157047-10-4Relevant academic research and scientific papers
Transition-metal derivatives of cyclopentadienylphosphine ligands. 10. ((Cyclopentadienylethyl)diphenylphosphine) rhodium and -iridium chelated and bridged complexes: Crystal and molecular structures of the chelated complexes (η5:η1-C5H4(CH 2)2PPh2)RhI(C2H ...
Lee, Inja,Dahan, Fran?oise,Maisonnat, André,Poilblanc, René
, p. 2743 - 2750 (2008/10/08)
Full title: Transition-metal derivatives of cyclopentadienylphosphine ligands. 10. ((Cyclopentadienylethyl)diphenylphosphine) rhodium and -iridium chelated and bridged complexes: Crystal and molecular structures of the chelated complexes (η5:η1-C5H4(CH 2)2PPh2)RhI(C2H 4)and (η5:η1-C5H4(CH 2)2PPh2)RhIIII2. A series of new derivatives of (cyclopentadienylethyl)diphenylphosphine - a heterodifunctional ligand able to offer either chelating or bridging properties - has been synthesized from various rhodium and iridium derivatives. Interestingly, the synthesis of the monometallic chelated carbonyl compound (η5:η1-C5H4(CH 2)2PPh2)Rh(CO) (8) starting from the square-planar dimeric complex [RhCl(CO)2]2 and [((diphenylphosphino)ethyl)cyclopentadienyl]lithium involves a pathway beginning with coordination of the phosphorus moiety of the difunctional ligand. This pathway then includes the transient formation of cisoid and transoid isomers, 9a,b, of the bridged dimetallic complex [(μ-η5:η1-C5H4(CH 2)2PPh2)Rh(CO)]2, as kinetic products which transform into the thermodynamic product 8. A similar overall process is also suspected for the formation of the other chelated complexes-(η5:η1 C5H4(CH2)2PPh2)M(C 2H4) (M = Rh (14), Ir (12)) and ((η5:η1-C5H4(CH 2)2PPh2)M(cod) (M = Rh (15), Ir (16)), obtained from [RhCl-(C2H4)]2, [IrCl(C2H4)]n, and [MCl(cod)]2 (M = Rh, Ir), respectively. From 8 and 12 the chelated diiodo compounds (η5:η1-C5H4(CH 2)2 PPh2)MIIII2 (M = Rh (17), Ir (18)) were also synthesized. All of the more stable products (8, 12, 14-18) were fully characterized by their spectroscopic data (including phosphorus-rhodium coupling constant measurements) and by electron impact mass spectroscopy. Complex 14 crystallizes in the monoclinic space group P21/n with eight molecules in the unit cell, the dimensions of which are a = 9.808(1) A?, b = 28.515(3) A?, c = 13.094(1) A?, β = 98.34(1)°, and V = 3628.3(8) A?3. Least-squares refinement leads to a value for the conventional R index of 0.031 for 3035 reflections having I > 3σ(I). Complex 17 crystallizes in the monoclinic space group P21/n with four molecules in the unit cell, the dimensions of which are a = 10.439(1) A?, b = 16.557(2) A?, c - 11.458(1), A?, β = 95.85(1) A?, and V = 1970.1(8) A?3. Least-squares refinement leads to a value for the conventional R index of 0.027 for 1638 reflections having I > 3σ(I). In both compounds 14 and 17, the P-C-C-C(Cp) chain of the chelating arm deviates from planarity but the 1H NMR data clearly reveal for all the chelated complexes studied the occurrence of a fluxional process described essentially as an inversion of the Rh-P-CH2-CH2-C5H4 ring. In 14, this process is faster than the internal rotation also observed for the ethylene ligand.
