Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｂｉｌｉｔｙｏｆｄｉｔｈｉｏｃａｒｂａｍａｔｅ(ｄｔｃ)ｂｉｎｄｉｎｇｔｏｍｅｔａｌｓｈａｓｂｅｅｎｋｎｏｗｎｆｏｒｍａｎｙｙｅａｒｓ .Ｉｔｆｏｒｍｓｃｈｅｌａｔｅｓｗｉｔｈｖｉｒｔｕ ａｌｌｙａｌｌｔｒａｎｓｉｔｉｏｎｍｅｔａｌｓ.1Ｔｈｅｂｉｄｅｎｔａｔｅａｎｉｏｎｉｓａｌｓｏｗｅｌｌｋｎｏｗｎａｓａｂｒｉｄｇｅｂｅｔｗｅｅｎｔｗｏｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｅｎｔｅｒｓ.2 Ｗａ ｔｅｒ ｓｏｌｕｂｌｅｄｉａｌｋｙｌｄｉｔｈｉｏｃａｒｂａｍａｔｅｃｏｍｐｌｅｘｅｓ…     

Synthesis and properties of ms- and β-substituted Pt(II) and Pt(IV) tetraphenylporphyrinates

The interaction of 5,10,15,20-tetraphenylporphyrin, 5,10,15,20-tetra-(4-chlorophenyl)porphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, and 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with platinum(II) chloride in boiling phenol has been studied. The corresponding platinum(II) porphyrinates have been synthesized; their subsequent treatment with bromine in chloroform resulted in platinum(IV) porphyrinates. The Pt(II) and Pt(IV)(Br)₂ porphyrinates have been identified by elemental analysis, electron absorption, IR, and ¹H NMR spectroscopy.     

Enzymatic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol and (±)-cis- and (±)-trans-2-aminoindan-1-ol

Pseudomonas cepacia lipase (PSL) efficiently catalyses the kinetic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol through the O-acylation reaction of the corresponding N-benzyloxycarbonyl derivative using vinyl acetate as the acyl donor. In a similar way, cis-N-Cbz-2-aminoindan-1-ol is resolved when isopropenyl acetate is used as the acylating agent. The enantioselectivity of the reaction was lower for (±)-trans-N-Cbz-2-aminoindan-1-ol due to the different steric requirements for the two conformers of this substrate.     

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) bis -( O,O ′-alkylene dithiophosphates): synthesis and characterization

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) alkylene dithiophosphates, (M = Nb(V) or Ta(V); G =–CHMeCHMe–,–CMe₂CMe₂–,–CH₂CMe₂CH₂–,–CH₂CEt₂CH₂–or–CMe₂CH₂CHMe–and X = Cl or OPrⁱ) have been synthesized by reaction of metal(V) chloride, MCl₅, or triisopropoxymetal(V) dichloride, (PrⁱO)₃MCl₂, with the sodium salts of O,O′-alkylene dithiophosphoric acids, in 1 : 2 molar ratio in THF under anhydrous conditions. These pink-purple or light-yellow compounds are viscous, semi-solid or solid, hydrolyzable and soluble in common organic solvents. These compounds have been characterized by elemental analyses, molecular weight determinations and spectral studies like IR and heteronuclear NMR (¹H, ¹³C and ³¹P), which indicated a bidentate mode of chelation of dithio ligands, leading to a pentagonal bipyramidal geometry around the niobium(V) or tantalum(V) centers.     

Synthesis and Characterization of Chlorobis(cyclopentadienyl) Titanium(IV) and Zirconium(IV) O,O’-Dialkyl and Alkylene Dithiophosphates

Abstract

Reactions of O,O′-dialkyl and alkylene dithiophosphoric acids with bis (cyclopentadienyl) titanium(IV) and zirconium (IV) dichloride in a 1:1 molar ratio in refluxing benzene proceeds with elimination of HCl and formation of the substituted derivatives, Cp₂MCl[S₂P(OR)₂] (where R = Et, Pr-n, Pr-i, Bu-i and Ph), Cp₂MCl[S₂POGO] (where G = ?CH₂CMe₂CH₂?, ?CH₂CEt₂CH₂? and ?CMe₂CMe₂?), (M = Ti and Zr). The complexes are dark red and yellow solids, soluble in common organic solvents and monomeric in nature. These have been characterized on the basis of elemental analyses, molecular weight determinations, IR, and NMR (¹H, ¹³C, and ³¹P).

