Synthesis and Characterization of New Diiron and Diruthenium μ-Aminocarbyne Complexes Containing Terminal S-, P- and C-Ligands

Abstract

The diiron aminocarbyne complexes [Fe 2 {µ-CN(Me)(R)}(µ-CO)(CO)(NCMe)(Cp) 2 ][SO 3 CF 3 ] (R = Xyl, 1a; R = Me, 1b; R = CH 2 Ph, 1c; Xyl = 2,6-Me 2 C 6 H 3 ) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe 2 {µ-CN(Me) (R)}(µ-CO)(CO)(X)(Cp) 2 ] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R = CH 2 Ph, X = Cl, 4c; R = CH 2 Ph, X = Br, 4d; R = CH 2 Ph, X = I, 4e; R = Xyl, X = SC(S)NEt 2 , 5a; R = Me, X = SC(S)NEt 2 , 5b; R = Xyl, X = CH(CN) 2 , 7), in good yields. The molecular structure of 5a shows an unusual η 1 coordination mode of the dithiocarbamate ligand.a series of phosphanes generates the cationic complexes [M 2 {µ-CN(Me)(R)}(µ-CO)(CO)(P)(Cp) 2 ][SO 3 CF 3 ] (M = Fe, R = Xyl, P = PPh 2 H, 6a; M = Fe, R = Xyl, P = PPh 3 , 6b; M = Fe, R = Xyl, P = PMe 3 , 6c; M = Fe, R = Me, P = PMe 2 Ph, 6d; M = Fe, R = Me, P = PPh 3 , 6e; M = Fe, R = Me, P = PMePh 2 , 6f; M = Ru, R = Xyl, P = PPh 2 H, 6g; M = Ru, R = Me, P = PPh 2 H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO)(NCR )(Cp) 2 ][SO 3 CF 3 ] [R = Me, 1a; R = tBu, 3] with PhLi and PPh 2 Li yield [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO)(Ph)(Cp) 2 ] (8) and [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO)(PPh 2 )(Cp) 2 ] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe 2 {C(Me)N(Me)(Xyl)}(µ-CO) 2 (CO)(Cp) 2 ] (10). Finally, the acetone complex [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO)(OCMe 2 )(Cp) 2 ][SO 3 CF 3 ] (12) reacts with lithium acetylides to give complexes [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO)(C≡CR)(Cp) 2 ] (R = p-C 6 H 4 Me, 11a; R = Ph, 11b; R = SiMe 3 , 11c), in high yields. Filtration through alumina of a solution of 11a in CH 2 Cl 2 results in hydration of the acetylide group and C-Si bond cleavage, affording [Fe 2 {µ-CN(Me)(Xyl)}(µ-CO)(CO){C(O)Me}(Cp) 2 ] (12).

Easily Available, Amphiphilic Diiron Cyclopentadienyl Complexes Exhibit in Vitro Anticancer Activity in 2D and 3D Human Cancer Cells through Redox Modulation Triggered by CO Release

“…Then, in order to clarify the possible effect of the net ionic charge of the complex, we also synthesized and characterized the novel neutral derivative [Fe 2 Cp 2 Cl(CO)(μ‐CO){μ‐CNMe(Cy)}], 6 (see Experimental Section). Based on a comparison of the 1 H NMR and IR spectra with data available in the literature for similar compounds, [28] 6 exists in CDCl 3 solution as a nearly equimolar mixture of two isomers, maintaining the cis ‐geometry of the Cp ligands (as ascertained by 1 H NOE experiments, Figure S32) and differing in the orientation of the N ‐substituents with respect to the chloride ( E / Z isomers). This feature suggests that the (μ‐C)−N bond in the neutral 6 still holds a substantial double bond character.…”

Regioselective Nucleophilic Additions to Diiron Carbonyl Complexes Containing a Bridging Aminocarbyne Ligand: A Synthetic, Crystallographic and DFT Study

“…Complexes of the type [Fe 2 {µ‐CN(R)(R′)}(µ‐CO)(CO)(L)Cp 2 ] (R ≠ R′, L = halide, CN, Ph), in chlorinated solvents, preferentially adopt the E configuration, with the Cp ligands in mutual cis position. [11c], [11e], …”

“…To introduce further carbene functionality in 1a , c , the compounds [Fe 2 {µ‐CN(Me)(R)}(µ‐CO)(CO){(C=O)Me}Cp 2 ] (R = Me, Xyl) were preliminarily prepared. These were reacted with methyl triflate in dichloromethane, thus affording [Fe 2 {µ‐CN(Me)(R)}(µ‐CO)(CO){C(OMe)Me}Cp 2 ][SO 3 CF 3 ] (R = Me, 5a ; R = Xyl, 5b ) in 80–85 % yields, Scheme .…”

“…[Fe 2 (CO) 4 Cp 2 ] was purchased from Strem and was used as received. The compounds CNMe, Li 2 Cu(CN)Me 2 , [Fe 2 {µ‐C(CN)NMe 2 }(µ‐CO)(CO) 2 Cp 2 ] and [Fe 2 {µ‐CN(Me)(R)}(µ‐CO)(CO){(C=O)Me}Cp 2 ] (R = Me, Xyl) were prepared according to published procedures. Once isolated, the metal products were conserved under nitrogen.…”

A Comprehensive Analysis of the Metal–Nitrile Bonding in an Organo-Diiron System

“…As expected, the NMR spectra of (2–12)CF 3 SO 3 reveal the existence in solution of E-Z isomers, with reference to the different orientations assumed by the aminocarbyne (iminium) substituents with respect to the terminal CO and L ligands. This kind of isomerism was previously recognized in many other diiron aminocarbyne complexes of general formula [Fe 2 Cp 2 (CO)(X)(µ-CO){µ-CN(Me)(Y)}] 0/+ (X = anionic or neutral ligand ≠ CO; Y ≠ Me), and isomers were generally named α and β ( Figure 2 ); in most cases, Y and X are bulkier than Me and CO, respectively, therefore the α form is expected to be favoured over the β one for steric reasons [ 42 , 45 , 53 , 54 ].…”