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Synthesis and Characterization of a New Family of Square‐Planar Nickel( II ) Carbonyl Derivatives
Author(s) -
Forniés Juan,
Martín Antonio,
Martín L. Francisco,
Menjón Babil,
Kalamarides Heather A.,
Rhodes Larry F.,
Day Cynthia S.,
Day Victor W.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20021104)8:21<4925::aid-chem4925>3.0.co;2-4
Subject(s) - protonolysis , chemistry , nickel , medicinal chemistry , halide , phosphonium , stoichiometry , stereochemistry , polymer chemistry , inorganic chemistry , catalysis , organic chemistry
The reaction of [NBu 4 ] 2 [Ni(C 6 F 5 ) 4 ] ( 1 ) with solutions of dry HCl(g) in Et 2 O results in the protonolysis of two NiC 6 F 5 bonds giving [NBu 4 ] 2 [{Ni(C 6 F 5 ) 2 } 2 ( μ ‐Cl) 2 ] ( 2 a ) together with the stoichiometrically required amount of C 6 F 5 H. Compound 2 a reacts with AgClO 4 in THF to give cis ‐[Ni(C 6 F 5 ) 2 (thf) 2 ] ( 3 ). Reacting 3 with phosphonium halides, [PPh 3 Me]X, gives dinuclear compounds [PPh 3 Me] 2 [{Ni(C 6 F 5 ) 2 } 2 ( μ ‐X) 2 ] (X=Br ( 2 b ) or I ( 2 c )). Solutions of compounds 2 in CH 2 Cl 2 at 0 °C do not react with excess CN t Bu, but do react with CO (1 atm) to split the bridges and form a series of terminal Ni II carbonyl derivatives with general formula Q cis ‐[Ni(C 6 F 5 ) 2 X(CO)] ( 4 ). The ν (CO) stretching frequencies of 4 in CH 2 Cl 2 solution decrease in the order Cl (2090 cm −1 )>Br (2084 cm −1 )>I (2073 cm −1 ). Compounds 4 revert to the parent dinuclear species 2 on increasing the temperature or under reduced CO pressure. [NBu 4 ] cis ‐[Ni(C 6 F 5 ) 2 Cl(CO)] ( 4 a ) reacts with AgC 6 F 5 to give [NBu 4 ][Ni(C 6 F 5 ) 3 (CO)] ( 5 , ν CO (CH 2 Cl 2 )=2070 cm −1 ). Compound 5 is also quantitatively formed ( 19 F NMR spectroscopy) by 1:1 reaction of 1 with HCl(Et 2 O) in CO atmosphere. Complex 3 reacts with CO at −78 °C to give cis ‐[Ni(C 6 F 5 ) 2 (CO) 2 ] ( 6 , ν CO (CH 2 Cl 2 )=2156, 2130 cm −1 ), which easily decomposes by reductive elimination of C 6 F 5 C 6 F 5 . Compounds 3 and 6 both react with CN t Bu to give trans ‐[Ni(C 6 F 5 ) 2 (CN t Bu) 2 ] ( 7 ). The solid‐state structures of compounds 3, 4 b, 6 , and 7 have been established by X‐ray diffraction methods. Complexes 4 – 6 are rare examples of square‐planar Ni II carbonyl derivatives.