Two Succinato‐bridged Zinc(II) Phenanthroline Complexes: [Zn(phen)L2/2](H2L) and [(phen)2Zn(μ‐L)Zn(phen)2]L � 11H2O with H2L = Succinic Acid

Two mixed ligand Zn^II complexes [Zn(phen)L_2/2](H₂L) ( 1 ) and [(phen)₂Zn(μ‐L)Zn(phen)₂]L � 11H₂O ( 2 ) with H₂L = suc‐cinic acid were prepared and crystallographically characterized. Complex 1 crystallizes in the monoclinic space group C2/c (no. 15) with a = 13.618(1) Å, b = 9.585(1) Å, c = 15.165(1) Å, β = 96.780(6)°, V = 1965.6(3)ų, Z = 4 and complex 2 in the triclinic space group P 1¯ (no. 2) with a = 12.989(2)Å, b = 14.464(2)Å, c = 18.025(3)Å, α = 90.01(1)°, β = 109.69(1)°, γ = 112.32(1)°, V = 2917.4(8) ų, Z = 2. 1 consists of succinic acid molecules and 1D zigzag [Zn(phen)(C₄H₄O₄)_2/2] polymeric chains, in which the tetrahedrally coordinated Zn atoms are bridged by bis ‐ monodentate succinato ligands. Succinic acid molecules play an important role in supramolecular assemblies of the polymeric chains into 2D layers as well as in the stacking of 2D layers. 2 is composed of [(phen)₂Zn(μ‐L)Zn(phen)₂]²⁺ complex cations, succinate anions and hydrogen bonded water molecules. Within the divalent cations, Zn atoms are octahedrally coordinated by four N atoms of two phen ligands and two O atoms of one bis‐chelating succinato ligand. Through the intermolecular π—π stacking interactions, the complex cations form positively charged 2D layers, between which the noncoordinating succinate anions and water molecules are sandwiched.     

Selective Determination of Zn2+ Ion in Various Environmental,Biological and Medicinal Plant Samples Using a Novel Coated Graphite Electrode

Novel Zn²⁺ ion‐selective PVC based coated graphite electrodes were fabricated using the ionophores N‐((1H‐indol‐3‐yl)methylene)thiazol‐2‐amine (I₁), N‐((1H‐indol‐3‐yl)methyl)‐thiazol‐2‐amine (I₂) and 1‐((1H‐indol‐3‐yl)methylene)urea (I₃). Their potentiometric performance was examined in dependence of the addition of plasticizers and anion excluders and compared. It is found that the coated graphite electrode with the composition I₁:KTpClPB:o‐NPOE:PVC=9 : 1.5 : 51 : 38.5 is the best with respect to the wide working concentration range (4.2×10^?8–1.0×10^?1 mol L^?1), low detection limit (1.6×10^?8 mol L^?1) and wide pH range of 3.0–8.0. The proposed electrode was successfully applied to quantify Zn²⁺ in various environmental, biological and medicinal plant samples and used as indicator electrode.     

Synthesis,X‐ray Structure of Ferrocene Bearing Bis(Zn‐cyclen) Complexes and the Selective Electrochemical Sensing of TpT

The new ligand, [Fc(cyclen)₂] ( 5 ) (Fc=ferrocene, cyclen=1,4,7,10‐tetraazacyclododecane), and corresponding Zn^II complex receptor, [Fc{Zn(cyclen)(CH₃OH)}₂](ClO₄)₄ ( 1 ), consisting of a ferrocene moiety bearing one Zn^II‐cyclen complex on each cyclopentadienyl ring, have been designed and prepared through a multi‐step synthesis. Significant shifts in the ¹H NMR signals of the ferrocenyl group, cf. ferrocene and a previously reported [Fc{Zn(cyclen)}]²⁺ derivative, indicated that the two Zn^II‐cyclen units in 1 significantly affect the electronic properties of the cyclopentadienyl rings. The X‐ray crystal structure shows that the two positively charged Zn^II‐cyclen complexes are arranged in a trans like configuration, with respect to the ferrocene bridging unit, presumably to minimise electrostatic repulsion. Both 5 and 1 can be oxidized in 1:4 CH₂Cl₂/CH₃CN and Tris‐HCl aqueous buffer solution under conditions of cyclic voltammetry to give a well defined ferrocene‐centred (Fc^0/+) process. Importantly, 1 is a highly selective electrochemical sensor of thymidilyl(3′‐5′)thymidine (TpT) relative to other nucleobases and nucleotides in Tris‐HCl buffer solution (pH 7.4). The electrochemical selectivity, detected as a shift in reversible potential of the Fc^0/+ component, is postulated to result from a change in the configuration of bis(Zn^II‐cyclen) units from a trans to a cis state. This is caused by the strong 1:1 binding of the two deprotonated thymine groups in TpT to different Zn^II centres of receptor 1 . UV‐visible spectrophotometric titrations confirmed the 1:1 stoichiometry for the 1 :TpT adduct and allowed the determination of the apparent formation constant of 0.89±0.10×10⁶ M ^?1 at pH 7.4.     

