Selina Hollstein

Communications Chemistry, Published online: 21 May 2021; doi:10.1038/s42004-021-00511-4

This study reports the precise synthesis of a 3D highly strained all-phenylene conjoined bismacrocycle (SCPP[10]). Theoretical calculations indicate that this bismacrocycle has a very high strain energy of 110.59 kcal mol⁻¹ and the largest interphenylene torsion angle of 46.07°. A 1:2 host–guest complex of SCPP[10] and PCBM was formed and investigated.

Abstract

Herein, we report the precise synthesis of a 3D highly strained all-phenylene bismacrocycle, termed conjoined (1,4)[10]cycloparaphenylenophane (SCPP[10]). This structure consists of a twisted benzene ring which is bridged twice by phenylene units anchored in two para-positions. The conjoined structure of SCPP[10] was confirmed in real space at the atomic scale by scanning tunneling microscopy. Theoretical calculations indicate that this bismacrocycle has a very high strain energy of 110.59 kcal mol⁻¹ and the largest interphenylene torsion angle of 46.07° caused by multiple repulsive interactions. Furthermore, a 1:2 host–guest complex of SCPP[10] and [6,6]-phenyl-C₆₁-butyric acid methyl ester was investigated, which represents the first peanut-shaped 1:2 host–guest complex based on bismacrocycles.

Nature Chemistry, Published online: 25 March 2021; doi:10.1038/s41557-021-00652-y

Nature Chemistry, Published online: 01 March 2021; doi:10.1038/s41557-021-00642-0

Communications Chemistry, Published online: 15 February 2021; doi:10.1038/s42004-021-00454-w

Communications Chemistry, Published online: 16 February 2021; doi:10.1038/s42004-021-00457-7

Communications Chemistry, Published online: 02 February 2021; doi:10.1038/s42004-021-00448-8

Nature Chemistry, Published online: 29 January 2021; doi:10.1038/s41557-020-00630-w

Nature Chemistry, Published online: 25 January 2021; doi:10.1038/s41557-020-00627-5

Communications Chemistry, Published online: 17 December 2020; doi:10.1038/s42004-020-00438-2

Addition of a bipyridyl embedded cycloparaphenylene (CPP) nanohoop to [Fe{H₂B(pyz)₂}] (pyz=pyrazolyl) produces the distorted octahedral complex [Fe(bipy[9]CPP){H₂B(pyz)₂}₂]. Its spin‐crossover (SCO) properties are strongly influenced by a distortion associated with the nanohoop, implying that variations in nanohoop size may provide a way of tuning the SCO properties of iron compounds.

Abstract

Addition of the bipyridyl‐embedded cycloparaphenylene nanohoop bipy[9]CPP to [Fe{H₂B(pyz)₂}] (pyz=pyrazolyl) produces the distorted octahedral complex [Fe(bipy[9]CPP){H₂B(pyz)₂}₂] (1). The molecular structure of 1 shows that the nanohoop ligand contains a non‐planar bipy unit. Magnetic susceptibility measurements indicate spin‐crossover (SCO) behaviour with a T _1/2 of 130 K, lower than that of 160 K observed with the related compound [Fe(bipy){H₂B(pyz)₂}₂] (2), which contains a conventional bipy ligand. A computational study of 1 and 2 reveals that the curvature of the nanohoop leads to the different SCO properties, suggesting that the SCO behaviour of iron(II) can be tuned by varying the size and diameter of the nanohoop.

Nature Chemistry, Published online: 22 October 2020; doi:10.1038/s41557-020-00564-3

Nature Chemistry, Published online: 22 October 2020; doi:10.1038/s41557-020-00567-0