Synthesis, crystal structures and magnetic properties of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical and its Cu^II complex

Abstract

The synthesis, structures and magnetic properties of an unprecedented P-stereogenic phosphinic amide-4-amino-TEMPO radical and its Cu(hfac)2 complex are reported.

Two temperature-induced 1D CuII chain enantiomeric pairs showing different magnetic properties and nonlinear optical responses

“…In this case, the 3d x 2 −y 2 magnetic orbital for one of the Cu II ions and the 2p z orbital of the O atom from NO 3 − are orthogonal, which has been proven to be favorable for the occurrence of a weak ferromagnetic interaction between Cu II spin centers. 50,51 Similar results also were observed in the 1D Cu II chain CPs with carboxylates as the bridging ligands in an eq-ax binding fashion ( J = 0.071 cm −1 ). 52 However, the 1D Cu II chain [Cu (NO 3 ) 2 (bipy)] n (5) was reported to show a weak antiferromagnetic coupling between Cu II ions ( J = −0.11 cm −1 ) due to the presence of a classical Cu 2 O 2 moiety with the Cu-O-Cu angle being 112.41°(>99°), usually resulting in an antiferromagnetic coupling.…”

“…S5. † 41,50 However, according to Kahn's orthogonal theory, strict orthogonality between the magnetic orbitals across the bridging ligand should result in a ferromagnetic interaction. 58 The observation of weak antiferromagnetic interaction in S-2-Cu can be ascribed to the deviation of a strict perpendicular arrangement at the axial coordination for bridging the pyz moiety with the angle of Cu1-N1-N3 being 173.06 (15)°, 54 which is far from the 180°for a strict perpendicular arrangement.…”

A Powerful P−N Connection: Preparative Approaches, Reactivity, and Applications of P‐Stereogenic Aminophosphines

“…The absolute configuration at phosphorus of products ( S C , S P )‐ 99 could be revealed by X‐ray structure determination of a representative derivative [56c] . The newly introduced functional unit at the ortho ‐position could then be replaced by alkyl or aryl moieties [56b] or by the 4‐amino‐TEMPO (4‐amino‐2,2,6,6‐tetramethylpiperidinyloxyl) radical [56d] . Analogous asymmetric ortho ‐substitutions were reported for aminophosphazenes, which contain a P + −N − −COOMe instead of a P + −O − unit.…”