Synthese und Kristallstruktur von Na2Zn(OH)4

Synthesis and Crystal Structure of Na₂Zn(OH)₄ Crystallization from saturated sodium hydroxozincate solutions yields colourless platelets of crystals of Na₂Zn(OH)₄. The X‐ray structure determination on these crystals was successful including all hydrogen positions. P2₁/n, Z = 4, a = 7.959(3) Å, b = 6.534(1) Å, c = 8.501(3) Å, β = 93.97(3)°, N(F²_o ° 2σ F²_o) = 1668, N(Var.) = 81, R₁/wR₂ = 0.043/0.107. Na₂Zn(OH)₄ crystallizes in a layered structure. Alternate layers contain Na⁺ in octahedral and Zn²⁺ in tetrahedral coordination by OH^–.     

Influence of the Counterions on the Structures of Ternary Zn/Sn/Se Anions: Synthesis and Properties of [Rb10(H2O)14.5][Zn4(μ4‐Se)2(SnSe4)4] and [Ba5(H2O)32][Zn5Sn(μ3‐Se)4(SnSe4)4]

Reactions of rubidium or barium salts of the ortho‐selenostannate anion, [Rb₄(H₂O)₄][SnSe₄] ( 1 ) or [Ba₂(H₂O)₅][SnSe₄] ( 2 ) with Zn(OAc)₂ or ZnCl₂ in aqueous solution yielded two novel compounds with different ternary Zn/Sn/Se anions, [Rb₁₀(H₂O)_14.5][Zn₄(μ₄‐Se)₂(SnSe₄)₄] ( 3 ) and [Ba₅(H₂O)₃₂][Zn₅Sn(μ₃‐Se)₄(SnSe₄)₄] ( 4 ). 1 – 4 have been determined by means of single crystal X‐ray diffraction: 1 : triclinic space group lattice dimensions at 203 K: a = 8.2582(17) Å, b = 10.634(2) Å, c = 10.922(2) Å, α = 110.16(3)°, β = 91.74(3)°, γ = 97.86(3)°, V = 888.8(3) ų; R₁ [I > 2σ(I)] = 0.0669; wR₂ = 0.1619; 2 : orthorhombic space group Pnma; lattice dimensions at 203 K: a = 17.828(4) Å, b = 11.101(2) Å, c = 6.7784(14) Å, V = 1341.5(5) ų; R₁ [I > 2σ(I)] = 0.0561; wR₂ = 0.1523; 3 : triclinic space group ; lattice dimension at 203 K: a = 17.431(4) Å, b = 17.459(4) Å, c = 22.730(5) Å, α = 105.82(3)°, β = 99.17(3)°, γ = 90.06(3)°, V = 6563.1(2) ų; R₁ [I > 2σ(I)] = 0.0822; wR₂ = 0.1782; 4 : monoclinic space group P2₁/c; lattice dimensions at 203 K: a = 25.231(5) Å, b = 24.776(5) Å, c = 25.396(5) Å, β = 106.59(3)°, V = 15215.0(5) ų; R₁ [I > 2σ(I)] = 0.0767; wR₂ = 0.1734. The results serve to underline the crucial role of the counterion for the type of ternary anion to be observed in the crystal. Whereas Rb⁺(aq) stabilizes a P1‐type Zn/Sn/Se supertetrahedron in 3 like K⁺, the Ba²⁺(aq) ions better fit to an anionic T3‐type Zn/Sn/Se cluster arrangement as do Na⁺ ions. It is possible to estimate a radius:charge ratio for the stabilization of the two structural motifs.     