GRAPHICAL ABSTRACT      

α-hydroaxyalkyl(benzyl)furozans and α-hydroxyalkyl(benzyl)furoxans synthesis and reactivity

A general and simple preparative method for the synthesis of -hydroxyalky(benzyl)furazan and -furoxan derivatives is proposed, The method involves reduction of acyl or ethoxycarbonyl substituents in these heterocyclic compounds with NaBH₄ in ethanol. Based on the alcohols thus prepared, a number of previously unknown functional derivatives (-nitroxyalkyl--haloalkyl-, and -azidoalkylfurazans and -furoxans) have been synthesized.Translated fromInvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7. pp, 1782–1788, July, 1996.     

Determinations of combustion and formation enthalpies of C_(60)and C_(70)

Ｆｕｌｌｅｒｅｎｅｓａｒｅａｋｉｎｄｏｆｃａｒｂｏｎａｌｌｏｔｒｏｐｅｓｆｏｕｎｄｒｅｃｅｎｔｌｙ,ａｎｄｈａｖｅｄｉｓｔｉｎｃｔｉｖｅｓｔｒｕｃｔｕｒｅｓａｎｄｐｒｏｐｅｒｔｉｅｓ.Ｆｏｒｅｘａｍｐｌｅ,Ｃ60ｈａｓａｆｏｏｔｂａｌｌｌｉｋｅｃａｒｂｏｎｓｋｅｌｅｔｏｎｗｉｔｈ20ｓｉｘｍｅｍｂｅｒｅｄｒｉｎｇｓ,12ｆｉｖｅｍｅｍｂｅｒｅｄｒｉｎｇｓａｎｄａｌａｒｇｅｂａｌｌｓｈｅｌｌｌｉｋｅπｂｏｎｄｓｙｓｔｅｍ.Ａｌｔｅｒｎａｔｉｖｅｌｙ,Ｃ70ｈａｓａｎｅｌｌｉｐｓｏｉｄｌｉｋｅｃａｒｂｏｎｓｋｅｌ…     

Structures and Spectroscopic Properties of(1)Dipyridine Quinoxaline with Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ)

The interaction of Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ) with dipyridine quinoxaline ligand 2,3-bis(2-pyridyl)quinoxaline(DPQ) were investigated, and three new complexes have been synthesized and characterized. Complex 1 exhibits a 0D dual-core structure, complex 2 is a 0D tetra nuclear case based on a dual-core Cu unit, and complex 3 shows a one-dimensional pipeline structure. Furthermore, the optical properties of complex and DPQ were also investigated, and the results showed that the fluorescence intensity of complexes was weaker than that of ligand DPQ.     

F+ and F⁻ affinities of simple N(x)F(y) and O(x)F(y) compounds

Atomization energies at 0 K and heats of formation at 0 and 298 K are predicted for the neutral and ionic N(x)F(y) and O(x)F(y) systems using coupled cluster theory with single and double excitations and including a perturbative triples correction (CCSD(T)) method with correlation consistent basis sets extrapolated to the complete basis set (CBS) limit. To achieve near chemical accuracy (±1 kcal/mol), three corrections to the electronic energy were added to the frozen core CCSD(T)/CBS binding energies: corrections for core-valence, scalar relativistic, and first order atomic spin-orbit effects. Vibrational zero point energies were computed at the CCSD(T) level of theory where possible. The calculated heats of formation are in good agreement with the available experimental values, except for FOOF because of the neglect of higher order correlation corrections. The F(+) affinity in the N(x)F(y) series increases from N(2) to N(2)F(4) by 63 kcal/mol, while that in the O(2)F(y) series decreases by 18 kcal/mol from O(2) to O(2)F(2). Neither N(2) nor N(2)F(4) is predicted to bind F(-), and N(2)F(2) is a very weak Lewis acid with an F(-) affinity of about 10 kcal/mol for either the cis or trans isomer. The low F(-) affinities of the nitrogen fluorides explain why, in spite of the fact that many stable nitrogen fluoride cations are known, no nitrogen fluoride anions have been isolated so far. For example, the F(-) affinity of NF is predicted to be only 12.5 kcal/mol which explains the numerous experimental failures to prepare NF(2)(-) salts from the well-known strong acid HNF(2). The F(-) affinity of O(2) is predicted to have a small positive value and increases for O(2)F(2) by 23 kcal/mol, indicating that the O(2)F(3)(-) anion might be marginally stable at subambient temperatures. The calculated adiabatic ionization potentials and electron affinities are in good agreement with experiment considering that many of the experimental values are for vertical processes.     

