Treatment of 1,2-(C6H5CH2)2-1,2-C2B10H10 with excess Na or K metal in THF at room temperature gave closo-exo-[(C6H5CH2)2C2B10H10]Na2(THF)4 (1) or [closo-exo-{(C6H5CH2)2C2B10H10}K2(THF)2(O2C4H8)0.5] n (2) in good yield after recrystallization from a THF solution or a THF/dioxane solution, respectively. Dissolution of 2 in a THF solution of 18-crown-6 ether afforded an exo-nido-{K(18-crown-6)}{[(C6H5CH2)2C2B10H10]K(18-crown-6)} (3). An equimolar reaction between 1,2-(C6H5CH2)2-1,2-C2B10H10 and K metal or 1,2-(C6H5CH2)2-1,2-C2B10H10 and [(C6H5CH2)2C2B10H10]K2 in THF at room temperature in the presence of 18-crown-6 ether generated two monoanion carborane compounds, [(THF)2K(18-crown-6)][nido-(C6H5CH2)2C2B10H11] (4) and {(THF)K(18-crown-6)}{1-(C6H5CH2)-2-(C6H5CH)-1,2-C2B10H10} (5), respectively. All of these complexes have been fully characterized by various spectroscopic data, elemental analyses, and X-ray diffraction studies. Compounds 1 − 3 represent the first structurally characterized examples of group 1 salts of carborane dianions of the C2B10 system.

The compound Me 2 C(C 5 H 5 )(C 2 B 10 H 11 ) (I) could be conveniently converted into the monoanion [Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] -(I-1) and the dianion [Me 2 C(C 5 H 4 )(C 2 B 10 H 10 )] 2-(I-2) by treatment with excess NaH and 2 equiv of n-BuLi, respectively. The monoanion I-1 could be further converted into the trianion [Me 2 C(C 5 H 4 )(nido-C 2 B 10 H 11 )] 3-(I-3) by reaction with 2 equiv of Na metal in THF and into the pentaanion [Me 2 C(C 5 H 4 )(arachno-C 2 B 10 H 11 )] 5in the presence of LnCl 3 and excess Na metal in THF. Reactions of LnCl 3 with the monoanion I-1 in molar ratios of 1:1, 1:2, and 1:3 generated the mono-, bis-, and tris-ligated organolanthanide compounds 4), and [η 5 -Me 2 C(C 5 H 4 )-(C 2 B 10 H 11 )] 3 Sm‚0.5C 7 H 8 (5), respectively. Reaction of LnCl 3 with 1 or 2 equiv of the dianion I-2 gave the same compound, [{η 5 :σ-Me 2 C(C 5 H 4 )(C 2 B 10 H 10 )} 2 Ln][Li(DME) 3 ] (Ln ) Sm (6), Yb ( 7)). 6 could also be prepared by treatment of 2 with 1 equiv of the dianion I-2. Reaction of YbI 2 with 1 equiv of I-2, followed by treatment with 1 equiv of I-1, also gave compound 7. However, YbI 2 reacted with 2 equiv of I-1 to afford the organoytterbium(II) compound [η 5 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )] 2 Yb(THF) 2 (8). Interaction of SmI 2 with 2 equiv of I-1 yielded two compounds, the redox product [η 5 :η 6 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Sm(THF) 2 ( 9) and the tris-ligated compound 5. The compound [η 5 :η 6 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Er(THF) 2 ( 10), an analogue of 9, was prepared by treatment of 1 with 2 equiv of Na metal or by reaction of ErCl 3 with 1 equiv of I-3. Treatment of 10 with excess Na metal gave the first organolanthanide compound containing a η 7 -carboranyl ligand, [{[η 5 :η 7 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Er} 2 {Na 4 (THF) 9 }] n (11). Its Dy analogue, [{[η 5 :η 7 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )]Dy} 2 {Na 4 (THF) 9 }] n (12), could also be prepared by a "one-pot" reaction of DyCl 3 , I-1, and excess Na metal. Treatment of 11 with 2 equiv of ErCl 3 in THF gave the novel tetranuclear cluster [{η 5 :η 7 -Me 2 C(C 5 H 4 )(C 2 B 10 H 11 )}Er 2 (µ-Cl)-(THF) 3 ] 2 (13), in which the Er 3+ ions replace all Na + ions in 11. All of these compounds were fully characterized by various spectroscopic data and elemental analyses. The solid-state structures of compounds 4-11 and 13 have been confirmed by single-crystal X-ray analyses.

Treatment of 1,2-(C 6 H 5 CH 2 ) 2 -1,2-C 2 B 10 H 10 with excess Na or Li metal in THF followed by reaction with MCl 3 in the presence of excess alkali metal gave novel 13-vertex closo-metallacarboranes 5), Er ( 6)) in moderate to good yield, respectively. Recrystallization of 3 from a DME solution afforded DME-coordinated metallacarborane {[(C 6 H 5 CH 2 ) 2 C 2 B 10 H 10 ]Er(DME)} 2 {Na(DME) 2 } 2 (4). 2 and 5 are the first examples of d 0 metallacarboranes incorporating a η 7 -carboranyl ligand. All of these complexes have been fully characterized by various spectroscopic date, elemental analyses, and X-ray diffraction studies. Molecular orbital calculations indicate that the metal-carborane bonding is well delocalized and can be described as the orbital interactions between the metal's five d orbitals and the cage's five symmetryadapted frontier orbitals. It is anticipated that only the d 0 /f n transition metal ion with the proper size is capable of being η 7 -bound to an arachno-carboranyl ligand.

Treatment of Me3NHF with 1 equiv of [(Me3Si)2C5H3]3Ln or (C5H5)3Ln in THF gave [{(Me3Si)2C5H3}2LnF]2 (Ln = La (1), Nd (2), Sm (3), Gd (4)) or [(C5H5)2LnF(THF)]2 (Ln = Y (5), Yb (6)) in moderate to good yield. All of them were fully characterized by elemental analyses, spectroscopy, and X-ray analyses. Compound 3 reacted with Na, AlCl3, (C6H5)3SiOH, and 2,6-Pr i 2C6H3OH to form [(Me3Si)2C5H3]2Sm(THF), [{(Me3Si)2C5H3}2SmCl]2, [(C6H5)3SiO]3Sm(THF)3 (7), and [2,6-Pr i 2C6H3O]3Sm(THF)3 (8), respectively. The molecular structures of [{(Me3Si)2C5H3}2SmCl]2, 7, and 8 were confirmed by X-ray diffraction study. The 3/NaH system can convert C6H5Br into C6H6 in 32% yield.