Analysis of the spatial structure of rigid polyphenylene dendrimers by small-angle neutron scattering

Rosenfeldt, Sabine; Dingenouts, N.; Pötschke, D.; Ballauff, Matthias; Berresheim, Alexander J.; Müllen, Kläus; Lindner, Peter; Saalwächter, Kay

doi:10.1016/j.jlumin.2004.10.004

Cited by 25 publications

(47 citation statements)

References 34 publications

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“…For example, a recent investigation of poly-p-phenylene dendrimers of fourth generation synthesized by Müllen and co-workers [10][11][12][13] demonstrated clearly the rigid spatial structure that is maintained in solution. [14,15] The analysis of the SANS data showed unambiguously that the units setting up the consecutive generations of the dendritic scaffold are rather well-localized and no back folding of the terminal groups can occur. A general feature of the poly-p-phenylene building block is its finite angle formed by two subsequent phenyl groups.…”

Section: Introductionmentioning

confidence: 94%

“…[6,8,9,15,20] Therefore it suffices to only delineate the main points of this method as well as the equations used for evaluation of the data.…”

Section: Theorymentioning

confidence: 99%

“…All previous investigations of dendrimers in solution have demonstrated that I incoh must be removed carefully from the measured data in order to arrive at meaningful data. [6,8,9,14,15,20] There is no such contribution in SAXS. The scattering intensity measured by both methods will be markedly different because of the different contrast D1 = 1 À 1 m where 1 is the average scattering length density of the solute and 1 m is the respective quantity of the solvent.…”

Section: Theorymentioning

confidence: 99%

“…The evaluation of the SANS data can be done as follows: [8,9,14,15,20] 1. The incoherent contribution I incoh of the SANS intensities is determined and subtracted from the scattering data.…”

Section: Theorymentioning

confidence: 99%

“…As a consequence of this, the poly-p-phenylene dendrimers must exhibit a three-dimensional structure which is found indeed by SANS. [14,15] No such steric hindrance exists in dendritic scaffolds set up from stilbenoid units. Figure 1 displays the chemical structure of a stilbenoid dendrimer of third generation synthesized recently.…”

Section: Introductionmentioning

confidence: 99%

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The Solution Structure of Stilbenoid Dendrimers: A Small‐Angle Scattering Study

et al. 2006

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The spatial structure of a stilbenoid dendrimer is investigated by small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) in dilute solution. All measurements are performed in toluene. The dendrimer consists of a stilbenoid scaffold with appended hexyloxy chains. SAXS is mainly sensitive to the dendrimer scaffold whereas SANS intensity, measured in fully deuterated toluene, derives from the solute molecules. The resulting SAXS and SANS intensities are analyzed by comparison with various models. It is found that the model of a circular disk gives the best description of the data. SAXS data demonstrate that the stilbenoid scaffold is flat as expected for benzene rings conjugated through vinylene units. Thus, it can be described by a circular disk with a radius of 1.6 nm and a thickness of 0.7 nm. SANS, on the other hand, shows that the hexyloxy chains are not confined in the plane defined by the core. This is derived from modeling the SANS data with a much thicker circular disk (radius: 2.4 nm, thickness: 1.8 nm). The structure factor S(q), describing the interaction of the dendrimers at higher concentrations, is modeled quantitatively with the "polymer reference interaction site model" (PRISM) integral equation formalism for hard plates such as particles. Here the structural data obtained from the analysis of the SANS data are used so that no new adjustable parameter is necessary for this description.

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Section: Introductionmentioning

confidence: 94%

“…[6,8,9,15,20] Therefore it suffices to only delineate the main points of this method as well as the equations used for evaluation of the data.…”

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Solution Structure of Stilbenoid Dendrimers: A Small‐Angle Scattering Study

et al. 2006

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NMR Spectroscopy

Spieß

2007

Macromolecular Engineering

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NMR Spectroscopy

Spieß¹

2022

Macromolecular Engineering

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The function of synthetic macromolecular materials critically depends on the packing and dynamics of the components of such systems. Solid‐state NMR can provide structural information with atomic resolution and moreover can characterize the amplitude and time scale of motions over broad ranges of length and time. These movements include molecular dynamics, rotational, and translational motions of the building blocks, and also the motion of the functional species themselves, such as protons or ions. In this article, current NMR techniques are introduced and their applications illustrated by numerous examples of a broad range of synthetic macromolecular systems.

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Analysis of the spatial structure of rigid polyphenylene dendrimers by small-angle neutron scattering

Cited by 25 publications

References 34 publications

The Solution Structure of Stilbenoid Dendrimers: A Small‐Angle Scattering Study

The Solution Structure of Stilbenoid Dendrimers: A Small‐Angle Scattering Study

NMR Spectroscopy

NMR Spectroscopy

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