The addition of 12-crown-4, in stoichiometric amounts or in excess, to a solution of LiC5H5 in THF affords the complex [(12-crown-4)Li(eta-5-C5H5)] (1). X-ray structural data demonstrate that it possesses a unique sandwichlike structure in which the Li+ ion is coordinated on one side by four oxygens from a 12-crown-4 ligand and on the other side by the cyclopentadienide anion, [C5H5]-, in an eta-5 fashion. In contrast, the addition of 12-crown-4 to THF solutions of Li(1,2,4-(Me3Si)3C5H2) gives the ion pair [Li(12-crown-4)2]+[1,2,4-(Me3Si)3C5H2]- (2), which has a free (eta-0) substituted-cyclopentadienide ion as part of its lattice. The latter complex represents a very rare example of the structure of an eta-0 delocalized carbanion, and the structure of 1 is the first of a new class of sandwich structures. Crystal data at 130 K: 1, C13H21LiO4, a = 7.729 (5) angstrom, b = 11.268 (7) angstrom, c = 15.618 (8) angstrom, orthorhombic, P2(1)2(1)2(1), Z = 4; 2, C30H61LiO8Si3, a = 11.924 (4) angstrom, b = 12.565 (4) angstrom, c = 14.530 (3) angstrom, alpha = 92.65 (2)-degrees, beta = 90.03 (2)-degrees, gamma = 120.28 (2)-degrees, triclinic, P1BAR, Z = 2.

AbstractDie Umsetzung von substituierten Cyclopentadienen mit Calciumamid und THF in flüssigem Ammoniak als Lösungsmittel liefert die kristallinen, luftempfindlichen THF‐Addukte (Me5C5)2Ca · 2THF (1), [1,3‐(Me3C)2C5H3]2Ca · THF (2), [(Me3Si)C5H4]2Ca · THF (4) und [1,3‐(Me3Si)2C5H3]2Ca · THF (5). Aus 1,2‐Dimethoxyethan‐Lösungen der Komplexe 1, 4, 5 erhält man die DME‐Komplexe 6, 7, 8. Der Komplex 1 wird durch Erhitzen im Vakuum in (Me5C5)2Ca · THF (9) übergeführt. Die Kristallstrukturuntersuchung von 5 zeigt das Vorliegen monomerer, gewinkelter Metallocene. Das Molekül THF ist Metall‐koordiniert.

ChemInformVolume 18, Issue 38 Physical Organic Chemistry ChemInform Abstract: Structure of a Crystalline Alkali Metal Cyclopentadienide P. JUTZI, P. JUTZI Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorW. LEFFERS, W. LEFFERS Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorB. HAMPEL, B. HAMPEL Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorS. POHL, S. POHL Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorW. SAAK, W. SAAK Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this author P. JUTZI, P. JUTZI Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorW. LEFFERS, W. LEFFERS Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorB. HAMPEL, B. HAMPEL Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorS. POHL, S. POHL Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this authorW. SAAK, W. SAAK Fak. Chem., Univ., D-4800 BielefeldSearch for more papers by this author First published: September 22, 1987 https://doi.org/10.1002/chin.198738055Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue38September 22, 1987 RelatedInformation

The solid potassium trimethylsilylcyclopentadienide 1 may be viewed as a “supersandwich” complex. It represents the first base-free alkali-metal cyclopentadienide to be obtained in crystalline form. Complex 1 contains parallel-arranged, one-dimensional, infinite structural units in which the potassium atoms (black) and the cyclopentadienyl rings (pentahapto-bonded on both sides) alternate. Weak interactions exist between the strands.

Reaction of indium(I) chloride with trimethylsilylated cyclopentadienyllithium species yields the air- and moisture-sensitive cyclopentadienylindium complexes In[(Me3Si)C5H4] (1), In[(Me3Si)2C5H3] (2) and In[(Me3Si)3C5H2] (3), which are volatile and easily soluble in nonpolar solvents. Compound 1 crystallizes as a chain polymer.

AbstractDie Umsetzung von Tris‐[trimethylsilyl]‐cyclopentadienyllithium mit Stickstoffbasen in Hexan führt zur Isolierung der kristallinen, luftempfindlichen Titelkomplexe (I), die in der Gasphase, in Lösung und in festem Zustand monomer vorliegen.

The introduction of three trimethylsilyl groups alters the nature of cyclopentadienyl–thallium interactions towards a situation where covalency is dominant and gives rise to a drastic change in the physical properties.