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Magnesiated and Calciated N ‐Mesityl Diphenylphosphinic Amides
Author(s) -
Schönherr Paul R. W.,
Hempel Niklas A.,
Görls Helmar,
Krieck Sven,
Westerhausen Matthias
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000164
Subject(s) - chemistry , metalation , amide , medicinal chemistry , hydrogen , intramolecular force , stoichiometry , magnesium , resonance (particle physics) , proton nmr , stereochemistry , crystallography , inorganic chemistry , organic chemistry , physics , particle physics
Metalation of N ‐mesityl‐ P,P ‐diphenylphosphinic amide ( 1 ) in THF at room temperature with MgBu 2 and [(thf) 2 Ca{N(SiMe 3 ) 2 } 2 ] yields [(thf) n M{Ph 2 P(=O)–N–Mes} 2 {Ph 2 P(=O)–NH–Mes} 2 ] [M/ n = Mg/0 ( 2 ), Ca/2 ( 3 )] regardless of the applied stoichiometry. These complexes are stabilized by weak intramolecular N–H ··· N hydrogen bridges. In both complexes only one NMR signal set is observed, however, for the magnesium complex 2 the 1 H NMR chemical shift of the hydrogen bridge shifts toward higher field with increasing temperature. For the calcium congener 3 two resonance sets are observed at low temperature, allowing to determine an energy barrier of 52.4 kJ mol –1 for the proton exchange between adjacent nitrogen bases.