652135-11-0Relevant academic research and scientific papers
The substitution chemistry of the tris(3,5-dimethylpyrazolyl)-methanerhodium complex [Rh(CO)2{HC(pz′)3}]+
Adams, Christopher J.,Connelly, Neil G.,Emslie, David J.H.,Hayward, Owen D.,Manson, Tania,Orpen, A. Guy,Rieger, Philip H.
, p. 2835 - 2845 (2003)
The complex [Rh(CO)2{HC(pz′)3}][PF6], 1 +[PF6]- {HC(pz′)3 = tris(3,5-dimethylpyrazolyl)methane}, prepared by reacting [{Rh(CO)2(μ-Cl)}2] with HC(pz′)3 in the presence of Tl[PF6], has a distorted square pyramidal structure with a κ3-HC(pz′)3 ligand. Carbonyl substitution with Lewis bases gives [Rh(CO)L{HC(pz′)3}] [PF6] {L = PPh3, 2+[PF6]-; L = AsPh3, 3+[PF6]-; L = P(o-tolyl)3, 4+[PF6]-}, which have square planar κ2 structures, confirmed by X-ray crystallography for 2+[PF6]-. The cations 2+ and 3+ have the third pyrazolyl ring orientated pseudo-parallel to the square planar metal whereas 4+ more likely has the third ring orientated exo to that plane. One-electron oxidation of 2+ and 3+ gives the Rh(II) dications [Rh(CO)(PPh3){HC(pz′)3}]2+, 22+, and [Rh(CO)(AsPh3){HC(pz′)3}]2+, 32+, characterised by ESR spectroscopy. Complex 1+[PF6]- reacts with PhC≡CPh to give [Rh(CO)(η2-PhC≡CPh)-{HC(pz′)3}] [PF6], 5+[PF6]-, in which the two-electron donor alkyne occupies an equatorial position in a trigonal bipyramidal κ3 structure. With MeC≡CR (R = Me or Et), 1+[PF6]- gives the κ2 square planar complexes [Rh{η4-C4Me2R2C(O)}{HC(pz′ )3}][PF6] (R = Me, 6+[PF6]-; R = Et, 7+[PF6]-) in which the cyclopentadienone ligands are coordinated via two Rh-monoalkene bonds; the structurally characterised form of 7+ has the two alkyne units linked head-to-head with the CEt termini bound to the ketonic CO group. With HC≡CPh or HC≡CH, 1+ gives the octahedral, κ3 rhodium(III) metallacyclopentadienes [Rh(CO)(η1:η1′-CHCRCHCR) {HC(pz′)3}][PF6] (R = Ph, 8+[PF6]-; R = H, 9+[PF6]-) with the two alkynes linked head-to-tail in 8+. The reaction of 1+ with HC≡CH also gives the cycloheptatrienone (tropone) derivative [Rh{η4-C6H6C(O)}{HC(pz′)3} ][PF6], 10+[PF6]-, with a κ3 ligand and the cycloheptatrienone ligand bound to the metal via two Rh-C σ-bonds and one Rh-monoalkene interaction.
