Coinage (Cu,Ag) metal derivatives of salicylaldehyde N-ethylthiosemicarbazone: synthesis,spectroscopy, and structures

Reactions of copper(I) halides with triphenyl phosphine in acetonitrile followed by the addition of salicylaldehyde N-ethylthiosemicarbazone {(2-OH–C₆H₄)(H)C²=N³–N²H–C¹(=S)N¹HEt, H₂stsc-NEt} in chloroform in 1?:?2?:?1 (Cl) or 1?:?1?:?1 (Br, I) molar ratios yield mononuclear, [CuCl(η ¹-S-H₂stsc-NHEt)(PPh₃)₂] (1) and sulfur-bridged dinuclear, [Cu₂X₂(μ-S-H₂stsc-NEt)₂(PPh₃)₂] (X?=?Br, 4; I, 5) complexes. Similarly, reaction of silver halides (Cl, Br) with H₂stsc-NEt in acetonitrile followed by the addition of PPh₃ to the solid that formed (1?:?1?:?2 molar ratio), yielding mononuclear complexes, [AgX(η ¹-S-H₂stsc-NHEt)(PPh₃)₂] (Cl, 2; Br, 3). All these complexes are characterized with analytical data, IR, and NMR spectroscopy and single-crystal X-ray crystallography. The ligand favored η ¹-S bonding in 1, 2, and 3, and μ-S bonding in 4 and 5. Cu?···?Cu contacts were 3.063?Å. The complexes form 1-D or 2-D H-bonded networks, entrapping solvent in some cases.     

Oximato-bridged copper(II) compounds: syntheses,molecular structures,magnetic, thermal and spectroscopic properties

Reaction of the Schiff base, 1-(4-methylimidazol-5-yl) phenylhydrazonopropane-2-one oxime (LH), with copper(II) perchlorate hexahydrate and copper(II) nitrate trihydrate in a 1 : 1 M proportion in methanol affords [Cu₂L₂(H₂O)(ClO₄)](ClO₄) (1) and [Cu₂L₂(H₂O)₂](NO₃)₂] (2) in moderate yields. Both 1 and 2 have been characterized by elemental analysis, ESI-MS, FT-IR, UV–vis absorption spectroscopy, EPR, electric conductivity, and magnetic susceptibility measurements. The X-ray crystal structures of 1·CH₃COCH₃ and 2 have been determined. Both compounds are dinuclear copper(II) complexes, with each copper μ₂-bridged by two oxime ligands in a μ₂-η¹,η² fashion. Variable temperature magnetic studies on 1 and 2 show that both compounds are dominated by an antiferromagnetic coupling through the oxime bridges.     

Acetamidiniumhexafluorometallate von Aluminium,Gallium, Indium,Vanadium, Chrom,Mangan, Eisen und Cobalt

Acetamidiniumhexafluorometallates of Aluminium, Gallium, Indium, Vanadium, Chromium, Manganese, Iron and Cobalt The title compounds were crystallized from F-containing aqueous solutions of their hexafluoro-metallate acids by adding acetamidine. Their unit cells were determined and the thermal decomposition was investigated thermoanalytically. The crystal structure of [CH₃C(NH₂)₂]₃AlF₆ was determined: Space group P4₁2₁2/P4₃2₁2, a = 8,987(1), c = 17,894(3) Å, R = 0,054. The unit cell parameters: .     

