Octacoordinate Metal Carbonyls of Lanthanum and Cerium: Experimental Observation and Theoretical Calculation

Abstract

The octacoordinate metal carbonyls La(CO)8(+) and Ce(CO)8(+) were observed in laser vaporization of La and Ce in pure CO gas. The peak intensities in the mass spectra, the infrared photodissociation spectra, and the theoretical calculations indicate that all CO ligands in these two complexes are bonded with the central metal atoms. The CO stretching frequencies in La(CO)8(+) and Ce(CO)8(+) are determined to be 2110 and 2108 cm(-1), respectively. Theoretical studies indicate that the most stable structures for La(CO)8(+) and Ce(CO)8(+) are an Oh geometry at its triplet state and a slightly distorted Oh geometry at its quartet state, respectively. These two complexes represent new octacoordinate metal carbonyls after previously determined U(CO)8(+) and Y(CO)8(+).

NATURE OF Mδ+···δ+C-Oδ-INTERACTIONS IN METAL CARBONYLS. AN ELECTRONIC STUDY BASED ON THE TOPOLOGY OF THE ELECTRON CHARGE DENSITY DISTRIBUTION AND ITS LAPLACIAN FUNCTION

“…[8][9][10][11][12][13]21,22,33 Por otra parte, es conocido el hecho que en la molécula de CO el átomo de carbono tiene carga positiva (+1,17) y el átomo de oxígeno tiene carga negativa (-1,17). 34 Esto nos lleva a preguntarnos ¿Cómo es posible que cationes metálicos interactúen atractivamente con átomos de C en los carbonilos metálicos?…”

Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2014

“…Crystals containing the two larger metals, Gd and Tb, were found to be structurally straightforward and isomorphous with crystals of [Cp * 2 SmH] 2 . However, only for Tb the locations of the hydride ligands in this structural type could be identified for the first time and were found to be consistent with a Cp * 2 Ln(µ-H) 2 variations of Cp * 2 Ln(µ-H)(µ-η 1 :η 5 -CH 2 C 5 Me 4 )Ln′Cp * compounds could be definitively identified by 1 H NMR spectroscopy with the similarly sized metals yttrium and lutetium.…”

“…Reactivity preferences could not be determined in the C-H bond activation conversion of Cp * 2 Ln(µ-H) 2 Ln′Cp * 2 to Cp * 2 Ln(µ-H)(µ-η 1 :η 5 -CH 2 C 5 Me 4 )Ln′Cp * because of the lability of the ligands in this particular system and exchange reactions. However, the analogous chemistry with combinations of metals with different sizes showed a decided preference for the heterometallic complexes Cp * 2 Lu(µ-H) 2 La′Cp * 2 and Cp * 2 Y(µ-H) 2 La′Cp * 2 over the homometallic species and for the specific heterometallic tuckover hydride complexes with the larger metal in the lower coordinate site.…”

“…A reaction of the heteroleptic formamidinato-samarium(II) complex Sm(DippForm) 2 (THF) 2 (DippForm = N,N′-bis (2,6-diisopropylphenyl)formamidinate, (CH(NC 6 H 3 i Pr 2 -2,6) 2 ) with carbon disulfide produced a light green dinuclear formamidinato-samarium(III) complex (µ-η 2 (C,S):κ(S′,S′′)-SCSCS 2 )[Sm(DippForm) 2 (THF)] 2 through an unusual C-S coupling (Scheme 1). The product contains a rare thioformyl carbonotrithioate ((SCSCS 2 ) 2-) bridging ligand rather than the expected tetrathiooxalate ligand as confirmed by single-crystal X-ray crystallography.…”

“…Each adopts a distorted octahedral coordination geometry around the six-coordinate Yb II ion. [5] Yb[N(TMS) 2 Hydrogenolysis of (CzPz iPr )Lu(CH 2 SiMe 3 ) 2 afforded a trimetallic lutetium hydride complex that possesses five bridging hydride ligands (Scheme 7 and Figure 2). Notably, intramolecular C-H bond activation of the CzPz iPr ligand was found to occur during the formation of this latter hydride complex, with metalation of a pyrazole carbon atom.…”