Kunihiko Mizumachi

Trans-influence of a coordinating nitrosyl group: preparation and structure of cis-trihalogeno(8-quinolinolato or its derivative)nitrosylruthenate(1−)

Abstract Hydrous nitrosylruthenium(III) halide reacts with 8-quinolinol or its derivative (2-methyl- or 5-chloro-8-quinolinol) in ethyl alcohol or acetonitrile to give [RuX3(N-O)(NO)]− [X = Cl or Br; H(N-O) = 8-quinolinol or its derivative]. All the halide ions are coordinated cis to the nitrosyl and the 8-quinolinolato oxygen trans to the nitrosyl, as found from an X-ray crystallographic study. The structure of the complex anion reflects a strong π-acceptor ability of the nitrosyl. The compounds obtained were also examined by 13C NMR and negative-SIMS (secondary-ion mass spectrometry).

CRYSTAL STRUCTURES AND REVERSIBLE THERMAL ISOMERIZATION OF THREE GEOMETRICAL ISOMERS OF CHLOROBIS(2-ETHYL-8-QUINOLINOLATO) NITROSYLRUTHENIUM(II)

Abstract Crystal structures of the three geometrical isomers (1, 2 and 3) of [RuCl(2eqn)2NO] (H2eqn = 2-ethyl-8-quinolinol) have been determined by X-ray diffraction. The Cl atom is cis to the NO group in 1 and 2, and is trans to the NO group in 3. The N and O atoms of the two quinolinolato ligands for 1, 2 and 3 are in trans(N,N) and cis(O,O), in cis(N,N) and cis(O,O) and in trans(N,N) and trans(O,O) configurations, respectively. Crystallographic data for 1: triclinic, a = 10.140(4), b = 13.498(5), c = 7.902(3) A ; α = 94.08(3), β = 104.19(2), γ = 73.35(3)°, V = 1006.8(6) A 3 , Z = 2 , space group P 1 ; for 2; monoclinic, a = 14.730(2), b = 10.028(2), c = 13.761(4) A , β = 92.65(2)°, V = 2030.5(7) A 3 , Z = 4 , space group P21/a for 3: monoclinic, a = 14.830(4), b = 8.700(2), c = 16.711 (4) A , β = 110.40(3)°, V = 2021,0(9) A 3 , Z = 4 , space group Cc. The structures were solved by the heavy-atom method and were refined by fullmatrix (1 and 2) and block-diagonal (3) least-squares procedures to R = 0.0378 (1), 0.0320 (2) and 0.0397 (3) for 5207 (1), 4032 (2) and 1675 (3) reflections with I≥3 σ(I). The variable-temperature 1H NMR spectra in dimethyl sulfoxide-d6 revealed the steric hindrance due to the ethyl group of the quinolinolato ligands, reflecting the results of the crystal structure analysis. At high temperature (373–413 K), the reversible thermal isomerizaion reaction among the three isomers was observed un degassed dimethyl sulfoxide (DMSO). The mole ratio of 1, 2 and 3 was 19:4:1 at 413 K and did not depend on the starting species. Kinetic analysis revealed that the reaction was reversible between any two isomers and the isomerization between 1 and 3 proceeded by a mechanism distinct from the others.

Preparation and characterization of cis- and trans-[Ru(OAc)(2mqn)2NO] (OAc=acetate, 2mqn=2-methyl-8-quinolinolate), and their mutual photoisomerization reactions

Abstract A mixture of hydrated nitrosylruthenium(III) chloride and 2-methyl-8-quinolinol (H2mqu) (1:4 molar ratio) in acetic acid aqueous solution adjusted to pH 5.5 and warmed at c. 70 °C for 2 h led to preparation of cis- [Ru(OAc)(2mqn)2NO] which has cis(0,0) and trans(N,N) configuration for the ligating atoms of the 2mqn ligands. The trans isomer was photochemically prepared from the cis isomer in CH2Cl2 using an Xe lamp as the light source. The photoisomerization in deaerated CH2Br2 was examined at −5 to 30 °C using a super high-pressure Hg lamp (436 mm). Quantum yields of the cis to trans and the trans to cis isomerizations were 1–2.5×10−3 and 8–11×10−3, respectively. Solvent effect studies by adding liquid paraffin to the CH2Br2 solution on the photoreaction and the NO scramble on the irradiation in the presence of 15NO gas showed that RuNO bond rupture takes part in the isomerization.

The structure of carbonatobis(2,2'-bipyridine)ruthenium(II) tetrahydrate

[Ru(C10H8N2)2CO3]. 4H20 is monoclinic, space group C2/c, with a = 15.775 (3), b = 19.738 (4), and c = 7.1467 (15) A, fl = 96.42 (2) ° , U = 2211.3 (8) A 3, Z -4. The final R value is 0.040 for 1552 independent reflections. The crystal structure consists of a monomeric complex with a bidentate carbonato ligand and four water molecules. The complex molecule has twofold symmetry.