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

• Published in: Journal of organometallic chemistry 1996-07, Vol.514 (1), p.219-226
• Main Authors: Varga, Vojtech, Hiller, Jörg, Polášek, Miroslav, Thewalt, Ulf, Mach, Karel
• Format: Article
• Language: English
• Subjects: Alkali metal ions; Titanium(III), Titanium tweezer; X-ray structure
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(95)06041-T

Complexes [ η 5-C 5HMe 4) 2Ti( η 1- C CSiMe 3) 2] −M + (M  Li (2), Na (3), K (4) and Cs ( 4) and 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), b = 18.047(8), c = 16.562(3) A ̊ , 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) and 2.949(4) Å) than to the outer ones (3.021(4) 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 characteristics EPR spectra ( g = 1.9924–1.9935, ΔH = 2.0–2.4 G, a Ti = 7.8–8.4 G), IR (ν(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.