Synthesen von Verbindungen mit M–N‐Bindungen (M = Li,Ga, In)

Syntheses of Compounds with M–N Bonds (M = Li, Ga, In) The adducts [GaCl₃(HNⁱPr₂)] ( 1 ) and [InCl₃{HN(CH₂Ph)₂}₂] ( 2 ) can be obtained by the reactions of the corresponding metal(III) halides with the amines. The In amide In(N^cHex₂)₃ ( 3 ) can be formed by treatment of InCl₃ with three equivalents of LiN^cHex₂. Reaction with four equivalents of LiN^cHex₂ leads to the same product. However, the treatment of InCl₃ with four equivalents of LiN(CH₂Ph)₂ gives the desired metalate [Li(THF)₄][In{N(CH₂Ph)₂}₄] ( 4 ). From the corresponding reaction of InCl₃ with LiNⁱPr₂ no In‐containing product could be identified. Instead, the aggregate of LiCl with three units of LiNⁱPr₂, [Li₄(NⁱPr₂)₃(THF)₄Cl] ( 5 ), was isolated. 1 – 4 were characterized by NMR, IR and MS techniques as well as by X‐ray structure determinations. According to them, 1 possesses a tetrahedrally coordinated Ga atom, at which two units of 1 are connected by hydrogen bridges to centrosymmetrical dimers. The In atoms in 2 have a trigonal‐bipyramidal coordination sphere; the amine molecules occupy the apical positions. The central metal atom in 3 and the anion of 4 exhibit trigonal‐planar and distorted tetrahedral environments, respectively. The novel structural motif in 5 is the Cl^– ion, only partly surrounded by Li⁺ ions in a strongly distorted trigonal‐bipyramidal fashion. The dominating angle amounts to 165.2(2)°.     

Organometallische Alkoxo–Indium‐Käfigverbindungen

Compounds with Organometallic Alkoxo–Indium Cages The reaction of InMe₃ with PhCH₂OH (molar ratio 1 : 2) at 20 °C in toluene gives the tetranuclear complex [In{(PhCH₂O)₂InMe₂}₃] ( 2 ) in good yield. A further reaction under reflux conditions was not observed. However, at 160 °C in PhCH₂OH a reaction could be realized, which forms an O‐centred corner‐cutted rhombic dodecahedron, [(MeIn)₅(OCH₂Ph)₈(O)] ( 3 ), under evolution of methane. This In–O skeleton can be degraded with elemental cesium to a hexa‐ and heteronuclear complex [Cs{Cs(THF)}{[MeIn(OCH₂Ph)₂]₄O}] ( 4 ). 2 – 4 were characterized by IR, RE, NMR and MS techniques as well as by X‐ray analyses. According to them 2 can be described as In³⁺ ion, coordinated by three metalate units [Me₂In(OCH₂Ph)₂]^–. 3 loses one MeIn fragment during the transfer of two electrons. Two Cs⁺ ions complete the new rhombic dodecahedron, at which different coordination spheres were observed. One Cs⁺ ion possesses additional contacts to a THF ligand and four π‐electron systems from four phenyl rings, while the THF ligand is missing in the environment of the second alkali cation.     

Sesquialkoxide von Gallium und Indium

Sesquialkoxides of Gallium and Indium Treatment of GaMe₃ with one equivalent of HO^cHex in toluene at 20 °C leads to [Me₂GaO^cHex]₂ ( 4 ) under evolution of methane. The reaction of InMe₃ with two equivalents of HO^cHex leads under similar conditions not to [MeIn(O^cHex)₂]_n but to the sesquialkoxide [In{Me₂In(O^cHex)₂}₃] ( 5 ). 5 can be described also as [{Me₂InO^cHex)}₂{MeIn(O^cHex)₂}₂]. The use of an excess of cyclohexanol in boiling toluene gives the same result. Under these reflux conditions, the reaction of GaMe₃ with an excess of PhCH₂OH leads exclusively to another type of sequialkoxides, [Ga{MeGa(OCH₂Ph)₃}₃] ( 6 ). 4 — 6 were characterized by NMR, vibrational and MS spectra, as well as by X‐ray structure determinations. According to this, 4 forms centrosymmetrical and therefore planar Ga₂O₂ four‐membered rings. 5 and 6 possess basically the same structural motif, central M³⁺ ion ( 5 : In³⁺; 6 : Ga³⁺) coordinated by three metalate units ( 5 : [Me₂In(O^cHex)₂]^—; 6 : [MeGa(OCH₂Ph)₃]^—). The central M³⁺ ions have always coordination number (CN) six while the three surrounding metal ions possess CN 4. Because of the spectroscopic findings 6 must exist in two isomers (1:1). The C₃‐symmetrical isomer C₃‐ 6 was characterized by X‐ray analysis, while the isomer C₁‐ 6 could by described mainly by the complex NMR data.     