Kalium-Lanthanoid-Carbonate,KM(CO3)2 (M  Nd,Gd, Dy,Ho, Yb)

Potassium Lanthanoid Carbonates, KM(CO₃)₂ (M ? Nd, Gd, Dy, Ho, Yb) The ternary potassium lanthanoid carbonates KM(CO₃)₂ (M ? Nd, Gd, Dy, Ho, Yb) are obtained as single crystals by high-pressure synthesis in steel autoclaves with carbon dioxide (starting pressure approximately 50 bar at ambient temperature) in the presence of water from a mixture of K₂CO₃ and MCl₃ · x H₂O (x = 7 and 6, respectively) at 450°C within 4 weeks. In KNd(CO₃)₂ (orthorhombic, Pmn2₁, Z = 4, a = 973.1(2), b = 645.69(8), c = 855.58(14) pm, R₁ = 0.0763 for all data) [Nd-μ₁-(CO₃)₃-μ₂-(CO₃)₃] polyhedra are connected three-dimensionally to [Nd(CO₃)] layers as similarly in UO₂(CO₃); these layers are connected via the second half of the carbonate ligands and K⁺ ions. In KDy(CO₃)₂ (monoclinic, C2/c, Z = 4, a = 853.8(2), b = 949.1(1), c = 694.5(1) pm, β = 111.1(2)°, R₁ = 0.0266 for all data) and in the isotypic carbonates KM(CO₃)₂ (M = Gd, Ho, Yb) the polyhedra [Dy-μ₁-(CO₃)₄-μ₂-(CO₃)₂] and [K-μ₁-(CO₃)₆] are connected to “syndiotactic” zig-zag chains and by further O-ligator atoms of the carbonate ligands such that each zig-zag chain is surrounded by four unlike chains and vice versa.     

Synthesis,characterization, crystal structure,and biological studies of vanadium complexes with glycolic acid

Synthesis, characterization, crystal structure, and biological studies of two complexes with glycolic acid are described. The solid complexes were formulated as K₂[VO(C₂H₂O₃)(C₂H₃O₃)₂] · H₂O (1) and K₂[{VO₂(C₂H₂O₃)}₂] (2) and characterized by X-ray studies, Fourier transform infrared spectroscopy (FTIR), Electron paramagnetic resonance (EPR), and magnetic susceptibility. Conversion of 1 to 2 was studied in aqueous solution by UV–Vis spectroscopy and in the solid state by diffuse reflectance spectroscopy. Complex 2 contains dinuclear [{VO₂(C₂H₂O₃)}₂]^2? anions in which glycolate(2?) is a five-membered chelating ring formed by carboxylate and α-hydroxy groups. The geometry around the vanadium in 2 was interpreted as intermediate between a trigonal bipyramid and a square pyramid. Vanadium(IV) is pentacoordinate in 1 as a distorted square pyramid. Complex 1 contains a vanadyl group (V=O) surrounded by two oxygens from deprotonated carboxylate and hydroxy groups forming a five-membered ring. Two oxygens from different glycolates(1?) are bonded to the (V=O) also. Biological analysis for potential cytotoxic effects of 1 was performed using Human Cervix Adenocarcinoma (HeLa) cells, a human cervix adenocarcinoma-derived cell line. After incubation for 48 h, 1 causes 90 and 95% of HeLa cells death at 20 and 200 μmol L^?1, respectively.     

[Boranato-bis(dimethylphosphonium-methylid)]-Komplexe der do- und d10-Metalle: Li,Be, Mg,Zn, Cd,Hg, Al und Ga

Dehydrohalogenation and metallation of boranato-bis-trimethylphosphonium salts (1), using two equivalents of a lithiumalkyl in tetrahydrofuran, leads to a solvated organolithium reagent H₂B[(CH₃)₂PCH₂]₂Li (3) which can be converted into a 1:1n1-complex with tetramethylethylenediamin (4).3 reacts with anhydrous metal(II) halides to form spirocyclic coordination compounds of the type H₂B[(CH₃)₂PCH₂]₂ M[CH₂P(CH₃)₂]₂BH₂ (5–9,M=Be, Mg, Zn, Cd, Hg). The reaction of [(CH₃)₃PBH₂P(CH₃)₃]Br (1) with lithium tetramethylmetalates Li[M(CH₃)₄],M=Al, Ga, on heating in the absence of a solvent affords the metallocycles H₂B[(CH₃)₂PCH₂]₂ M(CH₃)₂ (10, 11) with evolution of methane. The products can be sublimed from the reaction mixture. The proposed structures of the new compounds, with tetrahedrally coordinated central atoms and strong covalent metal-carbon interactions, are supported by mass, IR and¹H,⁷Li,¹¹B,¹³C, and³¹P NMR spectra. Compound9 represents a rare case of a tetracoordinate organomercurial, compound5 is the first nonionic tetraalkylberyllate.

