Luminescence Spectral Properties of Europium(III) and Terbium(III) Complexes with Cinnamic Acid

Europium and terbium mixed-ligand complexes with cinnamic acid of composition Ln(Cin)₃· nD · xH₂O, where Ln = Eu³⁺or Tb³⁺, Cin is a cinnamate ion (C₆H₅CH=CHCOO^–), D = 1,10-phenantroline, 2,2"-dipyridyl, benzotriazole (n= 2, x= 0), triphenylphosphine oxide (n= 1, x= 2), or H₂O (n= 0 or 1, x= 0), were synthesized. The compounds were characterized by elemental analysis, IR and luminescence spectroscopy. The Stark structure of the ⁵ D ₀–⁷ F _j(j= 0, 1, 2) electronic transitions in the low-temperature luminescence spectra of europium complexes was analyzed. IR study has revealed a bidentate coordination of the cinnamate ion in the compounds.     

Synthesis,Structures, and Some Reactions of [(Thioacyl)thio]‐ and (Acylseleno)antimony and ‐bismuth Derivatives ((RCSS)xMR$\rm{_{{\bf 3 - }{\bf x}}^{\bf 1} }$ and (RCOSe)xMR$\rm{_{{\bf 3 - }{\bf x}}^{\bf 1} }$ with M = Sb,Bi and x = 1–3)

A series of [(thioacyl)thio]‐ and (acylseleno)antimony and [(thioacyl)thio]‐ and (acylseleno)bismuth, i.e., (RCSS)_xMR and (RCOSe)_xMR (M = Sb, Bi, R¹ = aryl, x = 1–3), were synthesized in moderate to good yields by treating piperidinium or sodium carbodithioates and ‐selenoates with antimony and bismuth halides. Crystal structures of (4‐MeC₆H₄CSS)₂Sb(4‐MeC₆H₄) ( 9b′ ), (4‐MeOC₆H₄COSe)₂Sb(4‐MeC₆H₄) ( 12c′ ), (4‐MeOC₆H₄COS)₂Bi(4‐MeC₆H₄) ( 15c′ ), and (4‐MeOC₆H₄CSS)₂BiPh ( 18c ) along with (4‐MeC₆H₄COS)₂SbPh ( 6b ) and (4‐MeC₆H₄COS)₃Sb ( 7b ) were determined (Figs. 1 and 2). These compounds have a distorted square pyramidal structure, where the aryl or carbothioato (= acylthio) ligand at the central Sb‐ or Bi‐atom is perpendicular to the plane that includes the two carbodithioato (= (thioacyl)thio), carboselenato (= acylseleno), or carbothioato ligand and exist as an enantiomorph pair. Despite the large atomic radii, the C?S ??? Sb distances in (RCSS)₂MR¹ (M = As, Sb, Bi; R¹ = aryl) and the C?O ??? Sb distances in (RCOS)_xMR (M = As, Sb, Bi; x = 2, 3) are comparable to or shorter than those of the corresponding arsenic derivatives (Tables 2 and 3). A molecular‐orbital calculation performed on the model compounds (MeC(E)E¹)_3?xMMe_x (M = As, Sb, Bi; E = O, S; E¹ = S, Se; x = 1, 2) at the RHF/LANL2DZ level supported this shortening of C?E ??? Sb distances (Table 4). Natural‐bond‐orbital (NBO) analyses of the model compounds also revealed that two types of orbital interactions n_S → σ and n_S → σ play a role in the (thioacyl)thio derivatives (MeCSS)_3?xMMe_x (x = 1, 2) (Table 5). In the acylthio‐MeCOSMMe₂ (M = As, Sb, Bi), n_O → σ contributes predominantly to the orbital interactions, but in MeCOSeSbMe₂, none of n_O → σ and n_O → σ contributes to the orbital interactions. The n_S → σ and n_S → σ orbital interactions in the (thioacyl)thio derivatives are greater than those of n_O → σ and n_O → σ in the acylthio and acylseleno derivatives (MeCOE)_3?xMMe_x (E = S, Se; M = As, Sb, Bi; x = 1, 2). ?The reactions of RCOSeSbPh₂ (R = 4‐MeC₆H₄) with piperidine led to the formation of piperidinium diphenylselenoxoantimonate(1?) (= piperidinium diphenylstibinoselenoite) (H₂NC₅H₁₀)⁺Ph₂SbSe^?, along with the corresponding N‐acylpiperidine (Table 6). Similar reactions of the bis‐derivatives (RCOSe)₂SbR¹ (R, R¹ = 4‐MeC₆H₄) with piperidine gave the novel di(piperidinium) phenyldiselenoxoantimonate(2?) (= di(piperidinium) phenylstibonodiselenoite), [(H₂NC₅H₁₀)⁺]₂(PhSbSe₂)^2?, in which the negative charges are delocalized on the SbSe₂ moiety (Table 6). Treatment of RCOSeSbR (R, R¹ = 4‐MeC₆H₄) with N‐halosuccinimides indicated the formation of Se‐(halocyclohexyl) arenecarboselenoates (Table 8). Pyrolysis of bis(acylseleno)arylbismuth at 150° gave Se‐aryl carboselenoates in moderate to good yields (Table 9).     

