209 research outputs found
(1R,2R)-N,N′-Diisobutyl-N,N′-dimethylcyclohexane-1,2-diamine
The title compound, C16H34N2, is a chiral diamine with fixed R configuration at both stereogenic carbon centres of the cyclohexane backbone. Due to their different substituents, the two N atoms also become stereogenic. In the crystal structure, the configuration at one of the two nitrogen centres is fixed, with the free electron pair pointing inward and the isobutyl group in a trans position towards the cyclohexane backbone resulting in an R configuration. The isobutyl group at the second N atom, however, is disordered with 75% S configuration and 25% R configuration. In both cases, the isobutyl group is arranged in a trans position towards the cyclohexane backbone
Dibromido[(tert-butylamino)dimethyl(piperidin-1-ylmethyl)silane-κ2 N,N′]zinc(II)
The title compound, [ZnBr2(C12H28N2Si)], is an example of a neutral coordination compound of a bidentate ligand to a metal centre with the Zn atom being coordinated by two Br and two N atoms, yielding a slightly distorted tetrahedral coordination environment
(1R,2R)-N,N′-Dimethylcyclohexane-1,2-diamine
The molecule of the title compound, C8H18N2, possesses C
2 symmetry. Owing to its stereochemistry, it is used in the synthesis of chiral ligands and metal complexes for asymmetric synthesis. The cyclohexane ring shows a chair conformation with the amino groups in equatorial positions. Contrary to the literature, the title compound is not a liquid, but a crystalline solid at room temperature (293 K). The absolute configuration is assigned from the synthesis
Influence of lithium coordinating additives on the structure of phenyldimethylsilyllithium
The synthesis and structural investigation of two dimethylphenylsilyllithium adducts with coordinating nitrogen donors quinuclidine and 1,3,5-tri-tert-butylhexahydro-1,3,5-triazine (tbtac) are presented. The structures show a comparatively long Si−Li distance and one amongst the shortest in monomeric silyllithiums reported so far, respectively. The structural investigations shed light on the influence of the donating additive for the lithium center on the structure of silyllithium compounds
THF-solvated heavy alkali metal benzyl compounds (Na, Rb, Cs): defined deprotonation reagents for alkali metal mediation chemistry
The incorporation of heavy alkali metals into substrates is both challenging and essential for many reactions. Here, we report the formation of THF-solvated alkali metal benzyl compounds [PhCH2M ⋅ (thf)n] (M=Na, Rb, Cs). The synthesis was carried out by deprotonation of toluene with the bimetallic mixture n-butyllithium/alkali metal tert-butoxide and selective crystallization from THF of the defined benzyl compounds. Insights into the molecular structure in the solid as well as in solution state are gained by single crystal X-ray experiments and NMR spectroscopic studies. The compounds could be successfully used as alkali metal mediating reagents. The example of caesium showed the convenient use by deprotonating acidic C−H as well as N−H compounds to gain insight into the aminometalation using these reagents
(S)-1,2-Dimethyl-1,1,2-triphenyl-2-(4-piperidiniomethyl)disilane chloride
The title compound, C26H34NSi2
+·Cl−, shows chirality at silicon. Because of its highly selective synthesis with an e.r. of >99:1 by means of a racemic resolution with mandelic acid, the free disilane is of great importance to the chemistry of highly enantiomerically enriched lithiosilanes and their trapping products. N—H⋯Cl hydrogen bonding is present between the protonated nitrogen atom of the piperidino group and the chloride counter-anion. The silicon–silicon distance as well as silicon–carbon and carbon–nitrogen bond lengths are in the same ranges as in other quaternary, functionalized di- and tetrasilanes
Crystal structure of 2-methyl-1,2,3,4-tetrahydroisoquinoline trihydrate
The crystal structure of the title compound, C10H13N·3H2O, a heterocyclic amine, was determined in the presence of water. The compound co-crystallizes with three water molecules in the asymmetric unit, which leads to the formation of hydrogen bonding in the crystal
Crystal structure and quantum-chemical calculations of a trimethylaluminium–THF adduct
The title compound, trimethyl(tetrahydrofuran-κO)aluminium(III), [Al(CH3)3(C4H8O)], is an addition product of trimethylaluminium and tetrahydrofuran (THF). Instead of a dimeric structure, which is very common for these types of compounds, a monomeric molecular structure is observed. The C—Al—C angles in the molecule are very different from the C—Al—C angles found in dimeric molecular structures, leading to a different symmetry around the AlIII atom. The reasons for these differences are discussed
[μ-Bis(diphenylphosphanyl)methane]tricarbonyl(μ-p-toluenesulfonylmethyl isocyanato)(triphenylphosphane)ironplatinum(Fe—Pt)
The title compound, [FePt(C9H9NO2S)(C18H15P)(C25H22P2)(CO)3], represents a rare example of an isonitrile-bridged heterobimetallic complex (here Pt and Fe) and is an interesting precursor for the preparation of heterodinuclear μ-aminocarbyne complexes, since the basic imine-type N atom of the μ2-C=N–R ligand readily undergoes addition with various electrophiles to afford iminium-like salts. In the crystal, the almost symmetrically bridging μ2-C=N-R ligand (neglecting the different atomic radii of Fe and Pt) is strongly bent towards the Fe(CO)3 fragment, with a C=N-R angle of only 121.1 (4)°
Influences of steric factors on the reactivity and structure of diorganoalkoxysilylamides
The combination of an alkoxy and an amino function combined in one silane is rarely found due to the difficult synthesis and isolation.[1] However, this combination offers unique opportunities to investigate the influence of steric requirements or the size of a metal on the structure or reactivity of alkoxysilylamides towards electrophiles by varying the metallating reagent (n-butyllithium or di-n-butylmagnesium) or the organo group on the amino function. For this purpose, we synthesized two alkoxyaminosilanes with acidic NH units that can be metalated. On the one hand, the tert-butylamino-substituted (tert-butylamino)-methoxydiphenylsilane (1) and on the other hand the isopropylamino-substituted methoxydiphenyl(isopropylamino)silane (2). The resulting structures showed an interesting interrelation between the Si–O or Si–N bond lengths and the strength of the coordinative bond to the corresponding metal cation (lithium or magnesium)
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