     

Synthesis,structures, catalytic,and anticancer activities of some coordination compounds involving two new triazole derivatives

Five N-heterocyclic carboxylate-based coordination complexes, [Co(L¹)₂(H₂O)₂]·2H₂O (1), [Cd(L¹)₂(H₂O)₂]·2H₂O (2), [Co(L²)(H₂O)₃] (3), [Ni(L²)(H₂O)₃] (4), and [Cu₂(L²)₂(H₂O)₂] (5), have been synthesized and characterized by elemental analysis, IR spectroscopy, Powder X-ray diffraction, thermogravimetric analyses, and single-crystal X-ray crystallography, where HL¹ is 2-((5-amino-1H-1,2,4-triazol-3-yl)thio)acetic acid and H₂L² is 2-((5-amino-1-(carboxymethyl)-1H-1,2,4-triazol-3-yl)thio)acetic acid. In these complexes, the hydrogen bonds (H-bonds) play an important role in their packing structures. Complex 1 has nine H-bonds showing a 3-D sqc38 topology. Complex 2 has 17 H-bonds exhibiting a 3-D hxl network. Complexes 3 and 4 are isomorphic, both of which possess ten H-bonds to present a 3-D btc topology. Complex 5 with eight H-bonds forms a 2-D sq1 structure. In addition, complex 3 catalyzes the decolorization of methyl orange. Meanwhile, 1, 3, and 5 show certain anticancer activities to inhibit the growth of HepG2 cells.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von [PtX2ox]2−, X = Cl,Br

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of [PtX₂ox]²⁻, X = Cl, Br By treatment of [PtX₄]^2— (X = Cl, Br) with C₂O₄^2— (ox^2—) in water [PtCl₂ox]^2— and [PtBr₂ox]^2— are formed which have been isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of [(C₅H₅N)₂CH₂][PtCl₂ox]·2H₂O ( 1 ) (orthorhombic, space group Pbca, a = 18.451(1), b = 18.256(1), c = 19.913(1)Å, Z = 16) and [(C₅H₅N)₂CH₂][PtBr₂ox] ( 2 ) (monoclinic, space group P2₁/c, a = 7.249(1), b = 10.180(1), c = 21.376(1)Å, β = 93.415(9)°, Z = 4) reveal nearly planar complex anions with C_2v point symmetry. The bond lengths are Pt‐Cl = 2.286, Pt‐Br = 2.405 und Pt‐O = 2.016 ( 1 ) und 2.030Å ( 2 ). In the vibrational spectra the PtX stretching vibrations are observed at 335 and 336 ( 1 ) and 219 and 231 cm^—1 ( 2 ). The PtO stretching vibrations are coupled with internal modes of the oxalato ligands and appear in the range of 350 — 800 cm^—1. Using the molecular parameters of the X‐Ray determinations the IR and Raman spectra of the (n‐Bu₄N) salts are assigned by normal coordinate analysis. The valence force constants are f_d(PtCl) = 1.97, f_d(PtBr) = 1.78 and f_d(PtO) = 2.48 ( 1 ) and 2.38 mdyn/Å ( 2 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 3603.9 ( 1 ) and 3318.1 ppm ( 2 ).     

