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Monoalkylaluminium Complexes Stabilized by a Rigid Dianionic Diimine Ligand: Synthesis, Solid State Structure, and Dynamic Solution Behaviour of (dpp‐BIAN)AlR (R = Me, Et, i Bu)
Author(s) -
Lukoyanov Anton N.,
Fedushkin Igor L.,
Schumann Herbert,
Hummert Markus
Publication year - 2006
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200600033
Subject(s) - chemistry , diimine , ligand (biochemistry) , acenaphthene , metallacycle , alkyl , medicinal chemistry , molecule , tetracoordinate , ether , derivative (finance) , diethyl ether , crystallography , stereochemistry , aryl , dimethylaniline , x ray crystallography , photochemistry , organic chemistry , pyrene , biochemistry , receptor , physics , computer graphics (images) , computer science , diffraction , financial economics , optics , economics , planar , catalysis
(dpp‐BIAN)Na 2 (dpp‐BIAN = 1,2‐bis[(2,6‐di‐ iso ‐propylphenyl)imino]acenaphthene) reacts with two equivalents of R 2 AlCl in Et 2 O to give the monoalkylaluminium complexes (dpp‐BIAN)AlR(Et 2 O) (R = Me, 1 ; Et, 2 ; i Bu, 3 ). Compounds 1‐3 have been characterized by elemental analysis, IR and 1 H NMR spectroscopy. Single crystal X‐ray diffraction has been used to determine the molecular structures of 1 and 2 . Both structures show the aluminium atom tetrahedrally coordinated by the two N atoms of the dianionic dpp‐BIAN ligand, the alkyl group, and a diethyl ether molecule. Temperature dependent 1 H NMR spectroscopic measurements of 2 in THF‐d 8 revealed a dynamic process caused by positional exchange between the ethyl group and the ether molecule relative to the metallacycle, which slows down with decreasing temperature. In the case of the methyl derivative 1 , the corresponding process is fast at ambient as well as at low temperatures, whereas in the case of the isobutyl derivative 3 the larger size of the alkyl group prevents such a positional ligand exchange already at room temperature.