Preparation,Spectroscopic Properties,and Crystal Structures of Fe2(CO)6(μ‐CO)(μ‐CF2)2, Fe2(CO)6(μ‐CO)2(μ‐CF2), and Fe2(CO)6(μ‐CF2)(PPh3)2 – Theoretical Studies of Methylenic vs. Carbonyl Bridges in Diiron Complexes

The reaction of Na₂[Fe(CO)₄] with Br₂CF₂ in n‐pentane generates a mixture of the compounds (CO)₃Fe(μ‐CO)_3–n(μ‐CF₂)_nFe(CO)₃ ( 2 , n = 2; 3 , n = 1) in low yields with 3 as the main product. 3 is obtained free from 2 by reacting Br₂CF₂ with Na₂[Fe₂(CO)₈]. The non‐isolable monomeric complex (CO)₄Fe=CF₂ ( 1 ) can probably considered as the precursor for 2 . 3 reacts with PPh₃ with replacement of two CO ligands to form Fe₂(CO)₆(μ‐CF₂)(PPh₃)₂ ( 4 ). The complexes 2 – 4 were characterized by single crystal X‐ray diffraction. While the structure of 2 is strictly similar to that of Fe₂(CO)₉, the structure of 3 can better be described as a resulting from superposition of the two enantiomers 3 a and 3 b with two semibridging CO groups. Quantum chemical DFT calculations for the series (CO)₃Fe(μCO)_3–n(μ‐CF₂)_nFe(CO)₃ (n = 0, 1, 2, 3) as well as for the corresponding (μ‐CH₂) derivatives indicate that the progressively larger σ donor and π acceptor properties for the bridging ligands, in the order CO < CF₂ < CH₂, favor a stronger Fe–Fe bond.     

Halogenverbrückte Heterometallatomcluster der drei Typen Re2(CO)4L2(μ-X)2(μ-Y) (L = (C6H5)3P; X = Br,I; Y = GaRe(CO)4ax-L), Re2(CO)6L2(μ-X)(μ-GaX2) (X = I) und Re3(CO)9L3(μ-X)3(μ-Y) (X = Cl)

Halogeno-Bridged Heteronuclear Metal Atom Clusters of the Three Types Re₂(CO)₄L₂(μ-X)₂(μ-Y) (L = (C₆H₅)₃P; X = Br, I; Y = GaRe(CO)₄ax-L), Re₂(CO)₆L₂(μ-X) (μ-GaX₂) (X = I), and Re₃(CO)₉L₃ (μ-X)₃(μ₃-Y) (X = Cl) The title compounds of the both types Re₂(CO)₄L(μ-X)₂(μ-Y) [L = (C₆H₅)₃P; X = Br, I; Y = GaRe(CO)₄ax-L] and Re₃(CO)₉L₃(μ-X)₃ (μ₃-Y) (X = Cl) were prepared by the reaction of GaX₃ (X = Cl, Br, I) and Re₂(CO)₈(ax-L)₂ in boiling mesitylene solution. The obtained substance Re₂(CO)₄L₂(μ-I)₂(μ-Y) and carbon monoxide gave the compound of the third type Re₂(CO)₆L₂(μ-I)(μ- GaI₂). The last-named single iodo-bridged dirhenium cluster could be therefore a precursor complex of the double iodo-bridged compound. The four diamagnetic substances were characterized by ³¹P n.m.r. spectroscopy and their molecular structures were acertained by X-ray measurements. The result of the single crystal X-ray analysis of Re₂(CO)₄L₂(μ-Br)₂ [μ-GaRe(CO)₄ax-L], a bridged coordination octahedron pair with a common face, and that of the edge-bridged pair Re₂(CO)₆L₂(μ-I)(μ-GaI₂) each possessing a Re? Re bond are especially treated in the present work.     

Stereochemie der Metall—Metall-Bindung Die Strukturen der Verbindungen (CO)4Cr[μ-PMe2]2Ni(CO)2 und (CO)3Fe[μ-PMe2, μ-I]Fe(CO)3 mit je zwei verschiedenen Komplexhälften

Die Kristallstrukturen der Titelkomplexe, deren einer zwei verschiedene Carbonylmetall-Einheiten, deren anderer zwei verschiedene Brückenliganden besitzt, wurden bestimmt. Die Stereochemie des Cr? Ni-Komplexes entspricht der Erwartung, seine Metall—Metall-Bindung ist jedoch kürzer als der Durchschnittswert aus den entsprechenden Cr₂- bzw. Ni₂-Verbindungen. Bei dem Fe₂-Komplex ist die Gesamt-Molekülgeometrie ebenfalls normal, doch der Metall—Metall-Abstand ist deutlich kürzer als erwartet. Die Verkürzung der Metall—Metall-Bindungen steht bei beiden Komplexen in Zusammenhang mit der Minimisierung der intramolekularen sterischen Hinderung. Stereochemistry of the Metal—Metal Bond. Structures of the Compounds (CO)₄Cr[μ-PMe₂]₂Ni(CO)₂ and (CO)₃Fe[μ-PMe₂, μ-I]Fe(CO)₃. Each with Two Different Complex Halves The crystal structures of the title complexes, one of which has two different carbonylmetal units and the other has two different bridging ligands, were determined. The stereochemistry of the Cr? Ni complex is as expected, its metal—metal bond however is shorter than the average value of the corresponding Cr₂ and Ni₂ compounds. For the Fe₂ complex the overall molecular geometry is also normal, but the metal—metal distance is considerably shorter than expected. The shortening of the metal—metal bonds is in both complexes correlated with the minimization of intramolecular steric strain.     

