N‐Cesiocarbazole ṁ pmdta and N‐Potassiocarbazole ṁ pmdta (PMDTA = N,N,N′,N″,N″‐Pentamethyldiethylenetriamine). Cation Size and Multihapto Bonding

Gregory, Karina; Bremer, Matthias; Schleyer, Paul von Ragué; Klusener, Peter A. A.; Брандсма, Л.

doi:10.1002/anie.198912241

Cited by 56 publications

(29 citation statements)

References 16 publications

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“…[ 21 ] In previous literature examples, increasing alkali metal ionic radius tends to favour the adoption of a multi-hapto binding motif through the five-membered condensed ring of the carbazolyl ligand. [ 5 , 7 , 11 ] The behaviour of the K + ion within dimer 2 appears to be closer to that in the powder X-ray diffraction structure of the unsolvated caesium carbazolyl complex Cs(NC 12 H 8 ), which in the main displays a combination of η 1 -nitrogen and η 6 -arene interactions in the solid state. [ 8 ]…”

Section: Resultsmentioning

confidence: 75%

“…22 Of particular interest is [K(THF)][ZrCl 2 (NC 12 H 8 ) 3 (THF)], in which: 1) the average length of the K ⋅⋅⋅ C interactions is 3.248(3) Å, a value consistent with the distances measured for 2 (ave. K ⋅⋅⋅ C 3.226(7) Å); 2) the complex features an additional η 2 ‐interaction with a second carbazolyl unit, with distances of 3.147(3) and 3.268(2) Å 21. In previous literature examples, increasing alkali metal ionic radius tends to favour the adoption of a multi‐hapto binding motif through the five‐membered condensed ring of the carbazolyl ligand 5. 7, 11 The behaviour of the K + ion within dimer 2 appears to be closer to that in the powder X‐ray diffraction structure of the unsolvated caesium carbazolyl complex Cs(NC 12 H 8 ), which in the main displays a combination of η 1 ‐nitrogen and η 6 ‐arene interactions in the solid state 8…”

Section: Resultsmentioning

confidence: 86%

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Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

Ortu

Moxey

Blake

et al. 2015

Chemistry A European J

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1,3,6,8-Tetra-tert-butylcarbazol-9-yl and 1,8-diaryl-3,6-di(tert-butyl)carbazol-9-yl ligands have been utilized in the synthesis of potassium and magnesium complexes. The potassium complexes (1,3,6,8-tBu4carb)K(THF)4 (1; carb=C12H4N), [(1,8-Xyl2-3,6-tBu2carb)K(THF)]2 (2; Xyl=3,5-Me2C6H3) and (1,8-Mes2-3,6-tBu2carb)K(THF)2 (3; Mes=2,4,6-Me3C6H2) were reacted with MgI2 to give the Hauser bases 1,3,6,8-tBu4carbMgI(THF)2 (4) and 1,8-Ar2-3,6-tBu2carbMgI(THF) (Ar=Xyl 5, Ar=Mes 6). Structural investigations of the potassium and magnesium derivatives highlight significant differences in the coordination motifs, which depend on the nature of the 1- and 8-substituents: 1,8-di(tert-butyl)-substituted ligands gave π-type compounds (1 and 4), in which the carbazolyl ligand acts as a multi-hapto donor, with the metal cations positioned below the coordination plane in a half-sandwich conformation, whereas the use of 1,8-diaryl substituted ligands gave σ-type complexes (2 and 6). Space-filling diagrams and percent buried volume calculations indicated that aryl-substituted carbazolyl ligands offer a steric cleft better suited to stabilization of low-coordinate magnesium complexes.

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Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 86%

Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

Ortu

Moxey

Blake

et al. 2015

Chemistry A European J

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“…It is noteworthy that a further recrystallization of this mixture gave pure dienic substrate 6b in 61% yield. With cesium tert-butoxide, 16 a 1:2 mixture of compounds 7b:8b was isolated in 70% overall yield (Table 2, entry 6). By using Cs 2 CO 3 , the selectivity of the reaction was completely reversed as only the coupling product 8b was obtained in an excellent 87% yield (Table 2, entry 7).…”

Section: Methodsmentioning

confidence: 99%

“…Other enynes 2d-f were tested for this reaction but, in these cases, we were not able to obtain the 1,3-bis-exocyclic dienes 7 selectively since various amounts of the direct coupling products 8 were also detected ( Table 2, entries [13][14][15][16][17][18][19][20]. It is important to note that the desired dienes 7 were easily separated from the direct coupling products by conventional flash chromatography.…”

