. Both of them are double-stranded chains and further assembled into three-dimensional networks by π-π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.

Three new complexes of [Co(H2biim)2(1,2-bdc)] (1), [Cd(H2biim)(1,3-bdc)]2 (2), and [Cd3(H2biim)2(1,4-bdc)3]·2H2O (3) (bdc = benzenedicarboxylate, H2biim = 2,2‘-biimidazole) have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 exhibits a 2-D herringbone architecture with mononuclear building blocks assembled via a robust hydrogen-bonded synthon R22(9). The homo- and heterochiral assemblies were observed in 1 between the H2biim ligand and carboxylate group via single and double hydrogen-bonded synthons R22(9). Complex 2 is a ribbonlike polymer based on a binuclear unit, and the ribbons are alternately decorated by H2biim ligands on both sides and further packed through intercalation of the lateral H2biim ligands and hydrogen bonds between the H2biim and carboxylate oxygen atoms into 2-D networks. These layers extend into a 3-D architecture via π−π stacking interactions. Complex 3 is a 3-D coordination polymer with a α-Po net topology based on linear trinuclear {Cd3O14N4} cl...

A new one-dimensionally neutral coordination polymer, namely {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10-phenanthroline, ox = oxalate) (1), has been synthesized under hydrothermal condition and characterized by X-ray crystallography. Complex 1 crystallizes in the orthorhombic space group Pban (No. 50) with a = 19.358(2), b = 6.8135(6), c = 9.7015(8)A, V = 1279.6(2)A3, and Z = 2. Each Pb(II) atom is eight-coordinated in a square-antiprismatic D4d geometry by four nitrogen atoms from two phen groups and four oxygen atoms from two ox ligands. The polymeric chains further constructed into a three-dimensional network via strong π—π stacking interactions and hydrogen bonds. The complex exhibits intense blue photoluminescence with an emission maximum at 403 nm at room temperature. Hydrothermale Synthese und Kristallstruktur eines neuen polymeren oxalatverbruckten Blei(II)-Komplexes {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10-Phenanthrolin, ox = Oxalat) Eine neue eindimensional-polymere, neutrale Koordinationsverbindung, {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10-Phenanthrolin, ox = Oxalat) (1), wurde unter hydrothermalen Bedingungen synthetisiert und durch Rontgen-Kristallstrukturanalyse charakterisiert. 1 kristallisiert orthorhombisch, Raumgruppe Pban (No. 50) mit a = 19.358(2), b = 6.8135(6), c = 9.7015(8)A, V = 1279.6(2)A3, Z = 2. Jedes Blei(II)-Atom ist achtfach koordiniert in quadratisch-antiprismatischer D4d-Geometrie von vier Stickstoffatomen der zwei Phen-Gruppen und vier Sauerstoffatomen der zwei Oxalat-Liganden. Die polymeren Ketten bilden durch starke π—π-Wechselwirkungen und Wasserstoffbruckenbindungen ein dreidimensionales Gerust. Der Komplex zeigt intensiv-blaue Photolumineszens mit einem Emissionsmaximum von 403 nm bei Zimmertemperatur.

Five new silver(I) complexes with dimeric units, namely [Ag2(bib)2](BrO3)21, [Ag2(bib)2](ClO3)22, [Ag2(bib)2](ClO4)23, [Ag2(bib)2](NO3)2·2H2O 4 and [Ag2(bib)2(SCN)2] 5 (bib = 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)benzene), have been synthesized and characterized by X-ray diffraction to observe the influence of the counter anions on crystal structures. Each bib acts as a bidentate ligand and every two bib ligands ligate a pair of Ag(I) ions resulting in a [2∶2] metallomacrocyclic motif that is further stabilized by intracyclic π–π interactions. 3 exhibits a dimeric structure, while 1, 2 and 4 are 1-D coordination polymers extended via interconnection of the dimeric units by the oxygen atoms from XO3− (X = Br and Cl) anions or Ag(I)⋯Ag(I) interactions. In 5, each Ag(I) ion is four-coordinate, and each dimeric unit is linked to the four adjacent dimeric units by four μ-sulfur atoms from SCN− groups into 2-D layer and further packed in 3-D network via hydrogen bonds. The photoluminescent properties of 1–4 have been observed in the solid state and dichloromethane solution at room temperature. The possible emission mechanisms have been proposed based on molecular orbital (MO) calculations.