Crystal and molecular structure of (μ-p-CH3C6H4C2S) (μ-n-C3H7S)Fe2(CO)6Co2(CO)6

The crystal and molecular structure of the complex containing cobalt-carbon and iron-sulfur cluster cores, (μ-p-CH₃C₆H₄C₂S) (μ-n-C₃H₇S)Fe₂(CO)₆Co₂(CO)₆, has been determined by X-ray diffraction method. The crystals are triclinic, space group P&1bar;, with a — 9.139(2), b=9.610(1), c-17.183(2) Å, α = 84.36(1), β-89.45(1), γ=88.15(1)°, V-1501.0 ų; Z=2, D_c=1.74 g/cm³. R=0.072, Rw=0.081. The results of the structure determination show a cobalt-carbon cluster core formed through the reaction of (μ-p-CH₃C₆H₄C₂S)(μ-n-C₃H₇S)Fe₂(CO)₆ with Co₂(CO)₈. In the cobalt-carbon cluster core, the bond length of the original C≡C lengthened to 1.324 Å which is close to the typical value of carbon-carbon double bond. The groups connecting the carbons of the cluster core are in cis position and lie on the opposite side of cobalt atoms. In this complex, the conformation of —SC₃H₇ is e-type, while that of —SC₂C₆H₄CH₃ is a-type.     

Heterodinukleare Komplexe: Synthese und Kristallstrukturen von [RuRh(μ‐CO)(CO)4(μ‐PtBu2)(tBu2PH)], [RuRh(μ‐CO)(CO)3(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [CoRh(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)]

Heterobinuclear Complexes: Synthesis and X‐ray Crystal Structures of [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)], [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)], and [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] [Ru₃Rh(CO)₇(μ₃‐H)(μ‐P^tBu₂)₂(^tBu₂PH)(μ‐Cl)₂] ( 2 ) yields by cluster degradation under CO pressure as main product the heterobinuclear complex [RuRh(μ‐CO)(CO)₄(μ‐P^tBu₂)(^tBu₂PH)] ( 4 ). The compound crystallizes in the orthorhombic space group Pcab with a = 15.6802(15), b = 28.953(3), c = 11.8419(19) Å and V = 5376.2(11) ų. The reaction of 4 with dppm (Ph₂PCH₂PPh₂) in THF at room temperature affords in good yields [RuRh(μ‐CO)(CO)₃(μ‐P^tBu₂)(μ‐dppm)] ( 7 ). 7 crystallizes in the triclinic space group P 1 with a = 9.7503(19), b = 13.399(3), c = 15.823(3) Å and V = 1854.6 ų. Moreover single crystals of [CoRh(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 9 ) could be obtained and the single‐crystal X‐ray structure analysis revealed that 9 crystallizes in the monoclinic space group P2₁/a with a = 11.611(2), b = 13.333(2), c = 18.186(3) Å and V = 2693.0(8) ų.     

Cluster chemistry. 61. Addition of HX (XCl,Br,I) or AuCl(PPh3) to an open Ru5 cluster. X-ray structures of Ru5(μ-H)(μ5-C2PPh2)(μ-PPh2)(μ-Br)(CO)13 and Ru5(μ-H)(μ5-C2PPh2)(μ3-I)(μ-PPh2)(CO)12

Reactions of aqueous HX (X?Cl, Br) or of AuCl(PPh₃) with Ru₅(μ₅-C₂PPh₂)(μ-PPh₂)(CO)₁₃ result in addition of the 4e-donor set (H + X) or (Au(PPh₃) + Cl) with concomitant opening of two Ru? Ru bonds to give complexes containing dimetallated triangular of ‘scorpion’ cores. Aqueous HI reacts similarly, but in this case the iodide ligand spans three Ru atoms, the (H + I) set acting as 6e-donor. The structures of the two title compounds were confirmed by X-ray crystallographic studies. Ru₅(μ-H)(μ₅-C₂PPh₂)(μ-PPh₂)-(μ-Br)(CO)₁₃ is triclinic, space group P1 , a = 9.689(2), b = 11.874(2), c = 20.005(4) Å, α = 84.66(2), β = 82.90(6), λ = 67.51(6)°, Z = 2; 6478 data with I > 2σ(I) were refined to R = 0.0368, R_w = 0.0362. Ru₅(μ-H)(μ₅-C₂PPh₂)(μ₃-I)(μ-PPh₂)-(CO)₁₂.CH₂Cl₂ is monoclinic, space group P2₁/n, a = 14.809(4), b = 20.721(4), c = 17.698(5) Å, β = 111.42(2)°, Z = 4; 7815 data with I > 2σ(I) were refined to R = 0.0440, R_w = 0.0416.     

Synthese und Kristallstrukturen der Phosphanimin-Komplexe [Cu(μ-HNPEt3)]4(O3S–CF3)4 und [Pt2Me6(μ-I)2(μ-HNPMe3)]

Synthesis and Crystal Structures of the Phosphaneimine Complexes [Cu(μ-HNPEt₃)]₄(O₃S–CF₃)₄ and [Pt₂Me₆(μ-I)₂(μ-HNPMe₃)] The title compounds have been prepared by the reaction of copper(I)triflate with [NiBr(NPEt₃)]₄ in CH₂Cl₂ suspension in the presence of water, and by the reaction of [PtMe₃I]₄ with Me₃SiNPMe₃ in boiling toluene in the presence of cesium fluoride, respectively. According to the crystal structure determinations the cation of the copper complex forms tetrameric units [Cu(HNPEt₃)]₄⁴⁺ with S₄ symmetry with Cu–N bond lengths of 191.6 and 192.1 pm. In the platinum complex the platinum atoms are linked by two μ-I bridging atoms as well as by the μ-N atom of the HNPMe₃ ligand with Pt–N bond lengths of 228.1 and 229.5 pm.