Novel Trisphosphine Ligand Containing 1,3,5-Triazine Core, [2,4,6‑C3N3{C6H4PPh2‑p}3]: Synthesis and Transition Metal Chemistry

• Published in: Inorganic chemistry 2014-02, Vol.53 (3), p.1370-1381
• Main Authors: Naik, Susmita, Kumaravel, Maruthai, Mague, Joel T, Balakrishna, Maravanji S
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic402150k

The trisphosphine ligand with triazine core, 2,4,6-tris{4-(diphenylphosphino)phenyl}-1,3,5-triazine (2), was synthesized in moderate yield by reacting 2,4,6-tris(4-bromophenyl)-1,3,5-triazine with 3 equiv of KPPh2. The tris(phosphine) 2 undergoes facile oxidation to give trischalcogenides 2,4,6-C3N3{C6H4P(E)Ph2-p}3 (E = O, 3; S, 4; Se, 5) on treatment with aqueous H2O2, elemental sulfur, or selenium. The reaction between 2 and [AuCl(SMe2)] yielded a trinuclear complex, [(AuCl)3{2,4,6-C3N3(C6H4PPh2-p)3}] (6), which on further treatment with pyridyl ligands such as 2,2′-bipyridine (2,2′-bpy) and 1,10-phenanthroline (1,10-phen) produced the mixed-ligand complexes [{Au(2,2′-bpy)}3{2,4,6-C3N3(C6H4PPh2-p)3}](OTf)3 (7) and [{Au(1,10-phen)}3{2,4,6-C3N3(C6H4PPh2-p)3}](OTf)3 (8), where OTf indicates trifluoromethansulfonate. Several trimetallic complexes such as [{Ru(η6-cymene)Cl2}3{2,4,6-C3N3(C6H4PPh2-p)3}] (9), [{Pd(η3-C3H5)Cl}3{2,4,6-C3N3(C6H4PPh2-p)3}] (10), [{Rh(COD)Cl}3{2,4,6-C3N3(C6H4PPh2-p)3}] (11) and [{Ir(COD)Cl}3{2,4,6-C3N3(C6H4PPh2-p)3}] (12) have also been synthesized and characterized. The reactions of 2 with [M(COD)Cl2] and CuI afforded metallo-cyclophane type complexes, [(MCl2)3L2] (M = Pd; 13, Pt; 14) (L = 2,4,6-tris{4-(diphenylphosphino)phenyl}-1,3,5-triazine) and [(CuI)3L2] (15), in good yield.