Syntheses on the basis of 2H-chromen-2-one and 2H-chromene-2-thione

4-Hydroxy-2H-chromen-2-one and 4-hydroxy-2H-chromene-2-thione reacted with allyl bromide, 1,1,3-trichloroprop-1-ene, and 1,3-dichlorobut-2-ene to give the corresponding ethers, which were oxidized to (2-oxo-2H-chromen-4-yloxy)acetic acid with potassium permanganate, and various derivatives of that acid were obtained. 3-(3,3-Dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromen-2-one and 3-(3,3-dichloroprop-2-enyl)-7-hydroxy-4-methyl-2H-chromene-2-thione were synthesized, and some their transformations were studied.     

Reactivity of 2-halo-2H-azirines. Part 3: Dehalogenation of 2-halo-2H-azirine-2-carboxylates

The dehalogenation of 2-halo-3-phenyl-2H-azirine-2-carboxylates is described. Using sodium borohydride and tributyltin hydride 3-phenyl-2H-azirine-2-carboxylates were obtained in moderate yields. The synthesis of a new 2-bromo-2H-azirines with a chiral auxiliary, 10-phenylsulfonylisobornyl 2-bromo-3-phenyl-2H-azirine-2-carboxylate, is reported. Its dehalogenation led to 10-phenylsulfonylisobornyl 2H-azirine-2-carboxylate as single stereoisomer together with the formation of 10-phenylsulfonylisobornyl acetate.     

Structural chemistry of Ba2CdS3, Ba2CdSe3, BaCdS2, BaCu2S2 and BaCu2Se2

The structures of all compounds were determined from three dimensional single crystal X-ray diffraction data and refined by least squares. Ba₂CdS₃ and Ba₂CdSe₃ are isostructural, Pnma, a = 8.9145(6)Å, b = 4.3356(2)Å, c = 17.2439(9)Å for the former compound and a = 9.2247Å, b = 4,4823(6)Å, c = 17.8706(11)Å for the latter, z = 4, R = 0.0751 and R = 0.0462, respectively. The compounds are isostructural with the previously reported Mn analogues and with K₂AgI₃. Cd ions are in tetrahedral environment and the tetrahedra form infinite linear chains by corner sharing. Ba ions are in 7-fold coordination in which 6 anions form a trigonal prism and 1 anion caps one of the rectangular faces. BaCdS₂, Pnma, a = 7.2781(3)Å, b = 4.1670(1)Å, c = 13.9189(6)Å, z = 4, R = 0.0685. Cd ions can be considered to have a triangular planar coordination with CdS distances of 2.47 and 2.53 Å (twice). Two additional S ions are at 2.89 and 3.22 Å to complete a triangular bipyramidal configuration. Ba is in 7-fold coordination with the anions forming a trigonal prism which is capped on one rectangular face. The compound is isostructural with BaCdO₂ and is related to the structure of BaMnS₂. BaCdSe₂ could not be prepared. BaCu₂S₂ and BaCu₂Se₂ are isostructural, Pnma, a = 9.3081(4)Å, b = 4.0612(3)Å, c = 10.4084(5)Å for the sulfide and a = 9.5944(6)Å, b = 4.2142(4)Å, c = 10.7748(8)Å for the selenide, z = 4, R = 0.0634 and 0.0373, respectively. Ba ions are in the usual 7-fold, capped hexagonal prism, coordination. However, 9 Cu ions also can be considered to form a trigonal prism with all rectangular faces capped, around Ba since the BaCu distances range from 3.24 to 3.54 Å for the sulfide and from 3.37 to 3.67 Å for the selenide. One of the Cu ions is in a very distorted tetrahedral environment and the second one is located in a more regular tetrahedral configuration of the anions. Two independent infinite chains of tetrahedra are present. They are formed by sharing of two adjacent edges of each tetrahedron and then these chains in turn are linked by corner sharing into a three-dimensional network of tetrahedra.     

Die Struktur von Cp2TiMe2

The structure of dimethyltitanocene, Cp₂TiMe₂, has been determined: monoclinic, space group P2₁/n, lattice constants (at −100°C) a = 6.818(2), b = 11.571(2), c = 13.387(3) Å, β = 92.36(2)°, and Z = 4. It is isostructural with Cp₂ZrMe ₂ and Cp₂HfMe₂. The Ti-C(σ) bond lengths are 2.170(2) and 2.181(2) Å and the C(σ)-Ti-C(σ) angle is 91.3(1 )°.     