Conformational Heterogeneity in Diphthalocyaninato(2–)metallates(III) of Sc,Y, In,Sb, Bi,La, Ce,Pr, and Sm

Potassium diphthalocyaninato(2–)metallate(III), K[M(pc^2–)₂] (M = Bi, La, Ce, Pr, Sm, Sb, In) has been prepared by melting the metal chloride, iodide or acetate with 1,2‐dicyanobenzene in the presence of potassium methylate. Crystallisation with tetra(n‐butyl)ammonium bromide or hydroxide ((ⁿBu₄N)Br/OH), tetra(n‐pentyl)ammonium chloride ((ⁿPe₄N)Cl) or bis(triphenylphosphine)iminium halide ((PNP)X; X = Br, I) yields the corresponding red‐purple complex salt (ⁿBu₄N)[M(pc^2–)₂] (M = Bi ( 1 ), La ( 3 ), Ce ( 2 )), (ⁿBu₄N)[M(pc^2–)₂] · x CH₃OH (M = Bi ( 5 ), Pr ( 6 ), Sm ( 7 ); 0 9 x 9 1), (ⁿPe₄N)[La(pc^2–)₂] ( 4 ), (ⁿBu₄N)[Pr(pc^2–)₂] · 2 py ( 10 ), (ⁿBu₄N)[Sb(pc^2–)₂] · 2 thf ( 11 ), (PNP)₂[M(pc^2–)₂]Br · 2 Et₂O (M = Sb ( 12 ), Bi ( 13 )), and (PNP)₂[In(pc^2–)₂]I · 2 Et₂O ( 14 ). Bronze coloured diphthalocyaninato(1–)metal(III) polyiodide, [M(pc^–)₂]I₂ (M = Sc, Y) has been prepared similarly in the presence of ammonium iodide. Reduction with (ⁿBu₄N)OH provides (ⁿBu₄N)[M(pc^2–)₂] · x CH₃OH (M = Y ( 8 ), Sc ( 9 ); 0 9 x 9 1). Spectral properties (UV/VIS/NIR; IR; resonance Raman) of diphthalocyaninates in their different ring oxidation states (2–/2–; 2–/1–; 1–/1–) are discussed. 1 – 3 crystallise in the tetragonal (P4/ncc), 5 – 9 in the orthorhombic (Pna2₁), 10 , 11 in the triclinic (P‐1), and 4 , 12 – 14 in the monoclinic crystal system ( 4 : P2₁/m; 12 : C2/c; 13 , 14 : P2/c). Ecliptic rotamers with skew angles ranging from 4.1° to 6.0° are found in 1 – 3 , and staggered rotamers with skew angles ranging from 35.8° to 45.0° are found in 4 – 14 . The mean M–N_i bond lengths and interplanar distances increase monotonically with the ionic radius of the metal ion. Both distances deviate notably from this linear correlation in the Sb^III and Bi^III derivatives. The discrepancy is presumably due to the sterical dominance of the ns² lone‐pair character. The actual size of eight co‐ordinated Sb^III and Bi^III is estimated to be R₈ ≈ 1.02(Sb)/1.11(Bi) Å. In every complex salt, the pc ligand is severely distorted from planarity and can adopt domed, saddled, waved and mixed non‐planar conformations; the crystal symmetry is the most important factor for the conformational heterogeneity.     

Assignment on the X,A, B,C, and D states of the C6H5Br+ cation based on high‐level calculations

Geometries, frequencies, and energies of the 1²B₁, 1²A₂, 1²B₂, 2²B₁, 2²B₂, and 1²A₁, of the C₆H₅Br⁺ ion were calculated by using CASSCF and CASPT2 methods in conjunction with an ANO‐RCC basis. The CASPT2//CASSCF adiabatic excitation energies and CASPT2 relative energies for the six states are in good agreement with experiment. The X, A, B, C, and D electronic states of the C₆H₅Br⁺ ion were assigned to be X²B₁, A²A₂, B²B₂, C²B₁, and D²B₂ based on the CASSCF and CASPT2 calculations. The assignment on the D state of the C₆H₅Br⁺ ion is different from the previously published works. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Synthesis,characterization, and biological investigation of new mixed-ligand complexes

