It is extremely important for synthetic chemists to control the structure of new compounds. We have constructed ruthenium-based mononuclear complexes with the tridentate 2,6-di(1,8-naphthyridin-2-yl)pyridine (dnp) ligand to investigate a new synthetic approach using a specific coordination space. The synthesis of a family of new ruthenium complexes containing both the dnp and triphenylphosphine (PPh 3) ligands, [Ru(dnp)(PPh 3)(X)(L)] n + (X = PPh 3, NO 2 ？, Cl ？, Br ？; L = OH 2, CH 3CN, C 6H 5CN, SCN ？), has been described. All complexes have been spectroscopically characterized in solution, and the nitrile complexes have also been characterized in the solid state through single-crystal X-ray diffraction analysis. Dnp in the present complex system behaves like a “molecular sieve” in ligand replacement reactions. Both experimental data and density functional theory (DFT) calculations suggest that dnp plays a crucial role in the selectivity observed in this study. The results provide useful information toward elucidating this facile and selective synthetic approach to new transition metal complexes.
References
[1]
Chowdhury, A.D.; Das, A.; Irshad, K.; Mobin, S.M.; Lahiri, G.K. Isomeric complexes of [RuII(trpy)(L)Cl] (trpy = 2,2':6',2"-terpyridine and HL = quinaldic acid): Preference of isomeric structural form in catalytic chemoselective epoxidation process. Inorg. Chem. 2011, 50, 1775–1785, doi:10.1021/ic102195w.
[2]
Dakkach, M.; López, M.I.; Romero, I.; Rodríguez, M.; Atlamsani, A.; Parella, T.; Fontrodona, X.; Llobet, A. New Ru(II) complexes with anionic and neutral N-donor ligands as epoxidation catalysts: An evaluation of geometrical and electronic effects. Inorg. Chem. 2010, 49, 7072–7079, doi:10.1021/ic100862y.
[3]
Oyama, D.; Yamanaka, T.; Fukuda, A.; Takase, T. Modulation of intramolecular hydrogen bonding strength by axial ligands in ruthenium(II) complexes. Chem. Lett. 2013, 42, 1554–1555, doi:10.1246/cl.130805.
[4]
Campos-Fernández, C.S.; Thomson, L.M.; Galán-Mascarós, J.R.; Ouyang, X.; Dunbar, K.R. Homologous series of redox-active, dinuclear cations [M2(O2CCH3)2(pynp)2]2+ (M = Mo, Ru, Rh) with the bridging ligand 2-(2-pyridyl)-1,8-naphthyridine (pynp). Inorg. Chem. 2002, 41, 1523–1533.
[5]
Tseng, H.-W.; Zong, R.; Muckerman, J.T.; Thummel, R. Mononuclear ruthenium(II) complexes that catalyze water oxidation. Inorg. Chem. 2008, 47, 11763–11773, doi:10.1021/ic8014817.
Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coordination Compounds, 4th ed. ed.; John Wiley & Sons: New York, NY, USA, 1986; pp. 221–227.
[12]
Ooyama, D.; Nagao, N.; Nagao, H.; Miura, Y.; Hasegawa, A.; Ando, K.-I.; Howell, F.S.; Mukaida, M.; Tanaka, K. Redox- and thermally-induced nitro-nitrito linkage isomerizations of ruthenium(II) complexes having nitrosyl as a spectator ligand. Inorg. Chem. 1995, 34, 6024–6033, doi:10.1021/ic00128a013.
[13]
Juris, A.; Balzani, V.; Barigelletti, F.; Campagna, S.; Belser, P.; von Zelewsky, A. Ru(II) polypyridine complexes: Photophysics, photochemistry, electrochemistry, and chemiluminescence. Coord. Chem. Rev. 1988, 84, 85–277, doi:10.1016/0010-8545(88)80032-8.