Solid Solution Formation between Vanadium(V) and ­Tungs­ten(V) Oxide Phosphate

The solid solutions (V_1–xW_x)OPO₄ with β‐VOPO₄ structure type (0.0 ≤ x ≤ 0.01) and α_II‐VOPO₄ structure type (0.04 ≤ x ≤ 0.26) were obtained from mixtures of V^VOPO₄ and W^VOPO₄ by conventional solid state reactions and by solution combustion synthesis. Single crystals of up to 3 mm edge length were obtained by chemical vapor transport (CVT) (800 → 700 °C, Cl₂ as a transporting agent). Single crystal structure refinements of crystals at x = 0.10 [a = 6.0503(2) Å, c = 4.3618(4) Å, R₁ = 0.021, wR₂ = 0.058, 21 parameters, 344 independent reflections] and x = 0.26 [a = 6.0979(2) Å, c = 4.2995(1) Å, R₁ = 0.030, wR₂ = 0.081, 21 parameters, 346 independent reflections] confirm the α_II‐VOPO₄ structure type (P4/n, Z = 2) with mixed occupancy V/W for the metal site. Due to the specific redox behavior of W⁵⁺ and V⁵⁺, solid solutions (V_1–xW_x)OPO₄ should be formulated as (V^IV_xV^V_1–2xW^VI_x)OPO₄. The valence states of vanadium and tungsten are confirmed by XPS measurements. V⁴⁺ with d¹ configuration was identified by EPR spectroscopy and magnetic measurements. Electronic spectra of the solid solutions show the IVCT(V⁴⁺ → V⁵⁺) and the LMCT(O^2– → V⁵⁺). (V_0.74W_0.26)OPO₄ powders exhibit semi‐conducting behavior (E_g = 0.7 eV).     

Polar Isotactic and Syndiotactic Polypropylenes by Organozirconium-Catalyzed Masking-Reagent-Free Propylene and Amino–Olefin Copolymerization

Polar functionalized isotactic and syndiotactic polypropylenes (PPs) are synthesized by direct, masking-reagent-free propylene and amino–olefin (AO, CH₂=CH(CH₂)_xNⁿPr₂, x=2, 3, 6) copolymerizations using the activated precatalysts rac-[Me₂Si(indenyl)₂]ZrMe₂ and [Me₂C(Cp)(fluorenyl)]ZrMe₂, respectively. Polymerization activities at 25 °C are as high as 4208 and 535 kg/(mol h atm) with AO incorporation up to 4.0 mol % and 1.6 mol %, respectively. Remarkably, introducing the amino-olefin comonomers significantly enhances stereoselection for both isotactic (mmmm: 59.5 %→91.0 %) and syndiotactic (rrrr: 66.3 %→81.3 %) products.     

