Biphenyl-4,4′-diyl bis(2,2,5,5-tetramethyl-1-oxyl-3-pyrroline-3-carboxylate)

Abstract

In the title compound, C30H34N2O6, the complete molecule is generated by a crystallographic 2/m symmetry operation. The 1-oxyl-3-pyrroline-3-carboxyl­ate group lies on a mirror plane. The dihedral angle between the ring planes of the biphenyl fragment is constrained by symmetry to be zero, resulting in rather short intramolecular H⋯H contact distances of 2.02 Å. In the crystal, molecules are connected along the a-axis direction by very weak intermolecular methyl–phenyl C—H⋯π interactions. The C—H bond is not directed to the center of the benzene ring, but mainly to one C atom [C—H⋯C(x − 1, y, z): H⋯C = 2.91 Å and C—H⋯C = 143°].

Crystal structure of 4′-{[4-(2,2′:6′,2′′-terpyridyl-4′-yl)phenyl]ethynyl}biphenyl-4-yl (2,2,5,5-tetramethyl-1-oxyl-3-pyrrolin-3-yl)formate benzene 2.5-solvate

“…It is essentially planar with the two outer rings B (N3/C35-C39) and C (N4/ C40-C44) being inclined to the central pyridine ring A (N2/ C30-C34) by 8.70 (15) and 14.55 (14) , respectively. The conformation of the nitroxyl group in (1) is similar to that found in (3), with a planar pyrroline (N1/C1-C4) ring assuming an angle of 72.61 (15) to the central pyridine ring A [see also Margraf et al (2009) and Schuetz et al (2010)]. In (3) this dihedral angle is 88.44 (7) , while in (2) the same dihedral angle is 21.6 (2) .…”

Pulsed electron–electron double resonance spectroscopy between a high-spin Mn2+ ion and a nitroxide spin label

“…The synthesis of the model compound 4 with a distance of approximately 2.7 nm between the unpaired electron of the nitroxide and the Mn 2+ ion [20][21][22] is schematically represented in Fig. 1.…”

4,4′,4′′-(Methanetriyl)triphenyl tris(2,2,5,5-tetramethyl-1-oxyl-3-pyrroline-3-carboxylate) benzene trisolvate

“…Planarity of this group also has been observed in a related crystal structure (Margraf et al, 2009). The acetoxyphenyl groups are non-planar [torsion angles: C8-O1-C5-C6=-68.2 (3)° , C23-O4-C20-C19=86.6 (3)° , C38-O7-C35-C34=-78.9 (5)° and C38′-O7-C35-C34=67.7 (5)° .…”

“…For a related structure, see: Margraf et al (2009). For the treatment of the disordered solvent, see: Spek (2009).…”