A novel series of mixed-ligand complexes of 5,5′-{(1E,1E′)-1,4-phenelynebis(diazene-2,1-diyl)}bis(quinolin-8-ol) (H₂L₁) as a primary ligand and 4-aminoantipyrine(L₂) as a secondary ligand with Mn(II) ion were prepared using two general formulae: [Mn₂(H₂L₁)₂(L₂)₂X₄].4Cl (X = OH₂( 1 ), ONO₂⁻( 2 ), Cl=nil; OAc( 3 ), Cl = nil) and [Mn₂(H₂L₁)(L₂)₂(O₂SO₂)₂]( 4 ). Free ligands and their complexes were characterized. Electronic absorption spectra of the mixed-ligand complexes indicate a distorted octahedral geometry around the central metal ion, and the anions X⁻ are in the axial positions for all compounds. The ligands behave in a neutral bidentate manner, through nitrogen atoms and oxygen atoms of the carbonyl group (L₂), whereas H₂L₁ coordinated through nitrogen and OH groups as a neutral bidentate ligand. All complexes do not contain coordinated water molecules, but complex ( 1 ) contains four water molecules. The water molecules are removed in a single step. The complexes exhibited magnetic susceptibility corresponding to five unpaired electrons. The antimicrobial activity of the Mn(II) mixed-ligand complexes ( 1–4 ) against two gram-positive bacteria, three local gram-negative bacteria, and three fungi species was tested. Mn(II) mixed-ligand complex ( 2 ) exhibited significant antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp. Mixed-ligand complex ( 2 ) exhibited a high potential cytotoxicity against the growth of human lung cancer cells.     

A CNDO study of the electronic structure of oxyanions XO4n− with X = Si,P, S,Cl, Ge,As, Se and Br

The orbital order, the bonding properties of the orbitals and the orbital populations are discussed. It is concluded that the orbital order in the valence shell in all the ions is 1a₁, 1t₂, 2a₁, 2t₂, 1e, 3t₂ and 1t₁. The results are compared when possible with experimental data and ab initio results.     

Synthesis,crystal structures,antimicrobial activities,and DFT calculations of two new azido nickel(II) complexes

Two new complexes, [Ni(HL¹)(N₃)(μ_1,1N₃)]₂ (1) [HL¹: NC₅H₄CH₃C=NNH (C=O) NH₂] and [Ni(L²)N₃] (2) [HL²: NC₅H₄HC=N NH(C=S)NH₂], have been synthesized by reaction of Ni(OAC)₂·4H₂O and sodium azide with HL¹ and HL² and characterized by elemental analysis, FT-IR, and UV–vis spectral studies. Single-crystal X-ray diffraction reveals that 1 is dinuclear with nickel(II) in an octahedral environment of NNO donors of HL¹, two nitrogens of azide bridges and one nitrogen of terminal azide; 2 is mononuclear containing nickel(II) in a distorted square-planar environment of NNS donors of HL² and one terminal azide. The structures of 1 and 2 have been optimized by density functional theory. The results of antimicrobial activities of ligands, 1 and 2 demonstrated that HL² and 2 have good antimicrobial activity in contrast with HL¹ and 1, related to the presence of sulfur donor in HL².     

Synthesis,crystal structure,and properties of cobalt,zinc, and manganese coordination polymers based on fluconazole

Three complexes based on fluconazole, namely, {[Co₂(HFlu)(dpa)₂(H₂O)₂]·H₂O}_n (1), {[Zn(HFlu)(IPA)]·H₂O}_n (2), and {[Mn(HFlu)₂(IPA)(H₂O)]·H₂O}_n (3) (HFlu?=?fluconazole, 2-(2,4-difluoro-phenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol; H₂dpa?=?diphenic acid; H₂IPA?=?isophthalic acid) have been synthesized. Single-crystal X-ray analysis revealed that 1 is a 2-D-network framework containing a trinuclear Co(II) unit, 2 is a 3-D framework, and 3 is 1-D double chain structure with a Mn₂ metallocyclic core. The complexes have also been characterized by elemental analyses, IR, UV/vis and fluorescence spectroscopy, and thermal gravimetry. The phase purity of these polymers has been confirmed via powder X-ray diffraction.     

