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Amminelithium Amidoborane Li(NH 3 )NH 2 BH 3 : A New Coordination Compound with Favorable Dehydrogenation Characteristics
Author(s) -
Xia Guanglin,
Yu Xuebin,
Guo Yanhui,
Wu Zhu,
Yang Chuanzhen,
Liu Huangkun,
Dou Shixue
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200903220
Subject(s) - dehydrogenation , chemistry , ammonia , orthorhombic crystal system , thermal decomposition , lithium (medication) , hydrogen bond , decomposition , atmospheric temperature range , crystallography , amorphous solid , inorganic chemistry , lithium amide , desorption , crystal structure , molecule , catalysis , organic chemistry , medicine , physics , adsorption , meteorology , endocrinology , enantioselective synthesis
The monoammoniate of lithium amidoborane, Li(NH 3 )NH 2 BH 3 , was synthesized by treatment of LiNH 2 BH 3 with ammonia at room temperature. This compound exists in the amorphous state at room temperature, but at −20 °C crystallizes in the orthorhombic space group Pbca with lattice parameters of a =9.711(4), b =8.7027(5), c =7.1999(1) Å, and V =608.51 Å 3 . The thermal decomposition behavior of this compound under argon and under ammonia was investigated. Through a series of experiments we have demonstrated that Li(NH 3 )NH 2 BH 3 is able to absorb/desorb ammonia reversibly at room temperature. In the temperature range of 40–70 °C, this compound showed favorable dehydrogenation characteristics. Specifically, under ammonia this material was able to release 3.0 equiv hydrogen (11.18 wt %) rapidly at 60 °C, which represents a significant advantage over LiNH 2 BH 3 . It has been found that the formation of the coordination bond between ammonia and Li + in LiNH 2 BH 3 plays a crucial role in promoting the combination of hydridic BH bonds and protic NH bonds, leading to dehydrogenation at low temperature.