Photoisomerization Mechanism of Ruthenium Sulfoxide Complexes: Role of the Metal‐Centered Excited State in the Bond Rupture and Bond Construction Processes

Phototriggered intramolecular isomerization in a series of ruthenium sulfoxide complexes, [Ru(L)(tpy)(DMSO)]ⁿ⁺ (where tpy=2,2’:6’,2’’‐terpyridine; DMSO=dimethyl sulfoxide; L=2,2’‐bipyridine (bpy), n=2; N,N,N’,N’‐tetramethylethylenediamine (tmen) n=2; picolinate (pic), n=1; acetylacetonate (acac), n=1; oxalate (ox), n=0; malonate (mal), n=0), was investigated theoretically. It is observed that the metal‐centered ligand field (³MC) state plays an important role in the excited state S→O isomerization of the coordinated DMSO ligand. If the population of ³MC_S state is thermally accessible and no ³MC_O can be populated from this state, photoisomerization will be turned off because the ³MC_S excited state is expected to lead to fast radiationless decay back to the original ¹GS_S ground state or photodecomposition along the Ru²⁺?S stretching coordinate. On the contrary, if the population of ³MC_S (or ³MC_O) state is inaccessible, photoinduced S→O isomerization can proceed adiabatically on the potential energy surface of the metal‐to‐ligand charge transfer excited states (³MLCT_S→³MLCT_O). It is hoped that these results can provide valuable information for the excited state isomerization in photochromic d⁶ transition‐metal complexes, which is both experimentally and intellectually challenging as a field of study.     

A conjecture for some partial differential operators on L 2( R n)

OnX =L ²(R ⁿ), letQ = (Q ₁,Q ₂,…,Q _n) andP = (P ₁,P ₂, …,P _n) be the operators given by (Q _jf) (x) =x _jf(x),P _j = - i∂/∂x _j. For anyC ^∞ functionh:R ⁿ →R putH ₀ =h(P) andH =H ₀ + (1 +Q ²)^-δ, where δ > 1/2. By the method of scattering theory we prove thatH _ac, the absolutely continuous part ofH is unitarily equivalent toH ₀ when (a)n = 1 and (b) forn ≥ 2, whenh is in a large class of polynomials. It is conjectured that the results are true for any polynomialh. We use the techniques of Enss’ method and the idea of bound states for momentum.     

A configuration interaction study of the spin dipole-dipole parameters for formaldehyde and methylene

The electron spin dipole-dipole contribution to the zero field splitting has been evaluated for the ³A₂ (n → π*) and ³A₁ (π → π*) states of formaldehyde using a CI wave function constructed from contracted Gaussian-lobe functions. The values D = 0.539 cm^?1 and E = 0.031 cm^?1 were obtained for the ³A₂(n → π*) state and D = ?0.588 cm^?1 and E = 0.058 cm^?1 were obtained for the ³A₁ (π → π*) state using the CI wave function constructed from SCF orbitals of the respective parent configurations. An analysis of the effect of CI on the parameters is given for the ³A₂ (n n → π*) state of formaldehyde and the ³B₁ ground state of methylene. Numerical results are given which show that internally consistent self-consistent field orbitals (ICSCF ) are superior to canonical SCF orbitals as a starting point for a CI calculation. Our CI wave function for the ¹A₁ ground state gave an energy of ?114.13658 hartrees which is significantly lower than any previously reported energy calculation. This wave function gives a dipole moment of 2.22 Debye (C⁺O^?) in good agreement with the experimental value of 2.33 ± 0.02 Debye.     

Synthesis,electrochemical and antimicrobial studies of mono and binuclear iron(III) and oxovanadium(IV) complexes of [ONO] donor tridentate Schiff-base ligands

Tridentate Schiff bases (H₂L¹ or H₂L²) were derived from condensation of acetylacetone and 2-aminophenol or 2-aminobenzoic acid. Binuclear square pyramidal complexes of the type [M₂(L¹)₂]?·?nH₂O (M?=?Fe–Cl, n?=?0; M?=?VO, n?=?1) were accessed from interaction of H₂L¹ with anhydrous FeCl₃ and VOSO₄?·?5H₂O, respectively. A similar reaction with H₂L², however, produced mononuclear complexes [ML²(H₂O) _x ]?·?nH₂O (M=Fe–Cl, x?=?0, n?=?0; M=VO, x?=?1, n?=?1). The compounds were characterized using elemental analysis, FT-IR, UV-Vis, and NMR (for ligand only), and mass spectroscopies and solution electrical conductivity studies. Magnetic susceptibility measurements suggest antiferromagnetic exchange in binuclear Fe(III) and VO(IV) complexes. Thermo gravimetric analysis (TGA) provided unambiguous evidence for the presence of coordinated as well as lattice water in [VOL²(H₂O)]?·?H₂O. Cyclic voltammetric studies showed well-defined redox processes corresponding to Fe(III)/Fe(II) and VO(V)/VO(IV). In vitro antimicrobial activities of the compounds were investigated against Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeroginosa, Escherichia coli, Bacillus subtilis, and Proteus vulgaris. H₂L¹ and its binuclear complexes exhibited pronounced activity against all the microorganisms tested.     

