New Zwitterionic Spirocyclic λ5Si-Silicates with Two Ethane-1,2-diolato(2–), Oxalato(2–), or Benzene-1,2-diolato(2–) Ligands – Synthesis,Structure, and Dynamic Behavior

The syntheses of the zwitterionic spirocyclic λ⁵Si-silicates 6–9 are described. These chiral zwitterions contain a pentacoordinate (formally negatively charged) silicon atom and a tetracoordinate (formally positively charged) nitrogen atom. Compounds 6 · ¹/₂ HO(CH₂)₂OH, 7 , 8 · CH₃CN, and 9 were studied by solution-state (¹H, ¹³C, ²⁹Si) and solid-state (²⁹Si CP/MAS) NMR experiments. In addition, all compounds were structurally characterized by single-crystal X-ray diffraction. The dynamic behavior (Berry-type enantiomerization) of 7–9 in solution was studied by VT ¹H NMR experiments. These experimental studies were completed by ab initio investigations of the related anionic model species 10–12 .     

Ein- und zweikernige MoII-Phthalocyaninate(2–): Darstellung und Eigenschaften von Bis(cyano)phthalocyaninato(2–)molybdat(II) und Bis(phthalocyaninato(2–)molybdän(II))

Mono- and Dinuclear Mo^II Phthalocyaninates(2–): Syntheses and Properties of Bis(cyano)phthalocyaninato(2–)molybdate(II) and Bis(phthalocyaninato(2–)molybdenum(II)) Blue diamagnetic bis(phthalocyaninato(2–)molybdenum(II)) is synthezied by reduction of oxophthalocyaninato(2–)molybdenum(IV) with boiling triphenylphosphine. The Mo–Mo stretching vibration ist observed in the resonance Raman spectrum at 374 cm^–1. It is chemically inert and dissolves in conc. sulfuric acid without decomposition. It reacts with molten tetra(n-butyl)ammonium cyanide to yield redbrown paramagnetic bis[tetra(n-butyl)ammonium] biscyanophthalocyaninato(2–)molybdate(II) (μ_eff = 3.15 μ_B; S = 1). The complex salt is very instable and demetallizes in solution. In the extraordinary UV-VIS-NIR spectrum an intense trip-triplet transition at 7780 cm^–1 together with a very structured B region between 14000 and 21000 cm^–1 of comparable absorbance is observed.     

N–H(N)…S Bonding in Tetrahedral [Zn(NCS)2L]0 Complexes (L = MexH2–xN(CH2)2NH2–yMey,x, y = 0 – 2)

The crystal structures of uncharged tetrahedral dithiocyanato zinc complexes with N-methylated ethylenediamines have been determined with a view to a study of intermolecular hydrogen-bonding interactions in these compounds. It is found that the H(N) hydrogen atoms are exhaustively engaged in N–H(N) … S bonds. The majority of these bonds are branched (bifurcated or trifurcated), and the hydrogen-bond systems they form all contain one of the two characteristic primitive core motifs: either a discrete centrosymmetric […S…H…]₂ dimer or an infinite […S…H…]_∞ helix about a 2₁ or pseudo-2₁ axis. The hydrogen bonding is analyzed in detail, with particular attention to the existence of correlations between the N–H(N)–S angles and the H(N) … S distances as well as between the corresponding N–H(N)–S/H(N)…S pairs in the bifurcated N–H(N)…2 S bonds.     

