Synthesis and structure of titanium(III) tweezer complexes with embedded alkali metal ions: [( η5-C 5HMe 4) 2Ti( η1-CCSiMe 3) 2] −M + (M  Li, Na, K, and Cs)

• Published in: Journal of organometallic chemistry 1996-05, Vol.515 (1), p.57-64
• Main Authors: Varga, Vojtech, Hiller, Jorg, Polasek, Miroslav, Thewalt, Ulf, Mach, Karel
• Format: Article
• Language: English
• Subjects: Alkali metals; Octamethyltitanocene; Titanium tweezer; Titanium(III); Trimethylsilylethynyl arms; X-ray structure
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(95)06092-B

Complexes [( η 5-C 5HMe 4) 2Ti( η 1-CCSiMe 3) 2] −M + (M  Li ( 2), Na ( 3), K ( 4), and Cs ( 5)) were prepared by the redox reaction of ( η 5-C 5HMe 4) 2Ti( η 1-CCSiMe 3) 2 ( 1) with the alkali metals in toluene. The X-ray crystal analysis of 4 (monoclinic, P2 1/ c, a = 10.888(3) Å, b = 18.047(8) Å, c = 16.562(3) Å, β = 104.10(2)°, Z = 4) revealed a tweezer structure with the potassium cation embedded between the trimethylsilylacetylide tweezer arms in a position which is slightly closer to the inner acetylide carbon atoms (2.946(4) Å and 2.949(4) Å) than to the outer ones (3.021(4) Å and 2.961(4) Å). The K + ion simultaneously binds a C 5HMe 4 ligand of the adjacent molecule at the K-centroid distance of 3.186(5) Å, thus forming a polymer chain arrangement of molecular units. The complexes 2–5 afford characteristic EPR spectra ( g = 1.9924–1.9935, Δ H= 2.0–2.4 G, a Ti = 7.8–8.4 G), infrared ( v(CC) at 1935–1948 cm −1) and UV-vis spectra (two CT bands in the region 355–390 nm). The molecular ions of 2–5 were observed in El mass spectra.