Cationic half-sandwich complexes (Rh, Ir, Ru) containing 2-substituted-1,8-naphthyridine chelating ligands: Syntheses, X-ray structure analyses and spectroscopic studies

Reactions of the dinuclear complexes [(η⁶-arene)Ru(^μ-Cl)Cl]₂ (arene = C₆H₆, <i>p-ⁱ</i>PrC₆H₄Me) and [(η⁵-C₅Me₅)M(μ-Cl)Cl]₂ (M = Rh, Ir) with 2-substituted-1,8-naphthyridine ligands, 2-(2-pyridyl)-1,8-naphthyridine (pyNp), 2-(2-thiazolyl)-1,8-naphthyridine (tzNp) and 2-(2-furyl)-1,8-naphthyridine (fuNp), lead to the formation of the mononuclear cationic complexes [(η⁶-C₆H₆)Ru(L)Cl]+ {L = pyNp (<b>1</b>); tzNp (<b>2</b>); fuNp (<b>3</b>)}, [(η⁶-<i>p-ⁱ</i>PrC₆H₄Me)Ru(L)Cl]⁺ {L = pyNp (<b>4</b>); tzNp (<b>5</b>); fuNp (<b>6</b>)}, [(^η5-C₅Me₅)Rh(L)Cl]+ {L = pyNp (<b>7</b>); tzNp (<b>8</b>); fuNp (<b>9</b>)} and [(η⁵-C₅Me₅)Ir(L)Cl]⁺ {L = pyNp (<b>10</b>); tzNp (<b>11</b>); fuNp (<b>12</b>)}. All these complexes are isolated as chloro or hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV/Vis spectroscopy. The molecular structures of [<b>1</b>]Cl, [<b>2</b>]PF₆, [<b>4</b>]PF₆, [<b>5</b>]PF₆ and [<b>10</b>]PF₆ have been established by single crystal X-ray structure analysis.