[C sub(6)F sub(5)Xe] super(+) and [C sub(6)F sub(5)XeNCCH sub(3)] super(+) Salts of the Weakly Coordinating Borate Anions, [BY sub(4)] super(-) (Y = CN, CF sub(3), or C sub(6)F sub(5))

New examples of [C sub(6)F sub(5)Xe] super( +) salts of the weakly coordinating [BY sub(4)] super(-) (Y = CN, CF sub(3), or C sub(6)F sub(5)) anions were synthesized by metathesis of [C sub(6)F sub(5)Xe][BF sub(4)] with M super(I)[BY sub(4)] (M super(I) = K or Cs; Y = CN, CF sub(3), or C sub(6)F sub...

Full description

Saved in:
Bibliographic Details
Published in:Inorganic chemistry 2008-04, Vol.47 (8), p.3205-3217
Main Authors: Koppe, Karsten, Frohn, Hermann-J, Mercier, Helene P A, Schrobilgen, Gary J
Format: Article
Language:English
Subjects:
Anions
Bonding
Cations
Charge
Dissociation energy
Electronic structure
Mathematical analysis
Solvents
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:New examples of [C sub(6)F sub(5)Xe] super( +) salts of the weakly coordinating [BY sub(4)] super(-) (Y = CN, CF sub(3), or C sub(6)F sub(5)) anions were synthesized by metathesis of [C sub(6)F sub(5)Xe][BF sub(4)] with M super(I)[BY sub(4)] (M super(I) = K or Cs; Y = CN, CF sub(3), or C sub(6)F sub(5)) in CH sub(3)CN at -40 [degrees]C, and were crystallized from CH sub(2)Cl sub(2) or from a CH sub(2)Cl sub(2)/CH sub(3 )CN solvent mixture. The low-temperature (-173 [degrees]C) X-ray crystal structures of the [C sub(6)F sub(5)Xe] super( +) cation and of the [C sub(6)F sub(5)XeNCCH sub(3)] super(+) adduct-cation are reported for [C sub(6)F sub(5)Xe][B(CF sub(3)) sub(4)], [C sub(6)F sub(5)XeNCCH sub(3)][B(CF sub(3)) sub(4)], [C sub(6)F sub(5)Xe][B(CN) sub(4)], and [C sub(6)F sub(5)XeNCCH sub(3)][B(C sub(6)F sub(5) ) sub(4)]. The [C sub(6)F sub(5)Xe] super( +) cation, in each structure, interacts with either the anion or the solvent, with the weakest cation-anion interactions occurring for the [B(CF sub(3)) sub(4)] super(-) anion. The solid-state Raman spectra of the [C sub(6)F sub(5)Xe] super( +) and [C sub(6)F sub(5)XeNCCH sub(3)] super(+) salts have been assigned with the aid of electronic structure calculations. Gas-phase thermodynamic calculations show that the donor-acceptor bond dissociation energy of [C sub(6)F sub(5)XeNCCH sub(3)] super(+) is approximately half that of [FXeNCCH sub(3)] super(+). Coordination of CH sub(3)CN to [C sub(6)F sub(5)Xe] super( +) is correlated with changes in the partial charges on mainly Xe, the ipso-C, and N, that is, the partial charge on Xe increases and those on the ipso-C and N decrease upon coordination, typifying a transition from a 2c-2e to a 3c-4e bond.
ISSN:0020-1669
DOI:10.1021/ic702259c