Two novel metal organic frameworks of Sn(II) and Pb(II) with Pyridine-2,6-dicarboxylic Acid and 4,4′-Bipyridine: syntheses, crystal structures and solution studies

Two novel compounds with formulae [Sn₂(pydcH)₂(H₂O)₂O]_n, 1, and (4,4′-bpyH₂)_0.5[Pb(pydc)₂(4,4′-bpyH)].4,4′-bpy.4H₂O, 2, were obtained from a one-pot reaction between pyridine-2,6-dicarboxylic acid (pydcH₂) and 4,4′-bipyridine (4,4′-bpy) with corresponding Sn(II) and Pb(II) salts. In compound 1 with a polymeric structure, each Sn(II) atom is six-coordinated by one water molecule, two (pydcH)^? groups and one oxide group resulted in a coordination polymer. Compound 2 has a seven-coordinated environment around Pb(II) atom by two (pydc)^2? groups and one (4,4′-bpyH). The anionic complex is balanced by half a (4,4′- bpyH₂)²⁺ as counter ion. There are four uncoordinated water molecules and one 4,4′-bpy in the crystal lattice. Therefore, in compound 2, we have neutral, mono- and biprotonated forms of 4,4′-bipyridine, simultaneously. Several interactions including O-H??? O, O-H???EN and C-H???O hydrogen bonds, ion pairing, C-O???π (O???Cg 3.324(3) Å and 3.381(3) Å in 1 and O???Cg 3.346(4) Å in 2), C-H???π (C???Cg 3.618(4) Å in 2), and π???π stackings (with Cg ??? Cg distances of 3.613(2) and 3.641 (2) Å in 2) are present to expand and stabilize the structure. The complexation reactions of bpy and pydc-bpy with Sn²⁺ and Pb²⁺ ions in aqueous solution were investigated by potentiometric pH titrations, and the resulting equilibrium constants and species distributions at various pHs for major formed complexes are described.     

Synthesis and characterization of spiro-, ansa-, and spiro-ansa-cyclic derivatives of cyclotetraphosphazene with the reactions of pentane-1,5-diol

The reactions of octachlorocyclotetraphosphazatetraene, N₄P₄Cl₈ (1) with difunctional aliphatic reagent, HO-(CH₂)₅-OH (3) have aroused a good deal of attention, and four types of products have been realized: one 2-open chain-(1′-oxy-5′-hidroxy-pentane)-2,4,4,6,6,8,8-heptachlorocylotetraphosphazatetraene, N₄P₄Cl₇[O(CH₂)₅OH] (4); one 2,2-mono-spiro-(1′,5′-pentanedioxy)-4,4,6,6,8,8-hexachlorocyclotetraphosphazatetraene, N₄P₄Cl₆[O(CH₂)₅O] (5); its isomers 2,4-mono-ansa-((1′,5′-pentanedioxy)-2,4,6,6,8,8- hexachlorocyclotetraphosphazatetraene (6) and 2,6-mono-ansa-(1′,5′-pentanedioxy)-2,4,6,6,8,8-hexachlorocyclotetraphosphazatetraene (7); one 2,2,6,6-dispiro-(1′,5′-pentanedioxy)-4,4,8,8-tetrachlorocyclo- tetraphosphazatetraene, N₄P₄Cl₄[O(CH₂)₅O]₂ (8); two isomeric 2,4,6,8-bisansa-(1′,5′-pentanedioxy)-2,4,6,8-tetrachlorocyclotetraphosphazatetraene (9) and 2,6,4,8-bisansa-(1′,5′-pentanedioxy)-2,4,6,8-tetrachloro-cyclotetraphosphazatetraene (10); one 4,4,8,8-dispiro-2,6-ansa- (1′,5′-pentanedioxy)-2,6-dichlorocyclotetra-phosphazatetraene, N₄P₄Cl₂[O(CH₂)₅O]₃ (11), one 2,2,4,4,6,6-trispiro-(1′,5′-pentanedioxy)-8,8-dichlorocyclo-tetraphosphazatetraene, N₄P₄Cl₂[O(CH₂)₅O]₃ (12); and a 2,2,4,4,6,6,8,8-tetraspiro-(1′,5′-pentanedioxy)-cyclotetraphosphazatetraene derivative, N₄P₄[O(CH₂)₅O]₄, (13). The respective structures were deduced by means of elemental analysis, mass spectrum, and ³¹P, ¹H, and ¹³C nuclear magnetic resonance spectroscopic investigations.     