Two new neutral polymeric layer compounds, [Cu3(bpy)2(Hip)2(ip)2] (1) and [Cu3(phen)2(Hip)2(ip)2] (2) (bpy = 2, 2′-bipyridine, phen = 1, 10-phenanthroline, ip = isophthalate), have been synthesized under hydrothermal conditions and characterized by X-ray crystallography. Complex 1 crystallizes triclinic, P1¯ (No. 2), a = 10.352(5), b = 10.859(6), c = 11.602(6)A, α = 83.25(1), β = 84.71(1), γ = 66.19(1)°, V = 1183.5(11)A3, Z = 1; 2 triclinic, P1¯ (No. 2), a = 10.375(1), b = 10.668(1), c = 11.758(1)A, α = 83.179(2), β = 86.228(2), γ = 71.187(2)°, V = 1222.7(2)A3, Z = 1. The complexes consist of trinuclcear copper units that are bridged via two ip ligands forming zigzag polymeric chains. These chains are further extended into layers via aromatic π-π interactions as well as hydrogen bonds between the free carboxyl groups and carboxylates. Synthese und strukturelle Charakterisierung von zwei neuen 2D-Isophthalatverbruckten Kupfer(II)-Polymeren mit Cu3-Einheiten Zwei neue polymere Schichtverbindungen, [Cu3(bpy)2(Hip)2(ip)2] (1) und [Cu3(phen)2(Hip)2(ip)2] (2) (bpy = 2, 2′-bipyridin, phen = 1, 10-phenanthrolin, ip = isophthalat), wurden unter hydrothermalen Bedingungen synthetisiert und mittels Rontgen-Kristallstrukturanalyse charakterisiert. Complex 1 kristallisiert triklin, P1¯ (No. 2), a = 10.352(5), b = 10.859(6), c = 11.602(6)A, α = 83.25(1), β = 84.71(1), γ = 66.19(1)°, V = 1183.5(11)A3, Z = 1; 2 triklin, P1¯ (No. 2), a = 10.375(1), b = 10.668(1), c = 11.758(1)A, α = 83.179(2), β = 86.228(2), γ = 71.187(2)°, V = 1222.7(2)A3, Z = 1. Die Komplexe bestehen aus dreikernigen Kupfer-Einheiten, die uber zwei ip-Liganden unter Bildung von polymeren zick-zack-Ketten verbruckt sind. Diese Ketten bilden Schichten uber aromatische π-π-Wechselwirkungen und Wasserstoffbruckenbindungen zwischen den freien Carboxyl-Gruppen und Carboxylaten.

Four novel aqua-bridged dinuclear complexes with a formula M 2 (μ-H 2 O)(μ-OAc) 2 (Im) 4 (OAc) 2 (where Im=imidazole, M=Mg 2+ 1 , Mn 2+ 2 , Ni 2+ 3 and Co 2+ 4 ) have been synthesized and characterized. Complexes 1 , 2 and 3 have been characterized by X-ray crystallography. Two M 2+ ions are bridged by an aqua molecule and two carboxylate anion with M⋯M=3.635–3.777 A, M–OH 2 =2.109–2.246 A and M–OH 2 –M=114.4–119.0°, respectively. Each complex is further stabilized by two intramolecular hydrogen bonds between the hydrogens of the bridging aqua and the oxygens of the terminal monodentate acetates with a distance of O⋯O=2.6 A. The terminal monodentate acetates display ‘reversed’ C–O distances, namely the C–O(free) distances are actually longer than the C–O(coordinating) distances. This abnormal geometry of a monodentate carboxylate would be caused by the strong ‘pulling effect’ on the terminal carboxylates by intra- and intermolecular hydrogen bonds. The O–H stretching vibration of the bridging water was identified at ca. 2328 cm −1 in IR spectra based on the deuterium isotope shift. The solid state 13 C and 15 N NMR spectra of 1 displayed two sets of peaks for acetate and Im ligands, respectively, consistent with the presence of two types of coordination modes of acetate and the two symmetrically non-equivalent Im as revealed by X-ray structure. 15 N chemical shift of NH in Im ligands underwent about 6 ppm downfield shift due to its involvement in an intermolecular hydrogen bond.

