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Synthesis and Properties of New (Phosphinoylmethyl)Pyridine N‐Oxides
Author(s) -
Pailloux Sylvie L.,
RosarioAmorin Daniel,
Chakravarty Manab,
Camus JeanMichel,
Smith Karen Ann,
Duesler Eileen N.,
Dickie Diane A.,
Paine Robert T.,
Klausmeyer Kevin K.,
Padron Daniel A.,
Hay Benjamin P.,
Delmau Laetitia H.
Publication year - 2013
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300099
Subject(s) - chemistry , pyridine , denticity , steric effects , ligand (biochemistry) , stereochemistry , methylene , molecule , crystal structure , medicinal chemistry , lanthanide , crystallography , organic chemistry , ion , biochemistry , receptor
Syntheses for 2‐[1‐(diarylphosphinoyl)‐1‐(pyridin‐2‐yl)methyl]pyridines, ( 8a, b ), and 2‐[1‐(diarylphosphinoyl)‐1, 1‐bis(methylpyridin‐2yl)methyl]pyridines, ( 11a, b ), (Ar = C 6 H 5 and 2‐CF 3 C 6 H 4 ), based on substitution of 2‐methylpyridine fragments onto the exo methylene carbon atom of 2‐[(diaryl)phosphinoylmethyl]pyridine platforms, are described. N‐oxidations of 8a, b and 11a, b produced the 2‐[1‐(diarylphosphinoyl)‐1‐(1‐oxy‐pyridin‐2yl)methyl]pyridine N ‐oxides ( 5a, b ) and the 2‐[1‐(diarylphosphinoyl)‐1, 1‐bis(1‐oxy‐methylpyridin‐2‐yl)methyl]pyridines ( 6a, b ), respectively. The “short‐arm“ pyridine fragment of 11a, b resists N‐oxidation, and the fully oxidized molecules, 2‐[1‐(diarylphosphinoyl)‐1, 1‐bis(1‐oxy‐methylpyridin‐2‐yl)methyl]pyridine N ‐oxides ( 7a, b ) were not isolated. Molecular mechanics calculations for gas phase 1:1 ligand/lanthanide complexes indicated that 5a should accommodate a tridentate NO(meNO)PO coordination mode with minimal steric strain. In contrast, 7a cannot form tetradentate NO(meNO) 2 PO chelates; however, tridentate binding should be accessible with minimal ligand strain. Coordination complexes of 8a, b , 5a, b , 6a, b and 11a, b with Ln(NO 3 ) 3 salts were isolated and a X‐ray crystal structure for [Er( 8a )(NO 3 ) 3 (MeOH) 2 ]·CH 2 Cl 2 , revealed a monodentate Er–O=P interaction. On the other hand, complexes formed by a more symmetrical trifunctional phenylphosphino‐bis‐2‐methylpyridine N, N, P‐trioxide ligand, (meNO) 2 PO* , {La[( meNO) 2 PO* )](OTf) 2 (MeOH) 3 (H 2 O) + }(OTf – ) and {Pr[ (meNO) 2 PO* )](OTf)(MeOH) 4 + }(OTf – ) 2 , realized a tridentate coordination mode. Solvent extraction behaviors for Eu III and Am III in nitric acid solutions using 5a, b , 6a, b , Ph 3 PO and the parent bifunctional ligand 2‐[(diphenylphosphanyl)methyl]pyridine N, P‐dioxide ( 3a ) in 1, 2‐dichloroethane were assessed, and 5a, b and 6a, b were found to behave more like Ph 3 PO than 3a .