Synthesis and some reactions of a 2,2′-biphospholyl

1,1′-Diphenyl-3,3′,4,4′-tetramethyl-2,2′,5,5′-tetrahydro-2,2′-biphosphole obtained by reductive dimerization of the appropriate phosphole has been converted into the corresponding 2,2′-biphosphole by P-bromination followed by dehydrobromination of the resulting P,P′-tetrabromo compound with α-picoline. This 2,2′-biphosphole gives two isomeric P-sulfides upon reaction with sulfur, and a Mo(CO)₄ chelate upon reaction with Mo(CO)₆. Cleavage of the two P-phenyl bonds by lithium in THF yields the corresponding biphospholyl anion, which is converted into a mixture of two isomeric bis(η⁵,η⁵-2,2′-diphosphafulvalene)diirons by treatment with FeCl₂. The reaction of Mn₂(CO)₁₀ in boiling xylene affords a mixture of three complexes, including a (η⁵,η⁵-2,2′-diphosphafulvalene)hexacarbonyldimanganese produced by thermal cleavage of the two PPh bonds. Under CO pressure there is a [1,5] P → C shift of the two phenyl groups, leading to formation of (η⁵,η⁵-3,3′-diphenyl-2,2′-diphosphafulvalene)hexacarbonyldimanganese.     

Phosphorus-Nitrogen Compounds: The Reactions of Hexachlorocyclotriphosphazatriene with Pentane-1,5-Diol. Nuclear Magnetic Resonance Studies of The Products

Abstract

From the reactions of hexachlorocyclotriphosphazatriene, N₃P₃Cl₆ (1) with pentane-1,5-diol (2) in dichloromethane solution, the following derivatives have been isolated: 2,2-spiro(1′,5′-pentanedioxy)-4,4,6,6-tetrachlorocyclotriphosphazatriene, N₃P₃Cl₄[O(CH₂)₅O] (3); its ansa isomer, 1,3-ansa(1′,5′-pentanedioxy)-1,3,5,5-tetrachlorocyclotriphosphazatriene, (4); bis spiro(1′,5′-pentanedioxy)-6,6-dichlorocyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₅O]₂ (5); its spiro-ansa isomer, (1′,5′-pentanedioxy)-1,3-dichlorocyclotriphosphazatriene (6); as well as the bino(1,5-pentanedioxy)-di-(pentachlorocyclotriphosphazatriene), N₃P₃Cl₅ [O(CH₂)₅O]N₃P₃Cl₅ (7), and tri-bino(1,5-pentanedioxy)-di (trichlorocyclotriphosphazatriene), N₃P₃Cl₃[O(CH₂)₅O]₃N₃P₃Cl₃, (8) derivatives. Their structures were established by MS and NMR with the use of ¹H, ¹³C, and ³¹P spectroscopy. Product types and relative yields are compared with those of the previously investigated diol derivatives. The yield of the mono-ansa product (25%) obtained in this system was considerably increased relative to those of the propane-1,3-diol derivative (11.2%) and decreased relative to the 2,2-dimethyl-propane-1,3-diol (36.2%), and bis(2-hydroxyethyl) ether (34.5%) derivatives.     