Bis(triphenylphosphin)iminium-bis(methoxo)phthalocyaninato(2–)ferrat(III) – Synthese und Kristallstruktur

Bis(triphenylphosphine)iminium Bis(methoxo)phthalocyaninato(2–)ferrate(III) – Synthesis and Crystal Structure Chlorophthalocyaninato(2–)ferrate(III) reacts with bis(triphenylphosphine)iminium hydroxide in methanol/acetone solution to yield blue crystals of bis(triphenylphosphine)iminium bis(methoxo)phthalocyaninato(2–)ferrate(III). The complex salt crystallizes as an acetone/methanol solvate (^bPNP)[Fe(OCH₃)₂pc^2–] · (CH₃)₂CO · 1.5 CH₃OH in the triclinic space group P 1 (no. 2) with the cell parameters a = 13.160(5) Å, b = 15.480(5) Å, c = 17.140(5) Å, α = 97.54(5)°, β = 91.79(5)°, γ = 95.44(5)°. The Fe atom is located in the centre of the pc^2– ligand coordinating four isoindole N atoms (N_iso) of the pc^2– ligand and two O atoms of the methoxo ligands in a mutual trans arrangement. The average Fe–O and Fe–N_iso distances are 1.887 and 1.943 Å, respectively. The cation adopts the bent conformation (< P–N–P = 140.4(2)°) with P–N distances of 1.579(3) and 1.575(3) Å.     

(–)‐epi‐Inosose‐2

The structure of the title compound, C₆H₁₀O₆, was determined to confirm the position of the keto group in the mol­ecule prepared enantioselectively by a bioconversion from myo‐inositol. There are two independent mol­ecules showing similar geometry.     

[Bis(tetrahydrofuran–O)–bis(1,3–dialkyl–2–diphenylphosphanyl–1,3–diazaallyl)calcium] – Synthesis and Crystal Structures of Calcium Bis[phospha(III)guanidinates] and Investigations of Catalytic Activity

The reaction of [(thf)₄Ca(PPh₂)₂] ( 1 ) with diisopropyl– and dicyclohexylcarbodiimides yields the phospha(III)guanidinates [(thf)₂Ca{RNC(PPh₂)NR}₂] with R = isopropyl ( 2 ) and cyclohexyl ( 3 ). The metathesis reaction of K{RNC(PPh₂)NR} with anhydrous CaI₂ also allows the synthesis of these phospha(III)guanidinate complexes 2 and 3 . For 2 a cis arrangement is observed whereas 3 crystallizes as trans isomer. The phospha(III)guanidinates act as bidentate chelate bases with an average Ca–N distance of 242.5 pm. The C–P bond length between the PPh₂ fragment and the 1,3–diazaallyl unit is with values above 190 pm very large. The complexes 2 and 3 show a moderate catalytic activity in hydrophosphanylation reactions of dialkylcarbodiimides with diphenylphosphane.     

Tetra(n-butyl)ammoniumphthalocyaninato(2–)lithat-Tetrahydrofuran und Bis(tetra(n-butyl)ammonium)phthalocyaninato(2–)lithatfluorid-Hydrat; Synthese und Kristallstruktur

Tetra(n-butyl)ammonium Phthalocyaninato(2–)lithate Tetrahydrofurane and Bis(tetra(n-butyl)ammonium) Phthalocyaninato(2–)lithate Fluoride Hydrate; Synthesis and Crystal Structure Dilithiumphthalocyaninate(2–) reacts with excess tetra(n-butyl)ammonium fluoride trihydrate to yield a mixture of blue tetra(n-butyl)ammonium phthalocyaninato(2–)lithate tetrahydrofurane and bis(tetra(n-butyl)ammonium) phthalocyaninato(2–)lithate fluoride hydrate. The latter crystallizes triclinic with crystal data: a = 8.6480(1) Å; b = 12.620(2) Å; c = 14.866(5) Å; α = 82.44(2)°; β = 87.01(2)°; γ = 75.02°; space group P1 ; Z = 1. Fluoride is not coordinated to lithium. On the contrary, a double-salt is formed, which consists of alternating layers of cations and anions. This arrangement opens a cavity in the centre of the unit cell which shares statistically a fluoride and a disordered fluoride hydrate. Pure tetra(n-butyl)ammonium phthalocyaninato(2–)lithate is obtained as a tetrahydrofurane solvate by the reaction of dilithiumphthalocyaninate(2–) with tetra(n-butyl)ammonium bromide in tetrahydrofurane. The solvate crystallizes monoclinic with crystal data: a = 12.455(5) Å; b = 23.396(5) Å; c = 16.120(5) Å; β = 94.986(5)°; space group P2/c1; Z = 4.     

