Dendrimer−Phosphine Complexes with Platinum(0) at the Core

Preparation of novel mono- and bidentate phosphine ligands having dendrimer moiety is reported. Monodentate ( 1a − c ) and bidentate ligands ( 5a,b ) were synthesized from bis(4-hydroxyphenyl)phenylphosphine oxide ( 3 ) and 1,2-bis(dichlorophosphino)ethane, respectively, in high yields. The defect-free monodisperse nature of these compounds was confirmed by 31 P NMR and elemental analysis as well as by ESI mass spectra. Complexation of these ligands with PtCl 2 (COD) followed by NaBH 4 reduction in a THF/H 2 O mixture gave Pt(0) complexes 10a,b (having 1a,b as the ligands) and 13a,b ( 5a,b as the ligands). Monodentate ligands gave PtL 3 complexes ( 10a,b ) and bidentate ligands gave Pt(L−L) 2 complexes ( 13a,b ), respectively. Preliminary studies on oxidative addition of RI (R = CH 3 or C 6 H 5 ) to 10a,b showed that the metal center is easily accessible. Further, molecular modeling of 13b showed nanoscale flattened globular structure of the complex with an approximate diameter of 4.4 nm.