Single-Crystal Structures of Polyphenylene Dendrimers

Abstract

A series of first‐generation polyphenylene dendrimers based on three different cores were prepared by Diels–Alder cycloaddition and their single‐crystal structures were determined. Consisting exclusively of interlocked, twisted phenyl rings, these polyphenylene nanostructures have exciting structural and dynamic properties. Single crystals of dendrimers, suitable for X‐ray structure analysis, were grown from different solvent mixtures by slow evaporation at room temperature. It should be pointed out that one of the described polyphenylene dendrimers represents up to now the biggest oligophenylene nanostructure from which crystallographic data is available.

NMR Study of Hyperbranched Polyphenylenes from the AB2, (AB2 + AB) and (A2 + B3) Methods

“…Such highfield shifted protons were also observed for similar structures as 1,3-bis(heptaphenylnaphthyl)benzene derivatives (albatrossenes) [21] and polyphenylene dendrimers. [22,23] Tr-NOESY cross peaks to the protons of the central ring located between pentaphenylphenyl blades indicate spatial neighbourhood. This is in agreement with X-ray structures of 14, [21] albatrossenes [21] and dendrimers, [22,23] showing that protons of ortho-phenyl rings of the blades are located above the centres of nearby aromatic rings and, thus, in the shielding region of their anisotropy cone.…”

“…[22,23] Tr-NOESY cross peaks to the protons of the central ring located between pentaphenylphenyl blades indicate spatial neighbourhood. This is in agreement with X-ray structures of 14, [21] albatrossenes [21] and dendrimers, [22,23] showing that protons of ortho-phenyl rings of the blades are located above the centres of nearby aromatic rings and, thus, in the shielding region of their anisotropy cone. Five different protons can be distinguished for the ortho-phenyl groups A of 13 and 14 from the 1 H-1 H COSY and TOCSY spectra [ Supplementary Information, Figure S-4(d-f)].…”

Polyphenylene Dendrimer‐Templated In Situ Construction of Inorganic–Organic Hybrid Rice‐Shaped Architectures

“…[13] Unlike the flexible PAMAM and PPI, polyphenylene-based dendrimers (PPDs) are rigid, and have a 3D framework [14] and extra optoelectronic properties. [15] PPDs have been found to self-assemble on solid substrates, [16] enabling their application in biosensing probes, [17] catalysts, [18] and lightemitting layers in organic light-emitting diodes (OLEDs). [19] In addition, PPDs were used to synthesize Au nanoparticles in 2003 by Müllen et al for the first time, but this inorganic-organic hybrid system has no specific morphology except a bimodal size distribution of Au nanoparticles.…”

Polytriphenylene Dendrimers: A Unique Design for Blue‐Light‐Emitting Materials

“…[14] The single crystal of dendrimer G1 (see Supporting Information, Figure S1) was obtained as colorless, tiny, needle-shaped crystals, by slow evaporation of a solution in a 1:1 mixture of tetrachloroethane and hexane at room temperature (see Supporting Information, Table S1, monoclinic, cell parameters: a = 17.46, b = 10.81, c = 35.86 , and b = 91.08). [14] The single crystal of dendrimer G1 (see Supporting Information, Figure S1) was obtained as colorless, tiny, needle-shaped crystals, by slow evaporation of a solution in a 1:1 mixture of tetrachloroethane and hexane at room temperature (see Supporting Information, Table S1, monoclinic, cell parameters: a = 17.46, b = 10.81, c = 35.86 , and b = 91.08).…”