Kristallstrukturen von TMEDA‐Addukten und Salzen mit protonierten TMEDA‐Molekülen

Crystal Structures of TMEDA Adducts and of Salts with Protonated TMEDA Molecules The reaction of TMEDA with two equivalents of [BH₃(SMe₂)] in toluene at 20 °C gives the adduct [TMEDA(BH₃)₂] ( 1 ). A similar reaction of pyrrolidine with [BH₃(SMe₂)] in a molar ratio of 1:1 leads to the adduct [pyrrolidine(BH₃)] ( 2 ). TMEDA can be introduced into the coordination sphere of In³⁺ by the treatment of InI₃ with TMEDA in toluene to give the complex [InI(TMEDA)] ( 3 ). The salt [HTMEDA]I ( 4 ), containing a mono‐protonated TMEDA molecule, is the result of the reprotonation of [NH₄]I and TMEDA in toluene at 20 °C. The salts [H₂TMEDA]—[InCl₄(TMEDA)]₂ ( 5 ) and [H₂TMEDA][InCl₅(THF)] ( 6 ) are formed in the reaction mixtures TMEDA/toluene/InCl₃/HCl and TMEDA/toluene/THF/InCl₃/HCl, respectively, whereupon 6 was characterized more closely. Crystals of [In₅I₆(OH)(TMEDA)₄]I·2, 5toluene ( 7 ·2.5toluene) can be obtained after treatment of InI₃ with non‐dried TMEDA; 4 was identifed as by‐product. 1 — 7 ·2.5toluene were partially investigated by NMR methods and vibrational spectroscopy. In all cases a characterization by single crystal X‐ray diffraction was performed. According to this, all nitrogen atoms in 1 and 2 are coordinated by BH₃ groups leading to a distorted tetrahedral environment at the nitrogen and the boron atoms. In 3 a distorted trigonal‐bipyramidal coordination sphere at the In³⁺ is present. The apical positions are occupied by I3 and N3. Strong N‐H···N bridges, running along [001] is the feature in 4 ; the ^I—‐Ions are not involved into the system of H‐bridges. A ion triple, [H₂TMEDA][InCl₄(TMEDA)]₂, hold together by bifurcated H‐bridges is the dominating structural motif in 5 , whereas alternation bifurcated and linear H‐bridges, leading zu a zig‐zag chain along [100], is the build‐up principle of 6 . In 7 ·2.5toluene a complex In₅O₈ skeleton was formed, consisting of a virtual corner‐connected doubled heterocubane. At every heterocubane a corner, occupied by a metal ion, is missing. The coordination spheres of the In atoms of the complex cation are completed by TMEDA molecules and iodide ions.     

Phosphaniminate von Alkalimetallen: Die Kristallstrukturen von [KNPCy3]4, [KNPCy3]4·2OPCy3, [CsNPCy3]4·4OPCy3 und [Li4(NPPh3)(OSiMe2NPPh3)3(DME)]

