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Intermediates and Side‐Reactions in the Synthesis of Molecular Diphenolatonickel Compounds Containing Trimethylphosphane Ligands
Author(s) -
Klein HansFriedrich,
Dal Attila,
Jung Thomas,
Flörke Ulrich,
Haupt HansJürgen
Publication year - 1998
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/(sici)1099-0682(199812)1998:12<2027::aid-ejic2027>3.0.co;2-x
Subject(s) - chemistry , nickel , delocalized electron , medicinal chemistry , phenols , crystal structure , crystallography , ionic bonding , inorganic chemistry , stereochemistry , ion , organic chemistry
Admission of molecular oxygen to a solution containing Ni(PMe 3 ) 4 and substituted phenols (ArOH) affords bisphenolatonickel compounds trans ‐Ni(OAr) 2 (PMe 3 ) 2 [ArOH = 2‐chlorophenol ( 1 ), 2‐bromophenol ( 2 ), 2,4,6‐trichlorophenol ( 3 )]. In the absence of dioxygen the phenols reversibly protonate the nickel complex to form ionic compounds [NiH(PMe 3 ) 4 ] + Y − containing hydrogen‐bonded anions Y = [H 2 (2‐Cl–C 6 H 4 O) 3 ] ( 4 ), [H(2‐OH–C 6 H 4 COO) 2 ] ( 5 ). As a side‐reaction, formal insertion of nickel to give 2‐hydroxyphenylnickel compounds Ni(Ar′)X(PMe 3 ) 3 [Ar′ = 2‐OH–C 6 H 4 ; × = Br ( 6 ), I ( 7 )], trans ‐Ni(Ar′)Cl(PMe 3 ) 2 [Ar′ = 2‐OH–3,5‐Cl 2 –C 6 H 2 ( 8 )] and trans ‐Ni(OAr)Cl(PMe 3 ) 2 [Ar = 2,4,6‐Cl 3 –C 6 H 2 ( 9 )] is observed. An X‐ray crystal structure determination of 1 shows a trans square planar arrangement of donor atoms, that of 6 shows a distorted square pyramid, while 4 contains tetrahedral nickel cations with a delocalized hydrogen atom and triphenolate anions H 2 (ArO) 3 − .