Supporting two metal binding sites by a tailored polydentate trop-based (trop = 5H-dibenzo[a,d]cyclohepten-5-yl) ligand yields highly unsymmetric homobimetallic rhodium(i) complexes. These were studied as models for Rh/C hydrogenation catalysts.

The nitrogen oxides NO 2 ,NO, and N 2 Oare among the most potent air pollutants of the 21 st century.Abimetallic Rh I -Pt II complex containing an especially designed multidentate phosphine olefin ligand is capable of catalytically detoxifying these nitrogen oxides in the presence of hydrogen to form water and dinitrogen as benign products.The catalytic reactions were performed at room temperature and low pressures (3-4 bar for combined nitrogen oxides and hydrogen gases). Aturnover number (TON) of 587 for the reduction of nitrous oxide (N 2 O) to water and N 2 was recorded, making these Rh I -Pt II complexes the best homogeneous catalysts for this reaction to date.L ower TONs were achieved in the conversion of nitric oxide (NO,TON = 38) or nitrogen dioxide (NO 2 ,T ON of 8). These unprecedented homogeneously catalyzedh ydrogenation reactions of NO x were investigated by ac ombination of multinuclear NMR techniques and DFT calculations,w hich provide insight into ap ossible reaction mechanism. The hydrogenation of NO 2 proceeds stepwise,t o first give NO and H 2 O, followed by the generation of N 2 Oand H 2 O, whichi st hen further converted to N 2 and H 2 O. The nitrogen À nitrogen bond-forming step takes place in the conversion from NO to N 2 Oa nd involves reductive dimerization of NO at ar hodium center to give ah yponitrite (N 2 O 2 2À ) complex, whichw as detected as an intermediate.

We report the synthesis of a series of ruthenium complexes supported by the phosphine olefin ligand tropPPh2 (trop=5-H-dibenzo-[a,d]cyclohepten-5-yl) in the oxidation states 0, +I, and +II, formed via successive one-electron oxidization steps from Ru(0) (tropPPh2 )2 . The bidentate character of the tropPPh2 ligand and its steric hindrance force the complexes to adopt uncommon geometries, which were investigated by X-ray diffraction analysis. EPR data of the mononuclear Ru(I) complex reveal couplings of the unpaired spin with the ruthenium and two phosphorus nuclei, as well as the olefinic protons which show that the spin is mainly localized on the Ru(I) center.

We report the synthesis of a series of ruthenium complexes supported by the phosphine olefin ligand tropPPh2 (trop=5‐H‐dibenzo‐[a,d]cyclohepten‐5‐yl) in the oxidation states 0, +I, and +II, formed via successive one‐electron oxidization steps from Ru0(tropPPh2)2. The bidentate character of the tropPPh2 ligand and its steric hindrance force the complexes to adopt uncommon geometries, which were investigated by X‐ray diffraction analysis. EPR data of the mononuclear RuI complex reveal couplings of the unpaired spin with the ruthenium and two phosphorus nuclei, as well as the olefinic protons which show that the spin is mainly localized on the RuI center.

The nitrogen oxides NO 2 ,NO, and N 2 Oare among the most potent air pollutants of the 21 st century.Abimetallic Rh I -Pt II complex containing an especially designed multidentate phosphine olefin ligand is capable of catalytically detoxifying these nitrogen oxides in the presence of hydrogen to form water and dinitrogen as benign products.The catalytic reactions were performed at room temperature and low pressures (3-4 bar for combined nitrogen oxides and hydrogen gases). Aturnover number (TON) of 587 for the reduction of nitrous oxide (N 2 O) to water and N 2 was recorded, making these Rh I -Pt II complexes the best homogeneous catalysts for this reaction to date.L ower TONs were achieved in the conversion of nitric oxide (NO,TON = 38) or nitrogen dioxide (NO 2 ,T ON of 8). These unprecedented homogeneously catalyzedh ydrogenation reactions of NO x were investigated by ac ombination of multinuclear NMR techniques and DFT calculations,w hich provide insight into ap ossible reaction mechanism. The hydrogenation of NO 2 proceeds stepwise,t o first give NO and H 2 O, followed by the generation of N 2 Oand H 2 O, whichi st hen further converted to N 2 and H 2 O. The nitrogen À nitrogen bond-forming step takes place in the conversion from NO to N 2 Oa nd involves reductive dimerization of NO at ar hodium center to give ah yponitrite (N 2 O 2 2À ) complex, whichw as detected as an intermediate.