Crystal structure of [Cu(NH3)4](ReO4)2

At T = 150 K, the crystal structure of [Cu(NH₃)₄](ReO₄)₂ is studied: a = 6.5167(3) ?, b = 6.7790(3) ?, c = 7.4627(3) ?, α = 67.336(1)°, β = 80.004(1)°, γ = 70.687(1)°, V = 286.70(2) ?³, P-1 space group, Z = 1, d _x = 3.661 g/cm³. We analyze the packing of ions using the translation sublattice isolation technique.     

Synthesis,characterization, theoretical calculations and catalase-like activity of mixed ligand complexes derived from alanine and 2-acetylpyridine

Mixed ligand complexes [M(2-AP)(Ala)Cl _x · mH₂O]nH₂O, where (M = Co^II, Ni^II, Cr^III and Fe^III, 2-AP = 2-acetylpyridine, Ala = alanine, x = 2–3, m = 0–1 and n = 3–5] are synthesized and characterized by elemental analysis, FTIR, UV/Vis., MS, TG, measurements and semi-empirical calculations ZINDO/1 and PM3. The results suggest an octahedral geometry for all isolated complexes. FTIR spectra show that alanine coordinates to the metal ions as a neutral unidentate through the amino nitrogen where 2-acetylpyridine coordinates to the metal ion in a bidentate manner through carbonyl oxygen and pyridyl nitrogen. Semi-empirical calculations have been used to study the molecular geometry and the harmonic vibrational spectra with the purpose to assist the experimental assignment of the complexes. The Fe complex showed significant activity as a catalase-like model.     

Ca3Ag1+xGe3–x (x = 1/3): New Transition Metal Zintl Phase with Intergrowth Structure and Alloying with Aluminum Metal

Abstract. The ternary Zintl phase Ca₃Ag_1+xGe_3–x (x = 1/3) was synthesized by the high‐temperature solid‐state technique and its crystal structure was refined from single‐crystal diffraction data. The compound Ca₃Ag_1.32Ge_2.68(1) adopts the Sc₃NiSi₃ type structure, crystal data: space group C2/m, a = 10.813(1) Å, b = 4.5346(4) Å, c = 14.3391(7) Å, β = 110.05(1)° and V = 660.48(10) ų for Z = 4. Its structure can be interpreted as an intergrowth of fragments cut from the CaGe (CrB‐type) and the CaAg_1+xGe_1–x (TiNiSi‐type) structures, and it therefore represents an alkaline‐earth member of the structure series with the general formula R_2+nT₂X_2+n with n = 4. Unlike the rare‐earth homologues that are fully ordered phases, one seventh of the atomic sites in the unit cell of the title compound are mixed occupied (roughly 2/3Ge and 1/3Ag), and this can be explained by the Zintl concept. The alloying of this phase using aluminum metal yielded the isotypic solid solution Ca₃(Ag/Al)_1+xGe_3–x, in which the aluminum for silver substitution is strictly localized in the TiNiSi substructure, revealing the very different functionality of the two building blocks.     

Experimental study of the D + H2(ν = 1) reaction

The D + H₂(ν = 1) reaction, D + H₂(ν = 1) → K_a HD(ν = 1) + H, → K_n HD(ν = 0) + H, → K_r D + H₂(ν = 0) has been studied. The measurements were made in a flow-tube apparatus at 300 K. Vibrationally excited H₂ was generated in a furnace and D atoms in a microwave discharge. EPR and thermometric techniques were used for the detection of D and H atoms and H₂(ν = 1). The product branching rate constants (in CM³/Molecule s) were found to be K_a = (10.7 ± 4.1) × 10^?13. K_n = (5.4 ± 2.7) × 10^?13, K_r, < 2.7 × 10^?13.     

