Rhodium complexes tridentate ligands

Cyclopentadienyl cobalt and rhodium complexes with 1,2-benzenedithiolate or S2C2R2 type ligands readily add unsaturated carbon molecules to form tridentate ligands exhibiting S2C donor sets. When nitrenes are added, dithio-lene derived ligands with S2N donor sets result. Scheme 3 shows examples of... 

The tridentate ligands (38)-(40) form rhodium(I) complexes. The complexes of the first two ligands readily undergo oxidative addition to form rhodium(III) complexes. The complex [RhCl(38)] also adds either SO2 or BF3 to form pentacoordinate rhodium(I) complexes. The tetraden-tate ligands (41) (Z = P, As) and (42) and the hexadentate ligand (43) form both rhodium(I) and (III) complexes. By contrast, the tri(tertiary arsine) ligand (44) fails to reduce hydrated rhodium trichloride and forms both fac- and mer-trihalorhodium(in) complexes. 

The rhodium anionic bis(phosphonate) complex [Rh(C5Me5)(I) PO-(OMe),, ] , can act as a tridentate ligand with the halogen atom as one of the donor centers (132). This behavior can be enhanced by introducing a pz group instead of the halogen atom. Bimetallic derivatives of the formula [Rh(C5Me5) PO(OMe)2 2(/i-pz )M] (M = Na or Tl) were prepared by addition... 

Partial or complete displacement of the coordinated acetonitrile ligands may be achieved with monodentate ligands (e.g., phosphines ), bidentate ligands (e.g., dienes), or tridentate ligands, providing a convenient entry to a range of (i -pentamethylcyclopentadienyl)rhodium and -iridium complexes. 

The presence of a MCH3 (M = Ir or Rh) moiety in new iridium and rhodium complexes of a tridentate pincer ligand, 2,6-bis(di-tert-butylphosphinito)-3,5-diphenylpyrazine (PONOP) (PONOP)RhMc3 and (PONOP)IrMc3, has been confirmed by Brookhart and co-workers by the observation of /hp coupling of 4.9 Hz for the rhodium complex also Vhrii of 3.1 and VpRji of 171 Hz have been reported. 

Asymmetric cycloisomerization of nitrogen-bridged 1,6-enynes occurs in the presence of a cationic rhodium complex coordinated with a chiral diene/phosphine tridentate ligand to give chiral 3-azabicyclo[4.1.0]heptenes with high enantioselectivity (Scheme 149). " ... 

The one-pot synthesis of a large family of hi- and tridentate phospholanes represented in Scheme 15.16 employed the air-stable chiral phospholanium chloride salts and primary amines or NH Cl as starting materials. These were transformed into the C2-symmetric dimethylphospholane and diphenylphospholane ligands which reacted with [Rh(COD)2]Bp4 to yield the rhodium complexes [Rh(L)(COD)]Bp4 (L = DMP or DPP bisphospholane ligands) [67]. 

L = C3H3, C H ) and then [Rh(acac)(CO),] to yield the tetranuclear species 180 (85ICA(i00)L5), where the heterocyclic ligands are tridentate. The product reacts with the rhodium(I) dimer [Rh(CO)2Cl]3 to give the trinuclear complex 181. In the solid state, the molecules of this complex form the intermolecular stacks along the z-axis. 

The tridentate BoxCarb ligand was used to synthesise the corresponding carbene complexes of silver(I), rhodium(III) and palladium(II) [101]. Interestingly, the potentially tridentate BoxCarb ligand coordinates in a bidentate fashion only in the case of the silver(l) complex and it is the linker-free oxazoline ring that remains pendant. The coordination... 

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