Lineare oligophosphaalkane: XVIII. Addition Ph-funktioneller methylenbisphosphane an die MoMo-Dreifachbindun in (η5-C5H5)2Mo2(CO)4

By means of the addition of the PH-functional methylenebisphosphanes R¹R²-PCH₂PR³H (PCP) to the MoMo triple bond in (η⁵-C₅H₅)₂Mo₂(CO)₄(MoMo) the complexes (η⁵-C₅H₅)₂Mo₂(CO)₄(PCP) containing a five-membered ring system Mo₂P₂C are obtained. Starting with unsymmetrically substituted methylenebisphosphanes R′₂PCH₂PRH only one isomer is formed, while the disecondary derivatives RHPCH₂PHR (as the diastereomeric mixture) gave two isomers of (η⁵-C₅H₅)₂Mo₂(CO)₄(PCP) (A₂ and AB) as indicated by the ³¹P{¹H} and ¹³C{¹H} NMR spectra.X-ray structural analysis of the derivative of the racemate of t-BuHPCH₂PH(t-Bu) space group C2/c, monoclinic, a 18.034(2), b 14.909(1), c 11.106(1) Å, α 90, β 99.788(8), γ 90°) reveals a puckered Mo₂P₂C five-membered ring system (dihedral angle PMoMo′P′ 54.4(2)°) with square-pyramidal coordination geometry at the Mo atoms. Two of the CO ligands (C(6)O(1) and C(6′)O(1′)) are almost coplanar with the molybdenum atoms, while the terminal CO groups (C(7)O(2) and C(7′)O(2′)) are about orthogonal (dihedral angle C(7)MoMo′C(7′) 88.4(3), MoMo′ 3.2109(4), MoP 2.4567(8), PC(8) 1.834(3), PH(P) 1.37(3) Å).     

Phosphoramidites of Chiral (Rp)-and (Sp)-Configurated d(T[P-18O]-A): Synthesis,Configurational Assignment,and Use as Dimer Blocks in Oligonucleotide Synthesis

The N,N-diisopropylphosphoramidites 10a and 10b of appropriately protected chiral diastereoisomers of d(T[P-¹⁸O]-A) ( 8a and 8b , resp.), chiral by virtue of the isotope ¹⁸O at the P-atom, have been synthesized. The ¹⁸O-isotope was incorporated by oxidation of the phosphite triester 3 with H₂[¹⁸O]/I₂. Separation of the diastereoisomers was accomplished by flash chromatography of the O-3′-deprotected phosphate triesters 5a/b . The absolute configuration at the chiral P-atom was deduced from the methylation products of the fully deprotected diastereoisomers 8a and 8b . Phosphinylation of 5a and 5b yielded the configurationally pure phosphoramidites 10a and 10b , respectively, which were then employed in solid-phase synthesis to yield the self-complementary oligomers d(G-A-G-T-(R_p)-[P-¹⁸O]-A-C-T-C) ( 13 ) and d(G-A-G-T-(S_P)-[P-¹⁸O]-A-C-T-C) ( 14 ), respectively.     

The unambiguous synthesis and NMR assignment of 4-alkoxy and 3-alkylquinazolines

Contrary to a number of reports, alkylations of the privileged 3,4-dihydroquinazoline scaffold provide N3-alkylated products, and not 4-alkoxyquinazolines. To correctly assign the structure, ¹³C NMR shifts of the –Z–CH_n– (Z=O, N) fragment are necessary; resonances in the 45–55 ppm range are indicative of N3-alkylation. Treatment of 3,4-dihydroquinazoline-4-one with p-TsCl afforded the N3-tosylated compound, whose reaction with an amine yielded the corresponding N3-alkyl derivative. A mechanism corroborated by ¹⁵N-labeling involving pyrimidine ring opening and recyclisation is proposed. Finally, the unambiguous preparation of 4-alkoxyquinazolines is described via treatment of 3,4-dihydroquinazoline-4-ones with PCl₅ followed by an alkoxide.     