1‐Aminoindan‐2‐ol,a Suitable Ligand for the Synthesis of Chiral,Intramolecularly Stabilized Compounds of Aluminum,Gallium, and Indium

The reactions of enantiomerically pure (1R, 2S)‐(+)‐cis‐1‐aminoindan‐2‐ol, (1S, 2R)‐(‐)‐cis‐1‐aminoindan‐2‐ol, and racemic trans‐1‐aminoindan‐2‐ol with trimethylaluminum, ‐gallium, and ‐indium produce the intramolecularly stabilized, enantiomerically pure dimethylmetal‐1‐amino‐2‐indanolates (1R, 2S)‐(+)‐cis‐Me₂AlO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 1 ), (1S, 2R)‐(‐)‐cis‐Me₂AlO‐2C*HC₇H₆‐1‐C*HNH₂ ( 2 ), (1R, 2S)‐(+)‐cis‐Me₂GaO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 3 ), (1R, 2S)‐(+)‐cis‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 4 ), (1S, 2R)‐(‐)‐cis‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 5 ), and racemic (+/‐)‐trans‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 6 ). The compounds were characterized by ¹H NMR, ¹³C NMR, ²⁷Al NMR and mass spectra as well as 1 and 3 to 6 by determination of their crystal and molecular structures. The dynamic dissociation/association behavior of the coordinative metal‐nitrogen bond was studied by low temperature ¹H NMR spectroscopy.     

Organylarsino-substituierte Schwefeldiimide: Die Kristallstrukturanalysen von 3, 7-Di-t-butyl-3H, 7H,-1λ4, 5λ4, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocin und Bis(diphenylarsino)schwefeldiimid

Organoarsino-Substituted Sulphur Diimides: Crystal Structure Analyses of 3, 7-Di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine and Bis (diphenylarsino)sulphur Diimide Reaction of the salt K₂SN₂ with organoarsenic chlorides leads to sulphur diimides containing organoarsino substituents at both ends. Single crystal X-ray structure analyses were carried out for two typical compounds, i.e. the cyclic eight-membered 3, 7-di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine ( 1a , prepared from K₂SN₂ and (t-Bu)AsCl₂ (1:1)) and the open-chain bis(diphenylarsino)sulphur diimide ( 2a , prepared from K₂SN₂ and Ph₂AsCl (1:2)). In both compounds the sulphur diimide groups are coplanar with their directly bound arsenic atoms. This coplanarity principle leads, in the case of 1a , to about conformation (mm2(C_2v) symmetry) of the eight-membered heterocycle; the t-butyl substituents occupy quasi equatorial positions. Small deviations from mm2 symmetry and torsions around the S?N bonds up to 12° can be explained as a consequence of the transnnular repulsion of the lone pairs at the arsenic atoms (As …As distance 3.683(1) Å). In the case of the open-chain S(N? AsPh₂)₂ ( 2a , 2(C₂) symmetry), a cis, cis configuration was found at the S?N double bonds which indicates As…As interaction. The As…As distance (3.379(1) Å) is shorter than in 1a and parallells a reduced interaction of the lone pairs at the As atoms. The S?N bond lenghts (1.517(5) Å in 1 a and 1.521(3) Å in 2a ) are characteristic of sulphur diimides withoug significant π-interaction with the substituents and correspond to S^IV?N double bonds.     

