Dendritic (phosphine)gold(i) thiolate complexes: assessment of the molecular size through PGSENMR studies

Abstract

The reactions of the tetraphosphine ligand DAB-G0-(PPh₂)₄ (DAB = 1,4-diaminobutane; G0 = Generation 0) or the octaphosphine ligand DAB-G1-(PPh₂)₈ (G1 = Generation 1) with the gold precursor [AuCl(tht)] (tht =tetrahydrothiophene) and the corresponding 4-substituted benzenethiolate lead to the (phosphine)gold(I) thiolate complexes [Au₄(S–C₆H₄–X)₄{(DAB-G0-(PPh₂)₄}] (X = F (11), MeO (12), Me (13) and NO₂ (14)) and [Au₈(S–C₆H₄–X)₈{(DAB-G1-(PPh₂)₄}] (X = F (15), MeO (16), Me (17) and NO₂ (18)). Complexes [Au₄Cl₄{(DAB-G0-(PPh₂)₄}] 5 and [Au₄(S–C₆H₄–OMe)₄{(DAB-G0-(PPh₂)₄}] 12 have been characterized by X-ray diffraction studies showing tetranuclear gold complexes in which the P–Au–X (X = Cl or S) structural units do not display aurophilic interactions. PGSE NMR studies of free ligands EN-G0-(PPh₂)₄ (EN = 1,2-ethylenediamine), DAB-G0-(PPh₂)₄, DAB-G1-(PPh₂)₈ and the (phosphine)gold(I) thiolate complexes permit the evaluation and comparison of the different molecular sizes depending on the ligand and the dendrimer generation.