doi:10.1039/d3dt02339gengBeard, SophieGrasa, AlejandroViguri, FernandoRodríguez, RicardoLópez, José A.Lahoz, Fernando J.García-Orduña, PilarLamata, PilarCarmona, DanielMolecular hydrogen and water activation by transition metal frustrated Lewis pairs containing ruthenium or osmium components: catalytic hydrogenation assaysART-2023-135121The transition metal frustrated Lewis pair compounds [(Cym)M(κ3S,P,N-HL1)][SbF6] (Cym = η6-p-MeC6H4iPr; H2L1 = N-(p-tolyl)-N′-(2-diphenylphosphanoethyl)thiourea; M = Ru (5), Os (6)) have been prepared from the corresponding dimer [{(Cym)MCl}2(μ-Cl)2] and H2L1 by successive chloride abstraction with NaSbF6 and AgSbF6 and NH deprotonation with NaHCO3. Complexes 5 and 6 and the previously reported phosphano–guanidino compounds [(Cym)M(κ3P,N,N′-HL2)][SbF6] [H2L2 = N,N′-bis(p-tolyl)-N′′-(2-diphenylphosphanoethyl) guanidine; M = Ru (7), Os (8)] and pyridinyl–guanidino compounds [(Cym)M(κ3N,N′,N′′-HL3)][SbF6] [H2L3 = N,N′-bis(p-tolyl)-N′′-(2-pyridinylmethyl) guanidine; M = Ru (9), Os (10)] heterolytically activate H2 in a reversible manner affording the hydrido complexes [(Cym)MH(H2L)][SbF6] (H2L = H2L1; M = Ru (11), Os (12); H2L = H2L2; M = Ru (13), Os (14); H2L = H2L3; M = Ru (15), Os (16)). DFT calculations carried out on the hydrogenation of complex 7 support an FLP mechanism for the process. Heating 9 and 10 in methanol yields the orthometalated complexes [(Cym)M(κ3N,N′,C-H2L3-H)][SbF6] (M = Ru (17), Os (18)). The phosphano–guanidino complex 7 activates deuterated water in a reversible fashion, resulting in the gradual deuteration of the three cymene methyl protons through sequential C(sp3)–H bond activation. From DFT calculations, a metal–ligand cooperative reversible mechanism that involves the O–H bond activation and the formation of an intermediate methylene cyclohexenyl complex has been proposed. Complexes 5–10 catalyse the hydrogenation of the C[double bond, length as m-dash]C double bond of styrene and a range of acrylates, the C[double bond, length as m-dash]O bond of acetophenone and the C[double bond, length as m-dash]N bond of N-benzylideneaniline and quinoline. The C[double bond, length as m-dash]C double bond of methyl acrylate adds to catalyst 9, affording complex 19 in which a new ligand exhibiting a fac κ3N,N′,C coordination mode has been incorporated.2023http://zaguan.unizar.es/record/12802810.1039/d3dt02339ghttp://zaguan.unizar.es/record/128028oai:zaguan.unizar.es:128028info:eu-repo/grantAgreement/ES/AEI/PID2020-119512GB-I00info:eu-repo/grantAgreement/ES/DGA/E05-20Rinfo:eu-repo/grantAgreement/ES/DGA/E05-23Rinfo:eu-repo/grantAgreement/ES/MCIU-AEI-FEDER/PID2021-122406NB-I00info:eu-repo/grantAgreement/ES/MICINN/CTQ2018-095561-BI00Dalton Transactions 52, 37 (2023), 13216-13228All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/openAccess