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Norbornadiene(bipyridyl)molybdenum(II) Complexes: Synthesis, Structure and Reactivity of [Mo(CO)(C 7 H 8 )(C 10 H 6 R 2 N 2 )X 2 ] (X = I, Br)
Author(s) -
Daniel Thomas,
Nagao Hirotaka,
Tanaka Koji,
Nakamura Akira
Publication year - 1995
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19951281008
Subject(s) - chemistry , molybdenum , acetonitrile , pentagonal bipyramidal molecular geometry , reactivity (psychology) , cationic polymerization , adduct , stereochemistry , crystallography , medicinal chemistry , norbornadiene , bimetallic strip , crystal structure , inorganic chemistry , catalysis , polymer chemistry , medicine , biochemistry , alternative medicine , organic chemistry , chromatography , pathology
The reaction of [Mo(CO) 4 (C 7 H 8 )] ( 1 ) with I 2 gave the norbornadienemolybdenum(II) complex [Mo(CO) 2 (C 7 H 8 )I 2 ] n≥1 ( 2 ), which existed in an equilibrium of two isomeric forms. In acetonitrile, 2 reversibly formed the adduct [Mo(CO) 2 ‐(C 7 H 8 )(NCCH 3 )I 2 ] ( 3 ), whereas on treatment with 2,2′‐bipyridine or 4,4′‐di‐2,2′‐ t Bu‐bipyridine, it gave stable 7‐coordinated molybdenum(II) complexes, [Mo(CO)(C 7 H 8 )‐(C 10 H 8 N 2 )I 2 ] ( 4 ) and [Mo(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )I 2 ] ( 5 ), in good yield. In similar reactions, the related dibromomolybdenum compounds [Mo(CO)(C 7 H 8 )(C 10 H 8 N 2 )Br 2 ] ( 6 ) and [Mo‐(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )Br 2 ] ( 7 ) were prepared by oxidation of 1 with two equivalents of CuBr 2 . The X‐ray structural analysis of 6 reveals that the geometry around the molybdenum atom is nearly perfectly pentagonal bipyramidal, with the CO and one of the bipyridyl rings perpendicular to the plane formed by the other ligands. The compounds 5 and 6 react with AgSbF 6 by halogen abstraction to give cationic complexes, {[Mo(CO)(C 7 H 8 )(C 10 H 8 N 2 )Br]SbF 6 } n≥1 ( 8 ) and {[Mo(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )I]SbF 6 } n≥1 ( 9 ): In acetone, 8 and 9 reversibly formed the adducts [Mo(CO)(C 7 H 8 )(C 10 H 8 N 2 )(acetone)Br]SbF 6 ( 8′ ) and [Mo(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )(acetone)I]SbF 6 ( 9′ ); while on treatment with PMe 3 , the stable monomeric complexes, [Mo(CO)(C 7 H 8 )(C 10 H 8 N 2 )(PMe 3 )Br]SbF 6 ( 10 ) and [Mo(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )(PMe 3 )I]SbF 6 ( 11 ), were isolated in almost quantitative yield. In the presence of KBr, compound 8′ reverted to the dibromo complex 6 , whereas 9 ′ reacted to produce a 1:1:2 mixture of 5, 7 and the bromo(iodo) complex [Mo(CO)(C 7 H 8 )(C 10 H 6 t Bu 2 N 2 )BrI] ( 12 ). The same mixture is available from the reaction of 5 with one equivalent of 7.