Remote C−F−Metal Interactions in Late-Transition-Metal Complexes

A series of phosphorus ligands containing the 5,6,7,8-tetrafluoronaphthalen-1-yl group (NpF4) has been prepared, starting from 1-bromo-5,6,7,8-tetrafluoronaphthalene. The coordination chemistry of diphenyl(5,6,7,8-tetrafluoronaphthalen-1-yl)phosphine (1) with Ir(III), Pd(II), Pt(II), Rh(I), Ir(I), and Au(I) has been investigated, focusing on a possible remote interaction of the fluorine atom at position 8 of the naphthyl group (F1) with the metal center. The Ir(III) complex [IrCp*Cl2(1)] (12) displays a weak J(P,F1) coupling constant of 8 Hz and no Ir−F1 interaction. A cationic derivative, the formally coordinatively unsaturated [IrCp*Cl(1)]SbF6 (13), is generated upon chloride abstraction. For this complex J(P,F1) is 80 Hz and the Ir−F1 distance is 2.956(2) Å. [MCl(η3-allyl)(1)] complexes (14, M = Pt; 15, M = Pd) display what is interpreted as a weaker M−F1 interaction despite corresponding J(P,F1) values of 67 and 98 Hz and M−F1 distances of 3.069(2) and 2.995(2) Å, respectively. Similar considerations apply to the analogous Rh(I) and Ir(I) complexes [IrCl(COD)(1)] (18) and [RhCl(COD)(1)] (19) (J(P,F1) = 62 and 75 Hz and M−F1 = 3.0744(14) and 3.0997(8) Å, respectively). With the chiral enantiopure ligand (11bS)-4-(5,6,7,8-tetrafluoronaphthalen-1-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine (10) analogous complexes were prepared. Ligand 10 is formally a derivative of 1 where the two phenyl groups have been replaced by a BINOL unit. In the case of [PtCl(η3-allyl)(10)] (16) and [RhCl(COD)(10)] (21) the coupling between F1 and the NMR-active nuclei 195Pt and 103Rh, respectively, was detected in 2D NMR heteronuclear correlation experiments.