Phases of tetraphosphorus triselenide analysed by magic angle spinning 31P NMR and Raman spectroscopy,and the Raman spectrum of tetraphosphorus tetraselenide

The local environments of the cage molecules in the phases of P₄Se₃ are analysed with ³¹P MAS-NMR and Raman spectroscopy.The ³¹P MAS-NMR spectra of the orientationally ordered α and α′,-phases have different chemical shifts for the apical P atom (α: 68.0, 86 and 88.0 ppm; α′: 75.8 ppm), but similar chemical shifts for the basal P atoms (α: −58.8 ppm, α′: −60.0 ppm).When either α or α′-P₄Se₃ is heated above 358 K, the resulting β-P₄Se₃ has a well-resolved, liquid-like spectrum, indicating extensive molecular re-orientation. The slowly quenched β-phase shows a remnant β-phase mixed with the α-phase as well as P₄Se₄. A rapidly quenched sample of β-P₄Se₃ also shows a small remnant β-phase in the α-phase, but also a new phase with sharp resonances at 12.5, 3.6, 0.1 and −12 ppm. These are probably due to a P₄Se₄ phase which may be orientationally disordered.The Raman spectrum of P₄Se₃ heated above the α-β phase transition temperature shows a disappearance of the lattice modes and the 373 cm⁻¹ mode as previously reported, but also shows some decomposition to P₄Se₄. The β-phase reverts into the α-phase on quenching, with only weak remnant bands attributable to P₄Se₄. The bands of P₄Se₄ become more prominent as the temperature of the β-phase is raised, but above the β-∂ phase transition they are less prominent.The Raman spectrum of P₄Se₄ is reported. The strongest band is at 350 cm⁻¹, with the next strongest band at 185 cm⁻¹. The spectra indicate that the dominant isomer is the selenium analogue of α-P₄S₄ (D_2h), confirming previous ³¹P MAS-NMR studies.     

Synthesis and molecular characterization of the coordination polymer [Pb(2,2′-Bipy)(NO3)2(H2O)] n

A new coordination polymer [Pb(2,2′-Bipy)(NO₃)₂(H₂O)] _n has been successfully synthesized and characterized (where 2,2′-Bipy = 2,2′-bipyridine). The crystal structure of the polymer was determined by single-crystal X-ray diffraction, crystallizing in the monoclinic crystal system, space group P2₁/n with unit cell parameters: a = 7.1673(5), b = 9.8706(6), c = 19.1825(12) Å; β = 90.0780(10)°; V = 1357.08(15) ų, and Z = 16. The Pb atom was six-coordinated with N(1) and N(2) from 2,2′-Bipy, O(2), O(3), and O(6) in nitrate; O(1) from coordinated water, forming a slightly distorted octahedral geometry. The structure units aggregate together to give birth to the infinite 1D chains via bridged nitrate, and 2D networks and three-dimensional frameworks were obtained through hydrogen bonding and π-π-stacking interaction among aromatic rings, respectively.     

Alkaloids of the flora of Siberia and Altai: XX. Synthesis of 5-aryl(hetaryl)-substituted anthranilic acid esters

Cross-coupling of methyl 2-acetylamino-5-bromobenzoate and 5′-bromolappaconitine with aryl-, furyl-, pyridyl-, and 5-acetylthiophen-2-ylboronic acids or 1-(2-fluoroquinolin-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane gave the corresponding 5-aryl(hetaryl)-substituted anthranilic acid derivatives. The use of the two-phase toluene-water system as reaction medium and addition of tetrabutylammonium bromide allows the cross-coupling to be accomplished under mild conditions. The catalytic system Pd(dba)₂-AsPh₃ was found to be efficient in the cross-coupling of methyl 2-acetylamino-5-bromobenzoate with furyl- and pyridylboronic acids, whereas the system Pd(OAc)₂-(o-Tol)₃P ensured good results in the reactions of 5′-bromolappaconitine with hetarylboronic acids. Facile esterification at the C⁸-OH and C⁹-OH groups of the aconitane skeleton was observed in the reactions of 5′-bromolappaconitine and 5′-phenyllappaconitine with phenylboronic acid. 5′-Bromo-8,9-O-(phenylboranediyl)lappaconitine under the Suzuki reaction conditions underwent hydrolysis of the boronic ester moiety with formation of the cross-coupling product of 5′-bromolappaconitine with phenylboronic acid.     

