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The spatial structure of dendritic macromolecules

J. Appl. Cryst. (2005). 38, 996–1003 [doi:10.1107/S0021889805032115]

[Dendritic macromolecules] Shape determination for polycarbosilane dendrimers with the three- (left) and four-functional branching center (right) topology. Ab initio models are displayed as beads and envelopes in orthogonal orientations.
Structural characterization of tree-like dendrimer macromolecules is very important for practical applications. This paper presents low-resolution shapes of polycarbosilane dendrimers in solution reconstructed ab initio from SAXS and SANS data. The bead and envelope models reveal anisometric shapes but also pronounced heterogeneity of the internal dendrimer structure allowing for penetration of solvent molecules. The ab initio models agree astonishingly well with the recent independent results of molecular dynamics simulations on dendrimers.
Alexander N. Ozerin, Dmitri I. Svergun, Vladimir V. Volkov, Alexander I. Kuklin, Valentin I. Gordelyi, Akmed Kh. Islamov, Lyudmila A. Ozerina and Denis S. Zavorotnyuk