Abstract
The compound [RhCl2(η5-C5Me5)(PPh3)] reacts with Li(CH2SiMe3) to give the ortho-metallated complex [R[graphic omitted]Ph2)(CH2SiMe3)(η5-C5Me5)](2), and with Mg(CH2SiMe3)Cl in CH2Cl2(molar ratio 1:1) to yield [RhCl(CH2SiMe3)(η5-C5Me5)(PPh3)], (3). Complex (3) is converted by the action of Li(CH2SiMe3) into the ortho-metallated compound (2). The reaction of [IrCl2(η5-C5Me5)-(PPh3)] with Mg(CH2SiMe3)Cl in CH2Cl2 gives [I[graphic omitted]Ph2)(CH2SiMe3)(η5-C5Me5)], (6), and [lrCl(Me)(η5-C5Me5)(PPh3)]. Reaction of [RhCl2(η5-C5Me5)(PPh3)] with Mg(CH2CMe3)Cl or Li(CH2CMe3) in diethyl ether affords a mixture of [R[graphic omitted]H2)(η5-C5Me5)(PPh3)], [R[graphic omitted]Ph2)(CH2CMe3)(η5-C5Me5)], and [Rh(η5-C5Me5)(C2H4)(PPh3)], while reaction in CH2Cl2 in equimolar amounts gives [RhCl(CH2CMe3)(η5-C5Me5)(PPh3)]. Reaction of [lrCl2(η5-C5Me5)(PPh3)] with Mg(CH2CMe3)Cl gives [I[graphic omitted]Ph2)(CH2CMe3)(η5-C5Me5)]. The X-ray crystal structure analysis of compound (6) has been carried out: a= 17.537(7), b= 11.304(4), c= 15.410(7)A, β= 94.49(1)°, space group P21/n, Z= 4, R= 0.0361 for 4114 observed reflections. The ‘piano-stool’ metal co-ordination polyhedron is deformed by ortho-metallation which imposes a 67.0(2)° angle at iridium in the metallacycle, while the other angles, P-Ir-C(17) 89.0(2) and C(17)-Ir-C(36) 89.2(2)°, between the ‘legs’ of the ‘stool’ are near to 90°. The bulky C5Me5 ligand (effective cone angle 146°), in approaching the metal, produces large widenings of the other co-ordination polyhedron angles: Cp–Ir–P 137.0(3), Cp–Ir–C(36)(benzene)133.4(3)°, and Cp–Ir–C(17)(silyl)122.6(3)°(Cp = centroid of C5Me5). The ortho-metallated ring is nearly planar, (P–Ir–C)⁁(P–C–C) 5.3(3)°, and bent by only 6.6(2)° with respect to the metal-bound benzene ring which maintains its planarity; the only deformation this ring suffers involves the endocyclic angles at the carbon bound to phosphorus which widen to 124.5(5)° and at the ortho carbons which narrow to 115.9(6) and 116.7(5)°.
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