The alkalimetal phosphoraneiminates [KNPCy₃]₄, ( 1 ) [KNPCy₃]₄·2OPCy₃ ( 2 ) and [CsNPCy₃]₄·4OPCy₃ ( 3 ) (Cy = cyclohexyl) which are obtainable by the reaction of pottassium amide or cesium amide with Cy₃PI₂ or Cy₃PBr₂ in liquid ammonia, as well as the lithium derivative [Li₄(NPPh₃)(OSiMe₂NPPh₃)₃(DME)] ( 4 ) have been characterized by crystal structure determinations. 4 has been formed by the insertion reaction of silicon greaze (‐OSiMe₂)n into the LiN bonds of [LiNPPh₃]₆ in DME solution (DME = 1, 2‐dimethoxyethane). 1 : Space group P&1macr;, Z = 2, lattice dimensions at 193 K: a = 1389.8(1); b = 1408.1(1); c = 2205.2(2) pm; α = 78.952(10)?; β = 81.215(10)?; γ = 66.232(8)?; R1 = 0.0418. 2 : Space group Pbcn, Z = 4, lattice constants at 193 K: a = 2943.6(2); b = 2048.2(1); c = 1893.8(1) pm; R1 = 0.0428. 3 : Space group Cmc2₁, Z = 4, lattice dimensions at 193 K: a = 2881.6(2); b = 2990.2(2); c = 1883.7(2) pm; R1 = 0.0586. 4 ·1/2DME: Space group R&3macr;c, Z = 12, lattice dimensions at 193 K: a = b = 1583.5(1); c = 11755.3(5) pm; R1 = 0.0495. All complexes have heterocubane structures. In 1‐3 they are formed by four alkali metal atoms and by the nitrogen atoms of the (μ₃‐NPCy₃^‐) groups, whereas 4 forms a "heteroleptic" Li₄NO₃ heterocubane.     

Synthesis and characterization of Ni(II) complex functionalized silica-based magnetic nanocatalyst and its application in C–N and C–C cross-coupling reactions

Molecular Diversity - A new magnetically recoverable silica-based nickel(II) nanocatalyst was synthesized by a simple cost-effective procedure, which was characterized by TEM, SEM, XRD, VSM...     

Coherent Control of the Goos-Hänchen Shifts in a Four-Level N Type Atomic Medium

The behavior of the Goos-Hänchen (GH) shifts of the reflected and transmitted probe light beams is theoretically investigated. In a fixed geometrical configuration, the effect of quantum interference induced by spontaneous emission on the phase control of the GH shifts is analyzed in this paper. It is found that in a four-level N-type atomic system as an intracavity medium, the GH shifts of the reflected and transmitted probe light beam are completely phase dependent.     

Nef‐Isocyanide ‐Based One‐pot Two‐step Three Component Dihydrobenzo[4,5]Imidazo[2,1‐b]thiazoles Synthesis

The reactive imidoyl chloride adducts generated in situ from the reaction of isocyanide and acyl chlorides were trapped by 2‐mercaptobenzimidazoles to yield highly functionalized dihydrobenzo[4,5]imidazo[2,1‐b]thiazoles in good yields.     

Monoacylglycerols as transmembrane Cl- anion transporters

We report that the amphiphilic natural product, monoacylglycerol 1, functions as a transmembrane Cl(-)/NO(3)(-) anion transporter. The 1,2-diol group is crucial for the transport function since diacylglycerol and triacylglycerol analogs are not anion transporters. Furthermore, adding another hydrogen bond donor to the glycerol head-group and perfluorination of the acyl tail gave synthetic analogs with improved Cl(-) membrane transport properties.     

Ultra-preconcentration and determination of thirteen organophosphorus pesticides in water samples using solid-phase extraction followed by dispersive liquid–liquid microextraction and gas chromatography with flame photometric detection

An ultra-preconcentration technique composed of solid-phase extraction (SPE) and dispersive liquid–liquid microextraction (DLLME) coupled with gas chromatography–flame photometric detection (GC–FPD) was used for determination of thirteen organophosphorus pesticides (OPPs) including phorate, diazinon, disolfotane, methyl parathion, sumithion, chlorpyrifos, malathion, fenthion, profenphose, ethion, phosalone, azinphose-methyl and co-ral in aqueous samples. The analytes were collected from large volumes of aqueous solutions (100 mL) into 100 mg of a SPE C₁₈ sorbent. The effective variables of SPE including type and volume of elution solvent, volume and flow rate of sample solution, and salt concentration were investigated and optimized. Acetone was selected as eluent in SPE and disperser solvent in DLLME and chlorobenzene was used as extraction solvent. Under the optimal conditions, the enrichment factors were between 15,160 and 21,000 and extraction recoveries were 75.8–105.0%. The linear range was 1–10,000 ng L^?1 and limits of detection (LODs) were between 0.2 and 1.5 ng L^?1. The relative standard deviations (RSDs) for 50 ng L^?1 of OPPs in water with and without an internal standard, were in the range of 1.4–7.9% (n = 5) and 4.0–11.6%, respectively. The relative recoveries of OPPs from well and farm water sat spiking levels of 25 and 250 ng L^?1 were 88–109%.