Cyclometallation of Phenyl Phosphine and Neopentyl Ligands in Ruthenium(II) Complexes: Synthesis and Crystal Structure of the Orthometallated Complexes [Ru(C6H4PR1R2)(CH2CMe3)(eta-6-C6Me6)] (R1 = R2 = Ph; R1 = Me, R2 = Ph; R1 =R2 = Me) and of the Metalla-cyclobutanes [Ru(CH2CMe2CH2)(eta-6-C6Me6)(PPhR1R2)] (R1 = R2 = Ph; R1 = Me, R2 = Ph)

The compounds [RuCl2(eta-6-C6Me6)L] (L = PPh3 1, or PMePh2 2) react with an excess of Mg(CH2CMe3)Cl to give the corresponding orthometallated complexes activated [Ru(C6H4PR1R2)(CH2CMe3)-(eta-6-C6Me6)] [R1 = R2 = Ph, 4; R1 = Me, R2 = Ph, 5, only the diastereomer (RS:SR)], and the metallacyclobutanes activated [Ru(CH2CMe2CH2)(eta-6-C6Me6) (PPhR1R2)] (R1 = R2 = Ph, 7; R1 = Me, R2 = Ph, 8). In contrast [(RuCl2(eta-6-C6Me6)(PMe2Ph)] 3 reacts to give only the orthometallated complex activated [Ru(C6H4PMe2)(CH2CMe3)(eta-6-C6Me6)] 6. The X-ray crystal structures of complexes 4-8 have been determined and their conformations are discussed. Crystal data are: 4, a = 10.483(2), b = 16.050(10), c = 18.451(9) angstrom, beta = 103.65(4)-degrees, Z = 4, space group P2(1)/c, R = 0.0548; 5, a = 11.926(3), b = 17.810(5), c = 12.780(3) angstrom, beta = 99.37(1)-degrees, Z = 4, space group P2(1)/c, R = 0.0480; 6, a = 16.762(21), b = 10.116(10), c = 14.874(15) angstrom, beta = 108.08(5)-degrees, Z = 4, space group P2(1)/n, R = 0.0441; 7, a = 10.720(20), b = 11.670(20), c = 12.050(10) angstrom, alpha = 80.32(4), beta = 78.60(10), gamma = 87.88(3)-degrees, Z = 2, space group P1BAR, R = 0.0232; 8, a = 8.842(10), b = 8.898(20), c = 17.840(70) angstrom, alpha = 92.91(6), beta = 102.48(50), 102.48(50), gamma = 103.12(9)-degrees, Z = 2, space group P1BAR, and R = 0.0529