Metal Tetrahydridoborates and Tetrahydroborato Metallates, 24 Solvates of Sodium Bis(borane)dimethylamide

摘要

The reaction of sodium metal with dimethylamine-borane in THF yields Na[(H_3B)_2NMe_2] (1) which can be isolated as {Na[(H_3B)_2NMe_2]}_5 (centre dot) THF or as Na[(H_3B)_2NMe_2] (centre dot) 15-crown-5 (2) and Na[(H_3B)_2NMe_2] (centre dot) benzo-15-crown-5 (3) after addition of the appropriate crown ether to the THF solution of 1. Reaction of 1 with ZrCl_4 yields Me_2HN-BH_2-NMe_2-BH_3 (4), the structure of which has been determined. In THF solution, 1 reduces aldehydes, ketones, acyl chlorides, and esters to the corresponding alcohols. It also reacts slowly with nitriles and allylbenzene. Compound (1)_5 (centre dot) THF crystallizes in an extended three-dimensional lattice, in which the Na atoms are coordinated by 6-9 hydridic H atoms, while 3 is a molecular compound in the solid state. Only one hydrogen atom of each BH_3 group coordinates to the sodium center. On the other hand, 4 forms dimeric associates in the solid state through N-H...H-B interactions.