Adamantane structure compounds

The reaction of this LijP with Me2SiCl2 in a molar ratio of 1 2 progresses very slowly in DME. After 12 hours at 0°C the suspension of the reaction mixture still has a light brown color. It is only after a 4-hour heating at 84° C that this color slowly clears up. During the reaction, compound 10 (adamantane structure) is formed, as well as small quantities of by-products. There was no indication of the formation of P(SiMe2)3P. 

In addition, the butylated compounds ClEt2SiP(SiEt2)2—PSiEt2Bu and (SiEt2)4P3SiEt2Bu (the butylated derivative of 22), and trace amounts of 13 are formed. A compound with the adamantane structure corresponding to compound 10 or to its precursor 11 can be excluded with certainty. 

The adamantane structure is unique as it combines three annullated cyclohexane subunits in a nearly spherical overall shape and, as such, it can be regarded as a section of the diamond crystal lattice578. Due to this property, adamantane and other diamondoid molecules are popular as model compounds for synthetic and spectroscopic purposes579 780. 

Heterocyclic Compounds with Adamantane Structure Z. Kafka and V. Galik, Chem. Listy, 1978, 72, 509-542. 

Finally, there are polycyclic P—N compounds such as those shown in Fig. 10-14. Note that (a) which has an adamantane-type structure and (c) are isomers when R = Me, the adamantane structure is thermally stable, but when R = Me C, the (a) structure converts to the (c) structure on heating for 12 days at 157°C. 

The tetraphosphorus(III)hexaazaadamantane derivative, P4(NMe)6, is obtained from phosphorus trichloride and methylamine, and a tricyclic compound of composition P4(NPT)6 is formed from ClP(NPri )2PNPri SiMcs by elimination of Me3SiCl. It isomerizes on heating into the adamantane structure. Another tricyclic compound, P4(NBfr)6 with nonadamantane structure is formed by reacting [ClPNBfr]2 with [(LiNBu )PNBfr]2- ... 

Cubane or adamantane structures were postulated 179) for compounds of stoichiometry Fe4X3(OCH3)g, the fits of magnetic data to a Heisen-... 

Organoalumi num compounds with 2 or 3 aluminum atoms on the same carbon atom disproportionate when distilled at low pressure. From tris-(diethylalanyl)propane, triethylalane is formed together with organic aluminum compounds which, from their properties, must be assigned an adamantane structure (259) ... 

The compounds are crystalline and can be sublimed when R and R are methyl groups. The crystalline compound with adamantane structure which can be prepared from dimethylalane and dimethylpropynylalane has a framework containing A1R2A1 bridge bonds and may be called a pseudo-aluminaadamantane ... 

Hydrolysis of (345) yields a colorless, sublimable compound (CH2)2As404 which has the adamantane structure (34. Reaction with H2S yields (347) which is insoluble in all common organic solvents, and so no structure proof has yet been possible. With methylamine or methyl-(bistrimethylsilyl)amine (345) reacts to give the 2,4,6,8-tetramethyl-2,4,6,8-tetraaza-l,3,5,7-tetra-arsaadamantane (348 R = Me) (Scheme 64) <70ZAAC(377)120>. Several other A-substituted derivatives of (348) have been described <75JOM(94)393>. 

An adamantane structure is consistent with the formula Me,gSijo, but the NMR spectrum of the compound is too complex for this formulation. 

Hexamethylenetetramine (urotropine) was not only the first but also for many years also the sole compound whose adamantane structure (tricyclo[3.3.1.1 Jdecane) was a certainty. Interestingly, hexamethylenetetramine was also the first organic compound whose structure was determined by X-Ray in 1923 ... 

A compound with 2,6-diaza-adamantane structure (diradical 106) was described for the first time in 1969 by Rassat. The Hofmann-Loffler-Freytag reaction of the bi-... 

Structure compounds characterized by structures which are related to zinc blende or wurtzite as substitution and/or vacancy variants (for details, see Parth, 1990). As example for a normal adamantane structure we shall present in Rgure 1 the zinc blende structure and, as example for a defect adamantane structure, the Cdlr Se4 structure, a vacancy and substitution variant of zinc blende. 

One has to assume that an anionic tetrahedron complex is formed and one has to make also assumptions which of the elements are the cations C, the central atoms C and the anions A. The parameters used in the Mooser - Pearson diagrams to separate compounds with adamantane structure from those having no adamantane structures are also here of some relevance, if the central atom and the anion is from the second period of the Periodic Table then a planar trianguleir anion complex is preferred to a tetrahedron complex, as for example with BOs) -, (003)2- or (NOs) -. Tetrahedral complexes are also rarely found if the central atom is from a very high period. Central atoms from periods inbetween can be expected to form tetrahedral complexes, but there are exceptions. 

According to their X-ray diffraction patterns, compounds (R—Si—Si 5)4, have an adamantane structure [324]. 

A comparison of the compounds now known containing more than 5 Si atoms in the molecule shows that 17 compounds contain the adamantane skeleton as the basic molecular unit (Fig. 5). Two other compounds contain the adamantane skeleton as a part of their overall skeleton. Only three other types are built based on a different structural principle. This outcome shows distinctly the significance of the adamantane structure in the formation of carbosilanes by pyrolysis reactions. 

The unexpectedly complex product was isolated as an almost colourless air-stable powder, and a single-crystal X-ray analysis showed that it had the molecular adamantane-like structure (5). This is very similar to the structure of the iso-electronic compound P4O10 (p. 504). 

This reviews contends that, throughout the known examples of facial selections, from classical to recently discovered ones, a key role is played by the unsymmetri-zation of the orbital phase environments of n reaction centers arising from first-order perturbation, that is, the unsymmetrization of the orbital phase environment of the relevant n orbitals. This asymmetry of the n orbitals, if it occurs along the trajectory of addition, is proposed to be generally involved in facial selection in sterically unbiased systems. Experimentally, carbonyl and related olefin compounds, which bear a similar structural motif, exhibit the same facial preference in most cases, particularly in the cases of adamantanes. This feature seems to be compatible with the Cieplak model. However, this is not always the case for other types of molecules, or in reactions such as Diels-Alder cycloaddition. In contrast, unsymmetrization of orbital phase environment, including SOI in Diels-Alder reactions, is a general concept as a contributor to facial selectivity. Other interpretations of facial selectivities have also been reviewed [174-180]. 

Later, the name diamondoids was chosen for all the higher cage hydrocarbon compounds of this series because they have the same structure as the diamond lattice highly symmetrical and strain-free so that their carbon atom structure can be superimposed on a diamond lattice, as shown in Fig. 5 for adamantane, diamantane, and triamantane. These compounds are also known as adamanto-logs and polymantanes. 

The approach in crystal engineering is to learn from known crystalline structures of, for example, minerals in order to design compounds with desired properties. Crystal engineering is considered to be a key new technology with applications in pharmaceuticals, catalysis, and materials science. The structures of adamantane and other diamondoids have received considerable attention in crystal engineering due to their molecular stiffness, derivatization capabilities, and their six or more linking groups [114-117]. 

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