Synthesis and Magnetic Properties of Fe(II) and Nd(III) Complexes of Poly(N-2-thiazolylacrylamide)

In recent years,the organic ferromagnets have drawn growing attention due to their characteristics of structural diversities,low density,and readily processing1-3.Design and synthesis of magnetic polymers are one of great challenges in today′s magnetic material research,and some significant achievements have been made in this field4,5.In this article,we describe the synthesis of acrylamide-type polymer with pendent thiazolyl groups(Scheme1).The as-prepared polymer exhibited better solubility …     

Spectroscopic and electrochemical studies on (2-hydroxypicolinate)-bis(2,2′-bipyridine)ruthenium(II) and related complexes

Summary The synthesis, spectra and electrochemistry of [Ru(bipy)₂-(picOH)]⁺ and -picO-[Ru(bipy)₂]₂ ²⁺ (bipy = 2,2-bipyridine and picOH = 3-hydroxypicolinate ion) are described. The spectroscopic properties in the visible region are dominated by the intense Ru bipy chargetransfer transitions. In the binuclear complex, the two [Ru(bipy)₂L]²⁺ moieties are nonequivalent, exhibiting E _1/2 = 0.69 and 1.20 V versus s.h.e. The partially oxidized species exhibits a weak intervalence transfer band at 1085 nm, and is consistent with a Robin-Day class II mixed valence complex.     

Total Synthesis of (±)-Boschnialactone and (±)-Tetrahydroanhydrodesoxyaucubigenin

A total synthesis of (±)-boschnialactone ( 1 ) and (±)-tertahydroanhydrodesoxyaucubigenin ( 2 ) is described and trisubstitued cyclopentenoid 3 is a key intermediate.     

Total synthesis of (±)-maistemonine and (±)-stemonamide

The first total synthesis of polycyclic Stemona alkaloid maistemonine has been achieved. The efficient approach features a stereoselective intramolecular Schmidt reaction, a ketone-ester condensation, and a Reformatsky reaction. Additionally, another Stemona alkaloid stemonamide was divergently synthesized from a common intermediate.     

99mTc labeled ethylene-bis (valine) and ethylene-bis (α-alanine) and their preliminary biobistribution

The preparation of^99mTc-Sn-EBV and^99mTC-Sn-EBA is described. Different parameters affecting the labeling efficiency (ligand concentration, pH, molar ligand: reducing agent ratio) as well as the time-dependent stability of labeled compounds were investigated. Preliminary biodistribution studies in Wistar rats showed accumulation of the above mentioned compounds in kidneys.     

Structure and stability for (AlN)_n~+ and (AlN)_n~- (n=1-15) clusters

Using density functional theory (DFT) method with 6-31G* basis set, we have carried out the optimizing calculation of geometry, vibrational frequency and thermodynamical stability for(AIN)n+ and (AIN)n- (n =1-15) clusters. Moreover, their ionic potential (IP) and electron affinity(EA) were discussed. The results show that the electrical charge condition of the cluster has a relatively great impact on the structure of the cluster and with the increase of n, this kind of impactis reduced gradually. There are no AI-AI and N-N bonds in the stable structure of (AIN)n+ or (AIN)n-, and the AI-N bond is the sole bond type. The magic number regularity of (AIN)n+, and (AIN)n- is consistent with that for (AIN)n, indicating that the structure with even n such as 2, 4,6, … is more stable. In addition, (AIN)10 has the maximal ionization power (9.14 eV) and the minimal electron affinity energy (0.19 eV), which manifests that (AIN)10 is more stable than other clusters.     

