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(Tetramethylcyclobutadiene)cobalt Complexes − Syntheses of Tris(ligand) Derivatives and Structures of [(C 4 Me 4 )Co(CO) 3 ]BF 4 and [(C 4 Me 4 )Co(NCMe) 3 ]PF 6
Author(s) -
Butovskii Mikhail V.,
Englert Ulli,
Fil'chikov Alexei A.,
Herberich Gerhard E.,
Koelle Ulrich,
Kudinov Alexander R.
Publication year - 2002
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 - 10.1002/1099-0682(200210)2002:10<2656::aid-ejic2656>3.0.co;2-j
Subject(s) - chemistry , acetonitrile , decarbonylation , ligand (biochemistry) , medicinal chemistry , iodide , ring (chemistry) , cobalt , stereochemistry , organic chemistry , catalysis , receptor , biochemistry
Photolysis of [Cb*Co(C 6 H 6 )]PF 6 ] ( 6 ) (Cb* = C 4 Me 4 ) in acetonitrile solution produces the red solvento complex [Cb* Co(NCMe) 3 ]PF 6 ( 8 ) in quantitative yield. Alternatively, heating of the acetonitrile solution to reflux temperature may effect the displacement of the benzene ligand. Photolysis of 6 in liquid ammonia gives [Cb*Co(NH 3 ) 3 ]PF 6 ( 9 ). Compound 8 is substitution‐labile and reacts with a wide variety of Lewis bases to produce substitution products [Cb*CoL 3 ]PF 6 with L = P(OMe) 3 ( 10 ), py ( 11 ), CN t Bu ( 12 ), and the related compound (NEt 4 ) 2 [Cb*Co(CN) 3 ] ( 13 ). Thermal reaction of [Cb*Co(CO) 3 ]BF 4 ( 7 ) with PMe 3 takes place spontaneously at ambient temperature and produces the monosubstitution product [Cb*Co(CO) 2 (PMe 3 )]BF 4 ( 14 ), while irradiation combined with a purging stream of N 2 effects an exhaustive decarbonylation and affords [Cb*Co(PMe 3 ) 3 ]BF 4 ( 16 ). Irradiation of 7 in acetonitrile produces mixtures of the mono‐ and disubstitution products; if a purging stream of N 2 is applied, [Cb*Co(CO)(NCMe) 2 ]BF 4 ( 18 ) is formed with a small admixture of [Cb*Co(NCMe) 3 ]BF 4 . The iodide Cb*CoI(CO) 2 reacts with 2,2′‐bipyridine to produce the monocarbonyl complex [Cb*Co(CO)(bipy)]I ( 15 ). Single‐crystal structure determinations of [Cb*Co(CO) 3 ]BF 4 ( 7 ) with Co−Cb(ring plane) 1.777(2) Å (av.) and of [Cb*Co(NCMe) 3 ]PF 6 ( 8 ) with Co−Cb(ring plane) 1.68(1) Å (av.) are reported. Synthetic procedures for the preparation of [Cb*Co(CO) 3 ]BF 4 ( 7 ), Cb*CoI(CO) 2 ( 2 ), and [Cb*Co(C 6 H 6 )]PF 6 ( 6 ) are also given. An electrochemical study of the compounds 8 , 10 − 13 , and 16 reveals chemically fully reversible oxidation reactions. Hard σ‐donor ligands (CN − , py, NCMe) stabilize the corresponding 17e species much more so than soft donor ligands [PMe 3 , CN t Bu, and P(OMe) 3 ]. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)