Diolefin derivatives of tetrairidium dodecacarbonyl. Synthesis and crystal structures of Ir4(CO)9L(2,3-.eta.:5,6-.eta.-norbornadiene) (L = PMe2Ph, PPh3)

Intramolecular Dynamics of Tetranuclear Iridium Carbonyl Cluster Compounds. Part V. Polysubstituted derivatives of [Ir4(CO)12]

“…2), PPh, (3), AsPh,) are known, and the crystal structures of the radial isomer with L = PMe,Ph and of the axial isomer with L = PPh, have been already reported [17]. The 3'P-NMR spectrum of 2 in CD,CI, at 193 K consists of two resonances at d -37.0 and -8.3 ppm (Ad = -8.7 and +20 ppm, respectively).…”

“…The related cluster 3 is present as a single, observable isomer in solution whose ground-state geometry was proposed to be the same as in the solid state, on the basic of its coordination chemical shift Ad(P) (Scheme 2) [17]. The I3C-NMR spectrum of a 13C-enriched sample of 3 in C,D,Cl, at 240 K consists of eight CO signals which were assigned by comparison with those of 2A (see Exper.…”

“…-The "P-NMR spectrum of [Ir4(CO)4@2-CO)3(v4-nbd),(PMePh,)] [17] in CD,C1, at 183 K presents two resonances at 6 -41.5 and -9.3 (A6 = -13.2 and +18.5 ppm, respectively). Therefore, two isomers are present in solution with the PMePh, ligand either in axial (12A, major species) or radial position (12R) with…”

Synthesis, Reactivity, and Fluxional Behaviour of [Ir2Rh2(CO)12], and Crystal Structure of [Ir2Rh2(CO)8(norbornadiene)2]

“…No appreciable shortening of the CO-bridged intermetallic distances with respect to the unbridged ones can be detected as in most Ir, and Rh, substituted derivatives [19]. The metal-C(dio1efin) interactions range from 2.18 (2) (2) and 2.18 (2) A for L = PMe,Ph and PPh,, respectively [20]). …”