Tartrate der TypenLn 2(H2 T)3·xH2O undLnH5 T 2·xH2O einiger Seltenerdmetalle

The following compounds were isolated and more closely studied by means of thermal analysis, X-ray scattering and IR absorption spectra and determination of solubilities: Pr₂(H₂ T)₃ · 6 H₂O, Nd₂(H₂ T)₃ · 6 H₂O, Sm₂(H₂ T)₃ · 5 H₂O, Gd₂(H₂ T)₃ · 5 H₂O, Tb₂(H₂ T)₃ · 5 H₂O, Dy₂(H₂ T)₃ · 5 H₂O, Ho₂(H₂ T)₃ · 5 H₂O, Er₂(H₂ T)₃ · 5 H₂O, PrH₅ T ₂ · 2 H₂O, NdH₅ T ₂ · 2 H₂O, SmH₅ T ₂ · 2 H₂O, GdH₅ T ₂ · 3 H₂O, TbH₅ T ₂ · 3 H₂O, DyH₅ T ₂ · 3 H₂O, HoH₅ T ₂ · 3 H₂O, ErH₅ T ₂ · 3 H₂O.     

Preparation of cis-Mo(CO)2(Ph2P(CH2)nPPh2)2 (n = 1, 2, 3) from cis-dicarbonylbis(norbornadiene)molybdenum and crystal structure of [cis-Mo(CO)2(Ph2P(CH2)3PPh2)2]

The complexes cis-Mo(CO)₂(Ph₂P(CH₂)_nPPh₂)₂ (n = 1, 2, 3) are synthesized by heating benzene solutions of cis-dicarbonylbis(norbornadiene)molybdenum and the corresponding diphosphines. The X-ray structural analysis of cis-Mo(CO)₂(Ph₂P(CH₂)₃PPh₂)₂ is reported, with the following crystal data: C₅₆H₅₂MoO₂P₄·2CH₂Cl₂·0.5C₆H₁₄, mol wt. 1189.81, monoclinic, space group P2₁/n, a 15.643(2), b 21.453(7), c 17.105(3) Å, β 100.75(1)°, V 5639.59 ų, Z = 4, D_c 1.39, D_m 1.36 g/cm³.     

Natural radiative lifetimes in the2 S 1/2 and2 D 3/2, 5/2 sequences of neutral copper

Natural radiative lifetimes have been measured of the 3d ¹⁰ ns ² S _1/2 (n=6?10) and of the 3d ¹⁰ nd ² D _{3/2, 5/2} (n=5?9) sequences by using two step excitation of copper atoms in an atomic beam. The states investigated were populated by the light from two pulsed dye lasers pumped by the same Nd:YAG laser. The lifetimes of the² D sequence increase regularly with increasing principal quantum number. This is not the case for the² S series, because of configuration interaction in the² P series. In addition the lifetime of the 3d ¹⁰5p ² P _3/2 state has been measured together with its branching ratio.     

Real structure of SrSi2O2N2

SrSi₂O₂N₂ is an important host lattice for Eu²⁺ doped phosphors. Its crystal structure (space group P1, a = 7.0802(2) Å, b = 7.2306(2) Å, c = 7.2554(2) Å, α = 88.767(3)°, β = 84.733(2)°, γ = 75.905(2)° and V = 358.73(2) Å³, Z = 4) is isotypic with EuSi₂O₂N₂: highly condensed silicate layers are separated by Sr²⁺. The samples are characterized by pronounced real structure effects owing to pseudosymmetry of partial structures. Polysynthetic twinning with domains of various sizes is ubiquitous and oriented intergrowth of domains with different orientations has also been observed and analysed in detail by means of electron diffraction and high-resolution electron microscopy. These effects also affect the X-ray powder pattern and were taken into account in a Rietveld refinement.     