Two di- and a tetranuclear zinc−carboxylate complexes with different coordination modes, [Zn2L(μ1,3-OAc)2](ClO4) (1), [Zn2L(μ1,3-Pro)2](ClO4) (2), and [Zn2L(μ1,1-HCO2)(μ1,3-HCO2)]2(ClO4)2 (3) (wher...

The reaction of Δ/Λ-[Ru(bpy)2(py)2](2+) with a prochiral sulfide ligand, and then in situ oxidation, provide the corresponding Δ-[Ru(bpy)2{(R)-OSO-iPr}](+) and Λ-[Ru(bpy)2{(S)-OSO-iPr}](+) (OSO-iPr = 2-isopropylsulfonylbenzonate) enantiomers in a yield of 83% with 98% ee. The chiral sulfoxides were obtained by treatment of the sulfoxide complexes with TFA in a yield of 90% with 88-91% ee.

The reactions of divalent metal acetate (M=Cd II , Co II , Cu II , Mn II and Ni II ) with 2,2′-bipyridine (bpy) were systematically observed at a ratio of 1:1 in methanol solution. Three kinds of complexes were isolated: mononuclear [Ni(bpy)(OAc) 2 (H 2 O) 2 ] ( 6 ), binuclear [Cd 2 (bpy) 2 (OAc) 4 (H 2 O) 2 ] ( 7 ) and [Cu 2 (bpy) 2 (OAc) 4 ]·2H 2 O ( 8 ), linear trinuclear [M 3 (bpy) 2 (OAc) 6 ] (M=Co II ( 11 ) and Mn II ( 12 )). When 1.5 equivalent NaClO 4 was added to the reaction solution, respectively two kinds of complexes were obtained: mononuclear [M(bpy) 2 (OAc)](ClO 4 )· n H 2 O (M=Cd II ( 1 ), Co II ( 2 ), Mn II ( 3 ) and Ni II ( 4 )) and binuclear [M 2 (bpy) 2 (μ-OAc) 3 ](ClO 4 ) (M=Cu II ( 9 ) and Zn II ( 10 )). The structures of complexes 1 , 7 and 11 were determined by X-ray diffraction analysis. Complex 7 is the first example of a dicadmium complex linked by two monoatomic bridging acetate ligands with the longest distance of 3.380(4) A between the dangling acetate oxygen and metal atoms. Several novel structural features in complex 7 have been found in comparison with the monodentate bridging carboxylate with no or only weak interaction between the dangling acetate oxygen atom and metal atom. The structure of complex 11 consists of linear trinuclear molecules; each pair of cobalt atoms are bridged by three acetate groups, two of them acting as bidentate bridging mode and the third as a monoatomic bridge plus bidentate chelating mode, at a distance of 3.459 A. The central cobalt(II) coordinates by six oxygen atoms from six different acetate groups, and the terminal ones have a distorted environment of four oxygen atoms and two nitrogen atoms from a bpy ligand.

The recent studies on supramolecular system assembled by Ru(II) polypyridyl complexes and B-form double-stranded DNA is reviewed. These complexes have been studied as DNA spectroscopic tags and structural probes. The studies focus on the recognition parameters of these complexes binding to DNA, including the influence of the shape and size of intercalative ligand, the ancillary ligands and the effects of hydrogen bonding. Enantioselectivities of these complexes binding to DNA are also briefly discussed.

