[1]Molybdarenophanes: Strained Metallarenophanes with Aluminum, Gallium, and Silicon in Bridging Positions
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- 作者：Clinton L. Lund ; Jö ; rg A. Schachner ; J. Wilson Quail ; Jens Mü ; ller
- 刊名：Journal of the American Chemical Society
- 出版年：2007
- 出版时间：August 1, 2007
- 年：2007
- 卷：129
- 期：30
- 页码：9313 - 9320
- 全文大小：138K
- 年卷期：v.129,no.30(August 1, 2007)
- ISSN：1520-5126
文摘
The first [1]molybdarenophanes were synthesized and structurally characterized. The aluminumand gallium compounds [(Me2Ntsi)Al(
6-C6H5)2Mo] (2a) and [(Me2Ntsi)Ga(6-C6H5)2Mo] (2b) [Me2Ntsi =C(SiMe3)2(SiMe2NMe2)] were obtained from [Mo(LiC6H5)2]·TMEDA and (Me2Ntsi)ECl2 [E = Al, Ga] inanalytical pure form with isolated yields of 74% (2a) and 52% (2b). The silicon-bridged species [Ph2Si(6-C6H5)2Mo] (2c) was synthesized from [Mo(LiC6H5)2]·TMEDA and Ph2SiCl2. Compound 2c was isolatedas a crystalline material in an approximately 90% overall purity, from which a single crystal was used forX-ray analysis. The molecular structures of all three [1]molybdarenophanes 2a-c were determined by single-crystal X-ray analysis. The ring-tilt angle 
was found to be 18.28(17), 21.24(10), and 20.23(29)
for 2a,2b, and 2c, respectively. Variable temperature NMR measurements of 2a and 2b (-80 to 80 C; 500MHz) showed a dynamic behavior of the gallium species 2b but not of compound 2a. The dynamic behaviorof 2b was rationalized by assuming that the Ga-N donor bond breaks, inversion at the nitrogen atomoccurs, and a rotation of the Me2Ntsi ligand takes place followed by a re-formation of the Ga-N bond onthe other side of the gallium atom. The analysis of the signals of meta and ortho protons of 2b gaveapproximate values of 
G
of 59.6 and 59.1 kJ mol-1, respectively. Compound 2b reacted with [Pt(PEt3)3]to give the ring-open product [(6-C6H6)Mo{6-C6H5[GaPh(Me2Ntsi)]}] (3b). The molecular structure of 3bwas deduced from a single-crystal X-ray determination. The formation of the unexpected platinum-freeproduct 3b can be rationalized by assuming that benzene reacted with 2b in a 1:1 ratio. Through aseries of 1H NMR experiments with 2b it was shown that small amounts of donor molecules (e.g., THF) inbenzene are needed to form 3b; in the absence of a donor molecule, 2b is thermally stable.
6-C6H5)2Mo] (2a) and [(Me2Ntsi)Ga(6-C6H5)2Mo] (2b) [Me2Ntsi =C(SiMe3)2(SiMe2NMe2)] were obtained from [Mo(LiC6H5)2]·TMEDA and (Me2Ntsi)ECl2 [E = Al, Ga] inanalytical pure form with isolated yields of 74% (2a) and 52% (2b). The silicon-bridged species [Ph2Si(6-C6H5)2Mo] (2c) was synthesized from [Mo(LiC6H5)2]·TMEDA and Ph2SiCl2. Compound 2c was isolatedas a crystalline material in an approximately 90% overall purity, from which a single crystal was used forX-ray analysis. The molecular structures of all three [1]molybdarenophanes 2a-c were determined by single-crystal X-ray analysis. The ring-tilt angle was found to be 18.28(17), 21.24(10), and 20.23(29) for 2a,2b, and 2c, respectively. Variable temperature NMR measurements of 2a and 2b (-80 to 80 C; 500MHz) showed a dynamic behavior of the gallium species 2b but not of compound 2a. The dynamic behaviorof 2b was rationalized by assuming that the Ga-N donor bond breaks, inversion at the nitrogen atomoccurs, and a rotation of the Me2Ntsi ligand takes place followed by a re-formation of the Ga-N bond onthe other side of the gallium atom. The analysis of the signals of meta and ortho protons of 2b gaveapproximate values of G of 59.6 and 59.1 kJ mol-1, respectively. Compound 2b reacted with [Pt(PEt3)3]to give the ring-open product [(6-C6H6)Mo{6-C6H5[GaPh(Me2Ntsi)]}] (3b). The molecular structure of 3bwas deduced from a single-crystal X-ray determination. The formation of the unexpected platinum-freeproduct 3b can be rationalized by assuming that benzene reacted with 2b in a 1:1 ratio. Through aseries of 1H NMR experiments with 2b it was shown that small amounts of donor molecules (e.g., THF) inbenzene are needed to form 3b; in the absence of a donor molecule, 2b is thermally stable.