Crystal structures of the first generation of phenyl-substituted and permethyl-substituted dendritic polysilanes

Nanjo, Masato; Sunaga, Tomoyasu; Sekiguchi, Akira; Horn, Ernst

doi:10.1016/s1387-7003(99)00049-0

Cited by 24 publications

(23 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Finally, dendrimer 47 was obtained in yields of 29% by dephenylation of 45 with TfOH, followed by addition of Li-19. Later, Sekiguchi et al [28] and Marschner et al [41] reported an improved procedure for the synthesis of phenylated dendrimer 45. Replacement of silyl trifilate 14 (X = OTf) with either bromosilane 14 (X = Br) or chlorosilane 15 avoided frequently encountered side-reactions of strong nucleophiles such as metal silanides with silyl triflates and produced 45 in much better yields (74% in both cases).…”

Section: Single-core Polysilane Dendrimers Of Second Generationmentioning

confidence: 99%

Polysilane Dendrimers

Krempner

2012

Polymers

View full text Add to dashboard Cite

Abstract:The synthesis, structure and electronic properties of polysilane dendrimers, a relatively new class of highly branched and silicon-rich molecular architectures is reviewed. After a detailed discussion of main synthetic strategies to well-defined single-core and double-core polysilane dendrimers, important structural and conformational features determined by single crystal X-ray crystallography and 29 Si-NMR spectroscopy are presented. The last part highlights the most interesting photochemical properties of polysilane dendrimers such as UV absorption and emission behavior, which are compared with those of linear and branched polysilanes.

show abstract

Section: Single-core Polysilane Dendrimers Of Second Generationmentioning

confidence: 99%

Polysilane Dendrimers

Krempner

2012

Polymers

View full text Add to dashboard Cite

show abstract

“…For l,u-3, the intense peak at 282 nm (e = 3.7 10 4 ) with a shoulder near 260 nm is significantly shifted to longer wavelength compared to that of 4 (l max = 269 nm, e = 5.2 10 4 ). [11] This red-shift is attributable to reduction in the optical-band-gap resulting from effective interactions between silicon s and oxygen lone pair nonbonding orbiScheme 1. Synthesis of l,l-3 and l,u-3.…”

mentioning

confidence: 99%

Hydroxy‐Substituted Oligosilane Dendrimers: Controlling the Electronic Properties through Hydrogen Bonding

et al. 2006

View full text Add to dashboard Cite

“…Indeed, the majority of dendritic molecules have low or no tendency to form crystals. There are only a few papers reporting single-crystal X-ray analysis of some dendritic structures of first (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) and second (29)(30)(31)(32)(33)(34) generations. Although these results are highly interesting, there is still the lack of a premeditated structural study of dendritic molecules, which might shed some light on the factors controlling self-assembly of these flexible architectures.…”

mentioning

confidence: 99%

Engineering crystals of dendritic molecules

Lukin

Schubert

Müller

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A detailed single-crystal X-ray study of conformationally flexible sulfonimide-based dendritic molecules with systematically varied molecular architectures was undertaken. Thirteen crystal structures reported in this work include 9 structures of the secondgeneration dendritic sulfonimides decorated with different aryl groups, 2 compounds bearing branches of both second and first generation, and 2 representatives of the first generation. Analysis of the packing patterns of 9 compounds bearing second-generation branches shows that despite their lack of strong directive functional groups there is a repeatedly reproduced intermolecular interaction mode consisting in an anchor-type packing of complementary second-generation branches of neighbouring molecules. The observed interaction tolerates a wide range of substituents in meta-and para-positions of the peripheral arylsulfonyl rings. Quantum chemical calculations of the molecule-molecule interaction energies agree at the qualitative level with the packing preferences found in the crystalline state. The calculations can therefore be used as a tool to rationalize and predict molecular structures with commensurate and non-commensurate branches for programming of different packing modes in crystal.dendrimers ͉ single-crystal X-ray ͉ sulfonimides ͉ supramolecular chemistry R evealing the interplay of noncovalent forces that direct processes of self-assembly and self-organization has been objective of numerous studies (1-4). This is central for the design and then the targeted synthesis of molecules capable of assembling into predefined supramolecular structures of practical significance. Although there are many examples in which the knowledge about the noncovalent interactions helped to arrive at predetermined complex molecular architectures (5, 6), the serendipity contributes to a large extent to supramolecular design. Once a new fascinating supramolecular structure is discovered, it is often difficult to decode the underlying principles of its assembly. In this context the crystallization of organic molecules is a specifically complicated case that remains poorly understood. Although it is now often possible with the aid of computations to predict a most favorable intermolecular interaction between molecules there is no guarantee that this particular intermolecular contact will be found in the crystal structure. Attempts at the rational design of organic crystals evolved into a nowadays well-established field of crystal engineering (7-11) that aims at general rules for crystal structure control. For the time being the field of crystal engineering has generated some knowledge that often helps to design organic crystals with desired properties. The main recipe is to use so-called ''tectons'' (12), which are small molecules with welldefined shape and strong directive functional groups, such as hydrogen-bonding units and metal-coordinating sites (13,14). In case reproducible trends in crystal packing for a given group of compounds are observed the molecules are usually sy...

show abstract

Crystal structures of the first generation of phenyl-substituted and permethyl-substituted dendritic polysilanes

Cited by 24 publications

References 9 publications

Polysilane Dendrimers

Polysilane Dendrimers

Hydroxy‐Substituted Oligosilane Dendrimers: Controlling the Electronic Properties through Hydrogen Bonding

Engineering crystals of dendritic molecules

Contact Info

Product

Resources

About