“…The CC trop bonds coordinated to Fe1 are significantly elongated (1.432(2) Å) compared to the free ligand (1.340(2) Å)7 or to H 2 Ntrop in the coordination sphere of Rh I (1.376(12)–1.398(5) Å)20 and indicate strong metal‐to‐ligand back‐bonding. The six terminal CO ligands bound to Fe2 and Fe3 show FeCO and CO bond lengths in the range of those observed in related 50 electron compounds 17b,e,j. The zero field 57 Fe Mössbauer spectrum of 2 at 77 K consists of two subspectra with a 2:1 intensity ratio (Figure 2).…”
Section: Resultsmentioning
confidence: 80%
“…Indeed, the three Fe–Fe distances in compound 2 (2.51–2.60 Å) fall into the range of metal‐metal bonding with the Fe2Fe3 bond being by 0.09 Å shorter than the Fe1Fe2/3 bonds 18. These three FeFe bonds are, however, slightly longer compared to the two FeFe bonds in the 50‐electron complexes (2.42–2.50 Å), but more than 0.4 Å shorter than the distance between the non‐bonded Fe(2)–Fe(3) centers in these compounds 17b,e,h–k. As a result, the largest Fe‐Fe‐Fe angle in 2 (61°) is about 15° smaller than that in related 50 electron complexes.…”
Section: Resultsmentioning
confidence: 82%
“…In contrast, the related 50‐electron species show a more irregular arrangement, in which the N atoms are positioned towards the non‐bonded Fe atoms 19. Due to the chelating nature of the (Ntrop) 2− ligand and the lower coordination number of Fe1, the Fe1–N distances in 2 (1.84 Å) are shorter than the Fe2/3–N distances (1.92 Å) (cf., 1.87–1.99 Å in [Fe 3 (μ 3 ‐NR) 2 (CO) 9− n (L) n ]) 17b,e,h–k. The CC trop bonds coordinated to Fe1 are significantly elongated (1.432(2) Å) compared to the free ligand (1.340(2) Å)7 or to H 2 Ntrop in the coordination sphere of Rh I (1.376(12)–1.398(5) Å)20 and indicate strong metal‐to‐ligand back‐bonding.…”
The reactivity of the all-ferrous FeN heterocubane [Fe4 (Ntrop)4 ] (1) with i) Brønsted acids, ii) σ-donors, iii) σ-donors/π-acceptors, and iv) one-electron oxidants has been investigated (trop = 5H-dibenzo[a,d]cyclo-hepten-5-yl). 1 showed self-re-assembling after reactions with i) and proved surprisingly inert in reactions with ii) and iii), with the exception of CO. Reductive and oxidative cluster degradation was observed in reactions with CO and TEMPO, respectively. These reactions yielded new cluster compounds, namely a trinuclear bis(μ3 -imido) 48 electron complex in the former case and a tetranuclear all ferric μ-oxo-μ-imido species in the latter case. Characterization techniques include NMR and in situ IR spectroscopy, single crystal X-ray analysis, Mössbauer spectroscopy, cyclic voltammetry, magnetic susceptibility measurements, and DFT calculations.
“…The CC trop bonds coordinated to Fe1 are significantly elongated (1.432(2) Å) compared to the free ligand (1.340(2) Å)7 or to H 2 Ntrop in the coordination sphere of Rh I (1.376(12)–1.398(5) Å)20 and indicate strong metal‐to‐ligand back‐bonding. The six terminal CO ligands bound to Fe2 and Fe3 show FeCO and CO bond lengths in the range of those observed in related 50 electron compounds 17b,e,j. The zero field 57 Fe Mössbauer spectrum of 2 at 77 K consists of two subspectra with a 2:1 intensity ratio (Figure 2).…”
Section: Resultsmentioning
confidence: 80%
“…Indeed, the three Fe–Fe distances in compound 2 (2.51–2.60 Å) fall into the range of metal‐metal bonding with the Fe2Fe3 bond being by 0.09 Å shorter than the Fe1Fe2/3 bonds 18. These three FeFe bonds are, however, slightly longer compared to the two FeFe bonds in the 50‐electron complexes (2.42–2.50 Å), but more than 0.4 Å shorter than the distance between the non‐bonded Fe(2)–Fe(3) centers in these compounds 17b,e,h–k. As a result, the largest Fe‐Fe‐Fe angle in 2 (61°) is about 15° smaller than that in related 50 electron complexes.…”
Section: Resultsmentioning
confidence: 82%
“…In contrast, the related 50‐electron species show a more irregular arrangement, in which the N atoms are positioned towards the non‐bonded Fe atoms 19. Due to the chelating nature of the (Ntrop) 2− ligand and the lower coordination number of Fe1, the Fe1–N distances in 2 (1.84 Å) are shorter than the Fe2/3–N distances (1.92 Å) (cf., 1.87–1.99 Å in [Fe 3 (μ 3 ‐NR) 2 (CO) 9− n (L) n ]) 17b,e,h–k. The CC trop bonds coordinated to Fe1 are significantly elongated (1.432(2) Å) compared to the free ligand (1.340(2) Å)7 or to H 2 Ntrop in the coordination sphere of Rh I (1.376(12)–1.398(5) Å)20 and indicate strong metal‐to‐ligand back‐bonding.…”
The reactivity of the all-ferrous FeN heterocubane [Fe4 (Ntrop)4 ] (1) with i) Brønsted acids, ii) σ-donors, iii) σ-donors/π-acceptors, and iv) one-electron oxidants has been investigated (trop = 5H-dibenzo[a,d]cyclo-hepten-5-yl). 1 showed self-re-assembling after reactions with i) and proved surprisingly inert in reactions with ii) and iii), with the exception of CO. Reductive and oxidative cluster degradation was observed in reactions with CO and TEMPO, respectively. These reactions yielded new cluster compounds, namely a trinuclear bis(μ3 -imido) 48 electron complex in the former case and a tetranuclear all ferric μ-oxo-μ-imido species in the latter case. Characterization techniques include NMR and in situ IR spectroscopy, single crystal X-ray analysis, Mössbauer spectroscopy, cyclic voltammetry, magnetic susceptibility measurements, and DFT calculations.