Metabolites with Cytotoxic Activity from the Formosan Soft Coral Cladiella Australis

The metabolites, (24S)‐3β‐acetoxyergost‐5‐en‐21‐oic acid ( 2 ), 5′‐O‐acetylthymidine ( 3 ), 3′‐O‐acetylthymidine ( 4 ), and p‐vinylbenzyl alcohol ( 5 ), along with a known steroid ( 1 ) were isolated from the EtOAc extract of the Formosan soft coral Caldiella australis. The structures of new metabolites were determined on the basis of spectroscopic (including 1D and 2D NMR) analyses and by comparison of their NMR spectral data with those of related compounds. Except for 3 , all compounds exhibited cytotoxic activity of various degrees of potency against a limited panel of human liver and breast cancer cell lines.     

Nucleotides. Part LIV. Synthesis of condensed N1-(2′-deoxy-β-D-ribofuranosyl)lumazines,New fluorescent building blocks in oligonucleotide synthesis

Various condensed areno[g]lumazine derivatives 2 , 3 , and 5 – 7 were synthesized as new fluorescent aglycones for glycosylation reactions with 2-deoxy-3, 5-di-O-(p-toluoyl)-α/β-D -erythro-pentofuranosyl chloride ( 10 ) to form, in a Hilbert-Johnson-Birkofer reaction, the corresponding N¹-(2′-deoxyribonucleosides) 15 – 21 . The β-D -anomers 15 , 17 , 19 , and 21 were deblocked to 24 – 27 and, together with N¹-(2′-deoxy-β-D -ribofuranosyl)lumazine ( 22 ) and its 6, 7-diphenyl derivative 23 , dimethoxytritylated in 5′-position to 28–33. These intermediates were then converted into the 3′-(2-cyanoethyI diisopropylphosphoramidites) 34 – 39 which function as monomeric building block in oligonucleotide syntheses as well as into the 3′-(hydrogen succinates) 40 – 45 which can be used for coupling with the solid-support material. A series of lumazine-modified oligonucleotides were synthesized and the influence of the new nucleobases on the stability of duplex formation studied by measuring the T_m values in comparison to model sequences. A substantial increase in the T_m is observed on introduction of areno[g]lumazine moieties in the oligonucleotide chain stabilizing obviously the helical structures by improved stacking effects. Stabilization is strongly dependent on the site of the modified nucleobase in the chain.     

Laser photoionization of metastable Xe* (J=0) atoms in the range 462–430 nm

Absolute cross sections for photoionization of metastable Xe* (5p ⁵ 6s′³ P ₀) atoms are presented over the wavelength range 462–430 nm (photoelectron energy ε=0–200 meV), including the 7p′[3/2]₁ and 7p′[1/2]₁ autoionization resonances. In addition the angular distribution of the photoelectrons is reported across the 7p′ resonances (ε=90–180 meV). The experimental data are compared with Hartree-Fock calculations of the photoionization process.     