A staggered arrangement like that of the hydrogen atoms in ethane is exhibited by the six phenol groups about each pair of silver atoms in the self-assembled three-dimensional coordination networks [Ag(2)(H(2)L)(3)](n)X(2n) (H(2)L=N,N'-bis(salicylidene)-1,4-diaminobutane; X(-)=NO(3)(-) or ClO(4)(-)); the former is depicted (for clarity the H(2)L ligands are represented by long rods and the Ag atoms by hatched circles). These solids contain short ligand-unsupported metal-metal bonds and display intense blue photoluminescence at room temperature.

Two monomeric zinc complexes, [Zn(H2biim)2(H2O)2](OAc)2·OHCH2CH2OH (H2biim=2,2′-biimidazole) (1) and [Zn(bipy)2(H2O)(CF3CO2)](ClO4) (bipy=2,2′-bipyridine) (2), have been synthesized and characterized by NMR and single-crystal structural analysis. The zinc ions in both complexes are coordinated in a distorted N4O2 octahedral geometry: the zinc ion in complex 1 is surrounded by two aqua [Zn–O 2.150 (3) A] and two H2biim ligands (Zn–N 2.150 A), the acetate groups act as counter-anions and form hydrogen bonds with H2biim; the zinc ion in 2 is ligated by two bipy ligands (Zn–N 2.144 A), one aqua molecule [Zn–O 2.148(2) A] and one monodentate carboxylate [Zn–O 2.154(2) A]. In both complexes, the aqua ligand forms strong donor hydrogen bonds with the hydroxyl or carboxylate groups, being analogous to those found for the active sites of several zinc enzymes.

A novel asymmetric ligand 3-(pyrazin-2-yl)-as-triazino[5,6-f ]1,10-phenanthroline (pztp) and its mono- and bi-nuclear complexes [Ru(bpy)2(pztp)]2+ 1 and [(bpy)2Ru(pztp)Ru(bpy)2]4+ 2 (bpy = 2,2′-bipyridine) have been synthesized and characterized by UV/VIS, IR, 1H NMR and mass spectra. The electrochemical behaviours of complexes 1 and 2 were observed and displayed oxidation potentials at 1.37 and 1.39 and 1.60 V vs. saturated calomel electrode, respectively. The binding of the two complexes with calf thymus DNA has also been investigated by a spectrophotometric method and viscosity measurements. The results indicated that the two complexes interact with DNA in sharply different ways. The mononuclear complex 1 intercalates into DNA base pairs despite its small hypochromicity value, while the binuclear complex 2 binds to DNA via electrostatic interaction. The circular dichroism signals of the dialysates of the racemic complexes against calf thymus DNA are discussed.

The ruthenium(II) complexes [Ru(dmb)2(LH)][ClO4]2 [dmb = 4,4′-dimethyl-2,2′-bipyridine; LH = 2-(4-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline (PNOPH), 2-(3-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline (MNOPH) and 2-(2-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline (ONOPH)] and their deprotonated complexes have been synthesized and characterized. The electrochemical behaviour of these complexes were examined and compared to that of [Ru(dmb)3]2+. Non-linear optical (NLO) properties of the complexes were investigated using Z-scan techniques. All of the complexes exhibit both NLO absorption and self-defocusing effect (n2 = –0.79 × 10–17 to –1.44 × 10–17 m2 W–1, α2 = 3.00 × 10–11 to 7.09 × 10–11 m W–1, [M] = 5 × 10–5 mol dm–3 in acetonitrile solution). The corresponding effective NLO susceptibilities |χ (3)| of the complexes are 2.86 × 10–12 to 5.07 × 10–12 esu. The results indicate that the substitution and deprotonation of the ligand have an effect on the NLO properties of the complexes. Finally, the crystal structure of [Ru(dmb)2(PNOP)][ClO4]·H2O·0.5C6H6 was determined by X-ray diffraction analysis; it contains two twisted dmb ligands and the bidentate ligand PNOP with torsional angles between each dmb ring pair of 3.4 and 8.7°.

