Expanding the Range of Pyrenylphosphines and Their Derived Ru(II)-Arene Complexes

The precursor PPyrCl(2) (Pyr = 1-pyrenyl) has been used to prepare a number of novel 1-pyrenylphosphines. Treatment of PPyrCl(2) with methylmagnesium chloride has provided the phosphine PPyrMe(2), with methanol/triethylamine, the phosphonite PPyr(OMe)(2) (1), with dimethylamine/triethylamine, the diaminophosphine PPyr(NMe2)(2) (2), and with lithium aluminum hydride, PPyrH(2) (3). From this primary phosphine, phosphirane PPyr(CH2CH2) (5) has been obtained. The phosphine PPyr(2)Ph (6) has been synthesized from 1-bromopyrene, while 1-bromo-2-(1-pyrenyl)benzene has been used to prepare Ph-PyrPhos (7) and i-Pr-PyrPhos (8). The new phosphines have subsequently been used to obtain the corresponding [RuCl2 (eta(6)-arene)(PPyrR(2))] complexes C1(Cym)-C3(Cym )and C6(Cym)-C8(Cym) (arene = p-cymene; Cym) and C1(Mba)-C3(Mba) and C6(Mba)-C8(Mba) (arene = methyl benzoate; Mba), which have been fully characterized; the crystal structures of C1(Cym), C1(Mba), C2(Cym), C2(Mba), C6(Mba), and C7(Cym) were determined by X-ray diffraction. Substitution of the methyl benzoate fragment of complexes C7(Mba) and C8(Mba) by the eta(6)-coordinated pyrenyl group of the coordinated phosphine was achieved photochemically, giving the tethered complexes C7(Tet) and C8(Tet). In these two complexes the phosphine acts as a kappa(1), eta(6)-coordinated ligand, as evidenced by the X-ray structure of C8(Tet). The antineoplastic activities of the pianostool Ru compounds revealed that they are highly phosphine dependent and two compounds, namely C1(Cym) and C2(Cym), exhibit interesting biological properties.