[(η⁵‐C₅Me₅)AlFe(CO)₄]—Synthesis, Structure, and Bonding

Abstract

crystal of dimensions 0.37 x 0.37 x 0.27 mm, rhombohedral. R3, a = b = 15.0677(7), c = 48.7214(49) A, 1 = = 1 102 g~m -~, 2 = 6, j~ = 12.22 cm-', 2328 independent reflections, R(Rw) = 0.105(0.103) for 1309 [I > 20(1)] observed reflections. Maximum final difference Fourier peak 0.83 e k ' . Seifert XRD3000-S, four-circle diffractometer, Cu,, radiation, graphite monochromator, 4 2 0 scan, Om,, = 60". Two set of data were collected due to the instability of the crystal, and although the present set was recorded more quickly the decay factor was 7%. Semiempirical Y-scan absorption correction was applied. Refinement on Fo with full matrix. The structure was solved by direct methods [15] and the molecule was located on a threefold crystallographic axis. An anisotropic thermal model was used for the non-hydrogen atoms, while the thermal and positional parameters for H atoms, which were obtained unambiguously from difference Fourier synthesis, were kept fixed during the last cycles of refinement. The water molecules appear to be disordered and the hydrogen atoms of the water molecule situated on the threefold axis could not be located. Moreover, in spite of the high displacement parameters of the C17-C22 atoms no disorder model could be obtained. The weighting scheme was established as to give no trends in

Ni[In{C(SiMe3)3}4]: An Organometallic Nickel-Indium Compound Analogous to [Ni(CO)4]

“…[8] In contrast to CO, the ER fragments almost exclusively occupy bridging positions between two metal atoms in the known derivatives. A single case of terminal coordination was recently reported by Fischer et al in [(CO) 4 Fe(AlCp*)], [9] for which significant p backbonding from the metal atom to the ligand was calculated. Up to now, analogues of mononuclear, binary carbonyl complexes with exclusively terminal ER groups were unknown.…”

“…The extent of the p backbonding in 2, indicated by the very short Ni ± In bonds, is uncertain. Theoretical investigations confirm such interactions in [Fe(CO) 4 (AlCp*)], [9] in which, however, the contributing orbitals on the aluminum atoms are partially occupied by the cyclopentadienyl ligands.…”

Metal Complexes Bearing Terminal Borylene Ligands

“…The bonding in 5 is similar to that in the homologous aluminum compound; [17] the boron atom possesses the formal oxidation number 1 and functions as a weak p acceptor. The chemical shift d( 11 B) À 35.3 lies in the range typical of apical 11 B nuclei in nido-carboranes.…”

[Pd3(InCp*)4(μ2‐InCp*)4]: drei linear angeordnete Palladium‐Atome in einer fluktuierenden Verpackung aus acht [Cp*In]‐Liganden

“…Gruppe die Vermutung, dass diese Verbindungen als Liganden in der ‹bergangsmetallchemie πwahrscheinlich einen immensen Einflu˚darauf haben, wie man k¸nftig neue Metall-MetallBindungen herstellt º und wir in der Zukunft zweifellos Zeugen der Herstellung vieler neuer Clustertypen sein werden.™ [1] [2] und [Ni(GaCp*) 4 ] [3] (Cp* ¼ Pentamethylcylopentadienid) legten diese Perspektive nahe. Bis dahin waren nicht zuletzt infolge unserer Arbeit¸ber [(CO) 4 Fe(AlCp*)] [4] haupts‰chlich Komplexe dieser neuen, zu CO isolobalen Liganden ER (E ¼ Al, Ga, In; R ¼ Alkyl, Aryl) an Carbonylmetall-Fragmenten [(CO) n M a ] untersucht worden. [5,6] Konstitution und strukturelle Charakteristika der neuen [Cp*Ga]-substituierten Ni 4 -und Rh 6 -Carbonylcluster von Jutzi et al [3,7] oder der Komplex [{(CpNi)(m-AlCp*)} 2 ] von Schnˆckel et al [8] 4 ] mit bindenden PdPd-Abst‰nden von 2.75±2.77 ä zeigt.…”