Synthesis of polycyclic hydrocarbon metal systems and ruthenium pyrazole systems
Date
1989
Authors
Beasley, Timothy John
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Abstract
Prolonged irradiation of a mixture of Fe(CO)₅ and l,4,5,8,9,10-hexahydroanthracene, HHA, results in the formation of mono- and di-iron derivatives [(C₁₄H₁₆)Feₙ(CO)₃ₙ], n = 1,2; for n = 2, two isomers are formed, with cis and trans arrangements of (diene)-Fe(CO)₃ fragments. An X-ray crystal determination for the trans compound shows that the molecule possesses Cᵢ symmetry. Treatment of HHA with Ru₃(CO)₁₂ results in catalytic disproportionation of the organic ligand and the isolation of five major organic components.
Reaction of RuCl₃•3H₂O with HHA leads to the formation of the polycyclic arene dimer [(η⁶-C₁₄H₁₄)Ru(µ-Cl)Cl]₂ which on dissolution in DMSO forms, as a result of the cleavage of the chloro bridges, the mononuclear adduct [(η⁶-C₁₄H₁₄)RuCl₂DMSO]. An X-ray crystal structure determination shows coordination of the DMSO ligand through the sulphur atom; substitution of the DMSO ligand by the phosphorus donor ligand, L, has yielded four mono phosphine adducts which show selective coupling of the phosphorus nucleus to two of the four coordinated arene protons; these protons are shielded by the phosphine ligands which contain phenyl rings (L = PPh₃ or PPh₂Me). The substitution of DMSO by Me₂pzH, which yields [(η⁶-C₁₄H₁₄)RuCl₂(Me₂pzH)], has been made the subject of a kinetic study, the results of which indicate that the reaction proceeds via an associative mechanism. A series of mononuclear ruthenium arene pyrazole species of general formula [(η⁶-arene)RuCl₂(pzH)ₙ] arene = C₁₄H₁₄, n = 2; arene = C₆H₆, C₁₀H₁₄, n = 1,2, have been formed, and are non-fluxional at ambient temperature on the NMR timescale.
The ruthenium pyrazolyl bridged dimers [(η⁶-arene)₂Ru₂(µ-pz)₂µ-Cl]Cl, arene = C₆H₆, C₁₀H₁₄, have been prepared. For arene = C₆H₆, an X-ray crystal structure determination shows a chlorine atom in a bridging position. For arene = C₁₀H₁₄, treatment with reducing agents, such as sodium/mercury amalgam, results in the formation of a Ru(I)-Ru(I) species, proposed to contain a metal-metal bond. A number of oxidative addition reactions have been attempted on this bimetallic system.
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UN SDG 6: Clean Water and Sanitation