The kinetics of Ogawa band chemiluminescence in the nitric oxide afterglow

Nitric oxide Ogawa band chemiluminescences emanating from NO(b⁴Σ⁻) υ′ = 4, 3 and 2, associated with combining N(⁴S) and O(³P) atoms in a discharge flow system, have been detected photoelectrically. In N₂ carrier the intensities (Iυ′) followed relationships Iυ′ = kυ′ [N][O] with kυ′ independent of [N₂] in the range (4 - 15) X 10⁻⁵ mol/dm³ at both 195 K and 298 K. The temperature coefficients of kυ′, expressed as T^-nv′, were n₃ = 1.8±0.4, n₂ = 1.5±0.8 and n₃ - n₄ = 0.62±0.20. Addition of Ar (⩽76%) had no effect upon kυ′ but distinct quenching of k₃ and k₂ occurred when N₂ was partly replaced with CO₂, N₂O and H₂O (⩽46%). On the simplest basis CO₂ was about twice, N₂O about four times and H₂O about six times as effective as N₂ in removing NO(b⁴Σ−) υ′ = 2, 3. Only with H₂O was any quenching detected for k₄ and that ∼3 times less than for k₃.The results for υ′ = 4 were interpreted in terms of the lowest rotational level being within 5 to 10 kJ/mol of the first dissociation limit of NO, so that preassociation/predissociation operates in the mechanism.Absolute intensity measurements gave 1/photons dm⁻³ s⁻¹ = 1.4 X 10³ ([N][O]/mol²/dm⁶) for the bands observed between 700 and 1000 nm. A lower radiative lifetime limit of 6 X 10⁻⁶ s is deduced for υ′ = 3 on the basis of a mechanism where depopulation is dominated by collisional removal and quenching in mixed carriers.     

Novel redox receptors for ion-pair and α-amino acid: synthesis and complexation properties of calix[4]arene derivatives bearing large conjugated ferrocene groups

By reacting calix[4]arene 1,3-bi-hydrazide derivative (2) with formacylferrocene in “1?+?2” condensation mode, novel calix[4]arene derivative bearing two conjugated ferrocene groups (3) was obtained in yield of 88%. By reacting 1,3-bi-substituted [2-(p-formylphenyloxy)ethyloxy]-p-tert-butylcalix[4]arene (5) with 1,1′-diacetylferrocene hydrazone (4) in “1?+?1” condensation mode, novel calix[4]arene derivative with 1,3-substituted large conjugated ferrocene bridge (6) was synthesized in yield of 83%. The structures and conformations of new compounds were confirmed by elemental analyses, IR spectra, ESI-MS, ¹H NMR, etc. The electrochemical cyclic voltammetry experiments revealed that compounds 3 and 6 possessed excellent reversible electrochemical properties. The ¹H NMR titration study showed that compound 6 possessed excellent complexation abilities for NaH₂PO₄ and glycine in 1:1 host–guest complex with the association constants of 3,850 and 2,460?M^?1, respectively.     

Chemistry of diphenyltetrafluorophosphazene: Reactions with dilithiated diols

Reaction of gem-diphenyltetrafluorophosphazene, [1,1-(C₆H₅)₂]P₃N₃F₄ (1) with LiO(CH₂)₃OLi resulted in the formation of four products, spiro-{3,3-[O(CH₂)₃O]}[1,1-(C₆H₅)₂]P₃N₃F₂ (2), ansa-{3,5-[O(CH₂)₃O]}[1,1-(C₆H₅)₂P₃N₃F₂] (3), bridged-[1,1-(C₆H₅)₂N₃P₃F₃][O(CH₂)₃O][1,1-(C₆H₅)₂N₃P₃F₃] (4) and dangling-[HO(CH₂)₃O][1,1-(C₆H₅)₂P₃N₃F₃] (5) derivatives of 1, among which compound 5 was found to be the major product. Reaction of 1 with the dilithiated ferrocene derived diol, FcCH₂P(S)(CH₂OLi)₂ resulted in the formation of two isomers of ansa substituted fluorophosphazenes namely endo-[1,1-(C₆H₅)₂]{3,5-[FcCH₂P(S)(CH₂O)₂]}P₃N₃F₂ (6) and exo-[1,1-(C₆H₅)₂]{3,5-[FcCH₂P(S)(CH₂O)₂]}P₃N₃F₂ (7). These were formed along with the spiro isomer [1,1-(C₆H₅)₂]{3,3-[FcCH₂P(S)(CH₂O)₂]}P₃N₃F₂ (8) the dangling derivative [1,1-(C₆H₅)₂P₃N₃F₃][OCH₂(FcCH₂)P(S)CH₂OH] (9) and the bridged compound [1,1-(C₆H₅)₂P₃N₃F₃][OCH₂(FcCH₂)P(S)CH₂O][1,1-(C₆H₅)₂P₃N₃F₃] (10). All compounds were separated by column chromatography and characterized by ¹H, ³¹P{¹H}, ¹⁹F NMR, mass spectra and elemental analysis. The spirocyclic compound 8 was also characterized by X-ray crystallography.     

