Vinylidene Transition‐metal complexes, VI. The rhodium compounds C₅H₅Rh(CCHR)PiPr₃ as building blocks for the synthesis of heterometallic Di‐ and trinuclear vinylidene‐bridged complexes

Abstract

The vinylidene rhodium complex CsH@ ( =C=CH jPiPr3 (1) reacts with C&6Cr(COh upon UV irradiation and with C5HsMn- During our investigations on electron-rich half-sandwich type compounds C5H5MLL' (M = Co, Rh, Ir; L and L' = two-electron donor ligands) we previously observed that the reaction of trans-[RhCl(RC =CH)L2] (L = PiPr3) with NaC5H5 not only leads to the formation of the expected alkyne complexes C5H5Rh(RC = CH)L but also to that of the unexpected vinylidene isomers C5H5Rh( = C = CHR)LZv3). These compounds reveal a remarkable reactivity towards electrophilic substrates as is illustrated with CH2N2, the chalcogens4), and CuC15) as examples in Scheme 1.As a continuation of these studies, we were interested to learn whether not only CuCl but also other metal-contain- -19). Die Kristall-und Molekiilstrukturen von 6, ll und 14 wurden bestimmt. Die Zweikernkomplexe 6 und 11 enthglten unsymmetrisch gebundene Briickenliganden (CO und C=CHd, was wahrscheinlich auf die unterschiadliche Elektronenkonf@ration der beiden Metallatome zuriickmfiihren ist. Das M s t des dreikemigen Clusters 14 besteht aus einem offmen Rh -Fe-Fe-Dreieck, das von der C = CHrEinheit iiberbriickt ist.ing species that have a free coordination site are able to react with the Rh = C bond of C5H5Rh( = C = CHR)L to form heterometallic dinuclear complexes. Prior to our work 6, Antonova, Kolobova, and coworkers ' ) as well as Berke *) reported that mononuclear manganese, rhenium, and iron compounds of general composition M( = C = CHR)L, react, e.g., with C5H5Mn(C0)z(THF), [dppm = CH2(PPh2)2], in which the unsubstituted :C = CH2

Use of the MnCC system in organometallic and organic synthesis

“…The equilibrium between 62 and 63 did not shift to the right by the addition of an excess of dppm. Stepwise substitution was observed [93] for monodentate ligands PR 3 at the Pt atom (reactions (24) and (25) in Scheme 13). However, we failed to isolate any complexes containing "dangling" 1 -P-P ligands in reactions (27) (Scheme 13), (29) and (30) (Scheme 14).…”

“…8) [33]. For (i-Pr 3 P)RhFe 2 ( 3 -C CH 2 )(-CO) 2 (CO) 4 Cp (76) containing the Fe Fe Rh chain, the d difference between the Rh C 1 and Rh C 2 bond lengths is 0.04Å [25].…”

“…In the second molecule 89, the Fe atom is inclined to this plane by ∼10 • . Similar features were observed for (i-Pr 3 P)RhFe 2 ( 3 -C 1 C 2 H 2 )(-CO) 2 (CO) 4 Cp (76) with a core as the Rh-Fe-Fe chain, where the RhFeFe angle is 85.6 • , the Rh-C 1 (2.18Å) and Rh-C 2 (2.22Å) bonds differ from each other a little and the configuration of the Rh atom is close to square-planar [25]. The above data are consistent with 89 [33] and 76 [25] being isolobal with 2 -olefinic derivatives of platinum and rhodium, respectively.…”

“…Addition of the coordinatively unsaturated [M L n ] fragments to the M C CHR system (A) became a common method of synthesis of the dinuclear heterometallic -vinylidene complexes with the central MM (-C CHR) fragment (B) [2]. Dozens of -vinylidene complexes with Mn M, Rh M, Os M bonds (M = Mo, W, Mn, Fe, Rh, Pd, Pt, Cu) were obtained by this method by the groups of Kolobova in Moscow, of Werner in Würzburg and in our group in Krasnoyarsk [21][22][23][24][25][26][27][28][29][30].…”

“…With the help of this reaction, -vinylidene complexes (L)MM (-C CHR)(L ) (M = Mn, Rh, Os; M = Cr, Mo, W, Mn, Re, Fe, Pd, Pt, Cu; R = H, alkyl, aryl, COOMe) were prepared from Cp(CO) 2 Mn C CHPh (1), Cp(CO) 2 Mn C C(H)COOMe (13), Cp(PR 3 )Rh C CHR, ( 6 -C 6 H 6 )(PR 3 )Os C CHR[2,4,[20][21][22][23][24][25][26][27][28][29][30].…”