Octacarbonylbis {μ‐(tris(trimethylsilyl)methyl]indany l} dimanganese with Two Monoalkyl Indium Groups Bridging the Mn–Mn Bond

Abstract

Key Words: Tetraindane(4) / Indium@) I Mn-Mn bond / Indium alkyl bridge Tetrclhedra-tetrakis[tris(trimethylsilyl)methyl]tetraindane(4)(1) reacts with decacarbonyldimanganese(0) to yield the bright red crystalline title compound 2, in which two and a planar MnzInz molecular center. carbonyl ligands are replaced by two InR fragments. The crystal structure determination of 2 shows two M n ( C 0 ) 4 groups (Mn-Mn 313.7 pm) bridged by two monoalkylindium units Recently, we succeeded in synthesizing and determining the crystal structure of the alkylindium(1) compound I I I~[ C ( S~M~~)~]~ (1) with a nearly undistorted tetrahedral In4 skeleton in the solid state"], which in contrast to the Ga4 analog[*] remains tetrameric in dilute benzene solutions. In the course of systematic investigations of the chemical properties of 1[1,3] we found that the monomeric In-C(SiMe& fragment is able to substitute carbonyl ligands in transition metal carbonyls. In this paper we report on the reaction of 1 with Mn2(CO)lo. Reaction of In4[C(SiMe3)3]4 with Mnz(CO)loMixtures of 1 and Mnz(CO)lo in n-hexane remain unchanged at room temperature for several days, while in boiling hexane the characteristically deep violet color of 1 disappears within two or three hours, depending on the excess of the manganese carbonyl used. A dark red solution is formed, from which after concentration and recrystallization dark red, very fine needles of the title compound 2 are isolated in 60% yield. The molar mass, cryoscopically determined in benzene solution, and the mass spectrum with a very characteristic isotopic pattern show that two carbonyl groups of the Mn2(CO)lo molecule are replaced by two monoalkylindium fragments [eq. The trimethylsilyl groups of 2 show one resonance in both the 'H-and I3C-NMR spectra. Although the molecular structure of 2 exhibits two chemically different carbonyl groups, only one I3C resonance is observed even at -65°C with the chemical shift 8 = 218. The assignment of the a-carbon atom of the tris(trimethy1si-1yl)methyl group in the 13C-NMR spectrum is not beyond doubt: there is only one further signal at 6 = 51.7 lying more than 25 ppm downfield with respect to the region normally observed for carbon atoms bound to indiumL61. The location of this carbon atom in the nodal plane of the p orbital, which is perpendicular to the molecular plane and can accept x electron density by backdonation, might be responsible for this unusual shift. Figure 1 shows the molecular structure of 2. Molecule 2 contains an Mn -Mn bond bridged by two monoalkylindium fragments. Crystal Structure of 2Whereas several compounds with bridged Mn-Mn bonds are known ['], only a few examples exhibit a bridging third main group element[8-'01. Indium as a bridging atom is mostly tetracoordinatedL9I, a lower coordination number is found in a dimanganese compound bridged by an In-Mn(CO)5 group[l0I. To our knowledge bridging alkylindium units with tricoordinated In atoms like in 2 have previously not been described. The synthesis according to eq. (1) therefore ope...

Tetrahedral homonuclear organoelement clusters and subhalides of aluminium, gallium and indium

“…8) (Dohmeier et al 1994a). Exceptions are the compounds Fe 3 (CO) 9 (-CO)(-GaR) 2 or Mn 2 (CO) 8 (-ER) 2 (E=Ga, In) (Uhl et al 1995b, which adopt molecular structures different from those of the pure carbonyls with the bridging of all Fe-Fe or Mn-Mn bonds. In these cases bridging carbonyl groups are replaced by ER ligands, while terminally arranged carbonyl groups remain unaffected.…”

Organometallic Iron Indium Derivatives Prepared by the Reaction of Carbonyliron Compounds with the Alkylindium(I) Derivative In4[C(SiMe3)3]4

“…InR would thus belong to the intensively studied group of CO-analogous compounds like isonitriles or phosphorus trifluoride, which have been successfully applied as σ-donor/π-acceptor ligands in transition metal complexes. Indeed, we succeeded in substituting CO ligands of binuclear transition metal carbonyl complexes by the reaction of 1 with Co 2 (CO) 8 or Mn 2 (CO) 10 , but the InR groups occupy exclusively bridging positions between both metal centers in all products. Two derivatives were isolated with octacarbonyldicobalt, in which, depending on the stoichiometric ratio of the components, one or both bridging CO ligands are replaced by InR .…”

Organometallic compounds containing tris(trimethylsilyl)methyl or related ligands †

“…The platinum derivative [Pt(InTsi) 4 ] has also been made, 152 and a range of compounds of Mn, Fe and Co having InTsi or GaTsi fragments in place of one or more CO groups in the parent carbonyl compounds. [153][154][155][156][157] The MTsi groups have also been incorporated into Main Group clusters. [158][159][160] The reduction of the ate complex [Li(thf) 3 (µ-Cl)InCl 2 Tsi] with LiAlH 4 gives a hydride-bridged compound Li(thf) 2 -(InTsi) 2 H 5 28b, 161 which is converted by methanol-water into 100 The hydroxide (InTsiPrOH) 3 has also been reported.…”