Syntheses of metal carbonyls. 23: Crystal structure and reactivity of heptamethylindenyl carbonyl metal complexes

Article abstract of DOI:10.1002/zaac.19976230808

Reaction of heptamethylindene (C₉(CH₃)₇, 1) with Re₂(CO)₁₀ yields [η⁵-C₉(CH₃)₇]Re(CO)₃ (2), which reacts with NO⁺BF₄^- to form the cationic complex [{η⁵-C₉(CH₃)₇}Re(CO) ₂NO]⁺BF₄^- (3). Irradiation of 2 with UV light in the presence of triethyl phosphite leads to formation of [η⁵-C₉)(CH₃)₇]Re(CO) ₂[P(OC₂H₅)₃] (4). Alkylation of (CH₃)₃SnCl with Ind*Li gives [η¹-C₉(CH₃)₇]Sn(CH ₃)₃ (5). All compounds were characterized by spectroscopic methods. The molecular structures of 3 and 5 were determined by single crystal X-ray diffraction (3: P2₁/n (14), a = 1497.7(4) pm, b = 879.0(2) pm, c = 1609.0(4) pm and β = 110.99(2)°, R₁ = 0.038, wR₂ = 0.080; 5: P2¹/n (14), a = 726.1(1) pm, b = 2930.7(3) pm, c = 930.0(1) pm and β = 112.834(5)°, R₁ = 0.044, R_w = 0.048). Complexes 2-4 exhibit a piano stool configuration with a η⁵-coordinated permethylindenyl ligand (Ind*). Compound 5 displays a η¹-coordination of the Ind* ligand. Temperature enhancement causes a hapticity change, as observed by NMR spectroscopy.