Polysulfonylamine. LVII. Zwei Silber(I)-di(organosulfonyl)-amide mit einer Silber-η2-Aryl- beziehungsweise einer Silber-Silber-Wechselwirkung: Kristallstrukturen von Silberdi(benzolsulfonyl)-amid-Wasser (1/0,5) und von wasserfreiem Silberdi(4-toluolsulfonyl)-amid

Polysulfonyl Amines. LVII. Two Silver(I) Di(organosulfonyl)-amides with Silver-η²-Aryl or Silver-Silver Interactions: Crystal Structures of Silver Di(benzenesulfonyl)amide-Water (1/0.5) and of Anhydrous Silver Di(4-toluenesulfonyl)-amide Crystals of [(PhSO₂)₂NAg(μ-H₂O)AgN(SO₂Ph)₂]_n ( 5 ) and [(4-Me? C₆H₄SO₂)₂NAgAgN(SO₂C₆H₄-4-Me)₂]_n ( 6 ) were obtained from aqueous solutions. The crystallographic data are for 5 (at ?95°C): monoclinic, space group C2/c, a = 2 743.8(5), b = 600.49(12), c = 1 664.5(3) pm, β = 101.143(15)°, V = 2.6908 nm³, Z = 8, D_x = 2.040 Mg m^?3; for 6 (at ?130°C): monoclinic, space group P2₁/n, a = 1 099.8(5), b = 563.7(3), c = 2 487.7(13) pm, β = 99.68(4)°, V = 1.5203 nm³, Z = 4, D_x = 1.888 Mg m^?3. In both crystals, the silver atom has a fivefold coordination. The structure of 5 displays [(RSO₂)₂N? Ag(μ-H₂O)Ag′? N(SO₂R)₂] units with Ag? N 226.9 pm, Ag? O 236.7 pm and Ag? O? Ag′ 95.3°; the water oxygen lies on a crystallographic twofold axis. These units are extended to two fused six-membered rings by intramolecular dative bonds (S)O → Ag′ and S(O)′ → Ag (249.3 pm). One phenyl group from each (PhSO₂)₂N moiety is η²-coordinated with its p-C and one m-C atom to a silver atom of a neighbouring bicyclic unit related by a glide plane to form infinite parallel strands (p-C? Ag 252.2, m-C? Ag 263.9 pm). The strands are interconnected into parallel layers through hydrogen bonds between H₂O and sulfonyl oxygens [O …? O(S) 276.1 pm]. These layers consist of a hydrophilic inner region containing metal ions, N(SO₂)₂ fragments and water molecules, and hydrophobic surfaces formed by phenyl groups. The structure of 6 features centrosymmetric [(RSO₂)₂N? Ag? Ag′? N(SO₂R)₂] units with two intramolecular dative bonds (S)O → Ag′ and (S)O′ → Ag (Ag? Ag′ 295.4, Ag? N 226.0, Ag? O 229.4 pm). These bi-pentacyclic units are associated by translation parallel to y into infinite strands by two dative (S)O → Ag bonds per silver atom (Ag? O 243.2 and 253.3 pm).     

N-representability of diagonal elements of second-order reduced density matrices

The problem of pure-state N-representability of the two-particle spin-dependent density function ρ(x₁, x₂) is considered for an N-electron system, and a procedure for finding an N-representable ρ(x₁, x₂) is advanced. The problem is formulated in the framework of a family of N × N matrices formed from integrals of auxiliary two-particle functions θ_n(x₁, x₂) converging at n → ∞ to ρ(x₁, x₂)/[N(N−1)]. The simple requirement of positive definiteness of these matrices is shown to play a decisive role in finding an N-representable ρ(x₁, x₂). The results obtained may open new possibilities for using ρ(x₁, x₂) in the density-functional theory. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65 : 127–142, 1997     

Novel vic-dioxime ligands and their poly-metal complexes bearing 1,8-diamino-3,6-dioxaoctane: synthesis, characterization, spectroscopy and electrochemistry

