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

• Published in: Dalton transactions : an international journal of inorganic chemistry 2021-02, Vol.50 (7), p.2585-2595
• Main Authors: Navarro, Yolanda, Guedes, Guilherme P, Del Águila-Sánchez, Miguel A, Iglesias, María José, Lloret, Francisco, López-Ortiz, Fernando
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d0dt04298f

The synthesis of phosphinic amides containing one 4-amino-TEMPO substituent at the ortho position has been achieved through copper(i) catalyzed cross-coupling reactions of ortho-iodophosphinic amides with 4-amino-TEMPO. The method has been extended to the preparation of the first example of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical 10. The reaction of 10 with Cu(hfac)2 afforded the P-stereogenic CuII complex 19. The crystal structure of both chiral compounds is reported. The molecular structure of 10 consists of a supramolecular zig-zag chain formed by intermolecular hydrogen bonds between the NH group of the phosphinic amide moiety and the nitroxide oxygen atom. In complex 19, the ligand acts as a bridge between two CuII ions coordinated to the oxygen atoms of the P[double bond, length as m-dash]O and N-O· groups leading to the formation of a polymeric helicate chain in which the metal ions exist in a distorted octahedral geometry. The magnetic behavior of ligand 10 is characterized by very weak intermolecular antiferromagnetic interactions, whereas ferro- and anti-ferromagnetic interactions are present in complex 19.