Two New Polyoxovanadate‐supported Transition Metal Complexes: [Zn(en)2][Zn(en)2(H2O)2][{Zn(en)(enMe)}As6V15O42(H2O)]·4H2O and [Zn2(enMe)2(en)3][{Zn(enMe)2}As6V15O42(H2O)]·4H2O

Two novel As‐V‐O cluster supported transition metal complexes, [Zn(en)₂][Zn(en)₂(H₂O)₂][{Zn(en)(enMe)}As₆V₁₅O₄₂(H₂O)]·4H₂O ( 1 ) and [Zn₂(enMe)₂(en)₃][{Zn(enMe)₂}As₆V₁₅O₄₂(H₂O)]·4H₂O ( 2 ), have been hydrothermally synthesized. The single X‐ray diffraction studies reveal that both compounds consist of discrete noncentral polyoxoanions [{Zn(en)(enMe)}As₆V₁₅O₄₂(H₂O)]^4? or [{Zn(enMe)₂}As₆V₁₅O₄₂(H₂O)]^4? cocrystallized with respective zinc coordination complexes. Interestingly, compounds 1 and 2 exhibit the first two polyoxovanadates containing As₈V₁₅O₄₂‐(H₂O)]^6? cluster decorated by only one transition metal complex. Crystal data: 1 , monoclinic, P2₁/n, a = 14.9037(4) Å, b = 18.1243(5) Å, c = 27.6103(7) Å, β = 105.376(6)°, Z = 4; 2 monoclinic, P2₁/n, a = 14.9786(7) Å, b = 33.0534(16) Å, c = 14.9811(5) Å, Z = 4.     

Electrochemical-hydrothermal Synthesis and Structural Characterization of Zn2(OH)VO4

A new zinc vanadate Zn₂(OH)VO₄ has been synthesized by an electrochemical-hydrothermal method and characterized by single crystal X-ray diffraction. The compound crystallizes in the orthorhombic system, space group Pnma, a = 14.645(1) Å, b = 6.0215(5) Å, c = 8.8757(8) Å, V = 782.7(1) ų, Z = 4, measured at 223 K. In the structure, rutile-type [ZnO₆] octahedral chains are interconnected by [VO₄] tetrahedra to form a framework of composition [Zn(OH)VO₄], the voids of which are filled by Zn cations with trigonal bipyramidal and octahedral coordination. The structure is closely related to that of the adamite-type phases and the minerals descloizite PbZn(OH)VO₄ and tsumcorite Pb_0.5Zn(H₂O)AsO₄.     

Two Heteroleptic Zinc(II) Complexes: [Zn(phen)(C9H15O6)2] and [Zn2(phen)2(H2O)2(C10H16O4)2] · 3H2O

Reactions of a freshly prepared Zn(OH)_2‐2x(CO₃)x · yH₂O precipitate, phenanthroline with azelaic and sebacic acid in CH₃OH/H₂O afforded [Zn(phen)(C₉H₁₅O₄)₂] ( 1 ) and [Zn₂(phen)₂(H₂O)₂(C₁₀H₁₆O₄)₂] · 3H₂O ( 2 ), respectively. They were structurally characterized by X‐ray diffraction methods. Compound 1 consists of complex molecules [Zn(phen)(C₉H₁₅O₄)₂] in which the Zn atoms are tetrahedrally coordinated by two N atoms of one phen ligand and two O atoms of different monodentate hydrogen azelaato groups. Intermolecular C(alkyl)‐H···π interactions and the intermolecular C(aryl)‐H···O and O‐H···O hydrogen bonds are responsible for the supramolecular assembly of the [Zn(phen)(C₉H₁₅O₄)₂] complexes. Compound 2 is built up from crystal H₂O molecules and the centrosymmetric binuclear [Zn₂(phen)₂(H₂O)₂(C₁₀H₁₆O₄)₂] complex, in which two [Zn(phen)(H₂O)]²⁺ moieties are bridged by two sebacato ligands. Through the intermolecular C(alkyl)‐H···O hydrogen bonds and π‐π stacking interactions, the binuclear complex molecules are assembled into layers, between which the lattice H₂O molecules are sandwiched. Crystal data: ( 1 ) C2/c (no. 15), a = 13.887(2), b = 9.790(2), c = 22.887(3)Å, β = 107.05(1)°, U = 2974.8(8)ų, Z = 4; ( 2 ) P1¯ (no. 2), a = 8.414(1), b = 10.679(1), c = 14.076(2)Å, α = 106.52(1)°, β = 91.56(1)°, γ = 99.09(1)°, U = 1193.9(2)ų, Z = 1.     