[14]
Thummel, R.P.; Decloitre, Y. Polyaza cavity-shaped molecules. VIII. Ruthenium(II) complexes with 3,3'-annelated derivatives of 2-(2'-pyridyl)quinoline and 2-(2'-pyridyl)-1,8-naphthyridine. Inorg. Chim. Acta 1987, 128, 245–249, doi:10.1016/S0020-1693(00)86552-4.
[15]
Ooyama, D.; Saito, M. Synthesis, characterization and reactivity of polypyridyl ruthenium(II) carbonyl complexes with phosphine derivatives: ruthenium-carbon bond labilization based on steric and electronic effects. Inorg. Chim. Acta 2006, 359, 800–806, doi:10.1016/j.ica.2005.04.040.
[16]
Chen, J.; Szalda, D.J.; Fujita, E.; Creutz, C. Iron(II) and ruthenium(II) complexes containing P, N, and H ligands: structure, spectroscopy, electrochemistry, and reactivity. Inorg. Chem. 2010, 49, 9380–9391, doi:10.1021/ic101077t.
[17]
Ooyama, D.; Sato, M. A synthetic precursor for hetero-binuclear metal complexes, [Ru(bpy)(dppy)2(CO)2](PF6)2 (bpy = 2,2'-bipyridine, dppy = 2-(diphenylphosphino)pyridine). Appl. Organomet. Chem. 2004, 18, 380–381, doi:10.1002/aoc.637.
[18]
Ooyama, D.; Sato, M. Crystal structure of (2,2'-bipyridine-N,N′)(diphenyl-2-phosphinopyridine-P)chloro(dicarbonyl)ruthenium(II) hexafluorophosphate. Anal. Sci. 2003, 19, x39–x40, doi:10.2116/analsci.19.39.
[19]
Becke, A.D. Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 1993, 98, 5648–5652, doi:10.1063/1.464913.
[20]
Lee, C.; Yang, W.; Parr, R.G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 1988, 37, 785–789, doi:10.1103/PhysRevB.37.785.
[21]
Sosa, C.; Andzelm, J.; Elkin, B.C.; Wimmer, E.; Dobbs, K.D.; Dixon, D.A. A local density functional study of the structure and vibrational frequencies of molecular transition-metal compounds. J. Phys. Chem. 1992, 96, 6630–6636, doi:10.1021/j100195a022.
[22]
Godbout, N.; Salahub, D.R.; Andzelm, J.; Wimmer, E. Optimization of Gaussian-type basis sets for local spin density functional calculations. Part I. Boron through neon, optimization technique and validation. Can. J. Chem. 1992, 70, 560–571, doi:10.1139/v92-079.
[23]
Hehre, W.J.; Ditchfield, R.; Pople, J.A. Self-consistent molecular orbital methods. XII. Further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules. J. Chem. Phys. 1972, 56, 2257–2261, doi:10.1063/1.1677527.
[24]
Francl, M.M.; Pietro, W.J.; Hehre, W.J.; Binkley, J.S.; Gordon, M.S.; DeFrees, D.J.; Pople, J.A. Self-consistent molecular orbital methods. XXIII. A polarization-type basis set for second-row elements. J. Chem. Phys. 1982, 77, 3654–3665, doi:10.1063/1.444267.
Methyl protons of both complexes could not be assigned due to their overlapping with solvent signals.
[27]
Rigaku. CrystalStructure. Version 3.8, Rigaku and Rigaku Americas, Woodlands, TX, USA, 2007.
[28]
Sheldrick, G.M. SHELX. SHELXL-97, University of G？ttingen, G？ttingen, Germany, 1997.
[29]
Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.; Burla, M.; Polidori, G.; Camalli, M. SIR92—A program for automatic solution of crystal structures by direct methods. J. Appl. Crystallogr. 1994, 27, 435.
[30]
Altomare, A.; Burla, M.; Camalli, M.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.; Molitern, A.; Polidori, G.; Spagna, R. SIR97: A new tool for crystal structure determination and refinement. J. Appl. Crystallogr. 1999, 32, 115–119.
[31]
Higashi, T. ABSCOR; Rigaku Corporation: Tokyo, Japan, 1995.