Five-, six- and eight-membered ring organosilicon chalcogenides of the types Z2(SiMe2)2E (Z = Me2Si, H2C; E = S, Se, Te), Z(SiMe2E)2MR2 (Z = Me2Si, H2C, O; E = S, Se, Te; M = Si, Ge, Sn, R = Me, Ph) and (SiMe2ZSiMe2E)2 (Z = Me2Si, H2C; E = S, Se)

Reactions of ClMe₂Si–Z–SiMe₂Cl (Z = SiMe₂ (1a), CH₂ (1c), O (1e)) with Li₂E (E = S, Se) yielded eight-membered ring compounds (SiMe₂ZSiMe₂E)₂ (3a–d) as well as acyclic oligomers (SiMe₂ZSiMe₂E)_x of different chain lengths. If 1:1 molar mixtures of 1a, 1c or 1e and a diorganodichlorosilane, -germane or -stannane (R₂MCl₂) are reacted with Li₂E (E = S, Se, Te), six-membered ring compounds Z(SiMe₂E)₂MR₂ (4a–7g) are formed exclusively. Five-membered rings Z₂(SiMe₂)₂E (Z = SiMe₂ (8a–c), CH₂ (9a–c); E = S, Se, Te) are obtained starting from the tetrasilane ClMe₂Si–(SiMe₂)₂–SiMe₂Cl (1b) or the disilylethane ClMe₂Si–(CH₂)₂–SiMe₂Cl (1d) by treatment with Li₂E. All products were characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ¹¹⁹Sn, ⁷⁷Se, ¹²⁵Te, including coupling constants) and the effects of the different ring sizes towards NMR chemical shifts are discussed.     

Syntheses,structures, and luminescence of three anion-dependent cadmium coordination polymers

Self-assembly of the flexible ligand 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) with Cd(II) salts gave three coordination polymers {[Cd(ttmb)₂](SO₄)(H₂O)₁₆} _n (1), {[Cd(ttmb)₂(H₂O)₂](NO₃)₂(H₂O)₆} _n (2), and {[Cd(ttmb)₂(H₂O)₂](ClO₄)₂(H₂O)₇} _n (3). Complex 1 has a (3,6)-connected CdCl₂-type 2-D network. However, 2 and 3 show the 2-D (4,4) network and 1-D double chain, respectively. Complexes 1, 2, and 3 exhibit luminescent emission maxima at 306, 339, and 298?nm, respectively, in the solid state at room temperature.     

Possible singlet oxygen generation from the photolysis of indigo dyes in methanol, DMSO, water, and ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate

We suggest that singlet molecular oxygen [¹O₂ (¹Δ_g)] is formed upon irradiation of indigo 1 [in air or O₂-saturated DMSO and DMSO (0.5% H₂SO₄)] and indigo carmine 2 [in air or O₂-saturated CH₃OH, D₂O, and 1-butyl-3-methylimidazolium tetrafluoroborate (BmIm-BF₄)]. The quantum yield for production of ¹O₂ is estimated to be 0.6 for 1 and 0.3-0.5 for 2. The rates of reaction of ¹O₂ with 1 and 2 were determined by monitoring the emission of ¹O₂ at 1270 nm over time. Low molar absorptivities (at 532 nm) and rapid physical quenching caused by 1 and 2 limit their utility as ¹O₂ photosensitizers in solution. Compounds 1 and 2 degrade slowly during the photolysis due to a self-sensitized (type I or II) photooxidation reaction. Oxidative cleavage of 1 by singlet oxygen and superoxide, and 2 by superoxide has been noted before (Kuramoto, N.; Kitao, T. J. Soc. Dyers Color. 1979, 95, 257-261; Kettle, A. J.; Clark, B. M.; Winterbourn, C. C. J. Biol. Chem. 2004, 279, 18521-18525).     