Alkyl- und aryl-komplexe des iridiums und rhodiums: X. Chelatphosphin-stabilisierte rhodiumorganyle Rh(R)[PhP(CH2CH2CH2PPh2)2]: synthese,NMR-spektroskopischer cis,trans-einfluss und molekülstruktur von Rh(2-MeC6H4)[PhP(CH2CH2CH2PPh2)2]

The organorhodium(I) complexes Rh(R)[PhP(CH₂CH₂CH₂PPh₂)₂] (R  CH₂CMe₃, CH₂SiMe₃; 2-MeC₆H₄, 4-MeC₆H₄, 2,4-Me₂C₆H₃, 2,4,6-Me₃C₆H₂; C₂Ph) have been prepared and characterized by ³¹P and ¹H NMR spectroscopy and an X-ray structure determination of the tolyl derivative Rh(2-MeC₆H₄)-[PhP(CH₂CH₂CH₂PPh₂)₂].For these compounds, the relative ³¹P coordination shifts Δ(PPh₂) > Δ(PPh) distinctly reflect the electron-releasing properties of the organoligands σ-bonded trans to PPh. As expected, coupling between the ¹⁰³Rh nucleus and phenylphosphino P atoms is weak and varies only little as the strong trans influence groups R are changed. In contrast to this insensitivity of ¹J(Rh-PPh) to R, Rh-P coupling within the Ph₂P-Rh-PPh₂ moieties shows considerable dependence upon the nature of the C-donor producing the cis influence series sp³-C <sp²-C < sp-C.The ortho-tolyl complex crystallizes from toluene as 1/1 solvate Rh(2-MeC₆H₄)[PhP(CH₂CH₂CH₂PPh₂)₂] · C₇H₈. Crystals are orthorhombic, space group Pbc2₁, with a 1017.9(7), b 1974.3(14), c 2177.6(11) pm, and Z = 4. The structure has been refined to R = 0.079 for 2249 unique data with F₀ > 3σ(F₀). Metal-phosphorus distances are 225.7(5) and 229.6(6) pm for Rh-PPh₂ and 227.3(6) pm for Rh-PPh.     

Low temperature specific heats and magnetic properties of LaRh2Si2 and HoRh2Si2

Specific heats, static magnetizations and a.c. susceptibilities have been measured on polycrystalline LaRh₂Si₂ and HoRh₂Si₂. Both compounds have been confirmed to have the ThCr₂Si₂-type crystal structure down to 4 K.LaRh₂Si₂ is not superconducting and shows no ordered magnetism above 1.3 K. It has a Debye temperature θ_D = 330 K, electronic specific heat coefficient γ = 6.4mJ mol⁻¹ K⁻², temperature-independent magnetic susceptibility χ_m = 1.6 × 10⁻⁴ e.m.u. mol⁻¹, and is considered to be an ordinary metal.HoRh₂Si₂ has two peaks in the specific heat vs. temperature curve, a broad peak at 11 K and a very sharp one at 27 K. The magnetization vs. temperature curve also shows two peaks at 10 K and 29 K. The magnetic part of the specific heat obtained by subtraction of the specific heat of LaRh₂Si₂ from that of HoRh₂Si₂, provides the total entropy ΔS = 24 J mol⁻¹ K⁻¹, which is close to Rln(2J + 1) for J = 8. This fact suggests that all the excess entropy is attributed to the ground state multiplet of Ho³⁺ ion (⁵I₈) and that the lower temperature peak observed in the specific heat (and also in the magnetization) does not originate in itinerant electrons nor in an impurity phase.     

Base dependent purported synthesis of congested 2-aminobenzylamines and tetrahydro-2-oxoquinazolines from 2-pyranones

An expeditious and concise synthesis of highly congested 2-amino-3-aminomethyl-5-methylsulfanyl/-sec-aminobiphenyl-4-carbonitrile 4 and 1-tert-butoxycarbonyl-6-sec-amino-8-aryl-5-cyano-2-oxo-1,2,3,4-tetrahydroquinazoline 5 has been delineated through base catalyzed ring transformation of 6-aryl-4-methylsulfanyl/-sec-amino-2H-pyran-2-one-3-carbonitrile 1 with 1,3-bis(tert-butoxycarbonylamino)-2-propanone 2, followed by TFA catalyzed hydrolysis of the intermediate [3-tert-butoxycarbonylaminomethyl-4-cyano-5-methylsulfanyl/-sec-aminobiphenyl-2-yl]carbamic acid tert-butyl ester 3 in moderate yield. The mechanism of formation of 5 has been established through isolation and transformation of the intermediate 3 to the 1-tert-butoxycarbonyl-6-sec-amino-8-aryl-5-cyano-2-oxo-1,2,3,4-tetrahydroquinazoline.     

