At Last, 1,10-Phenanthroline-N,N′-dioxide, A New Type of Helicene, has been Synthesized using HOF⋅CH3CN

Abstract

For more than 50 years the synthesis of 1,10-phenanthroline-N,N'-dioxide (2) has been sought. The reason for the failure of all the earlier attempts is that the limited space in the bay area of the starting material 1,10-phenanthroline (1) cannot accommodate two oxygen atoms. The oxidation has now been achieved with the oxygen-transfer agent HOF small middle dotCH(3)CN, and X-ray studies have revealed that the product is not planar but is a new type of helicene-in this way the "space problem" for the two oxygen atoms has been solved.

Helicene-Based Chiral Auxiliaries and Chirogenesis

“…However, there are some exceptions to this general rule. Interestingly, phenanthroline-N,N-dioxide 23 [33] ( Figure 5) is also classified as a helicene in the literature, despite the fact that n = 3. This is due to the fact that the N,N-dioxide functionalities at the peri positions in the bay area of the phenanthroline are able to introduce the corresponding spatial constraint to force the molecule to adopt a configurationally stable helical conformation.…”

Magnetization Dynamics and Coherent Spin Manipulation of a Propeller Gd(III) Complex with the Smallest Helicene Ligand

“…In this work we present a 4-fold propeller-shaped Gd III complex with the smallest helicene-type ligand N , N ′-dioxophenanthroline (phendo) 27 [Gd(phendo) 4 ](NO 3 ) 3 · x MeOH ( 1 ) with a slow relaxation of the magnetization governed by a Raman process and showing coherent spin dynamics. We demonstrate that the Raman relaxation process is intrinsic to the molecule in this case and depends weakly on temperature ∝ T 3 as compared to T 5 or T 9 , postulated for Kramers ions.…”

“…However, for the Gd III complexes studied so far, the slow magnetic relaxation is often attributed to the phonon bottleneck effect, and the spin− lattice relaxation was postulated to appear only under special circumstances, that is, in the presence of Gd−Pt bonds. 24 In this work we present a 4-fold propeller-shaped Gd III complex with the smallest helicene-type ligand N,N′dioxophenanthroline (phendo) 27 dynamics. We demonstrate that the Raman relaxation process is intrinsic to the molecule in this case and depends weakly on temperature ∝T 3 as compared to T 5 or T 9 , postulated for Kramers ions.…”

The Underexplored Field of Lanthanide Complexes with Helicene Ligands: Towards Chiral Lanthanide Single Molecule Magnets

“…Apart from helicenes with conventional donor atoms, which enables the classical coordination to lanthanides (Figure 1), the η 5 -and η 6 -helicenic ligands as well as helicenes decorated with alkynyl and vinyl groups were never used for the preparation of 'organometallic' lanthanide complexes. [66] and phendo = 1,10-phenanthroline-N,N'-dioxide [67].…”