Kobrsi Issam
Department of Chemistry, the Petroleum Institute, Abu Dhabi, United Arab Emirates.
PLoS One. 2014 Jun 19;9(6):e100626. doi: 10.1371/journal.pone.0100626. eCollection 2014.
The reaction of 3,5-di-2-pyridyl-1,2,4-triazole with excess Al(CH3)3 and Ga(CH3)3 afforded (3,5-di-2-pyridyl-1,2,4-triazolate)Al(CH3)2•3Al(CH3)3 (1) and (3,5-di-2-pyridyl-1,2,4-triazolate) Ga(CH3)2•3Ga(CH3)3 (2) respectively. 1 and 2 reacted with oxygen gas to produce (CH3)2M(µ-3,5-di-2-pyridyl-1,2,4-triazolate)(µ-OCH3)M(CH3)2 (M = Al, 3; M = Ga, 4). 3 and 4 contain the non-bulky dimethylalumino moiety, yet they are indefinitely stable in the presence of oxygen gas. This increased stability towards oxygen is due to ancillary 2-pyridyl groups bonding to the metal centers producing a pseudo-trigonal pyramidal Al and Ga environments. This environment blocks oxygen from further inserting into the M-C bond. The Al-N(pyridine) and Ga-N(pyridine) bonds reported herein are extremely elongated yet inactive towards dissociation due to the chelate effect.
3,5-二-2-吡啶基-1,2,4-三唑与过量的Al(CH₃)₃和Ga(CH₃)₃反应，分别得到(3,5-二-2-吡啶基-1,2,4-三唑基)Al(CH₃)₂•3Al(CH₃)₃ (1) 和(3,5-二-2-吡啶基-1,2,4-三唑基)Ga(CH₃)₂•3Ga(CH₃)₃ (2)。1和2与氧气反应生成(CH₃)₂M(µ-3,5-二-2-吡啶基-1,2,4-三唑基)(µ-OCH₃)M(CH₃)₂ (M = Al, 3；M = Ga, 4)。3和4含有体积不大的二甲基铝部分，但它们在氧气存在下能无限期稳定存在。对氧气稳定性的提高是由于辅助的2-吡啶基与金属中心键合，形成了伪三角锥型的Al和Ga环境。这种环境阻止氧气进一步插入M-C键。本文报道的Al-N(吡啶)键和Ga-N(吡啶)键极度拉长，但由于螯合效应而对解离不活跃。