Kinetics and mechanism of complex formation between O-bonded cis-(diglycinato)bis(ethylenediamine)cobalt(III) and α-cis-(diglycinato) (triethylenetetramine)cobalt(III) with nickel(II) in aqueous medium

Summary The kinetics of reversible complexation of Ni(OH₂) _inf6 ^sup2+ with oxygen-bonded glycinatocobalt(III) substrates N₄-Co(glyH)gly²⁺ [N₄ = (en)₂ or trien; glyH = H₃N⁺CH₂-COO^–] have been investigated by the stopped-flow technique in the 20–35° C range, at pH = 6.08–6.82 and I = 0.3 mol dm^–3. The formation of N₄Co(glyH)glyNi⁴⁺ occurred via the reaction of Ni(OH₂) _inf6 ^sup2+ with the deprotonated form of the cobalt(III) substrates, N₄Co-(glyH)gly²⁺. The rate and activation parameters for the formation and dissociation of the binuclear species are reported. The formation rate constants k _f (at 25° C), activation enthalpy and entropy H , S for N₄Co-(glyH)glyNi⁴⁺ are 320±49, 341 ± 52dm³mol^–1 s^–1, 78 ± 7, 79 ± 5 kJmol^–1 and 64 ± 24, 69 ± 18 JK^–1 mol^–1 for the ethylenediamine and triethylenetetraminecobalt(III) substrates, respectively. This result indicates that the rate and activation parameters are virtually independent of the nature of N₄ moities, which strongly suggests that the formation of mono-bonded species occurs via entry of one of the pendant NH₂ groups into the coordination sphere of nickel(II) via a rate-limiting Ni-OH₂ bond dissociation mechanism (I_d). The binuclear species exist in dynamic equilibrium between the monodentate and chelated forms, with the chelate form predominating. The low values of spontaneous dissociation rate constant for the binuclear species (k _r- 0.095^–1 at 25° C) in comparison with the high values of dissociation rate constants of monodentate nickel(II) complexes reported in the literature also support the chelate nature of the binuclear species.     

Six-Nuclear Complexes of Platinum(II) and Palladium(II) with Mercamine and β-Mercaptoethanol

The platinum(II) and palladium(II) complexes [Pt₆(SCH₂CH₂NH₂)₈]Cl₄ and [Pd₆(SCH₂CH₂OH)₈ Cl₄· 5H₂O with mercamine and β-mercaptoethanol, respectively, were synthesized. It was found on the basis of the comparison of IR and X-ray electron spectra of the ligands and complexes, and also of the data of X-ray diffraction analysis that the bidentate coordination of ligands through sulfur and nitrogen atoms is realized in the platinum(II) complex. In the palladium(II) complex β-mercaptoethanol is coordinated in a mixed-mode type. In both complexes sulfur atoms of the ligands occupy a bridging position.     

Metallothionein Induction by Cd(II) and Zn(II)

Blood may contain high proportion of the toxic and essential metals.Blood is responsiblefor the transport of ion of such metals.The organs such as the kidney,liver and placentaare exposed to a large proportion of the metals which enter the blood and may b…     

Intensity-tunable micelles and films containing bimetal ions—europium(III) and terbium(III)

In this paper, multicolored micelles were prepared by coordination of lanthanide(III) (europium(III) (Eu(III)) and terbium(III) (Tb(III))) ions with block copolymer in different molar ratios of n _Eu(III)/n _Tb(III). The micelles formed by polymer–Eu(III)/Tb(III) could emit higher quantum yield luminescence than the mixture of polymer–Eu(III) micelles and polymer–Tb(III) micelles. The micelles containing Eu(III) and Tb(III) could emit a yellow-green color, and the intensity varied with the molar ratios of n _Eu(III)/n _Tb(III). In the constant concentrations of Eu(III) and 1,10-phenanthroline (Phen), the intensity of ⁵D₀→⁷F₂ increased with the addition of Tb(III), and the intensity of ⁵D₄→⁷F₅ decreased with the increasing of Eu(III) in the constant concentrations of Tb(III) and Phen. All the multicolored micelles could be spin-coated as intensity-tunable films.     

Enantiospecific Synthesis of (–)-Cuspareine and (–)-Galipinine

An enantiospecific route to the synthesis of tetrahydroquinoline alkaloids (–)-cuspareine and (–)-galipinine is reported. Coupling of an iodide derivative of D-serine with aromatic dithianes and Pd-catalyzed intramolecular C–N coupling are the key steps in the synthesis.