Section: Methodsmentioning

confidence: 99%

New Method for the Synthesis of Functionalized 1,3-Bis-Exocyclic Dienes via a Palladium-Catalyzed Reaction. Scope and Synthetic Applications

Lomberget¹,

Bouyssi²,

Balme³

2005

Synthesis

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The palladium-catalyzed tandem cyclization-coupling reaction of conjugated enynes having a stabilizing carbon nucleophile with aryl iodides and vinyl halides or triflates produced stereodefined, functionalized five-and six-membered 1,3-bis-exocyclic dienes in moderate to good yields. These stereodefined dienes proved to be versatile substrates for the preparation of various polycyclic products through subsequent Diels-Alder, intramolecular Friedel-Crafts or thermal electrocyclization reactions.

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“…In addition, the small Pt particles dispersed in the carbon matrix can tentatively be ascribed to the existence of nitrogen-rich species in the precursor. [14] Due to the optical [15] and electronic [16] properties of poly(2,7-carbazole), interesting photovoltaic behaviors of these hierarchic-structured, carbon-rich membranes can be expected. Precursor 3 is a typical discotic mesogen, [17] and tends to form columnar aggregates owing to the pronounced aromatic p-stacking between the discs.…”

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confidence: 99%

From Well‐Defined Carbon‐Rich Precursors to Monodisperse Carbon Particles with Hierarchic Structures

et al. 2007

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The creation of nanoscale particles with well-defined structures has long been considered as a promising approach to generate materials with novel properties. Carbonaceous nanoparticles (CNPs) with defined architectures, such as carbon nanotubes (CNTs), C 60 , carbon onions, carbon spheres, and carbon rods are particularly attractive owing to their unique electronic properties and many potential applications.[1] At the same time, when these CNPs are regularly organized, additional functions appear.[2] Such materials are believed to have hierarchic structures, [3] in which the organization of the CNPs forms the first-order structure (FOS) and the configuration of the single CNP forms the second-or higher-order structure (SOS or HOS). Because both the FOS and HOS are responsible for the properties of the bulk material, simple methods to prepare multidimensional carbon materials with hierarchic structures are needed. Template methods are commonly used to produce 3D order in which the silica opal or inverse opal crystals are the most frequently selected templates. [3b,4] Carbonaceous materials have been prepared in these templates by using sucrose or phenolic reactants as precursors, [5] but only amorphous CNPs were obtained. Alternatively, chemical vapor deposition (CVD) over inverse opals was reported to produce crystalline carbons.[4a] Unfortunately, such CVD procedures resulted in inverse carbon opals, not CNPs, and the control over the carbon structures was limited. The preparation of well-defined CNPs with 3D organization is still a challenge owing to the difficulties of controlling molecular interactions at high temperatures. Recent studies on solid-state pyrolysis (SSP) have implied that the structures of CNPs could be controlled by choosing well-defined organometallic precursors. [6][7][8][9] Thus, CNTs were obtained in high yield from SSP of diphenylethyne-metal complexes; [6] while dicobalthexacarbonyl-functionalized poly(p-phenyleneethynylene) afforded carbon-cobalt spheres.[7] Our previous SSP of dendritic polyphenylene-cobalt complexes resulted in uniformly shaped carbon-cobalt nanorods with rectangular cross sections, [8] whereas disclike structures with extended p-systems furnished bamboolike CNTs and carbon shell/metal core cablelike structures. [9] However, in all these experiments, the metal catalysts play a more important role for product formation than the chemical structure of the precursors; and these processes incorporate metals into the pyrolysis products. To prepare metal-free CNPs with defined structures, the design of the precursors requires more attention. Our recent attempts at precursordefined pyrolyses (PDP) produced graphitic nanotubes with brick-walled structures [10] and CNTs with 3D porous-walled structures.[11]

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N‐Cesiocarbazole ṁ pmdta and N‐Potassiocarbazole ṁ pmdta (PMDTA = N,N,N′,N″,N″‐Pentamethyldiethylenetriamine). Cation Size and Multihapto Bonding

Abstract: 7] M. lyoda, K. Sato, M. Oda, Terrahedron Lrti. 26 (1985) 3829, and references cited therein.

Cited by 56 publications

References 16 publications

Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes

New Method for the Synthesis of Functionalized 1,3-Bis-Exocyclic Dienes via a Palladium-Catalyzed Reaction. Scope and Synthetic Applications

From Well‐Defined Carbon‐Rich Precursors to Monodisperse Carbon Particles with Hierarchic Structures

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