Iron(II)‐ and Cobalt(II) Complexes with Tridentate Bis(imino)pyridine Nitrogen Ligands Bearing Chiral Bulky Aliphatic and Aromatic Substituents: Crystal Structure of [CoCl2{2, 6‐bis[R‐(+)‐(bornylimino)methyl]pyridine}]

Iron(II) and cobalt(II) complexes ( 7 ‐ 15 ) based on new aldimine 2, 6‐bis[(imino)methyl]pyridine ( 1 , 2 , 4 , 6 ) and ketimine (2, 6‐bis[(imino)ethyl]pyridine ( 3 , 5 ) ligands with bulky chiral aliphatic or aromatic terminal groups have been prepared and characterized by ¹H NMR, ¹³C NMR, IR‐, mass spectroscopy (EI), and elemental analysis. The complex [CoCl₂(BBoMP)]·¹/₂ CHCl₃ ( 13 ) (BBoMP: 2, 6‐bis{(R‐(+)‐(bornylimino)‐methyl}pyridine) crystallizes in monoclinic space group P2₁ with cell dimensions: a = 7.6603(11) Å, b = 28.3153(14) Å, c = 13.537(2) Å, V = 2908.1(6) ų, Z = 4. The coordination sphere around Co is distorted trigonal bipyramidal.     

Synthese und Kristallstruktur von Sr2Zn(OH)6 und Ba2Zn(OH)6

Synthesis and Crystal Structure of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ Crystallization from supersaturated sodium hydroxozincate solutions by adding solutions of alkali earth metal hydroxides yields crystals of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆. The X-ray structure determination on these crystals was successful including all hydrogen positions: Sr₂Zn(OH)₆: P2₁/n, Z = 2, a = 5.794(1) Å, b = 6.160(1) Å, c = 8.141(1) Å, b = 91.23(1)°, N(F ³° 2σ F) = 1127, N(Var.) = 53, R₁/wR₂ = 0.047/0.081Ba₂Zn(OH)₆: P2₁/n, Z = 2, a = 6.043(1) Å, b = 6.336(1) Å, c = 8.451(2) Å, b = 91.23(2)°, N(F ° 2σ F) = 1669, N(Var.) = 54, R₁/wR₂ = 0.029/0.067. Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ crystallize isotypic in a distorted Li₂O structure type. Sr²⁺ resp. Ba²⁺ form a cubic primitive arrangement. Distorted octahedra of OH^– around Zn²⁺ fill therein alternating cubic gaps in an ordered way.     

Synthesis and Characterization of a New Layered Zinc Phosphite (NH4)[{Zn(H2O)4}0.5Zn2(HPO3)3]

A new layered zinc phosphite with the formula (NH₄)[{Zn(H₂O)₄}_0.5Zn₂(HPO₃)₃] has been synthesized under hydrothermal conditions. Its structure was determined by single‐crystal X‐ray diffraction. The compound crystallizes in the triclinic system, space group (No. 2), a = 7.2507(4), b = 9.7982(6), c = 10.2642(6) Å, α = 63.425(2), β = 87.165(2), γ = 72.999(3)°, V = 620.84(6) ų, Z = 2. The connectivity of ZnO₄ tetrahedra, HPO₃ pseudo pyramids and ZnO₂(H₂O)₄ octahedra results in macroanionic layers with 4.8 net.     

Zur Konkurrenz von Stickstoff- und Schwefel-Donoratomen in Zinkkomplexen: [Zn(bims)2][SiF6] · 5MeOH und [ZnCl(paps)]2(Zn2Cl6) (bims = Bis(2-benzimidazolylmethyl)sulfid; paps = o,o′-(N,N′-Dipicolinyliden)diazadiphenyldisulfid)

Competition between Nitrogen and Sulfur Donor Atoms in Zinc(II) Complexes: [Zn(bims)₂][SiF₆] · 5MeOH and [ZnCl(paps)]₂(Zn₂Cl₆) (bims = bis(2-benzimidazolylmethyl)sulfide; paps = o,o′-(N,N′-dipicolinylidene)diazadiphenyl-disulfide) [Zn(bims)₂](SiF₆) · 5 MeOH ( 1 ) was synthesized by reaction of Zn(SiF₆) with the ligand bis(2-benzimidazolylmethyl)sulfide (bims). Zinc is tetrahedrally coordinated by four benzimidazole nitrogen atoms of the two ligand molecules, the sulfur atom does not coordinate. From reaction of ZnCl₂ with o,o′-(N,N′-dipicolinylidene)diazadiphenyldisulfide (paps) [ZnCl(paps)]₂(Zn₂Cl₆) ( 2 ) was obtained. Here, an octahedral coordination by four nitrogen atoms, one sulfur atom of the ligand and one chloride ion was found. Both compounds were characterized by infrared and ¹H-NMR-spectroscopy as well as by single crystal X-ray structure analysis. Space groups and structural data: 1: P1 , a = 9.904(2), b = 10.951(3), c = 19.356(2) Å, α = 91.08(2), β = 91.11(2), γ = 95.74(2)°, R1 = 0.0631; 2: P1 , a = 9.051(3), b = 11.110(3), c = 15.170(4) Å, α = 92.99(2), β = 105.93(2), γ = 107.79(2)°, R1 = 0.0585.     