2-Chloro and 2-fluoro ketones derived from the chiral-pool

Both (2R,5R)- and (2S,5R)-isomers of 2-chloro-2-isopropyl-5-methyl-, 2-chloro-2-methyl-5-isopropyl- and 2-fluoro-2-methyl-5-isopropylcyclohexanones have been synthesized and fully characterized. It is shown that a rapid overview of the ¹H NMR spectrum allows an unambiguous assignment of the axial or equatorial position of the halogen atom and that the IR ν_CO absorption does not differ from one isomer to the other.     

Superconducting LaRu2P2 and other alkaline earth and rare earth metal ruthenium and osmium phosphides and arsenides with ThCr2Si2 structure

The ThCr₂Si₂-type compounds MRu₂P₂ (M = Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb), MOs₂P₂ (M = Sr, Ba, Eu), and MRu₂As₂ (M = Ca, Sr, Ba, La, Eu) were prepared by sintering techniques and/or by reaction of the elemental components in a tin flux. The crystal structures of SrRu₂P₂ and LaRu₂P₂ were refined from single-crystal diffractometer data to residuals of R = 0.019 (224 structure factors, 11 variable parameters) and R = 0.028 (510 F's, 11 variables), respectively. LaRu₂P₂ is diamagnetic and becomes superconducting at 4.1 K. No transition to a superconducting state was observed down to 1.8 K for the compounds MFe₂P₂ (M = Ca, Sr, Ba, La), MRu₂P₂ (M = Ca, Sr, Ba, Y), and MOs₂P₂ (M = Sr, Ba).     

Rhodium- and iridium-manganese carbonyl complexes containing bridging Ph2PCH2PPh2 ligands

Treatment of mer,cis-[MnCl(CO)₂(dppm-PP′)(dppm-P)] with [Rh₂Cl₂(CO)₄] in the presence of CO and PF₆⁻ gives [Cl(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which might have a bridging chloride ligand. Similar treatment of mer,cis-[MnBr(CO)₂(dppm-PP')(dppm-P)] gave [Br(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which ³¹P-{¹H} NMR spectroscopy showed to be a mixture of two closely related species. Treatment of mer,cis-[MnCl(CO)₂(dppm-PP') (dppm-P)] with [Rh₂Cl₂(CO)₄] at −30°C probably gave [Cl(OC)₂Mn(μ-dppm)₂ Rh(CO)₂]Cl but this decomposes above 0°C: the corresponding dibromide was made similarly and is somewhat more stable than the dichloride. Treatment of mer,cis-[MnX(CO)₂(dppm-PP')(dppm-P)] (X = Cl or Br) with [IrCl(CO)₂(p-toluidine)] and CO-PF₆⁻ gave [X(OC)₂Mn(μ-dppm)₂Ir(CO)₂]PF₆. Neutral complexes of type [X(OC)₂Mn (μ-dppm)₂Ir(CO)X'] (X and X' = Cl or Br) are very labile and rapidly decompose to give [Ir(CO)(dppm-PP')₂]⁺ and other (unidentified) products. Treatment of mer,cis-[MnX-(CO)₂(dppm-PP')(dppm-P)] with [RhH(CO)(PPh₃)₃] gave [X(OC)Mn(μ-dppm)₂(μ-H)(μ-CO)Rh(CO)] (X = Cl or Br). These heterobimetallic compounds generally showed broad ¹³P-{¹H} resonances for the P nuclei bonded to Mn at ca 20°C due to some coupling with the ⁵⁵Mn nucleus (I = 100% abundant), but at −30°C these resonances sharpened up due to more rapid quadrupolar relaxation at the lower temperature. NMR and IR data are given.     

Vibrational polarizabilities for H2+, H2 and N2

General formulae for the purely vibrational contributions to the static polarizabilities A_α,βγ, B_α,β,γδ,and C_αβ,γδ are presented. As specific examples, the vibrational contributions to the γ, B, and C tensors for H₂⁺, H₂ and N₂ are calculated. In addition values of the hexadecapole moment for H₂⁺ at a series of internuclear distances are given.     