Two one dimension copper (II) polymer chain complexes with an identical molecular formula, [Cu (dien) (OAc) ] n (ClO4) n, but different stuctural features were synthesized through the reaction of Cu2 (OAc) 4 · 2H2O with M (dien) 2 (ClO4) 2 (M = Cu2, Ni2 and Zn2 ; dien = diethylenetriamine) . In complex 1, the geometry at each Cu (II) ion is a distorted octahedron (4+2) (D. K. Towle, et al. Inorg. Chem. 1988, 27, 394–399) ; while in complex 2, that is pentacoordinate and best described as a distorted trigonal bipyramid. The acetate groups act as monodentate bridging mode in 1, but as single syn-anti bridging fashion (Cu — O = 2.008 (10) and 2.062 (11) A) in 2. These provide a good example for the suggested pathway in the ‘‘carboxylate shift’’. The isomer can also be diagnosed by FT-IR and FT-Raman spectroscopies, and X-ray powder diffraction.

Three monomeric nickel complexes [Ni(bipy)(O2CMe)2(H2O)2] 1 (bipy = 2,2′-bipyridine), [Ni(dmbipy)(O2CMe)2(H2O)2] 2 (dmbipy = 4,4′-dimethyl-2,2′-bipyridine) and [Ni(phen)(O2CMe)2(H2O)2]·0.5H2O 3 (phen = 1,10-phenanthroline) have been synthesized and characterized by single-crystal X-ray diffraction methods. In complexes 1 and 2 the molecules are self-assembled via double intermolecular hydrogen bonds to form one-dimensional infinite zigzag chains, which are stacked next to each other through the diimine aromatic rings in a zipper-like fashion, giving a novel two-dimensional co-operating structure. In 3 the molecule is linked by a hydrogen bond to form a one-dimensional chain, which is further associated with another adjacent chain via double hydrogen bonds forming a double chain. These double chains are intercalated to each other through the π–π interaction giving a novel two-dimensional structure.

Imidazo[4,5-f]1,10-phenanthroline (ip), 2-phenylimidazo[4,5-f][1,10]phenanthroline (pip) and their (bipy) 2 Ru 2+ complexes (bipy = 2,2′-bipyridine) have been synthesized and characterized. The oxidation potentials of [Ru(bipy) 2 (ip)] 2+ and [Ru(bipy) 2 (pip)] 2+ were found to be 1.254 and 1.284 V vs. saturated calomel electrode respectively; the reduction of ip and pip appears to be irreversible at ca. -0.85 V. The photophysical properties of the complexes were perturbed in the presence of calf thymus DNA. The distinct changes including hypo- or hyper-chromicity at different UV/VIS absorption bands, enhancements of integrated emission intensity and excited-state lifetime, and efficiency of emission quenching by [Fe(CN) 6 ] 4- all indicate the stronger binding affinity to DNA of [Ru(bipy) 2 (pip)] 2+ over that of [Ru(bipy) 2 (ip)] 2+ , consistent with the greater planar area and extended π system of the pip ligand. The luminescence of the complexes showed monoexponential decay at any [DNA]∶[Ru] ratio. The circular dichroism signals of the dialysates of the racemic complexes against calf thymus DNA suggest that the complexes bind to the DNA with enantioselectivity favouring the Δ isomers. These phenomena all suggest that the complexes bind through intercalation of ip or pip into base pairs. The crystal structure of [Ru(bipy) 2 (ip)][ClO 4 ] 2 ·H 2 O was determined; it contains the planar bidentate ligand ip and two twisted bipy ligands with torsional angles between each bipyridine ring pair of 5.7 and 8.6°.