Solubilization of Magnesium Octa[(4′-Benzo-15-Crown-5)Oxy]Phthalocyaninate in Aqueous Micellar Solutions of Hexadecyltriphenylphosphonium Bromide

Electronic absorption spectroscopy and fluorimetry have been employed to study the behavior of magnesium octa[(4′-benzo-15-crown-5)oxy]phthalocyaninate (Mg[(B15C5O)₈Pc]) in aqueous micellar solutions of sodium dodecyl sulfate and hexadecyltriphenylphosphonium bromide. Conditions have been found for the existence of monomeric Mg[(B15C5O)₈Pc] complex in surfactant solutions to provide the possibility of using mixed solutions of the complex and cationic surfactants (alkyltriphenylphosphonium bromides) for photodynamic therapy. In surfactant solutions with different concentrations of micelles (c_m) and the complex (c_p), the maximum amount of monomeric Mg[(B15C5O)₈Pc] is achieved at c_m/c_p ≥ 4.     

Complexation equilibria and spectrophotometric determination of zinc (II) with 2-(4′-methyl-2′-thiazolylazo)-4,6-dimethylphenol

2-(4′-methyl-2′-thiazolylazo)-4,6-dimethylphenol has been synthesized and its acid—base behaviour (pK_a1=0.03 ± 0.01, pK_a2=9.70±0.09) and complexation equilibria with zinc (logβ₁₀₁=6.70±0.04, logβ₁₀₂ = 13.70±0.02) studied in a 40% (v / v) ethanol—water medium at I=0.25 M NaClO₄. A spectrophotometric method for the determination of 0.2–1.5 ppm of zinc has been developed (ε=1.83 × 10⁴ 1. mol⁻¹ cm⁻¹ at 590 nm) and applied to its determination in lubricating oils.     

Spectroscopic characterization and crystal structure of cis-Bis(N-(2-benzoyl)-N′,N′-diphenylthioureato-k 2O,S)nickel(II)

The title compound [Ni(C₂₀H₁₅N₂OS)₂] is prepared by the reaction of metal acetate with the corresponding acylthiourea derivative. The complex is characterized by elemental analysis, IR, ¹H and ¹³C NMR, and its structure is determined by single crystal X-ray diffraction. The Ni(II) ion is coordinated by the S and O atoms of two N-benzoyl-N??,N??-diphenylthiourea ligands in a slightly distorted square-planar coordination geometry. The two O and two S atoms are mutually cis to each other. The substance crystallizes triclinic (P-1 space group) with cell dimensions a = 10.7262(9) ?, b = 12.938(3) ?, c = 14.2085(12) ?, ?? = 74.650(4)°, ?? = 78.398(4)°, ?? = 68.200(5)°, and two formula units in the unit cell. The structure is very close to the related N-(2-furoyl) Ni complex reported previously.     

A new Zn(II) complex of unusual unidentate coordination of 4,4′-bipyridine, a new precursor for the preparation of zinc(II) oxide nanoparticles

A 4,4′-bipyridine Zn(II) complex [Zn(4,4′-bipy)₂(H₂O)₄](ClO₄)₂·4(4,4′-bipy) is synthesized, characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR spectroscopy, and studied by X-ray crystallography. The compound forms monomeric units as a result of unusual unidentate coordination of 4,4′-bipy ligands. The thermal stability of the compound is studied by thermal analyses. Furthermore, the complex is luminescent with emission maxima at 329 nm in the methanol solvent. Different sizes of zinc(II) oxide nanoparticles are prepared by calcination of the [Zn(4,4′-bipy)₂(H₂O)₄](ClO₄)₂·4(4,4′-bipy) compound at two different temperatures. These nanostructures are characterized by X-ray powder diffraction and scanning electron microscopy.