The title carborane 1, a nearly nonvolatile air- and water-stable liquid, has been prepared in multigram quantities from dibenzylacetylene (l,4-diphenyl-2-butyne) and B6H9in the presence of triethylamine. The multifunctional reactivity of 1 has been systematically explored via the preparation of a variety of mixed iron-carborane-polyarene complexes in which one or more of the three bonding rings in 1 (C2B3and two C6) are coordinated to metals. Thus, 1 was bridge-deprotonated to give the (PhCH2)2C2B4H5- anion which in turn was treated with FeCl2and C8H82- ion to form the cyclooctatriene complex (η6-C8H10)Fe-[(PhCH2)2C2B4H4] (2). The C8H10ligand in 2 is readily displaced by arenes on heating, affording sandwich complexes of general formula (arene)Fe[(PhCH2)2C2B4H4] where the arene is [2.2]paracyclophane (3), 9,10-dihydroanthracene (4), or fluorene (o,o'-diphenylenemethane) (6). The reaction of 4 with 2 at elevated temperature yielded the staggered triple-decker diiron species (η6,η6-C14H12)Fe2[(PhCH2)2C2B4H4]2(5). Complexes 2–6 are air-stable orange crystalline solids. Treatment of 2 with chromium hexacarbonyl in refluxing butyl ether/tetrahydrofuran resulted in complexation of one phenyl ring with a Cr(CO)3group, forming (2-[(CO)3Cr(η6-C6H5)CH2]-3-PhCH2-2,3-C2B4H4)Fe(η6-C8H10) (7); reaction of 7 with Cr(CO)6gave the dichromium species (2,3-[(CO)3Cr(η6-C6H5)CH2]2-2,3-C2B4H4)Fe(η6-C8H10) (8) in which both of the phenyl rings and the carborane face are coordinated to metals. Complexes 7 and 8 are yellow, moderately air-and light-stable solids. Characterization of compounds 1–8 was achieved via11B and1H NMR, IR, and mass spectroscopy, supported by an X-ray diffraction analysis of a dichromium complex of 1 which is reported in the following paper.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry