Syntheses of new ionic technetium(III) complexes containing four monodentate phosphine ligands. Crystal structures of trans-[Tc(PMe2Ph)(4)Cl-2]PF6, trans- [Tc(PMe3)(4)Cl-2]BPh4, and trans-[Tc(PMe3)(4)Cl-2]PF6

New ionic technetium complexes of the type trans-[Tc(PR3)(4)Cl-2](+) are sy nthesized by various methods. The simplest method is the reaction of [TcO4] (-) with the phosphine in methanol in the presence of a chloride salt. Comp ounds containing PMe2Ph and PMe3 an synthesized and characterized by crysta llographic methods. The complexes containing the less bulky phosphine can b e prepared from complexes containing the bulkier phosphine. The compounds a re paramagnetic, with two unpaired electrons. The complexes studied by X-ra y diffraction methods are the trans isomers. [Tc(PMe2Ph)(4)Cl-2]PF6 crystal lizes in the monoclinic space group P2(1)/c, with a = 11.511(2) Angstrom, b = 26.713(7) Angstrom, c = 12.688(3) Angstrom, beta = 92.79(1)degrees, Z = 4, and R1 = 0.0574. [Tc(PMe3)(4)Cl-2]BPh4 (II) crystallizes in the orthorho mbic space group Pben, with a = 18.213(5) Angstrom, b = 22.950(5) Angstrom; c = 19.428(6) Angstrom, Z = 8, and R1 = 0.0691. [Tc(PMe3)(4)Cl-2]PF6 cryst allizes in the monoclinic space group P2(1)/c, with a = 18.152(7) Angstrom, b = 16.838(9) Angstrom, c = 18.090(6) Angstrom, beta = 106.63(1)degrees Z = 8, and R1 = 0.0670. The compounds all have octahedral coordination, but a n important tetrahedral deformation of the plane containing the Tc and the four P atoms is observed in each case. In II, the two independent Tc atoms are both located on 2-fold axes.