The correlation of dative bond length and parameter n in adducts Me₃N—AlMe_3-nCl_n (n ≤ 3)

Abstract

Complexes of the general formula Me 3 N± ±AlMe 3± ±n Cl n (Me = CH 3 ; n = 0, 1, 2, 3) 1±4 have been synthesized and structurally characterized by X-ray crystallography and NMR spectroscopy. The shape of the molecules is trigonal-antiprismatic with the nitrogen and aluminium atoms being tetrahedrally surrounded. The length of the dative bond N± ±Al is correlated with the parameter n due to inductive effects of the electronegative chlorine substituents, resulting in a difference in N± ±Al between 1 and 4 of 0.1 # e (2.045, 2.010, 1.971, and 1.949 # e). This shortening with increasing n, however, is not linear.

Activation of Molecular Hydrogen by Inter‐ and Intramolecular Al−N Lewis Pairs

“…Therein, the AlÀ N distance of 2.311(2) Å is significantly longer if compared to representative Al-N distances in similar compounds. Some selected representative compounds and their AlÀ N bond lengths are as follows, [Me 2 NÀ C 10 H 6 À AlH 2 ] 2 2.118(3) Å (hydride bridged dimer), [20] Me 3 NÀ AlMe 3 2.045(2) Å, [21] (Me 3 N) 2 AlH 3 2.163(2) Å, [22] [TEDAÀ AlH 3 ] n 2.161(2) Å (both AlÀ N distances are equal) [15] and TEDA-(AlMe 3 ) 2 2.065(8) Å. [23] FLPs and classic Lewis pairs can be discriminated by atomic distances.…”

Towards Weakly Coordinating Anions with the Extremely Electron Withdrawing Perfluoropyridinoxy Ligand –OC5F4N

“…The Al–O bond length of the axially located –OC 5 F 4 N ligand shows even greater elongation [1.853(2) Å]. The Al–N bond length of 2.078(2) Å is longer than those reported for the four‐coordinate neutral complexes Me 3–n Cl n Al · NMe 3 [ n = 0–3; 1.949(4)–2.045(1) Å] and that of the neutral five‐coordinate species H 3 Al · 2NMe 3 [2.0163(2) Å] indicating that the NMe 3 molecule is relatively weakly bound.…”

Base-Stabilized Monomeric Stibinoalane dmap–Al(Et2)Sb(tBu)2

“…(2.045 Å (single crystal) [9], 2.10(1) Å (electron diffraction) [10]), H3Al-NMe3 (2.09(2), 2.02 (2), 2.03 (2) Å (single crystal) [11], 2.063(8) Å (electron diffraction) [12]), and Me3Al-NH3 2.004(5) Å (powder diffraction) [13], respectively. This clearly demonstrates the strong -donor capacity of dmap and the strong Lewis acid character of the Al center.…”