Three novel vic-dioxime ligands containing the 1,8-diamino-3,6-dioxaoctane group, N,N′-(1,8-diamino-3,6-dioxaoctane)-p-tolylglyoxime (L¹SL¹H₄), N,N′-(1,8-diamino-3,6-dioxaoctane)-phenylglyoxime (L²SL²H₄), and N,N′-(1,8-diamino-3,6-dioxaoctane)-glyoxime (L³SL³H₄) have been prepared from 1,8-diamino-3,6-dioxaoctane with anti-p-tolylchloroglyoxime, anti-phenylchloroglyoxime or anti-monochloroglyoxime. Polynuclear complexes [M(L ^x SL ^x )] _n or [M(L ^x SL ^x )(H₂O)] _n (x = 1, 2 and 3), where M = Cu^II, Co^II, and Ni^II, have been obtained with 1:1 metal/ligand ratio. The Cu^II and Ni^II poly-metal complexes of these ligands are proposed to be square planar, while also the prepared Co^II complexes are proposed to be octahedral with two water molecules as axial ligands. The detection of H-bonding in the [Ni(L¹SL¹)] _n , [Ni(L²SL²)] _n and [M(L³SL³)(H₂O)] _n metal complexes by FT i.r. spectra revealed the square planar or octahedral [MN₄·H₂O)] _n coordination of poly-nuclear metal complexes. [MN₄] _n coordination of the [Ni(L¹SL¹)] _n and [Ni(L²SL²)] _n complexes were also determined by ¹H-n.m.r. spectroscopy. The ligands and poly-metal complexes were characterized by elemental analyses, FT-i.r., u.v.-vis., ¹H and ¹³C-n.m.r. spectra, magnetic susceptibility measurements, molar conductivity, cyclic voltammetry, and differential pulse voltammetric (DPV) techniques.     

Theoretically derived absorption and MCD spectral data for the cellular species produced in the hydrolysis of cis-diamminedichloroplatinum(II)

The cellular species formed in the hydrolysis of cis-Pt(NH₃)₂Cl₂ (DDP), namely, cis-[Pt(NH₃)₂XY]ⁿ⁺ (X, Y = Cl^?, H₂O, OH^?; n = 0, 1, 2) have been investigated theoretically using the relativistic and nonrelativistic extended Huckel molecular orbital method. Molecular orbital (MO) results for trans-DDP and its hydrolysis products are also reported for comparison. Transition energies, molar absorption coefficients (?), and B terms from magnetic circular dichroism (MCD) derived from theory are presented for each of the species studied. The electronic absorption and MCD spectra of all the complexes are predicted to exhibit ligand field transitions arising primarily from excitations between the occupied Pt 5d orbitals and the unoccupied Pt 5d and 6p_z orbitals, respectively. The 5d → 6p_z transitions are expected to yield intense absorptions in the UV spectral region. Some intensity is generated in the d → d transitions as a result of the low symmetry of these complexes. Correlation of available experimental data with theory allows spectral assignments to be made and predicted. Substituent effects in the cis- and trans-isomeric species are discussed. Finally, the applicability of the EHMO method to these systems is examined.     

Lewis‐Base Stabilized N‐Silver(I) Succinimide Complexes: Synthesis,Crystal Structures and Their Use as CVD‐Precursors

Four Lewis‐base stabilized N‐silver(I) succinimide complexes of type [L_n·R_m·AgNC₄H₄O₂] (L = N,N,N′,N′‐tetramethylethylenediamine (TMEDA), n = 1, m = 0, 2a ; L = P(OEt)₃, n = 2, m = 0, 2b ; L = PPh₃, m = 0, n = 2, 2c ; L = P(OMe)₃, R = TMEDA, n = 1, m = 1, 2d ) were prepared by a “one‐pot” synthesis methodology and characterized. The molecular structures of 2a and 2c have been determined by using X‐ray single crystal analysis. Complex 2a exists as ion pair {[Ag(TMEDA)₂]⁺[Ag(NC₄H₄O₂)₂]^–} in the solid state and complex 2c is a monomer with the three‐coordinate silver atom. Complex 2b was used as precursor in the deposition of silver for the first time by using MOCVD technique. The silver films obtained were characterized using scanning electron microscopy (SEM) and energy‐dispersion X‐ray analysis (EDX). SEM and EDX studies show that the dense and homogeneous silver films could be obtained.     

