Direct chlorination of 1-CH(3)-CB(11)H(11)(-) in glacial acetic acid gave the highly chlorinated carborane anion 1-CH(3)-CB(11)Cl(11)(-), and treatment of 1-CH(3)-CB(11)H(11)(-) with ICl in triflic acid afforded the highly iodinated carborane anion 1-CH(3)-CB(11)I(11)(-). Under similar or more vigorous reaction conditions, however, the reaction of 1-CH(3)-CB(11)H(11)(-) with Br(2) in triflic acid did not proceed to completion. The highly brominated carborane anion 1-CH(3)-CB(11)Br(11)(-) was achieved via a sealed-tube reaction. This new method has led to the isolation of 1-H-CB(11)X(11)(-) (X = Cl, Br, I) and 1-Br-CB(11)Br(11)(-) in high yield. The lithiation of 1-H-CB(11)X(11)(-) resembles that of its parent anion CB(11)H(12)(-). Treatment of these lithio species with methyl iodide gave the methylated carborane anions 1-CH(3)-CB(11)X(11)(-). These new weakly coordinating anions were fully characterized by (1)H, (13)C, and (11)B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further confirmed by single-crystal X-ray analysis.

A new carbon-bridged versatile ligand Me2C(C9H7)(C2B10H11) (1) has been designed and successfully prepared by treatment of Li2C2B10H10 with 1 equiv of 6,6-dimethylbenzofulvene followed by hydrolysis with a saturated NH4Cl aqueous solution. 1 can be conveniently converted into the monoanion [Me2C(C9H6)(C2B10H11)]Li (2) and the dianion [Me2C(C9H6)(C2B10H10)]Li2 (3) by treatment with 1 or 2 equiv of n-BuLi, respectively. Both NaNH2 and NaH can only convert 1 into the monoanion, but cannot deprotonate the CH proton of the carborane cage in 1. These results differ significantly from those of a closely related analogue, Me2Si(C9H7)(C2B10H11). Treatment of SmI2 with 1 equiv of 3, followed by reaction with 1 equiv of 2, gave the redox product rac-[Li(DME)2][{η5:σ-Me2C(C9H6)(C2B10H10)}2Sm] (4). 4 can also be prepared by reaction of SmI2 with 1 equiv of 3 in a relatively lower yield. These two reactions may undergo different pathways, an intramolecular electron-transfer pathway for the former and an intermolecular electron-transfer pathway for the latter. The latter reaction can be accelerated by addition of CS2 or PhC⋮CPh, which led to the isolation of rac-[Li(THF)4][{η5:σ-Me2C(C9H6)(C2B10H10)}2Sm] (5). Unlike the SmI2 case, an equimolar reaction between 3 and YbI2 afforded the Yb(II) compound [η5:σ-Me2C(C9H6)(C2B10H10)]Yb(DME)2 (6). 6 can react with 1 equiv of 2 to generate a C−H bond reduction product, rac-[Li(DME)3][{η5:σ-Me2C(C9H6)(C2B10H10)}2Yb]·C6H5CH3 (7). Reaction of LnCl3 with 1 or 2 equiv of 2 yielded organolanthanide dichloride and monochloride compounds, respectively, [η5-Me2C(C9H6)(C2B10H11)]GdCl2(THF)2 (15) and [η5-Me2C(C9H6)(C2B10H11)]2LnCl(THF)(OEt2) (Ln = Y (8), Yb (9)). Treatment of 9 with 1 or 2 equiv of MeLi gave deprotonation products rac-[{η5:σ-Me2C(C9H6)(C2B10H10)}{η5-Me2C(C9H6)(C2B10H11)}]Yb(μ-Cl)Li(DME)2 (10) and rac-[Li(DME)2][{η5:σ-Me2C(C9H6)(C2B10H10)}2Yb] (11), respectively. Reaction of LnCl3 with 2 equiv of 3 also afforded ionic compounds rac-[Li(DME)2][{η5:σ-Me2C(C9H6)(C2B10H10)}2Ln] (Ln = Yb (11), Nd (12), Er (13)). Recrystallization of 7 from a mixed solvent of toluene/DME (10:1) gave meso-[Li(DME)3][{η5:σ-Me2C(C9H6)(C2B10H10)}2Yb]·2C6H5CH3 (14). All of these compounds were fully characterized by various spectroscopic and elemental analyses. The molecular structures of 4−7, 11, 12, and 14 have been confirmed by single-crystal X-ray analyses. The structural analyses reveal that the anions in 7 (or 11) and 14 are one pair of diastereomers.

