Synthese, Struktur und Reaktivität von 2-Amino- und 2-Imino-2,3-dihydro-1H-1,3,2-diazaborolen / Synthesis, Structure and Reactivity of 2-Amino- and 2-Imino-2,3-dihydro-1H-1,3,2-diazaboroles

1999 ◽  
Vol 54 (3) ◽  
pp. 363-371 ◽  
Author(s):  
Lothar Weber ◽  
Eckhard Dobbert ◽  
Andreas Rausch ◽  
Hans-Georg Stammler ◽  
Beate Neumann

The 2-halo-2,3-dihydro-1H-1,3,2-diazaboroles (1a′: R = tBu, X = Br; 1b: R = 2,6-Me2C6H3; X = I) were converted into the 2-amino-2,3-dihydro-1H-1,3,2- diazaboroles (2a: R = tBu; 2b: 2,6-Me2C6H3) by treatment with dry gaseous ammonia. Similarly reaction of 1a′ with 2,6-dimethylaniline or tBuNH2 afforded the corresponding derivates (3; R1 = 2,6-Me2C6H3; 4; R1 = tBu). The treatment of 1a′ with the ethylene diamine adduct of lithium acetylide led to the formation of (5). Lithiation of 2 a and subsequent silylation gave 6 (R1 = SiMe3), which was transformed to the diborolylamine (7) upon exposure to 1a′. Borolylketimine (8 ) and borolylcarbodiimide (9) resulted from 1a′ and Ph2C=NSiMe3 or Me3SiN=C=NSiMe3, respectively. All the new compounds were characterized by elemental analyses as well as spectroscopic data (IR, 1H, 11B, 13C NMR, MS). Heterocycle 5 was also subjected to an X-ray diffraction analysis.

1998 ◽  
Vol 53 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Klaus Megges ◽  
Evgeni V. Avtomonov ◽  
Ralf Becker ◽  
Jörg Lorberth

Abstract 1,2,3,4-Tetraisopropylcyclopenta-2,4-dien-1-yl arsenic (III) dihalides, viz. TipCpAsX2 (1 X = Br, 2 X = I), have been prepared by direct metathesis reaction between the corresponding arsenic (III) trihalides with one equivalent of TipCpK at low temperature in good yields. Alternatively, 2 has been prepared via halogen exchange reaction between TipCpAsCl2 (3) and KI. New compounds have been characterised by spectroscopic m ethods ( 1H, 13C NMR. EI-MS) and elemental analyses. The crystal structures of 1 and 2 have been determined by X-ray diffraction methods. The AsX2-moiety in 1 and 2 occupies an allylic position neighbouring to an isopropyl substituent. The arsenic fragment is o-bound to the cyclopentadienyl ligand, indicating remarkable π-interactions with the diene part of the cyclopentadienyl ring.


1988 ◽  
Vol 43 (12) ◽  
pp. 1519-1523 ◽  
Author(s):  
Jörn Müller ◽  
Matthias Tschampel ◽  
Carl Krüger

Abstract Cyclization of two diphenylacetylene molecules occurs if [(cod)RhCl] 2 (cod = 1.5-cyclooc-tadiene) is treated with methyllithium in the presence of tolane. The isolated (cod)Rh complex 2 contains an exo-methyl-tetraphenylcyclobutenyl ligand and was characterized by X-ray diffraction analysis. Thermolysis of 2 in acetonitrile causes ring expansion of the methylcyclobutenyl unit with formation of the tretraphenylcyclopentadienyl complex 3 together with 3-methyl-tet-raphenylcyclobutene. Mechanistic aspects are discussed as well as spectroscopic data of the new compounds.


Author(s):  
Süheyla Özbey ◽  
Nilgün Karalı ◽  
Aysel Gürsoy

AbstractIn this study 4-(3-coumarinyl)-3-benzyl-4-thi azolin-2-one 4-methylbenzylidenehydrazone 3 was synthesised. An independent proof of the thiazolylhydrazone structure of 3 was achieved by single crystal X-ray diffraction analysis. Elemental analyses and spectral data (IR,


1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.


1983 ◽  
Vol 38 (2) ◽  
pp. 190-193 ◽  
Author(s):  
Reinhold Tacke ◽  
Hartwig Lange ◽  
Anke Bentlage ◽  
William S. Sheldrick ◽  
Ludger Ernst

Abstract The 2,2,5,5-tetraorganyl-1,4-dioxa-2,5-disilacyclohexanes 2a-2c were prepared by condensation of the corresponding (hydroxymethyl)diorganylsilanes 1 a-1 c. The constitution of the heterocycles was confirmed by elemental analyses, cryoscopic measurements, mass spectrometry, and NMR-spectroscopic (1H, 13C) investigations. The molecular structure of 2 b was determined by X-ray diffraction analysis.


