Search

The alkyne RCCR, R 4;= 4;CO2Me, reacts with 5-membered metallacycles [PtMe2{SnMe2ESnMe2E}(bu2bpy)], E 4;= 4;S, Se or Te, bu2bipy 4;= 4;4,4′-di-tert-butyl-2,2′-bipyridine, yielding the corresponding 7-membered metallacycles [PtMe2{SnMe2ESnMe2CR&z.dbd6;CRE}(bu2bpy)] which slowly eliminate “Me2SnE” to give new 5-membered metallacycles [PtMe2{SnMe2CR&z.dbd6;CRE}(bu2bpy)]; further reaction of which with excess RCCR gives [PtMe2(CR&z.dbd6;CRH)(CCR)(bu2bpy)], a complex which contains alkyl, alkenyl and alkynyl functionalities in the same molecule.

Orange platelets of [Pt(tmtaa)], where H2tmtaa 4;= 4;6,8,15,17-tetramethyl-5,6,9,14,15,18-hexahydrodibenzo[b,i ][l,4,8,11]tetraazacyclotetradecine, show the expected ‘pseudo-planar’ centrosymmetric macrocyclic conformation but red needles of another [Pt(tmtaa)] modification and purple trans-[PtCl2(tmtaa)] both show saddle-form co-ordination with the metal ion only 0.046(1) Å (Pt2+) or 0.024(5) Å (Pt4+) above the N4 plane; X-ray powder diffraction reveals similar dimorphism for [Pd(tmtaa)] but not for [Ni(tmtaa)].