Lund Clinton L, Schachner Jörg A, Quail J Wilson, Müller Jens
Department of Chemistry and Saskatchewan Structural Sciences Centre, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan, Canada.
J Am Chem Soc. 2007 Aug 1;129(30):9313-20. doi: 10.1021/ja072747w. Epub 2007 Jul 11.
The first [1]molybdarenophanes were synthesized and structurally characterized. The aluminum and gallium compounds [(Me2Ntsi)Al(eta6-C6H5)2Mo] (2a) and [(Me2Ntsi)Ga(eta6-C6H5)2Mo] (2b) [Me2Ntsi = C(SiMe3)2(SiMe2NMe2)] were obtained from [Mo(LiC6H5)2].TMEDA and (Me2Ntsi)ECl2 [E = Al, Ga] in analytical pure form with isolated yields of 74% (2a) and 52% (2b). The silicon-bridged species [Ph2Si(eta6-C6H5)2Mo] (2c) was synthesized from [Mo(LiC6H5)2].TMEDA and Ph2SiCl2. Compound 2c was isolated as a crystalline material in an approximately 90% overall purity, from which a single crystal was used for X-ray analysis. The molecular structures of all three [1]molybdarenophanes 2a-c were determined by single-crystal X-ray analysis. The ring-tilt angle alpha was found to be 18.28(17), 21.24(10), and 20.23(29) degrees for 2a, 2b, and 2c, respectively. Variable temperature NMR measurements of 2a and 2b (-80 to 80 degrees C; 500 MHz) showed a dynamic behavior of the gallium species 2b but not of compound 2a. The dynamic behavior of 2b was rationalized by assuming that the Ga-N donor bond breaks, inversion at the nitrogen atom occurs, and a rotation of the Me2Ntsi ligand takes place followed by a re-formation of the Ga-N bond on the other side of the gallium atom. The analysis of the signals of meta and ortho protons of 2b gave approximate values of DeltaG not equal of 59.6 and 59.1 kJ mol-1, respectively. Compound 2b reacted with [Pt(PEt3)3] to give the ring-open product [(eta6-C6H6)Mo{eta6-C6H5[GaPh(Me2Ntsi)]}] (3b). The molecular structure of 3b was deduced from a single-crystal X-ray determination. The formation of the unexpected platinum-free product 3b can be rationalized by assuming that benzene reacted with 2b in a 1:1 ratio. Through a series of 1H NMR experiments with 2b it was shown that small amounts of donor molecules (e.g., THF) in benzene are needed to form 3b; in the absence of a donor molecule, 2b is thermally stable.
首次合成并对[1]钼杂芳烃进行了结构表征。铝和镓化合物[(Me2Ntsi)Al(η6-C6H5)2Mo] (2a)和[(Me2Ntsi)Ga(η6-C6H5)2Mo] (2b) [Me2Ntsi = C(SiMe3)2(SiMe2NMe2)]由[Mo(LiC6H5)2].TMEDA和(Me2Ntsi)ECl2 [E = Al, Ga]制得，为分析纯形式，分离产率分别为74% (2a)和52% (2b)。硅桥连物种[Ph2Si(η6-C6H5)2Mo] (2c)由[Mo(LiC6H5)2].TMEDA和Ph2SiCl2合成。化合物2c以结晶材料形式分离出来，总体纯度约为90%，从中选取单晶用于X射线分析。通过单晶X射线分析确定了所有三种[1]钼杂芳烃2a - c的分子结构。发现2a、2b和2c的环倾斜角α分别为18.28(17)、21.24(10)和20.23(29)度。对2a和2b进行变温NMR测量（-80至80℃；500 MHz），结果表明镓物种2b有动态行为，而化合物2a没有。通过假设Ga - N供体键断裂、氮原子发生反转、Me2Ntsi配体发生旋转，随后在镓原子另一侧重新形成Ga - N键，对2b的动态行为进行了合理解释。对2b的间位和邻位质子信号分析得出ΔG不等的近似值分别为59.6和59.1 kJ mol-1。化合物2b与[Pt(PEt3)3]反应生成开环产物[(η6-C6H6)Mo{η6-C6H5[GaPh(Me2Ntsi)]}] (3b)。通过单晶X射线测定推导得出3b的分子结构。通过假设苯与2b以1:1比例反应，可以解释意外生成不含铂产物3b的原因。通过对2b进行一系列1H NMR实验表明，苯中需要少量供体分子（如THF）才能形成3b；在没有供体分子的情况下，2b热稳定。
