Synthesis and Reactivity Studies of Dicationic Dihydrogen Complexes Bearing Sulfur‐Donor Ligands: A Combined Experimental and Computational Study. Issue 9 (1st February 2013) - Gandhi, Thirumanavelan
Abstract: A series of dihydrogen complexes trans ‐[Ru(η 2 ‐H2 ){SC(SR)H}(dppe)2 ][X][BF4 ] (R = CH3, X = OTf; R = C6 H5 CH2, X = BPh4 ; R = H2 C=CHCH2, X = BPh4 ; dppe = Ph2 PCH2 CH2 PPh2 ) bearing sulfur‐donor ligands has been synthesized by protonation of the (alkyl dithioformate)hydrido complexes trans ‐[Ru(H){SC(SR)H}(dppe)2 ][X] by using HBF4 · Et2 O. Competitive substitution reactions between H2 and SC(SR)H in trans ‐[Ru(η 2 ‐H2 ){SC(SR)H}(dppe)2 ][X][BF4 ] have been studied by treatment with CH3 CN, CO, and P(OCH3 )3 . These resulted in the expulsion of SC(SR)H from the metal center, thus indicating that the alkyl dithioformate ligand is more labile than H2 . Bonding of alkyl dithioformate ligands (sulfur‐donor ligands) trans to H2 have been studied by comparing the H–H distances and chemical‐shift values ( 1 H NMR spectroscopy) of the various dihydrogen complexes bearing different trans ligands. This study qualitatively suggests that the alkyl dithioformate ligands in these trans ‐dihydrogen complexes show a poor π effect, and it is further supported by density functional theory calculations. The first example of a dihydrogen complex bearing dithioformic acid, trans ‐[Ru(η 2 ‐H2 ){SC(SH)H}(dppe)2 ][BF4 ]2, was obtained by protonation of trans ‐[Ru(H){SC(S)H}(dppe)2 ] by using HBF4 · Et2 O. Abstract : A series of dihydrogen complexes trans ‐[Ru(η 2 ‐H2 ){SC(SR)H}(dppe)2 ][X][BF4 ] (R = CH3, X = OTf; R = C6 H5 CH2, X = BPh4 ; R = H2 C=CHCH2, X = BPh4 ; dppe = Ph2 PCH2 CH2 PPh2 ) bearing sulfur‐donor ligands has been synthesized by protonation of the (alkyl dithioformate)hydrido complexes trans ‐[Ru(H){SC(SR)H}(dppe)2 ][X] by using HBF4 · Et2 O.