Two monomeric complexes [M(Him)2(O2CMe)2](M = ZnII1 or CoII2, Him = imidazole) have been synthesized and structurally characterised by X-ray analysis. The complexes are isostructural. In each structure the metal atom is co-ordinated by a pair of acetate groups and a pair of Him ligands in a distorted-tetrahedral N2O2 environment with M–O 1.965(3)–1.991(2) and 1.972(4)–2.013(4)A, and M–N 1.996(2)–2.005(2) and 2.020(4)–2.030(5)A for 1 and 2, respectively. The solid-state structures of both complexes involve intermolecular N–H ⋯ O hydrogen bonds between the non-co-ordinated Him nitrogen atoms and the acetate oxygen atoms, with the acetate groups acting in both syn and anti modes, resulting in two types of carboxylate–imidazole–metal systems analogoues to those found for metalloenzymes. The IR, Raman and 13C NMR spectra of the complexes have been recorded and discussed in relation to the crystal structures.

The title compound, [Zn(C15H13N2O)Cl(C15H14N2O)], has a mononuclear structure, in which the central zinc ion is coordinated by two benz­imidazole N atoms, one phenolate O atom and a chloride ion in a distorted tetrahedral arrangement. In the crystal structure, there are intramolecular π–π stacking interactions between the phenol and benz­imidazole ring systems; intermolecular π–π stacking interactions between the benz­imidazole ring systems of adjacent mol­ecules are also present. A strong intermolecular O—H⋯O hydrogen bond is also observed.

The title compound, [Mn(C6H2O4S)(C10H8N2)(H2O)3]·0.5C10H8N2·3H2O or [Mn(tdc)(bpy)(H2O)3]·3H2O·0.5(bpyn) (tdc is thio­phene-2,5-di­carboxyl­ate, bpy is 2,2′-bi­pyridine and bpyn is 4,4′-bi­pyridine), crystallizes in space group P\overline 1. Complex molecules are linked into one-dimensional chains, running along the b axis, by hydrogen bonds between the coordinated aqua ligands and uncoordinated carboxyl­ate groups of tdc. Double-stranded chains consist of two of the one-dimensional chains and uncoordinated centrosymmetric bpyn mol­ecules, connected by hydrogen bonds between N atoms of the bpyn mol­ecules and coordinated aqua ligands. These double chains are further assembled into layers parallel to the ab plane, which extend into three-dimensional networks via hydrogen bonds between the coordinated and uncoordinated water molecules, and O atoms of tdc.

Two cobalt(III) complexes with phenanthroline, [Co(phen)2(gly)]Cl2 · 4H2O (1) and [Co(phen)2(H2O)2](NO3)3 · 2H2O (2), (phen = phenanthroline and gly = glycine), were synthesized and characterized by IR and NMR spectra. Their structures were determined by single crystal X-ray diffraction techniques. The coordinated cations all contain a six-coordinated cobalt atom chelated by two phen ligands and one gly anion or two aqua ligands in cis arrangement. The CoN bond distances in the cations lie in the range 1.934–1.952 A, the bond distances of CoO = 1.919 A (H2O) are significantly longer than that of CoO = 1.884 A (COO−). The complex 2 contains a crystallographic two-fold axis.

A new anion sensor [Ru(bpy)(2)(DMBbimH(2))](PF(6))(2) (3) (bpy is 2, 2'-bipyridine and DMBbimH(2) is 7,7'-dimethyl-2,2'-bibenzimidazole) has been developed. Its photophysical, electrochemical and anion sensing properties are compared with two previously investigated systems, [Ru(bpy)(2)(BiimH(2))](PF(6))(2) (1) and [Ru(bpy)(2)(BbimH(2))](PF(6))(2) (2) (BiimH(2) is 2,2'-biimidazole and BbimH(2) is 2,2'-bibenzimidazole). The high acidity of the N-H fragments in these complexes make them easy to be deprotonated by strong basic anions such as F(-) and OAc(-), and they form N-H···X hydrogen bonds with weak basic anions like Cl(-), Br(-), I(-), NO(3)(-), and HSO(4)(-). Complex 3 displays strong hydrogen bonding with these 5 weak basic anions, with binding constants between 17,000 and 21,000, which are larger than those observed in complex 1, with binding constants between 3300 and 5700, and in complex 2, which shows no hydrogen bonding toward Cl(-), Br(-), I(-), and NO(3)(-), and forms considerable hydrogen bonds with HSO(4)(-) with a binding constant of 11,209. These hydrogen bonding behaviours give different NMR, emission and electrochemical responses. The different anion binding affinity of these complexes may be mainly attributed to their different pK(a1) values, 7.2 for 1, 5.7 for 2, and 6.2 for 3. The additional methyl groups at the 7 and 7' positions of complex 3 may also play an important role in the enhancement of anion binding strength.