A series of 14 heteroleptic rare earth sandwich complexes [M(III)-(nc)(oep)] (M=Y, La-Lu except Ce and Pm; nc=2,3-naphthalocyaninate; oep = octaethylporphyrinate) have been prepared by a one-pot procedure from corresponding [M(acac)3] . nH2O (acac = acetylacetonate), metal-free porphyrin H2(oep), and naphthalonitrile the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) in n-octanol. The molecular structures of four of these complexes (M = Sm, Gd, Y, Lu) are isostructural, exhibiting a slightly distorted square antiprismatic geometry with two domed ligands. The interplanar distance decreases from 2.823 to 2.646 A along the series as a result of lanthanide contraction. The whole series of complexes have also been characterized spectroscopically. All the electronic absorptions, except the two B-bands due to nc and the oep rings, are metal-dependent, indicating that there are substantial pi-pi interactions. The hole or the unpaired electron in these double-deckers is delocalized over both macrocyclic ligands, as evidenced by the co-appearance of the IR marker bands for the nc*- (1315-1325 cm(-1)) and oep*- (1510-1531 cm(-1)) T radical ions. Three one-electron oxidation couples and up to three one-electron reduction couples have been revealed by electrochemical methods. All the potentials are linearly dependent on the size of the metal center. The changes in absorption spectra during the first electro-oxidation and reduction of the La(III), Eu(III), and Y(III) double-deckers have also been studied spectroelectrochemically. The spectral data recorded for [M(III)(nc)(oep)]-(M = Y, La-Lu except Ce and Pm) reduced chemically with hydrazine hydrate are in accord with those obtained by spectroelectrochemical methods. The first heteroleptic naphthalocyaninate-containing triple-deckers [M(III)2(nc)-(oep)2] (M = Nd, Eu) have also been prepared by a raise-by-one-story method by using [M(III)(nc)(oep)] (M = Nd, Eu), [M(acac)3] . nH2O (M = Nd, Eu), and H2(oep) as starting materials. The compounds adopt a symmetrical triple-decker structure with two outer oep rings and one inner nc ring, which has been confirmed by 'H NMR spectroscopy and X-ray structural determination of the Nd complex. Both compounds give a near-IR absorption at 1021 nm (for M=Nd) or 1101 nm (for M = Eu), which has rarely been observed for neutral (or hole-free) triple-decker complexes and can be ascribed to the lowest-energy Q'(0, 0) transition. Similarly to the double-decker analogues. these triple-decker complexes undergo a series of one-electron transfer processes with a relatively small potential gap (1.1 -1.2 V) between the first oxidation and the first reduction.

Mixed halocarborane anions, 1-H-CB11Y5X6- (X, Y = Cl, Br, I), have been prepared by treatment of [Me3NH][1-H-CB11H5X6] (X = Cl, Br, I) with proper halogenating reagents at 180-220 degrees C in a sealed tube in high yield. These new anions are fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some are further confirmed by single-crystal X-ray analyses. The weakly coordinating nature of these anions is probed by 29Si chemical shifts of the resulting Pri3Si(1-H-CB11Y5X6) compounds. The results suggest that the coordinating ability of these anions is mainly dependent on the substituents at 7-12 positions (namely, X atoms), and the contribution from the upper belt substituents Y is relatively small. These suggestions are consistent with the results obtained from the structural study of silver salts of mixed halo- and perhalocarborane anions.

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.