Transition-metal complexes of cyclopentadienylphosphines XIV. Reduction reactions of various derivatives of the chelate fragment [{η5:η1-C5H4(CH2)2PPh2}MIII]2+, M = Rr Ir

Autor: Françoise Dahan, Andre. Maisonnat, Inja Lee, René Poilblanc
Rok vydání: 1997
Předmět:
Zdroj: Journal of Organometallic Chemistry. 532:159-170
ISSN: 0022-328X
DOI: 10.1016/s0022-328x(96)06803-9
Popis: Iodide abstraction by silver salts from the complexes [{η5:η1-C5H4(CH2)2PPh2}MI2], (1, M = Rh; 2, M = Ir), yields products whose structures are dependent on the coordinating ability of the anion originally associated with silver. Silver trifluoroacetate gave fully characterized disubstituted derivatives of the type [{η5:η1-C5H4(CH2)2PPh2}M(CF3COO)2], (3, M = Rh; 4, M = Ir), in which the trifluoroacetate anions are bound in a monodentate fashion. Silver hexafluorophosphate gave a dinuclear dicationic compound [{{η5:η1-C5H4(CH2)2PPh}2}Rh (μ−1)}2][PF6]2, 5, in which the metal atoms are bridged by iodide. Complex 3 crystallizes in the triclinic space group P 1 with two molecules in the unit cell, with a = 8.3060(7) A , b = 18.289(2) A , c = 7.9724(8) A , α=94.178(8)°, β = 106.477(8)°, γ = 93.964(7)° and V = 1153.2(2) A 3 . Least squares refinement leads to conventional R values R(Fo) = 0.041 and Rw = 0.042 for 3361 reflections having 1 > 3σ(1). Complex 5 crystallizes in the monoclinic space group P21/c with two molecules of 5 and two molecules of acetone in the unit cell, the dimensions of which are a = 13.838(1) A , b = 13.403(1) A , c = 14.362(1) A , β = 104.73(1)° and V = 2576.2(5) A 3 . Least squares refinement leads to conventional R values R(Fo) = 0.034 and Rw = 0.040 for 2246 reflections having 1 > 2σ(1). Surprisingly, the treatment of the bis-trifluoroacetato complexes 3 and 4 with lithium triethylhydroborate yields quantitatively the ethylene metal(I) derivatives [{η5:η1-C5H4(CH2)2PPh2}M(C2H4)], (9, M = Rh; 10, M = Ir), whereas unstable polyhydride derivatives result from the reaction of the diiodo complex 1 with lithium triethylhydroborate, and from the reaction of the bis-trifluoroacetato complex 3 with sodium tetrahydroborate. The chemical or electrochemical reduction of complex 5 leads to the solvated rhedium(III) species. [{(η5:η1-C5H4(CH2)2PPh2}RhI(THF)][PF6], 6, together with a dinuclear rhodium(II) species. [{{η5:η1-C5H4(CH2)2PPh2}RhI}2], 7. The protonation of 7 with tetrafluoroboric acid affords the monocationic dinuclear complex [{{η5:η1-C5H4(CH2)2PPh2}RhI}2}H][BF4], 8, in which the added proton bridges the rhodium atoms.
Databáze: OpenAIRE
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