Crystal structures and hydrogen bonding schemes in four benzamide derivatives (2-hydroxy-benzamide, 2-hydroxy-thiobenzamide, 2-hydroxy-N,N-dimethyl-benzamide,and 2-Hydroxy-N,N-dimethyl-thiobenzamide)

Summary 2-Hydroxy-benzamide, C₇H₇NO₂; monoclinic; I2/a-C _2h ⁶ ;a=12.901 (2),b=4.982 (1),c=20.987 (3) Å; =91.50 (2)°;Z=8. 2-Hydroxy-thiobenzamide, C₇H₇NOS; monoclinic; P2₁/n-C _2h ⁵ ;a=13.508 (5),b=6.780 (2),c=15.878 (6) Å; =93.74 (5)°;Z=8. 2-Hydroxy-N,N-dimethyl-benzamide, C₉H₁₁NO₂; orthorhombic; Pbca-D _2h ¹⁵ ;a=11.752 (2),b=16.680 (3),c=9.079 (2) Å;Z=8. 2-Hydroxy-N,N-dimethyl-thiobenzamide, C₉H₁₁NOS; monoclinic; P2₁/c-C _2h ⁵ ;a=6.983 (1),b=11.652 (3),c=11.704 (3) Å; =100.02 (2)°;Z=4. The crystal structures of these four compounds were determined (respectively refined: 2-hydroxy-benzamide) by single crystal X-ray data. The refinements of the structure parameters by least squares methods yielded in all casesR<0.056. The hydrogen atoms were located by means of difference Fourier summations. The O-H ... O distances are 2.513 (1) Å in 2-hydroxy-benzamide (intramolecular) and 2.625 (1) Å in 2-hydroxy-N,N-dimethyl-benzamide (intermolecular). The two O-H ... S distances in 2-hydroxy-thiobenzamide are 2.904 (2) Å and 2.918 (2) Å (intramolecular, two molecules in the asymmetric unit) and 3.228 (2) Å in 2-hydroxy-N,N-dimethyl-thiobenzamide (intermolecular). Clear N-H ... O hydrogen bonds with 2.926 (1) Å and 3.006 (1) Å occur only in the structure of 2-hydroxy-benzamide (intermolecular).

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Die Kristallstrukturen und Wasserstoffbrücken-Bindungsschemata in vier Benzamid-Derivaten

Zusammenfassung 2-Hydroxy-benzamid, C₇H₇NO₂; monoklin; I2/a-C _2h ⁶ ;a=12.901 (2),b=4.982 (1),c=20.987 (3) Å; =91.50 (2)°;Z=8. 2-Hydroxy-thiobenzamid, C₇H₇NOS; monoklin; P2₁/n-C _2h ⁵ ;a=13.508 (5),b=6.780 (2),c=15.878 (6) Å; =93.74 (5)°;Z=8. 2-Hydroxy-N,N-dimethyl-benzamid, C₉H₁₁NO₂; orthorhombisch; Pbca-D _2h ¹⁵ ;a=11.752 (2),b=16.680 (3),c=9.079 (2) Å;Z=8. 2-Hydroxy-N,N-dimethyl-thiobenzamid, C₉H₁₁NOS; monoklin; P2₁/c-C _2h ⁵ ;a=6.983 (1),b=11.652 (3),c=11.704 (3) Å; =100.02 (2)°;Z=4. Die Kristallstrukturen dieser vier Verbindungen wurden mittels Röntgen-Einkristalldaten bestimmt (bzw. verfeinert: 2-Hydroxy-benzamid). Die Verfeinerungen der Strukturparameter nach der Methode der kleinsten Quadrate ergab in allen FällenR<0.056. Die Wasserstoffatome konnten anhand von Differenz-Fourier-Summationen belegt werden. Die O-H ... O-Abstände haben folgende Werte: 2.513(1)Å in 2-Hydroxy-benzamid (intramolekular) und 2.625(1) Å in 2-Hydroxy-N,N-dimethyl-benzamid (intermolekular). Die zwei O-H ... S-Abstände sind in 2-Hydroxy-thiobenzamid 2.904(2)Å und 2.918(2)Å (intramolekular, zwei moleküle in der asymmetrischen Einheit) und 3.228(2)Å in 2-Hydroxy-N,N-dimethyl-thiobenzamid(intermollekular). Klar zuzuordnende N-H ... O-Wasserstoffbrücken mit 2.926(1)Å und 3.006(1)Å treten lediglich in der Struktur des 2-Hydroxy-benzamid auf (intermolekular).