New dihydrogen complexes: the synthesis and spectroscopic properties of iron(II), ruthenium(II), and osmium(II) complexes containing the meso-tetraphos-1 ligand

Abstract

Can. J. Chem. 72,547 (1994). The synthesis and properties of dihydrogen complexes trans-[MH(H2)L]+, M = Fe, Ru, Os, which contain the ligand mesotetraphos-1, S,R-Ph2PCH2CH2P(Ph)CH2CH2P(Ph)CH2CH2PPh2 (L) are described. There are interesting possibilities of isomerism in such trans complexes because the axial binding sites at the metal are different, one being surrounded by four phenyl groups and the other by two phenyl groups. The osmium complex is prepared in an unusual reaction of ci.~-p-Os(Cl)~L with HI, (1 atm) and NaBPh4 (1 mol) in THF or by the reaction of trans-OsH(C1)L with NaBPh4 and H2. The iron and ruthenium complexes were made by a reaction of HBF4 with complexes t r a n~-M ( H )~L that have inequivalent trans hydrides. The ruthenium complex was also prepared starting from isomers of t r a n s -R U H ( C~) L .~T~~ H-H distance in the rapidly spinning dihydrogen ligand has been calculated from Tl(min) data to be 0. [Traduit par la rtdaction]

An active, stable and recyclable Ru(ii) tetraphosphine-based catalytic system for hydrogen production by selective formic acid dehydrogenation

“…General methods and materials [RuCl 2 (benzene)] 2 22 and complexes 1-3 13 were prepared according to literature procedures. Formic acid and N,Ndimethyloctylamine were distilled in vacuum prior to use and stored under nitrogen.…”

“…Upon gentle heating (40 °C, 30 min), FA DH proceeded further and 31 P{ 1 H} and 1 H NMR analysis revealed the formation of the hydrido chloride complexes 2 (δ P : 92.1 (P A ), 54.1 (P X ), 2 J trans = 248 Hz) and 2' (δ P : 115.4 (P A ), 56.4 (P X ), 2 J trans = ca. 246 Hz), 13 with complex 1 still being the most abundant P-containing species in solution.…”

“…Accordingly, the only 1 H NMR resonances observed in the hydride region were the two pentets assigned to the hydride atoms of 2 (δ: -20.9, 2 J HP = 20 Hz) and 2' (δ: -17.89, 2 J HP = 18 Hz). 13 Next , Complex 4 was identified due to its characteristic 1 H NMR resonances at -4.99 (brs) and -12.33 ppm (pentet), 13 whereas the 31 P{ 1 H} NMR resonances of 4 could not be detected due to the very low concentration under such conditions. The 1 H NMR signal at 4.54 ppm indicated formation of H 2 .…”

Ketone Asymmetric Hydrogenation Catalyzed by P-NH-P′ Pincer Iron Catalysts: An Experimental and Computational Study

“…The trans-hydrides are diastereotopic due to the presence of the amine group. Complexes with inequivalent trans-dihydrides are rare: trans-FeH2(meso-tetraphos) has JHH 18 Hz 45,46 while cis dihydrides usually have JHH in the range 13-21 Hz. 7,26,[47][48][49] The 118 Hz 2 JPP of 3 is of similar magnitude to that of 2 ( 2 JPP 136 Hz) which has trans phosphorus nuclei in a mer P-N-P' configuration on the metal center 7 indicating that the ligand in 3 is also in the mer configuration as shown in Scheme 2.…”

Synthesis of Ruthenium Hydride Complexes Containing beta-Aminophosphine Ligands Derived from Amino Acids and their use in the H2-Hydrogenation of Ketones and Imines

“…However the hydride chemical shifts and the trans-J H,H of 8 Hz of the complex are comparable to those typically observed in neutral trans-dihydride ruthenium(II) complexes. [17,20] The ACMNX pattern of the two hydride resonances was simulated exactly where A and C represent the two non-equivalent hydrides and M, N and X represent the three non-equivalent 31 P nuclei. The MNX pattern in the 31 P{ 1 H} NMR spectrum is also consistent with the structure shown in Figure 5.…”