“…None of these compounds requires an E−E interaction by classical electron-counting formalisms, but the distances suggest partial bonding for Te 2 Fe 3 (CO) 9 L, a single bond for [Fe 2 (CO) 6 Bi 2 {μ-Co(CO) 4 }] - , and multiple bonding in the case of the E 2 {W(CO) 5 } 3 compounds. Similar but weaker interactions may be seen in comparing square-pyramidal E 2 M 3 clusters with and without substituents at E. − Selected compounds are provided in Table while a more exhaustive list is provided in the supplementary material.…”
The pyrolysis of [NEt 4 ] 2 [Bi 4 Fe 4 (CO) 13 ] in MeCN cleanly produces the square-pyramidal cluster [NEt 4 ] 2 [Fe 3 (CO) 9 -Bi 2 ]. An X-ray crystallographic study was carried out on this compound at 223 K (orthorhombic space group P2 1 2 1 2 1 (No. 19) with a ) 7.280(1) Å, b ) 20.642(4) Å, c ) 22.365(4) Å, V ) 3360.9(10) Å 3 , and Z ) 4) showing it to belong to the square-pyramidal class of 50 electron E 2 M 3 clusters. When the E atom bears a substituent, the E‚‚‚E distances are shorter, and the M basal -E-M basal angles are larger than when a lone pair of electrons resides on E. It has become fashionable to attribute such changes in bond parameters to the formation of E-E bonding, but rehybridization of the main group element could also explain this phenomenon. In order to shed light on this fundamental aspect of bonding in E-M clusters, a detailed extended Hückel molecular orbital analysis was undertaken. It appears that weak E-E bonding may be present in some cases but that this is not the dominant effect.
“…This complex consists of an open triangular cluster of three Os(CO) 3 units with triply-bridging phenylimido and sulfido groups on opposite sites of the Os 3 triangle. Compound 1 is structurally similar to Os 3 (CO) 9 (μ 3 -NSiMe 3 )(μ 3 -S), Ru 3 (CO) 9 (μ 3 -NPh)(μ 3 -S), Fe 3 (CO) 9 (μ 3 -NTol)(μ 3 -S), M 3 (CO) 9 (μ 3 -NPh) 2 (M = Fe, Ru 19 ), and M 3 (CO) 9 (μ 3 -S) 2 (M = Fe, Ru, Os 22 ), which contain 50 cluster valence electrons and require only two metal−metal bonds to satisfy the 18-electron rule on each metal atom. 3 ORTEP diagram of Os 3 (CO) 9 (μ 3 -NPh)(μ 3 -S) ( 1 ).…”
Reaction of Os(3)(CO)(12) with thionylaniline (PhN=S=O) in refluxing methylcyclohexane produces Os(3)(CO)(9)(&mgr;(3)-NPh)(&mgr;(3)-S) (1) in good yield. When Os(3)(CO)(10)(NCMe)(2) is treated with PhN=S=O at room temperature, compound 1 and Os(3)(CO)(9)(&mgr;(3)-eta(2)-(PhN)(2)SO)(&mgr;(3)-S) (2) result. Compound 1 reacts with trimethylamine oxide in the presence of acetonitrile to give Os(3)(CO)(8)(NCMe)(&mgr;(3)-NPh)(&mgr;(3)-S) (3). Compounds 1-3 were characterized by mass, IR, and NMR spectroscopies, and their structures were determined by single-crystal X-ray diffraction. Crystal data for 1: monoclinic (C2/c), a = 16.603(7) Å, b = 8.679(4) Å, c = 29.009(6) Å, beta = 102.08(2) degrees, Z = 8, R (R(w)) = 0.036 (0.039). Crystal data for 2: triclinic (P&onemacr;), a = 9.723(4) Å, b = 15.704(4) Å, c = 18.455(7) Å, alpha = 113.17(3) degrees, beta = 102.48(3) degrees, gamma = 89.97(3) degrees, Z = 4, R (R(w)) = 0.030 (0.026). Crystal data for 3: monoclinic (P2(1)/n), a = 18.792(3) Å, b = 8.856(3) Å, c = 26.210(9) Å, beta = 93.72(2) degrees, Z = 8, R (R(w)) = 0.066 (0.063).
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