Synthesis,Spectrothermal and Structural Characterization of Saccharinatobis(tris‐hydroxymethylaminomethane)zinc(II)saccharinate Complex, [Zn(sac)(tham)2](sac)

A novel Zn^II complex of the saccharinate ligand (sac) with tris‐hydroxymethylaminomethane (tham) was synthesized and characterized by elemental analysis, FT‐IR spectroscopy, simultaneous TG and DTA techniques, and X‐ray diffraction. The complex, [Zn(sac)(tham)₂](sac), crystallizes in monoclinic system with space group P2₁/c [a = 7.55954(3) Å, b = 13.0532(6) Å, c = 27.7777(10) Å, β = 100.539(3)°, Z = 4]. The Zn^II ion has a distorted octahedral coordination. The tham ligand has chemically different functions in the structure, acting as both bidentate and tridentate ligands. There are also sac moieties to act as N‐bonded ligand and as a counter anion. The molecular packing of the complex is provided by moderate hydrogen bonds as well as π···π interactions between the sac moieties. The IR spectra and the thermal decomposition of the complex are also discussed.     

Syntheses and crystal structures of Zn(II) and Co(II) complexes with ofloxacin and enoxacin

[Zn(Ofl) · (H₂O)] · 2H₂O (1) and [Co(Enox)₂] · 4H₂O (2) were obtained by hydrothermal reactions. The solid-state structures have been characterized by IR spectroscopy and single crystal X-ray diffraction analyses. Complex 1 crystallizes in the triclinic system, space group P 1, with lattice parameters a = 9.2923(5), b = 11.3432(6), c = 17.7722(10) Å, α = 92.839(3), β = 94.826(3), γ = 91.909(3)°, V = 1863.01(18) ų, Z = 2, D _Calcd = 1.494 mg m^?3. The coordination environment around Zn²⁺ is a slightly distorted square pyramid. Complex 2 crystallizes in the triclinic system, space group P2(1)/c, with lattice parameters a = 5.97980(10), b = 21.4183(3), c = 13.1539(2) Å, V = 100.2810(10), Z = 2, D _Calcd = 1.526 mg m^?3, Co(II) ion is a distorted octahedral geometry.     

{[Zn2(Bim)3(OH)(H2O)]·(DMF)(H2O)3}∞: A Two Dimensional Coordination Polymer with Layer Silicate‐like Structure

A layer silicate‐like zinc(II) benzimidazolate polymer {[Zn₂(Bim)₃(OH)(H₂O)]·(DMF)(H₂O)₃}_∞ ( 1 ) was synthesized at room temperature and characterized with X‐ray single‐crystallography: Monoclinic, space group C2/m (No.12), a = 10.423(3) Å, b = 17.416(6) Å, c = 16.583(5) Å, β = 92.698(4), V = 3006.8(17) ų.     

Spectrophotometric and conductometric studies of the thermodynamics complexation of Zn2+, Ni2+, Co2+, Pb2+ and Cu2+ ions with 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane ligand in acetonitrile solution

The complexation reaction between 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane ligand (Kryptofix5) and Zn²⁺, Ni²⁺, Co²⁺, Pb²⁺ and Cu²⁺ ions were studied conductometrically in acetonitrile solution. The formation constants of the resulting 1:1 complexes were calculated from the computer fitting of the molar conductance and absorbance measurements in various mole ratios. The enthalpy and entropy changes of the complexation reactions were derived from titration conductometry in acetonitrile at various temperatures. At 25 °C, the stability of the resulting complexes varied in the order Pb²⁺ > Zn²⁺ > Cu²⁺> Co²⁺> Ni²⁺.     

