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Stabilization of a Snub Bisphenoidal Environment of Strontium in Bis[3‐(1‐naphthyl)‐5‐(2‐pyridyl)‐2 H ‐pyrazole]strontium Bis[3‐(1‐naphthyl)‐5‐(2‐pyridyl)pyrazolate] by Strong Hydrogen Bridges
Author(s) -
Schowtka Björn,
Görls Helmar,
Westerhausen Matthias
Publication year - 2015
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.201400537
Subject(s) - strontium , pyrazole , chemistry , tetrahydrofuran , intramolecular force , toluene , ether , medicinal chemistry , metalation , stereochemistry , solvent , organic chemistry
Metalation of 3‐(1‐naphthyl)‐5‐(2‐pyridyl)‐2 H ‐pyrazole ( 1 ) with [(thf) 2 Sr{N(SiMe 3 ) 2 } 2 ] in toluene and recrystallization from tetrahydrofuran and diethyl ether yields ether‐free bis[3‐(1‐naphthyl)‐5‐(2‐pyridyl)‐2 H ‐pyrazole]strontium bis[3‐(1‐naphthyl)‐5‐(2‐pyridyl)pyrazolate] ( 2 ). This complex contains an octa‐coordinate central strontium atom in a snub bisphenoidal coordination sphere. Intramolecular N ··· H ··· N hydrogen bridges between pyrazolyl groups stabilize the large coordination number of the alkaline earth metal. Short N ··· N contacts of 272.5 and 274.5 pm verify the existence of strong hydrogen bridges; the chemical shift of δ = 19.7 for these protons underlines their extremely acidic character.