Synthesis and crystal structures of the dioxovanadium complexes [VO2L1] and [VO2L2]2

Two new oxovanadium complexes, [VO₂L¹] (I) and [VO₂L²]₂ (II), where L¹ and L² are the deprotonated forms of 4-bromo-2-[(2-diethylaminoethylimino)methyl]phenol (HL¹) and 4-bromo-2-{[2-(2-hydroxyethylamino)ethylimino]methyl}phenol (HL²), respectively, have been synthesized and characterized by IR spectra and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n, a = 14.300(3), b = 7.010(2), c = 15.460(2) ?, ?? = 107.401(2)°, V = 1478.7(5) ?³, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 7.270(2), b = 15.373(3), c = 11.893(3) ?, ?? = 99.302(2)°, V = 1311.8(5) ?³, Z = 2. Complex I is a mononuclear dioxovanadium(IV) complex. Complex II is a centrosymmetric dinuclear dioxovanadium(V) complex with a V...V distance of 3.117(2) ?. The Vatom in I is in a distorted square-pyramidal coordination, and that in II is in an octahedral coordination. The difference in the structures of the complexes is largely induced by the hydrogen bonds during the self-assembly process.     

Crystal structure of trans*-[PtEnPyNO2(OH,NO2)*]Cl·2H2O

The structure of trans*-[PtEnPyNO₂(OH,NO₂)*]Cl·2H₂O was determined by X-ray crystallography. The crystals are monoclinic, a = 31.185(6)Å, b = 12.198(2)Å, c = 8.432(2)Å, b = 100.8(2)°, Z = 8, space group C2/c, R = 0.031 for 2059 reflections with I > 2σ(I). In the complex cation, the polyhedron of the Pt atom is an octahedron formed by five nitrogen atoms from ethylenediamine (Pt-N(aver.), 2.062(7) Å), pyridine (Pt-N, 2.053(7) Å), two NO₂ groups (Pt-N, 2.064(7) Å), and the oxygen atom of the OH group in trans position to the nitro group (Pt-O, 1.999(7) Å). Complex cations, anions Cl^?, and crystal water molecules are linked together through a branched system of hydrogen bonds.     

Crystal structure of calcium dihydroethylenediaminetetraacetate(2-) dihydrate Ca(H2Edta)·2H2O

The crystals of Ca(H₂Edta)·2H₂O (orthorhombic system, a = 8.5919(7) Å, b = 17.807(2) Å, c = 18.941(2) Å; Z = 8, space group Pbca) precipitate from solutions of Na₂H₂Edta·2H₂O and CaCl₂. The Ca atom is surrounded by the oxygen atoms of the water molecule and the carboxyl groups of the five neighboring H₂Edta^2? anions with protonated nitrogen atoms (distorted octahedron). As a result, a three-dimensional framework of [Ca(H₂O)H₂Edta)] with built-in crystal water molecules is formed.     

Synthesis and x-ray crystal structure of OsBr2(CNBut)4·2CH2Cl2

Reaction of (NH₄)₂OsBr₆ with excess Na/Hg in THF in the presence of excess ^tBuNC yields trans-OsBr₂(CNBu^t)₄ in high yield. The bis-dichloromethane solvate crystallises from CH₂Cl₂ solutions and its X-ray crystal structure has been determined. Crystal data: C₂₂H₄₀Br₂Cl₄N₄Os, M = 852.40, monoclinic, space group P2₁/c, a = 9.702(3) Å, b = 10.143(5) Å, c = 18.497(5) Å, β = 104.28(3)°, U = 1764(1) ų, Z = 2 for D_c = 1.60 gcm^?3. λ(MoK_α) = 0.71069 Å (graphite monochromator), μ(MoK_α) = 65.44 cm^?1, final R = 0.044, R_w = 0.056 from 1105 observed reflections (1777 measured).     

Synthesis and properties of titanium glycolate Ti(OCH2CH2O)2

A new efficient method for the synthesis of extended micro-and nano-sized crystals (whiskers, fibers) of titanium glycolate Ti(OCH₂CH₂O)₂ has been suggested. The method implies the reaction of hydrated titanium dioxide with ethylene glycol on heating in air. Thermolysis of Ti(OCH₂CH₂O)₂ in air gives titanium dioxide as anatase (400–500°C) and rutile (T > 700°C), the morphology of titanium glycolate crystals being inherited by the oxide. The pseudocrystals of the thermolysis product in an inert gas medium (T = 500–950°C) represent aglomeration of nano-sized titanium dioxide particles and amorphous carbon. At temperatures up to 1300°C, the formation of the TiO_2?x C _x phase with a rutile structure is probable. In a wet air environment, titanium glycolate is partially hydrolyzed to give TiO _x (OCH₂CH₂O)_2?2x (OH)_2x ·xH₂O (0 ≤ x ≤ 1) and on keeping in water at room temperature, ethylene glycol is completely displaced from the crystals. This process is also not accompanied by changes in the particle morphology.