5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn2+的识别

本文利用2-氨基吡啶与4-二乙胺基水杨醛反应合成了5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),对其结构进行了表征。在DMSO/Tris(6:4, v/v, pH =7.4)溶液中,探针L高选择性荧光“关-开”识别Zn₂₊,在365 nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn₂₊的结合比为1:1,结合常数为2.6×10₃ L. mol_-1,检测限为 9.39×10_-7mol/L,pH适用范围为7-11,并可检测水样中的Zn₂₊。     

Neue ternäre Germanide: Die Verbindungen Ln4Zn5Ge6 (Ln: Gd,Tm, Lu)

New Ternary Germanides: The Compounds Ln ₄Zn₅Ge₆ ( Ln : Gd, Tm, Lu) Three new ternary germanides were prepared by heating mixtures of the elements. Gd₄Zn₅Ge₆ (a = 4.249(3), b = 18.663(17), c = 15.423(6) Å), Tm₄Zn₅Ge₆ (a = 4.190(1), b = 18.410(5), c = 15.105(5) Å), and Lu₄Zn₅Ge₆ (a = 4.179(1), b = 18.368(4), c = 15.050(3) Å) are isotypic and crystallize in a new structure type (Cmc2₁; Z = 4), composed of edge‐ and corner‐sharing ZnGe₄ tetrahedra. The rare‐earth atoms fill channels of the Zn,Ge network running along the a axis and predominantly have an octahedral coordination of Ge atoms or a pentagonal prismatic environment of Zn and Ge atoms. The ZnGe₄ tetrahedra are orientated to each other so that two of six Ge atoms form pairs, while the other ones have no homonuclear contacts. This is in accord with an ionic splitting of the formula: (Ln³⁺)₄(Zn²⁺)₅(Ge^3–)₂(Ge^4–)₄. LMTO band structure calculations support the interpretation of bondings derived from interatomic distances. The metallic conductivity of these compounds expected from the electronic band structure was confirmed by measurements of the electrical resistance of Tm₄Zn₅Ge₆.     

Two-dimensional arrays of amphiphilic Zn2+-cyclens for guided molecular recognition at interfaces

The sterically guided molecular recognition of nucleobases, phosphates, adenosine, and uridine nucleotides on Langmuir monolayers and Langmuir-Blodgett monolayers of amphiphilic mono- or bis(Zn2+-cyclen)s assembled on thiolated surfaces was investigated. The stepwise selective binding of metal ions, uracil, or phosphate by dicetyl cyclen monolayers with variously tuned structures at the air/water interface was corroborated by the measurements of the corresponding LB films deposited onto quartz crystals. Two types of recognition surfaces were fabricated from Zn2+-dicetyl cyclen. The surface covered with a complex preformed in the Langmuir monolayer was capable both of imide and of phosphate binding. The similar complex formed directly in an LB film on thiolated gold was inactive with respect to imide. The surface plasmon resonance measurements evidenced the stepwise assembly of complementary nucleotides on SAM/LB templates through consecutive phosphate-Zn2+-cyclen coordination. Base pairing between nucleotides resulted in a formation of A-U bilayers comprising two complementary monolayers. Finally, we report on SAM/LB patterns designed for divalent molecular recognition of uridine phosphate by amphiphilic bis(Zn2+-cyclen).     

Theoretical studies of the g factors and local structures of the Ni3+ centers in Na2Zn(SO4)2·4H2O and K2Zn(SO4)2·6H2O crystals

The local structures and the g factors g_i (i = x, y, z) for Ni³⁺ centers in Na₂Zn(SO₄)₂·4H₂O (DPPH) and K₂Zn(SO₄)₂·6H₂O (PHZS) crystals are theoretically studied by using the perturbation formulas of the g factors for a 3d⁷ ion with low spin (S = 1/2) in orthorhombically compressed octahedra. In these formulas, the contributions to g factors from both the spin-orbit coupling interactions of the central ion and ligands are taken into account, and the required crystal-field parameters are estimated from the superposition model and the local geometry of the systems. Based on the calculations, the Ni-O bonds are found to suffer the axial compression δz (or Δz) of about 0.111 Å (or 0.036 Å) along the z-axis for Ni³⁺ centers in DPPH (or PHZS) crystals. Meanwhile, the Ni-O bonds may experience additional planar bond length variation δx (≈0.015 Å) along x- and y-axes for the orthorhombic Ni³⁺ center in DPPH. The theoretical g factors agree well with the experimental data. The obtained local structural parameters for both Ni³⁺ centers are discussed.