Premium
Stepwise Formation of Quasi‐Octahedral Macrocyclic Complexes of Rhodium( III ) and Iridium( III ) Bearing a Pentamethylcyclopentadienyl Group
Author(s) -
Yamamotoa Yasuhiro,
Suzuki Hajime,
Tajima Nobuo,
Tatsumi Kazuyuki
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(20020118)8:2<372::aid-chem372>3.0.co;2-l
Subject(s) - rhodium , pyrazine , chemistry , iridium , octahedron , ligand (biochemistry) , denticity , moiety , crystallography , stereochemistry , isocyanide , medicinal chemistry , crystal structure , catalysis , biochemistry , receptor
Reactions of [{MCl 2 (Cp*)} 2 ] ( 1 : M=Ir, 2 : M=Rh) with bidentate ligands (L) such as 1,4‐diisocyano‐2,5‐dimethylbenzene ( a ), 1,4‐diisocyano‐2,3,5,6‐tetramethylbenzene ( b ), pyrazine ( c ) or 4,4′‐dipyridyl ( d ) gave the corresponding dinuclear complexes [{MCl 2 (Cp*)} 2 (L)] (M=Ir: 3 a, 3 b, 5 c, 5 d ; M=Rh: 4 b, 6 c, 6 d ), which were converted into tetranuclear complexes [{M 2 ( μ ‐Cl) 2 (Cp*) 2 } 2 (L) 2 ](OTf) 4 (M=Ir: 7 c, 7 d, 9 a, 9 b ; M=Rh: 8 c, 8 d, 10 b ) on treatment with Ag(OTf). X‐ray analyses of 8 c and 8 d revealed that each of four pentamethylcyclopentadienyl metal moieties was connected by two μ ‐Cl‐bridged atoms and a bidentate ligand to construct a rectangular cavity with the dimensions of 3.7×7.0 Å for 8 c and 3.7×11.5 Å for 8 d . Both the Rh 2 Cl 2 and pyrazine (or 4,4′dipyridyl) ring planes are perpendicular to the Rh 4 plane. Treatment of Cl‐bridged complexes ( 7 c, 7 d, 8 c, 8 d, 9 b , and 10 b ) with a different ligand (L′) resulted in cleavage of the Cl bridges to produce two‐dimensional complexes [{MCl(Cp*)} 4 {(L)(L′)} 2 ](OTf) 4 ( 11 ac, 11 bc, 11 bd, 12 bc , and 12 bd ) with two different ligand “edges”. Complex 10 b reacted readily with 1,4‐diisocyano‐2,3,5,6‐tetramethylbenzene ( b ) to give a tetranuclear rhodium( III ) complex 12 bb . The structure of tetranuclear complexes was confirmed by X‐ray analysis of 11 bc . Each {MCp*} moiety is surrounded by a Cl atom, isocyanide, and pyrazine (or 4,4′‐dipyridyl) and the dimensions of its cavity are 7.0×11.6 Å.