Formation, Dynamic Behavior, and Chemical Transformation of Pt Complexes with a Rotaxane‐like Structure

The reaction of [Pt(CH 2 COMe)(Ph)(cod)] (cod=1,5‐cyclooctadiene) with (ArCH 2 NH 2 CH 2 ‐C 6 H 4 COOH) + (PF 6 ) − (Ar=4‐ t BuC 6 H 4 or 9‐anthryl) in the presence of cyclic oligoethers such as dibenzo[24]crown‐8 (DB24C8) and dicyclohexano[24]crown‐8 (DC24C8) produces {(ce)[ArCH 2 NH 2 CH 2 C 6 H 4 COOPt(Ph)(cod)]} + (PF 6 ) − (ce=DB24C8 or DC24C8, Ar=4‐ t BuC 6 H 4 or 9‐anthryl) with interlocked structures. FABMS and NMR spectra of a solution of these compounds indicate that the Pt complexes with a secondary ammonium group and DB24C8 (or DC24C8) make up the axis and cyclic components, respectively. Temperature‐dependent 1 H NMR spectra of a solution of {(DB24C8)[4‐ t BuC 6 H 4 CH 2 NH 2 CH 2 ‐C 6 H 4 COOPt(Ph)(cod)]} + (PF 6 ) − ({(DB24C8)[ 4 ‐H]} + (PF 6 ) − ) show equilibration with free DB24C8 and the axis component. The addition of DB24C8 to a solution of {(DC24C8)[ 4 ‐H]} + (PF 6 ) − causes partial exchange of the macrocyclic component of the interlocked molecules, giving a mixture of {(DC24C8)[ 4 ‐H]} + (PF 6 ) − , {(DB24C8)[ 4 ‐H]} + (PF 6 ) − , and free macrocyclic compounds. The reaction of 3,5‐Me 2 C 6 H 3 COCl with {(DB24C8)[ 4 ‐H]} + (PF 6 ) − affords the organic rotaxane {(DB24C8)(4‐ t BuC 6 H 4 CH 2 NH 2 CH 2 ‐C 6 H 4 COOCOC 6 H 3 Me 2 ‐3,5)} + (PF 6 ) − through CO bond formation between the aroyl group and the carboxylate ligand of the axis component. The addition of 2,2′‐bipyridine (bpy) to a solution of {(DB24C8)[ 4 ‐H]} + (PF 6 ) − induces the degradation of the interlocked structure to form a complex with trigonal bipyramidal coordination, [Pt(Ph)(bpy)(cod)] + (PF 6 ) − , whereas the reaction of bpy with [Pt(OCOC 6 H 4 Me‐4)(Ph)(cod)] produces the square‐planar complex [Pt(OCOC 6 H 4 Me‐4)(Ph)(bpy)].