Molecular and crystal structure of a mixed-phosphine ligand Tc(II) complex, Tc(PMe₂Ph)₂(DMPE)Cl₂

Abstract

The reaction of Tc(PMe,Ph),Cl, with an excess of bis(dimethy1phosphino)ethane (DMPE) in ethanol solution produced a yellow compound, which was identified by X-ray diffraction methods as a mixed-ligand Tc(I1) complex, TC(?M~,P~)~(DMPE)C~,.The compound crystallizes in the P2,lc space group with a = 12.899(6), b = 13.142(8), c = 19.088(9) A, P = 121.13(3)", V = 2770(2) A~, Z = 4, R = 0.061, and R,,, = 0.05 1. The geometry around the Tc atom is octahedral with the chloro ligands trnr~s to each other, while the two PMe,Ph ligands are in cis positions. The Tc-C1 bond distances are 2.43 l(5) and 2.43 l(5) A while the Tc-P bond lengths are 2.434(4) and 2.435(4) A for PMe,Ph and 2.400(4) and 2.398(4) A for the bidentate DMPE ligand. An increase of multiple bonding of the Tc-P bond, as the oxidation state of Tc decreases, is suggested. [Traduit par la rCdaction]

Syntheses of New Ionic Technetium(III) Complexes Containing Four Monodentate Phosphine Ligands. Crystal Structures of trans-[Tc(PMe2Ph)4Cl2]PF6, trans-[Tc(PMe3)4Cl2]BPh4, and trans-[Tc(PMe3)4Cl2]PF6

“…The trans angles P−Tc−P are 168.17(3) and 170.84(3)°, while the Cl−Tc−Cl angle is 176.97(3)°. The Tc−Cl bond distances are 2.325(1) and 2.330(1) Å, close to the average value of 2.335 Å reported for 11 published similar Tc(III) structures . The Tc−P bonds vary between 2.490(1) and 2.536(1) Å.…”

“…These values are slightly long for Tc(III) compounds. In a short review, the average value found for Tc(III)−P bond distances for monodentate phosphines located in trans positions to other phosphines is 2.478 Å (based on nine structures) . The slightly longer value observed in crystal I (average 2.512(1) Å) probably results from the strain caused by the presence of four relatively bulky phosphine ligands.…”

Synthesis and Crystal Structures of (Phosphine)technetium(V) Complexes with Phenylimido and Phenyldiazenido Ligands Using the Precursor PhNHNHCO3

“…38( 2) C( 14) -874 (12) 2432( 9) 4511( 10) 54(2) C( 46) 6104( 11) 930( 8) 769( 10) 41(2) C (15) -1507 (12) 1867( 8) 4129( 10) 46(2) C( 51) 5554( 10) 363( 7) 2673( 8) 25(2) C( 16) -1054 (12) 1437( 8) 3530( 10) 41(2) C( 52) 5487( 11)…”

“…-882( 9) 2629( 11) 55(2) C( 22) -628 (12) -286( 8) 2051( 13) 58(2) C954) 6682 (13) -807( 9) 3565( 11) 59(2) C( 23) -879 (14) -979 (12) 2317( 16) 92(2) C( 55) 6747 (12) -176( 8) 3993( 10) 49(2) C(24) -584 (15) -1196( 9) 3149( 16) 89(2) C( 56) 6207( 11) 388( 8) 3556( 10) 42(2) C( 25) 63 (15) -789( 9) 3821( 14) 75( 2)…”

Synthesis and Crystal Structure of a New Type of Ionic Technetium(V) Dioxo Phosphine Complexes, [Tc(O)2(PR3)3]+. Reactions with Pyridine and Crystal Structures of trans,cis,cis-[Tc(O)2(PR3)2(py)2]+ Compounds

“…These values are not very precise for crystal I (even if the estimated standard deviations are acceptable), because of the important disorder of the ethyl groups on P(3), but similar angles were observed in other technetium-phosphine complexes. [22][23][24][25][26][27] The C-C-C angles of the PPr 3 compound are slightly flattened averaging 113.9(7)°.…”