Cu (DPM)2–initiated vinyl polymerization

The behavior of cupric dipivaloylmethide in vinyl polymerization systems was investigated with a view to understanding the mechanism of polymerization initiation. Results of polymerization reactions together with spectral investigation data are presented. Polymerization in the presence of the chelate proceeds through a free-radical process. The corresponding kinetic and transfer constants and activation energy values suggest a normal propagation step. With the help of spectral data an attempt is made to suggest a plausible mechanism of initiation.     

Tuning the band gap of easily oxidized bis(2-thienyl)– and bis(2-(3,4-ethylenedioxythiophene))–phenylene polymers

The synthesis, characterization and electrochemical polymerization, along with redox switching behavior of the resultant polymers, of 1,4-bis(2-(3,4-ethylenedioxy)thienyl)–2,5-difluorobenzene ( 1 ) and 1,4-bis(2-thienyl)–2,5-difluorobenzene ( 2 ) is presented. Compounds 1 and 2 were synthesized by a Pd°-catalyzed cross-coupling and in good yields (85% and 84%, respectively). Both monomers electropolymerize to form electroactive redox switchable films, with the more electron-rich 3,4-ethylenedioxythiophene derivative polymerizing and switching at lower potentials. The electronic band gaps were determined to be 1.9 eV for P1 and 2.3 eV for P2. Thin films of P1 and P2 were found to be electrochromic and exhibit color changes of red-to-blue/black for P1 and yellow-to-black for P2. These results are compared with various substituted bis(heterocycle)benzene derivatives in order to present a series of structure to property relationships. © 1998 John Wiley & Sons, Ltd.     

Darstellung,Kristallstrukturen und Schwingungsspektren von [Pt(N3)6]2– und [Pt(N3)Cl5]2–, 195Pt‐ und 15N‐NMR‐Spektren von [Pt(N3)nCl6–n]2– und [Pt(15NN2)n(N215N)6–n]2–, n = 0–6

