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

Abstract

The reaction of [Pt(CH2COMe)(Ph)(cod)] (cod = 1,5-cyclooctadiene) with (ArCH2NH2CH2-C6H4COOH)+ (PF6)- (Ar = 4-tBuC6H4 or 9-anthryl) in the presence of cyclic oligoethers such as dibenzo[24]crown-8 (DB24C8) and dicyclohexano[24]crown-8 (DC24C8) produces {(ce)[ArCH2NH2CH2C6H4COOPt(Ph)(cod)]}+ (PF6)- (ce = DB24C8 or DC24C8, Ar = 4-tBuC6H4 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 1H NMR spectra of a solution of {(DB24C8)[4-tBuC6H4CH2NH2CH2-C6H4COOPt(Ph)(cod)]}+ (PF6)- ({(DB24C8)[4-H]}+ (PF6)-) show equilibration with free DB24C8 and the axis component. The addition of DB24C8 to a solution of {(DC24C8)[4-H]}+ (PF6)- causes partial exchange of the macrocyclic component of the interlocked molecules, giving a mixture of {(DC24C8)[4-H]}+ (PF6)-, {(DB24C8)[4-H]}+ (PF6)-, and free macrocyclic compounds. The reaction of 3,5-Me2C6H3COCl with {(DB24C8)[4-H]}+ (PF6)- affords the organic rotaxane {(DB24C8)(4-tBuC6H4CH2NH2CH2-C6H4COOCOC6H3Me2-3,5)}+ (PF6)- through C-O 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]}+ (PF6)- induces the degradation of the interlocked structure to form a complex with trigonal bipyramidal coordination, [Pt(Ph)(bpy)(cod)]+ (PF6)-, whereas the reaction of bpy with [Pt(OCOC6H4Me-4)(Ph)(cod)] produces the square-planar complex [Pt(OCOC6H4Me-4)(Ph)(bpy)].

PdII and PtII Complexes with Amphiphilic Ligands: Formation of Micelles and [5]Rotaxanes with α‐Cyclodextrin in Aqueous Solution

“…at room temperature, although it is required for rotaxane formation via a "magic rod" procedure. [8,[17][18][19] Micelle formation of the Pd and Pt complexes with amphiphilic ligands and their rotaxanes is examined by using 4 (from 5 10 À6 to 1.5 10 À3 g mL À1 ). The solutions with [2]A C H T U N G T R E N N U N G [NO 3 ] 4 below 6.3 10 À4 g mL À1 do not show any significant peak at 564 nm, but increasing the concentration above 1.3 10 À3 g mL À1 causes the appearance of a new absorption peak at the position assigned to the dye encapsulated within micelles.…”

Recent Advances in the Synthesis of Ammonium-Based Rotaxanes

“…Among others, blocking reactions involving 1,3-dicyclohexylcarbodiimide (DCC) [51], trityl [52], diethylphosphoramidate [53], diphenylmethane [54], platinum complex [55], cycloheptadiene [56], substituted maleimide [57], boroxine [58] and pyridinium [59] have been used successfully to end-cap rotaxanes with various success.…”

Five Coordinate Platinum(II) in [Pt(bpy)(cod)(Me)][SbF6]: A Structural and Spectroscopic Study

“…Earlier reports postulated quite similar species [M(N^N)(cod)Cl] + (M = Pt or Pd) as intermediates during reactions of [M(diene)Cl2] complexes with N^N ligands in the presence of nucleophiles (Nu), finally forming complexes [M(en-yl)(N^N)] + in which a nucleophile has been added to one of the diene double bonds, creating a M-C-Nu sigma bond [74][75][76][77][78][79]. Reaction of the four coordinate cod complex [Pt(cod)(Ph)(L)] carrying the hemilabile amino-carboxylate ligand ce-ArCH2NH2CH2C6H4COO − (ce = crown ether) with 2,2'-bipyridine (bpy) produces the structurally-characterized five coordinate complex [Pt(bpy)(cod)(Ph)] + [80]. Further reported five coordinate Pt(II) complexes with diene or polyene ligands were the complexes (PPN)2[Pt(SnCl3)3L] (PPN = bistriphenylphosphiniminium; L = 1,5-cyclooctadiene (cod) or 2,5-norbornadiene (nbd)) [81], the complex [(DMBN)(C2H4)PtCl2] (DMBN = 3,7dimethylenebicyclo[3.3.l]nonane), which contains a diene and ethene at the same time [82], the tris-ene complex [(P)PtCl] + (P = tri(1-cyclohepta-2,4,6-trienyl)phosphine) [83] and the cod-bridged binuclear complex [(µ-cod){Pt(Me)(R2Bpz2)}2] (R2Bpz2 = diorganobis(l-pyrazolyl) borate) [84], a binding mode that has also been assumed for the above-mentioned reactions of [Pt(N^N)Cl2] with dienes [74].…”