Synthesis, Crystal Structures and Redox Properties of Mixed‐Sandwich Complexes of Ruthenium(II) with Cyclopentadienyl and Tris(pyrazolyl)methane Ligands

Abstract

New mixed‐sandwich ruthenium(II) complexes have been prepared by treatment of either [RuCp(acn)3][PF6] or [RuCp*(acn)3][PF6] (Cp = η5‐cyclopentadienyl; Cp* = η5‐pentamethylcyclopentadienyl, acn = CH3CN) with tris(pyrazolyl)methane (HTpm) and tris(3,5‐dimethylpyrazolyl)methane (MeTpm), respectively. [RuCp(HTpm)][PF6] (1), [RuCp*(HTpm)][PF6] (2) and [RuCp(MeTpm)][PF6] (3) have been examined by single‐crystal X‐ray diffraction (1, 2) and 2D NMR experiments, which reveal discrete units of cationic mixed‐sandwich complexes of the composition [RuCp(*)(RTpm)]+ featuring η5‐cyclopentadienyl and κ3N‐coordinated RTpm ligands. The air‐sensitive salt [RuCp*(acn)(MeTpm)][PF6] (4) exhibits a κ2N‐coordinated MeTpm and one remaining acetonitrile ligand, presumably due to steric interactions between the sterically more bulky Cp* and MeTpm ligands. Cyclic voltammetric studies of the symmetric mixed‐sandwich complexes 1–3 in acetonitrile show quasi‐reversible oxidation processes centred at E01/2 = +0.38 (1), +0.15 V (2) and +0.35 V (3) vs. Fc/Fc+. These values are mainly affected by the different nature of the Cp ligands; the differently substituted RTpm entities have very little influence.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Phosphine-functionalised tris(pyrazolyl)methane ligands and their mono- and heterobimetallic complexes

“…The coordination sphere of the ruthenium atom is complemented by one η 5 -C 5 H 5 ligand. The average Ru1-N bond length in 4 was found to amount to 209.1 pm, which is only slightly shorter than in comparable κ 3 N-Tpm (211.1 pm) 17 and κ 3 N-Tpmd (210.6 pm) 4n complexes published by our group. The Ru1-P1 bond length of 229.3 pm is in good agreement with those observed for other complexes from the literature.…”

“…(2b) C1-P1 192.2(13), C1-N10 145.3 (16), C1-N20 146.1 (14), C1-N30 145.1(16) P1-C10 184.8 (16), P1-C20 184.2 (16), P1-C1-N10 108.5 (8), P1-C1-N20 114.6(9), P1-C1-N30 111.3(9). (2c) C1-P1 192.7 (14), C1-N10 145.5 (18), C1-N20 145.7 (17), C1-N30 146.5(16) P1-C10 186.4(15), P1-C20 187.2 (16), P1-C1-N10 109.4(9), P1-C1-N20 109.1(9), P1-C1-N30 115.2(9).…”

“…We also became Scheme 2 Synthesis of 3a-c. 7, Rh1-Cl1 237.7 7, Rh1-N11 206.34 17, Rh1-C2 182.0(2), P1-C1 195.56 (19), P1-Rh1-Cl1 174.195 (19), N11-Rh1-P1 83.78(5), N11-Rh1-Cl1 90.44(6), C2-Rh1-P1 97.02 7, C2-Rh1-Cl1 88.76 7, C2-Rh1-N11 178.90 (8). (3b) Rh1-P1 219.14 13, Rh1-Cl1 235.50 14, Rh1-N11 208.6(3), Rh1-C2 180.1(5), P1-C1 192.4 4, P1-Rh1-Cl1 168.96(5), N11-Rh1-P1 81.67(10), N11-Rh1-Cl1 89.81(10), C2-Rh1-P1 97.12 17, C2-Rh1-Cl1 91.59 16, C2-Rh1-N11 178.03 (17). (3c) Rh1-P1 221.84(11), Rh1-Cl1 235.88 13, Rh1-N11 207.6(3), Rh1-C2 180.4(5), P1-C1 195.0(4), P1-Rh1-Cl1 169.85 4, N11-Rh1-P1 81.48(12), N11-Rh1-Cl1 88.39(12), C2-Rh1-P1 96.81 (19), C2-Rh1-Cl1 93.30 (19), C2-Rh1-N11 177.8 (3).…”

“…In an effort to prepare heterobimetallic complexes of the new hybrid ligands, various attempts have been made by treating 4-6 with various other metal sources, all of which were 18, Ru1-N21 209.00 (17), Ru1-Cp cent 181.9 P1-C1 193.9(2), P1-Ru1-Cp cent 135.27, N11-Ru1-Cp cent 145.60, N21-Ru1-Cp cent 130.00, N11-Ru1-P1 78.93(5), N21-Ru1-P1 82.74 7; 5: Au1-P1 = 223.38(15), Au1-Cl1 = 227.66(15), C1-P1 = 194.2(6), P1-Au1-Cl1 176.46(5), C1-P1-Au1 = 111.54 (18), Au1-P1-C200 = 114.93 (19); 6: Pd1-P1 232.0(2), Pd1-Cl1 235. 4(2), P1-C1 196.0(9), P1-Pd1-Cl1 93.97 (8), Pd1-P1-C1 116.5 (3).…”

“…C 22 H 19 N 6 P, M r = 398.40, orthorhombic, Pna2 1 (no. 33), a = 17.416(4) Å, b = 8.4390(17) Å, c = 40.806(8) Å, V = 5997(2) Å 3 , T = 200 K, Z = 12, μ(MoK α ) = 0.159, 80 621 reflections measured, 11 783 unique (R int = 0.0935) which were used in all calculations. The final wR 2 was 0.1631 (all data) and R 1 was 0.0580 (I > 2(I)).Crystal data 2b.…”