Synthesis, Crystal Structures, and Vibrational Spectra of [Pt(N₃)₆]^2– and [Pt(N₃)Cl₅]^2–, ¹⁹⁵Pt and ¹⁵N NMR Spectra of [Pt(N₃)_nCl_6–n]^2– and [Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n]^2–, n = 0–6 By ligand exchange of [PtCl₆]^2– with sodium azide mixed complexes of the series [Pt(N₃)_nCl_6–n]^2– and with ¹⁵N‐labelled sodium azide (Na¹⁵NN₂) mixtures of the isotopomeres [Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n]^2–, n = 0–6 and the pair [Pt(¹⁵NN₂)Cl₅]^2–/[Pt(N₂¹⁵N)Cl₅]^2– are formed. X‐ray structure determinations on single crystals of (Ph₄P)₂[Pt(N₃)₆] ( 1 ) (triclinic, space group P1, a = 10.175(1), b = 10.516(1), c = 12.380(2) Å, α = 87.822(9), β = 73.822(9), γ = 67.987(8)°, Z = 1) and (Ph₄As)₂[Pt(N₃)Cl₅] · HCON(CH₃)₂ ( 2 ) (triclinic, space group P1, a = 10.068(2), b = 11.001(2), c = 23.658(5) Å, α = 101.196(14), β = 93.977(15), γ = 101.484(13)°, Z = 2) have been performed. The bond lengths are Pt–N = 2.088 ( 1 ), 2.105 ( 2 ) and Pt–Cl = 2.318 Å ( 2 ). The approximate linear azido ligands with N^α–N^β–N^γ‐angles = 173.5–174.6° are bonded with Pt–N^α–N^β‐angles = 116.4–121.0°. In the vibrational spectra the PtCl stretching vibrations of (n‐Bu₄N)₂[Pt(N₃)Cl₅] are observed at 318–345, the PtN stretching modes of (n‐Bu₄N)₂[Pt(N₃)₆] at 401–428 and of (n‐Bu₄N)₂[Pt(N₃)Cl₅] at 408–413 cm^–1. The mixtures (n‐Bu₄N)₂[Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n], n = 0–6 and (n‐Bu₄N)₂[Pt(¹⁵NN₂)Cl₅]/(n‐Bu₄N)₂[Pt(N₂¹⁵N)Cl₅] exhibit ¹⁵N‐isotopic shifts up to 20 cm^–1. Based on the molecular parameters of the X‐ray determinations the vibrational spectra are assigned by normal coordinate analysis. The average valence force constants are f_d(PtCl) = 1.93, f_d(PtN^α) = 2.38 and f_d(N^αN^β, N^βN^γ) = 12.39 mdyn/Å. In the ¹⁹⁵Pt NMR spectrum of [Pt(N₃)_nCl_6–n]^2–, n = 0–6 downfield shifts with the increasing number of azido ligands are observed in the range 4766–5067 ppm. The ¹⁵N NMR spectrum of (n‐Bu₄N)₂[Pt(¹⁵NN₂)_n(N₂¹⁵N)_6–n], n = 0–6 exhibits by ¹⁵N–¹⁹⁵Pt coupling a pseudotriplett at –307.5 ppm. Due to the isotopomeres n = 0–5 for terminal ¹⁵N six well‐resolved signals with distances of 0.03 ppm are observed in the low field region at –201 to –199 ppm.     

(CH3)2SBr2 – einige Reaktionen und Strukturen

(CH₃)₂SBr₂ – Reactions and Structures (CH₃)₂SBr₂ ( 1 ) is a donor acceptor complex (8-S-3 + 10-Br-2) which reacts with (CH₃)₂S(?O)NSi(CH₃)₃ to yield [(CH₃)₂S(O)?N? S(CH₃)₂]⁺Br^? ( 2 ). With SbBr₃ (CH₃)₂SBr⁺SbBr₄^? ( 3 ) can be isolated. 1 crystallizes monoclinic in the space group P2₁/c with a = 733.8, b = 734.2, c = 1132.7 pm, β = 92.8° and Z = 4. 2 crystallizes in the orthorhombic space group Pnma with a = 967.2, b = 793.3, c = 1168.3 pm and Z = 4. The SBr and BrBr force constants of 1 are compared with those of S₂Br₂, 3 and Br₂ resp. The nmr and mass spectra of 1 and 2 are communicated.     

Synthesis and X-ray crystal structures of bis(bis(μ2-2-aminoethanolato–N,O,O)–cobalt(III))–cobalt(II) hydrate, tris(biscyclohexylammonium)μ-hydroxo–bis(μ2-nitro–N,O)–hexanitro–dicobaltate(III) and biscyclohexylammonium nitrate(III)

Two new cobalt complexes: Co₃(NO₂)₄(NH₂CH₂CH₂O)₄·H₂O (1) and (NH₂(C₆H₁₁)₂)₃[Co₂(NO₂)₈OH]·3H₂O (2) and the compound (NH₂(C₆H₁₁)₂)NO₂ (3) were synthesised and their structures have been determined using single-crystal X-ray diffraction. Compound 1 consists of two centrosymmetrical trinuclear complexes and a water molecule of crystallization. Ligands coordinated to Co atoms are nitro and aminoethanolato groups. Structure 2 is built up of biscyclohexylammonium cations, dinuclear anions with hydroxo and nitro groups coordinated to Co atoms and water molecules. The coordination of Co atoms in both structures is roughly octahedral.