Two new complexes [Co(H2O)6 Co8(L1)12]X6 x n H2O (X = NO3(-), n = 12 (1); X = HCO3-, n = 24, (2); HL1 = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol) have been synthesized and characterized by single-crystal X-ray diffraction. A [Co(H2O)6](2+) ion is encapsuled in the central cavity of the cubelike nanocage [Co(H2O)6 Co8(L1)12](6+) cation, assembled by eight cobalt ions at the corners and twelve bis-bidentate ligands L1 as the edges, via the formation of 12-fold strong hydrogen bonds between the six coordinated water molecules and the oxygen atoms of twelve L1 as a guest. Complex 1 crystallizes in a centrosymmetric space group P1, while 2 is in a very high symmetric space group Im3. In 2, a planar [(HCO3)2](2-) dimer motif R2(2)(8) synthon plus six lattice water molecules constitute a planar supramolecular synthon R8(8)(20), which acts as a four connector, generating a 3D hydrogen-bonded NbO net with cubelike host cavities of approximately 20 A diameter. Interestingly, the cubelike nanocage [Co(H2O)6 Co8(L1)12](6+) cations fill in the cavities as templates. The magnetic properties of 1 have also been studied in the temperature range of 2-300 K, and its magnetic susceptibility obeys the Curie-Weiss law, showing antiferromagnetic coupling.

In the solid state, interlocking of the lateral phen ligands at the acute angle sites of the molecular [Cu2(bpa)2-(phen)2(H2O)]2 rhombi via aromatic pi-pi stacking interactions into the cavities of the adjacent rhombi generates laminated polyrotaxanes that are further assembled into a 3D network via similar interactions between the phen ligands at the obtuse angle sites.

Acenaphtheno[1,2-b]-1,4,8,9-tetraazatriphenylene (atatp) and its complexes [Ru(L)2atatp](ClO4)2 x nH2O (L = 2,2'-bipyridine (bpy), n=2 (1); 1,10-phenanthroline (phen), n=2 (2); and 2,9-dimethyl-1,10-phenanthroline (dmp), n=1 (3)) have been synthesized and characterized by elemental analyses and 1H NMR. The spectral and electrochemical properties of these complexes are also examined. Complexes 1 and 2 display bright luminescence in acetonitrile but very weak luminescence in water solution. However, complex 3 is not luminescent in either solvent. The interaction of the complexes with calf thymus DNA (CT-DNA) has been studied by absorption, emission and viscosity measurements. The intrinsic binding constants of complexes 1 and 2 are 7.6 x 10(4) and 8.8 x 10(4) M(-1) respectively. The relatively low affinities of complexes 1 and 2 with DNA may arise from the atatp ligand, indicating that the size and shape of the intercalated ligand have a marked effect on the strength of interaction. Complexes 1 and 2 bind with CT-DNA in an intercalative mode but complex 3 in a non-intercalative one, showing that changing the ancillary ligand affects not only the binding magnitude, but also the binding mode of the interaction.