2006 ◽  
Vol 71 (9) ◽  
pp. 1278-1302 ◽  
Author(s):  
Martin Valík ◽  
Pavel Matějka ◽  
Eberhardt Herdtweck ◽  
Vladimír Král ◽  
Bohumil Dolensky

A new bis-Tröger's base was prepared from a tetraamine precursor as a mixture of two diastereoisomers. One of the isomers has a chair-like geometry, and the other possesses a boat-like geometry, embodying molecular tweezers. A one-pot preparation of bis-TB isomers and their interconversion under acid conditions was also studied. Structures of both isomers were confirmed by single-crystal X-ray diffraction. Extensive spectroscopic data, including 1H and 13C NMR, IR and Raman spectra of the isomers, are given.


2007 ◽  
Vol 62 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Karsten Schubert ◽  
Helmar Görls ◽  
Wolfgang Weigand

Starting from 4-bromoacetophenone 1, the 4-bromo-β -hydroxydithiocinnamic acid 2 and the 4-bromo-β -hydroxydithiocinnamic acid hexyl ester 3 were prepared using carbon disulfide and potassium-tert-butylate as a base. Acting as a ligand, the acid gives 1,1-ethenedithiolato complexes with (Ph3P)2Pt(II) (4a), (Et3P)2Pt(II) (4b), dppePt(II) (4c), (Ph3P)2Pd(II) (4d), dppePd(II) (4e), and dppeNi(II) (4f). In contrast to the acid, the deprotonated ester 3 forms a monoanionic bidentate ligand. [O,S] Complexes of Pt(II) (5a), Pd(II) (5b) and Ni(II) (5c) were obtained. All complexes have been fully characterised using 1H NMR, 13C NMR and 31P NMR spectroscopy, mass spectrometry, infrared spectroscopy and elemental analyses. The molecular structures of the complexes 4b and 5a - 5c were determined by X-ray diffraction analyses.


1980 ◽  
Vol 58 (8) ◽  
pp. 777-779 ◽  
Author(s):  
T. Stanley Cameron ◽  
Christine Chan ◽  
David G. Morris ◽  
Alistair G. Shepherd

The crystals belong to the orthorhombic space group C222, with a = 9.226, b = 12.092, c = 16.513 Å, Z = 4. A single crystal X-ray diffraction analysis has shown that the title compound, in which all carbon atoms are sp2 hybridized, exists with the ten membered ring in a slightly twisted tub conformation. The 13C nmr spectrum is also reported.


Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1025-1034 ◽  
Author(s):  
Marvin Linnemannstöns ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
Norbert W. Mitzel

Starting from trichloro(phenylethyl)silane, six differently fluorinated triaryl(phenylethyl)silanes were synthesized by salt elimination reactions and their structures were determined by X-ray diffraction analysis. Tris(pentafluorophenyl)(phenylethyl)silane reveals a folded structure due to intramolecular π-stacking interactions, while those with a lower degree of fluorination show either intermolecular π-stacking or no interplay between the aryl groups. A similar folded structure was observed for (4-methylphenethyl)tris(pentafluorophenyl)silane and [2-(naphth-2-yl)ethyl]tris(pentafluorophenyl)silane, both generated from the corresponding trichlorosilanes. In contrast, the inversely fluorinated [2-(pentafluorophenyl)ethyl]triphenylsilane only revealed intermolecular π-stacking interactions. Compounds with tetrafluoropyridyl substituents behave differently; with these compounds, π-stacking is only observed between the fluorinated units. All compounds were analyzed by NMR and IR spectroscopy, elemental analyses and single-crystal X-ray diffraction, and found to have strong H/C/N/F···F and N···C contacts.


1991 ◽  
Vol 46 (12) ◽  
pp. 1650-1658 ◽  
Author(s):  
Heinrich Lang ◽  
Michael Leise ◽  
Wolfgang Imhof

The reaction of bifunctional neutral phosphenium ion complexes, containing a carbon-carbon triple bond next to a phosphorus-molybdenum multiple bond, with carbenes and to carbene isolobal organometallic fragments is discussed.So, the reaction of (R)(PhC=C)P=MoCp′(CO), (R = 2,4,6-′Bu3C6H2O; Cp′ = η5-C5H5: la; Cp′ = η5-C5Me5: 1b) with CH2,Ν2 (2) yields the three membered heterocyclic compound (3). 3 reacts with Co2(CO)8 to afford complex (5) in which the phenylethynyl building block is η2-side-on coordinated to a Co2(CO)6 fragment. Similar to the reaction of 1 with 2, 1 forms with Fe2(CO)9 (6), compound (7). In 7 the PMo double bond is coordinated in a η2 fashion to the 16-electron organometallic fragment Fe(CO)4. Using an excess of 6 and a higher temperature, the phosphorus-alkynyl-carbon σ-bond is cleaved, and cluster MoCp*Fe3(CO)8η3-PR)(C≡CPh) (8) is formed.The reaction of 1 with Cr(CO)5(THF) yields 10, a complex, in which the PhC≡C ligand is η2-coordinated to Cp′(CO)2Mo, and the Cr(CO)5 group forms a dative bond with the phosphorus atom.All new compounds have been characterized by analytical as well as by spectroscopic data (IR, 1H, 31P, 13C NMR, MS), compound 10 by an X-ray analysis.


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