The synthesis, reactivity and modelling studies of [RuCl(CO)(η2-C,O-C6H4-2-CHO)(PPh3)2]: Crystal and molecular structures of [RuCl(CO)(η2-C,O-C6H4-2-CHO)(PPh3)2] · 3.5CHCl3 and [Ru(NCtBu)(CO)(η2-C,O-C6H4-2-CHO)(PPh3)2][BF4] · 2CHCl3

Treatment of [RuHCl(CO)(PPh3)3] with Hg(C6H4-2-CHO)2 in refluxing toluene gives [RuCl(CO)(η2-C,O-C6H4-2-CHO)(PPh3)2] 1 in good yield. Treatment of 1 with a stoichiometric amount of Ag[BF4] in CH2Cl2/acetone (1:1) followed by either NCMe, tBuCN or tBuNC to give [Ru(L)(CO)(η2-C,O-C6H4-2-CHO)(PPh3)2][BF4] 2–4 in excellent yields. All of the compounds 1–4 have been characterized by microanalysis, 1H, 13C–{1H} and 31P–{1H} NMR spectroscopy. In addition compounds 1 and 3 have been characterized by single crystal X-ray diffraction studies and the cycloruthenated aldehyde CO bond length noticeably increases in the cationic system. The complexes [RuCl(CO)(η2-C,O-C6H4-2-CHO)(PH3)2] 1a, [Ru(NCCH3)(CO)(η2-C,O-C6H4-2CHO)(PH3)2] 3a, [Ru(CNCH3)(CO)(η2-C,O-C6H4-2CHO)(PH3)2] 4a [RuCl2{OC(H)Me}(CO)(PH3)2] Xa and [RuCl2{OC(H)HCHCH2}(CO)(PH3)2] XIa have also been modelled using DFT calculations (B3LYP LanL2DZ) and the minimized structures are qualitatively in good agreement with experimentally determined structures. In all cases the calculated Ru–L distances were longer than those observed by experiment, the trend of Ru–C(metalated) did not model the crystallographically observed data and some disparity between the experimental and calculated CO bond length of the coordinated aldehyde is apparent.

Graphical abstractA collection of cycloruthenated benzaldehyde complexes have been synthesised. The aldehyde CO bond length increases significantly on going from neutral to cationic species. This has been seen in the solid state and modelled with DFT calculations (B3LYP LanL2DZ).Figure optionsDownload full-size imageDownload as PowerPoint slide