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Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 29. Synthetic and Structural Studies on Lanthanacarboranes with Two and Three \dqCarbons Apart\dq Carborane Cages Bonding to Ln(III) Metal (Ln(III) = Nd, Gd, Dy, Ho, Er, Tb, Lu)

, , , , , , und . Organometallics 22 (21): 4334--4342 (2003)

Zusammenfassung

The reactions of closo-exo-5,6-Na(THF)2-1-Na(THF)2-2,4-(SiMe3)2-2,4-C2B4H4 (1) with anhyd. LnCl3 (Ln = Nd, Gd, Dy, Ho, Er, Tb, Lu), in molar ratios of 2:1 in dry benzene (C6H6) at 60°, produced the full-sandwich lanthanacarborane complexes 2,2',4,4'-(SiMe3)4-3,5',6'-(m-H)3Na(X)n(Y)m-1,1'-commo-Ln(h5-2,4-C2B4H4)2 (2, Ln = Nd, X = THF, n = 2, Y = none; 3, Ln = Gd, X = THF, n = 3, Y = none; 4, Ln = Dy, X = THF, n = 1, Y = TMEDA, m = 1; 5, Ln = Ho, X = DME, n = 1, Y = none; 6, Ln = Er, X = THF, n = 1; Y = none; 7, Ln = Tb, X and Y = none; 8, Ln = Lu, X = THF, n = 2) in 70-93\% yields. However, the reactions of 1 at 60° with anhyd. LnCl3 (Ln = Dy, Er), at carborane to Ln molar ratios of 3:1 in dry benzene (C6H6), gave novel metallacarboranes, analogs of Cp3Ln, Na31,1'-5,6-(m-H)2-nido-2,4-(SiMe3)2-2,4-C2B4H4-2,2',4,4'-(SiMe3)4-1,1'-commo-Ln-(2,4-C2B4H4)2 (9, Ln = Dy; 10, Ln = Er) as yellow cryst. solids in 78 and 82\% yields, resp. While compds. 2-5 and 8-10 were characterized by single-crystal x-ray diffraction studies, the diamagnetic compd. 8 was also characterized by 1H, 13C, and 11B NMR spectroscopy and compds. 2, 3, and 5 were studied by EPR spectroscopy. Compds. 2, 4, and 8 are isostructural with bent-sandwich geometries, in which a Ln(III) center is coordinated to two carborane ligands. The solvated Na+ ions, present in each mol. for charge compensation, do not seem to influence the cage geometries. Complexes 2, 4, and 8 crystd. in the triclinic space group P1̅; complexes 3, 9, and 10 crystd. in the monoclinic space group P21/n; and complex 5 crystd. in the monoclinic space group C2/c. The final refinements of 2-5 and 8-10 converged at R1 = 0.0223, 0.0664, 0.0418, 0.0557, 0.0639, 0.0596, and 0.0770 and at wR2 = 0.0593, 0.1265, 0.1125, 0.1457, 0.1413, 0.1225, and 0.1594, resp. The room-temp. magnetic susceptibilities of 9 and 10 are 10.4 and 9.76 mB per metal atom, resp. on SciFinder(R)

Links und Ressourcen

DOI:
10.1021/om030426x
BibTeX-Schlüssel:
Wang.2003c
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