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

The extreme electron withdrawing properties of the perfluoropyridinoxy ligand –OC5F4N were used for the preparation of new (weakly) coordinating borate and aluminate anions of the type [E(OC5F4N)4]– (E = B or Al). These new anions are based on the potent parent Lewis acids E(OC5F4N)3, which possess...

Full description

Saved in:
Bibliographic Details
Published in:European journal of inorganic chemistry 2019-01, Vol.2019 (1), p.59-67
Main Authors: Riddlestone, Ian M., Keller, Sarah, Kirschenmann, Florian, Schorpp, Marcel, Krossing, Ingo
Format: Article
Language:English
Subjects:
Aluminum
Anions
Borates
Crystallization
Inorganic chemistry
Lewis acid
Lewis acids
Ligands
Lithium aluminum hydrides
Organic chemistry
Sodium
Supports
Weakly coordinating anions
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The extreme electron withdrawing properties of the perfluoropyridinoxy ligand –OC5F4N were used for the preparation of new (weakly) coordinating borate and aluminate anions of the type [E(OC5F4N)4]– (E = B or Al). These new anions are based on the potent parent Lewis acids E(OC5F4N)3, which possess exceptionally high calculated fluoride ion affinities (FIAs) of 500 and 587 kJ mol–1 for E = B and Al respectively. For aluminum, this extreme Lewis acidity dominates the chemistry and from mixtures of the neutral polymeric Lewis acid [Al(OC5F4N)3]n, the five‐ and six‐coordinate complexes Al(OC5F4N)3(OEt2)2 (1) and [Al(OC5F4N)2(µ‐OC5F4N) (NCMe)2]2 (2) were crystallized upon addition of ether or MeCN. The aluminate salts M[Al(OC5F4N)4] (M = Li or K) were prepared from the reaction between the alcohol 4‐HO–C5F4N and either LiAlH4 or K[AlEt4] respectively. The aluminate anion [Al(OC5F4N)4]– remains Lewis acidic coordinating small donor molecules forming [Al(OC5F4N)4(L)]– (L = THF or NMe3) and even supports formation and structural characterisation of the aluminum dianion containing salt [Na(OEt2)2][Na][Al(OC5F4N)5] (8). The from NaBH4 and 4‐HO–C5F4N accessible borate salt Na[B(OC5F4N)4] shows increased kinetic stability in comparison to the aluminum analogue. Very electron withdrawing …! Perfluoropyridinoxy ligands (–OC5F4N) possess extreme electron withdrawing properties that have been used to prepare (weakly) coordinating anions based on the Lewis superacids E(OC5F4N)3 (E = B or Al). The –OC5F4N ligand supports formation of neutral 5‐ and six‐coordinate aluminum species, a Lewis acidic aluminate anion, and even an aluminum dianion!
ISSN:1434-1948
1099-0682
DOI:10.1002/ejic.201801136