A series of enantiomerically pure polypyridyl ruthenium(II) complexes, delta- and lambda-[Ru(bpy)2 (HPIP)](PF6)2 (delta-1 and lambda-1; bpy=2,2'-bipyridine, HPIP = 2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), delta and lambda-[Ru(bpy)2(HNAIP)](PF6)2 (delta-2 and lambda-2; HNAIP = 2-(2-hydroxy-1-naphthyl)imidazo[4,5-f][1,10]phenanthroline), delta- and lambda-[Ru(bpy)2 (HNOIP)](PF6)2 (delta-3 and lambda-3; HNOIP = 2-(2-hydroxy-5-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline), and delta- and lambda-[Ru(bpy)2(DPPZ)](PF6)2 (delta-4 and lambda-4; DPPZ= dipyridophenazine), have been synthesized. Binding behavior of these chiral complexes to calf thymus DNA (CT-DNA) has been investigated by electronic absorption, steady-state emission, and circular dichroism spectroscopies, as well as by viscosity measurements and equilibrium dialysis binding studies. Several points came from the results. (1) The DNA-binding properties were distinctly different for the [Ru(bpy)2L]2+ (L=HPIP, HNAIP, HNOIP) series of ruthenium(II) complexes, which indicates that the photophysical behavior of the complexes on binding to DNA can be modulated through ligand design. (2) Different binding rates of individual enantiomers of complexes 1 and 4 to DNA were observed through dialysis experiments. The lambda enantiomer bound more rapidly than the lambda enantiomer and their different intercalative binding geometries were suggested to be responsible. (3) Both delta-2 and lambda-2 bound weakly to CT-DNA; delta-2 may bind through a partial intercalation mode, whereas lambda-2 may bind in the DNA groove. (4) There was no noticeable enantioselectivity for complexes 1, 3, and 4 on binding to CT-DNA. Both of their enantiomers can intercalate into DNA base pairs. It is noted that delta-3 and lambda-3 exhibited almost identical spectral changes on addition of CT-DNA, and a similar binding manner of the isomers to the double helix was proposed.

Two structurally related ligands (L) 4,5,9,18-tetraazaphenanthreno[9,10- b ] triphenylene (taptp) and 2,3-diphenyl-1,4,8,9-tetraazatriphenylene (dptatp), and their related complexes of [Ru(bpy) 2 L] 2+ have been synthesized and characterized by elemental analyses, 1 H NMR and mass spectra. Their electrochemical properties were also examined. Both complexes emit intense luminescence in organic solvent but are quenched in water to different extents. The interactions of the complexes with calf thymus DNA have been investigated by viscosity, absorption, emission and circular dichroism spectra. The intrinsic binding constants of [Ru(bpy) 2 (taptp)] 2+ and [Ru(bpy) 2 (dptatp)] 2+ are 1.7×10 5 and 3.8×10 4 M −1 , respectively. All data indicate that both complexes bind enantioselectively to double-stranded calf thymus DNA via the intercalative mode, with stronger affinity for the fully planar ligand complex of [Ru(bpy) 2 (taptp)] 2+ .

In the crystal structure of the title complex, C10H8N2·C6H4O4S or bpy·tdc (bpy is 4,4′-bi­pyridine and tdc is thio­phene-2,5-di­carboxyl­ic acid), bpy and tdc form one-dimensional zigzag chains as a result of O—H⋯N hydrogen bonds. These chains are further assembled into layers by van der Waals attractions, which are extended into a three-dimensional network by van der Waals and aromatic π–π stacking interactions.

Six possible isomers of mer-[M(II)(N,N,O-L)(2)] complex were observed in the solid state, in which spontaneous resolution of S,S-Lambda and R,R-Delta enantiomers of mer-[Co(N,N,O-L3)(2)] was achieved via pi-pi interactions.

A (10,3)-b framework is constructed by the reaction of [Ru(H2Biim)3](PF6)2 and trimesic acid in a ratio of 1 : 1, in which the (10,3)-b net exhibits a two-fold interpenetration featuring 1D nano-sized channels. An unprecedented water nanotube consisting of the fused (H2O)28 with a double crown fashion, anchors in the channel.

Two novel complexes Mg2(µ-H2O)(µ-OAc)2(L)4(OAc)2 (L = imidazole or benzimidazole) have been synthesized and characterized; they contain the first example of an aqua-bridged dimagnesium core, and may have implications for the hydrolytic activity of dimetallic hydrolases.