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Described are the synthesis and characterization of Ru(II) complexes of the type Ru[Cl.sub.2][L.sub.2](N-O), where [L.sub.2] is either 1,4-bis (diphenylphosphino)butane (dppb) or [(P[Ph.sub.3]).sub.2], and N-O represents chelated 2-benzoylpyridine (2-bzpy) or 2-acetylpyridine (2-acpy); the Ru presursors used were [Ru[Cl.sub.2][(dppb)].sub.2] ([mu]-dppb) or Ru[Cl.sub.2][(P[Ph.sub.3]).sub.3]. The crystal structure of cis-Ru[C1.sub.2](dppb)(2-bzpy) is presented, and three other Ru[Cl.sub.2][L.sub.2](N-O) complexes with cis-chlorines are isolated and characterized spectroscopically; of the trans-dichloro species, Ru[Cl.sub.2][(P[Ph.sub.3]).sub.2](N-O) complexes are isolated, while the corresponding dppb species are characterized in situ. In all cases, thermodynamically stable cis-complexes are formed from initially formed trans-species. Key words: ruthenium, phosphines, 2-benzoylpyridine, 2-acetylpyridine, X-ray structures.

The ruthenium(II) complex, [Ru[Cl.sub.2](NO)L] (I), (L = [[(2-py).sub.2]P[C.sub.2][H.sub.4]P[O.sub.2](2-py)]-) was obtained from recrystallization of Ru[Cl.sub.3]NO(d2pype) (d2pype = [(2-py).sub.2]P[C.sub.2][H.sub.4]P[(2-py).sub.2]) in the presence of HN[O.sub.3], crystallizing in the monoclinic space group [P2.sub.1] (no. 4), with a = 8.012(4) [Angstrom], b = 14.454(4) [Angstrom], c = 9.353(3) [Angstrom], [beta] = 105.77(3)[degrees], and Z = 2. Crystals of the DMSO solvate of the complex (II) were obtained from [(C[D.sub.3]).sub.2]SO solution, crystallizing in the monoclinic space group [P2.sub.1]/c (no.14) with a = 9.7080(2) [Angstrom], b = 22.2920(5) [Angstrom], c = 11.5230(3) [Angstrom], [beta] = 92.0450(10)[degrees], and Z = 4. In both complexes, the geometry about the ruthenium atom is a distorted octahedron mainly as a result of the tridentate [P,N,O]-bonding mode of L. The v (NO) bands at 1875 [cm.sup-1] in both complexes are consistent with the linear disposition of the NO group and the Ru atom as is observed in the X-ray crystal structure (Ru-N1-O1 angle = 178.5(4)[degrees]). Key words: pyridylphosphine, nitrosyl, ruthenium complex, X-ray structure.

An experiment has been developed for students of inorganic chemistry. In it they undertake synthesis of (RuCl(sub.2)(dppb)(PPH(sub.3))) and identification of the cis- and trans-(RuCl(sub.2)(dppb)(phen)) geometrical isomers using (super.31)P((super.1)H) NMR spectroscopy. All materials are commercially available and used as received. Students learn about setting up semirigorous inert atmosphere conditions and about spin-spin coupling for P atoms by assigning signals to equivalent and nonequivalent atoms.

A cyclic voltammetry (CV) experiment has been developed for students of inorganic chemistry. In this electrochemical experiment they monitor the isomerization of trans- to cis-(RuCl(sub.2)(dppb)(phen)). Students would have completed a lecture series on basic coordination chemistry and associated electrochemical techniques. They would have an understanding of linear sweep voltammetry at solid electrodes. CV theory need not have been extensively covered.