Synthesis,spectroscopic, thermal and biological aspects of drug‐based copper(II) complexes

A series of novel complexes of the type Cu(II)(L_n)₂(H₂O)₂]^•xH₂O [where L_n = L _1–4 , these ligands being described as: L ₁ , 2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)phenol, x = 1; L ₂ , 2‐({4‐[6,7‐dihydrothieno[3,2‐c] pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)‐5‐(methoxy)phenol, x = 2; L ₃ , 5‐chloro‐2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)phenol, x = 2; and L ₄ , 5‐bromo‐4‐chloro‐2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino} methyl)phenol, x = 1] was investigated. They were characterized by elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR and electronic spectra, magnetic measurements and thermal studies. The FAB‐mass spectrum of [Cu(II)( L ₁ )₂(H₂O)₂]^•H₂O was determined. A magnetic moment and reflectance spectral study revealed that an octahedral geometry could be assigned to all the prepared complexes. Ligands (L_n) and their metal complexes were screened for their in vitro antibacterial activity against Bacillus subtillis, Pseudomonas aeruginosa, Escherichia coli and Serratia marcescens bacterial strains. Kinetic parameters such as order of reaction (n), the energy of activation (E_a), the pre‐exponential factor (A), the activation entropy (ΔS^≠), the activation enthalpy (ΔH^≠) and the free energy of activation (ΔG^≠) are reported. Copyright © 2011 John Wiley & Sons, Ltd.     

A theoretical study of the photoelectron spectra of dichloroketene with accurate computation of ionization energies via complete basis set limit extrapolation

We calculated the equilibrium geometries and harmonic vibrational frequencies of the ground state and five cationic states of dichloroketene using (TD-)B3LYP, PBE0, and M06/M06-2X approaches. The photoelectron spectra of dichloroketene were simulated by computing Franck-Condon factors. The ionization energies were computed using the CCSD(T) approach with extrapolation to the complete basis set (CBS) limit. We propose two new CBS energy formulas (E = E_CBS + Aexp(-x) + B/(x−1) ⁿ, n = 2 or 3) and compare the performance of different CBS approaches. A new ionic state of dichloroketene belonging to the C_s point group is reported. This state is identified as the first excited state of Cl₂CCO⁺ having a double-well potential-energy curve along the CCO bending mode with a barrier height of 1.335 eV. The simulated photoelectron spectra are in agreement with the experiment. The vertical ionization energies calculated via spectral simulation are more accurate compared with those obtained at the ground-state structure. Among the CBS formulas used, the proposed ansatz with n = 2 performs best, with a mean absolute error of 0.021 and 0.012 eV for the adiabatic and vertical ionization energies, respectively.     

Conformational Studies of Dibenzo-30-crown-10 Complexes. Syntheses and Crystal Structures of Potassium and Ammonium Hexafluorophosphate Complexes

Abstract

Crown ether complexes formed by the dibenzo–30-crown–10 (DB30C10) with potassium and ammonium hexafluorophosphate have been prepared and their crystal structures have been determined by single crystal X-ray analyses. The potassium complex (compound 1) consists of [K(DB30C10)]⁺ cation and PF₆ ^? anion. Crystals are monoclinic, space group P2/n, with a = 11.9106(3), b = 9.8382(5), c = 14.3062(3) Å, β = 97.581(3)°, V = 1661.7(1) ų, D_c = 1.440 g cm^?3, Z = 4, R = 0.0675 for 2528 unique observed reflections. The potassium atom is coordinated to the ten oxygen atoms of the crown ligand at the distance from 2.859(3) to 2.930(3) Å. The ammonium complex (compound 2) has also 1:1 crown—cation ratio. Crystals are monoclinic, space group P2₁/n, with a = 12.5061(6), b = 19.3724(5), c = 14.2203(9) Å, β = 102.476(5)°, V = 3363.8(3) ų, D_c = 1.501 g cm^?3, Z = 4, R = 0.0677 for 4172 unique observed reflections. The ammonium cation is completely enclosed with crown oxygen atoms forming seven hydrogen bonds. The conformation of previously reported dibenzo-30-crown-10 complexes with potassium salts were investigated using polar coordinate maps.