Iron(0) and ruthenium(0) complexes with tridentate phosphonite ligands and their potential for ketene formation from methyl iodide, CO and a base

Reactivity of a (Bis-NHC)tricarbonylruthenium(0) Complex with Methyl Triflate and Methyl Iodide. Formation of Methyl- and Acetylruthenium(II) Derivatives: Experimental Results and Mechanistic DFT Calculations

“…Interestingly, while contradictory reports on the reaction of methyl iodide with trans -[Ru(κ P -PPh 3 ) 2 (CO) 3 ] have been published ( cis,trans,cis -[RuI(Me)(κ P -PPh 3 ) 2 (CO) 2 ] and mer,trans -[RuI 3 (κ P -PPh 3 ) 2 (CO)] have been described as reaction products), it has been shown that the reactions of methyl iodide with the ruthenium(0) complexes [Ru(κ P -PMe 3 )(CO) 4 ] and trans -[Ru(κ P -PMe 3 ) 2 (CO) 3 ] do not afford acetyl derivatives but the neutral iodido-methyl products fac -[RuI(Me)(κ P -PMe 3 )(CO) 3 ] and cis,trans,cis -[RuI(Me)(κ P -PMe 3 ) 2 (CO) 2 ] . Similar reactions of the dicarbonyl ruthenium(0) complexes [Ru(κ 3 P 3 -triphos)(CO) 2 ] (triphos = tridentate tripod or pincer P-donor ligand) with methyl iodide do not give acetyl derivatives either, but ionic methyl derivatives of the type [Ru(Me)(κ 3 P 3 -triphos)(CO) 2 ]I. , Therefore, as all previously reported reactions of methyl iodide with ruthenium(0) carbonyl complexes end in Ru-methyl derivatives and as all of these complexes contain less σ-donating ligands than MeIm(CH 2 ) 3 ImMe, the strong σ-donating character of this ligand has to be claimed as responsible for the formation of an acetyl derivative ( 3 ) as the final product of the reaction of 1 with methyl iodide.…”

“…Pentacoordinated ruthenium(0) complexes are saturated 18-electron species that frequently act as metallic nucleophiles. ,− Therefore, we computed the HOMO of compound 1 with the aim of obtaining information about its behavior as a nucleophile. Figure shows that this orbital has mostly metallic character and that it is asymmetrically located in the equatorial plane of the trigonal bipyramid defined by the coordinated atoms of the ligands.…”

“…It is noteworthy that no reaction of alkyl halides or pseudohalides with ruthenium(0) complexes of the type [Ru(κ 2 -L 2 )(CO) 3 ] (L 2 = chelating ligand) has been previously described, and although some reactions of methyl iodide with ruthenium(0) derivatives of the types [Ru(κ P -PR 3 )(CO) 4 ], trans- [Ru(κ P -PR 3 ) 2 (CO) 3 ], and [Ru(κ 3 P 3 -triphos)(CO) 2 ] (triphos = tridentate tripod or pincer P-donor ligand) have been reported, their mechanisms have not been studied by theoretical methods.…”

Heterolytic Cleavage of Dihydrogen by an Iron(II) PNP Pincer Complex via Metal–Ligand Cooperation

“…The overall geometry about the iron center is best described as distorted trigonal bipyramidal. For comparison, the related complexes [Fe­(PNP CH2 - i Pr)­(CO) 2 ] (Table ) and [Fe­(PhP­[CH 2 CH 2 CH 2 P­(O i Pr) 2 ] 2 )­(CO) 2 ] adopt an almost perfect trigonal-bipyramidal geometry, while the bulkier complex [Fe­(PNP CH2 - t Bu)­(CO) 2 ] (PNP CH2 - t Bu = bis­(di- tert -butylphosphinomethyl)­pyridine) has an unusual square-pyramidal structure. In complex 7 , the two carbonyl ligands and the pyridine nitrogen define the equatorial plane with bond angles of 113.88(9), 127.45(7), and 118.67(7)° for C18–Fe1–C19, N1–Fe1–C18, and N1–Fe1–C19, respectively.…”

The iron centre of the cluster-free hydrogenase (Hmd): low-spin Fe(ii) or low-spin Fe(0)?

“…To this end we have plotted the averages of the two infrared absorption bands for all complexes documented in the literature against the known iron oxidation state. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] z The left hand side of the plot shown in Fig. 3 shows the evident correlation between the observed oxidation states and the averages of the IR absorption bands.…”