Cation-π Interactions in the Solid State: Crystal Structures of M+(benzene)2CB11Me12- (M = Tl, Cs, Rb, K, Na) and Li+(toluene)CB11Me12-

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Title:Cation-π Interactions in the Solid State: Crystal Structures of M+(benzene)2CB11Me12- (M = Tl, Cs, Rb, K, Na) and Li+(toluene)CB11Me12-
Creators:
King, Benjamin T.
Noll, Bruce C.
Michl, Josef
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 64, 6, pp. 1001-1012
Uncontrolled Keywords:Sandwich complexes, Boranes, Carborane anions, Alkali metal cations, Cation-π interactions, Crystal structure determination, Carboranes, Noncovalent interactions, Arenes

Abstract

In these crystal structures, the relatively weak electrostatic interactions between the bulky CB<sub>11</sub>Me<sub>12</sub><sup>-</sup> anion and the title cations permit cation-π interactions in the solid state. In all cases, single-crystal X-ray diffraction analysis reveals η<sup>6</sup>-arene-cation interactions within 10% of the expected van der Waals distance. The Tl<sup>+</sup>, Cs<sup>+</sup>, Rb<sup>+</sup>, and K<sup>+</sup> structures are isomorphous, with the benzene molecules sandwiching the cation and four anions equatorially disposed in a nearly square arrangement. Both the cation and the near-square of closest anions are positioned to interact favorably with the local dipoles of benzene. The smaller Na<sup>+</sup> crystallizes in polymeric chains with a nearly tetrahedrally coordinated cation in van der Waals contact with two anions and two benzene molecules in a tilted-sandwich arrangement. The Li<sup>+</sup> structure possesses two motifs, a simple van der Waals sandwich of a toluene molecule and an anion, and chains of half-occupied toluene-Li complexes on inversion centers between anions. The simple van der Waals model is reasonably accurate for the cation-arene distances, only slightly underestimating the separation (2-10% deviation), with worse agreement for the smaller cations.

Title:Cation-π Interactions in the Solid State: Crystal Structures of M+(benzene)2CB11Me12- (M = Tl, Cs, Rb, K, Na) and Li+(toluene)CB11Me12-
Creators:
King, Benjamin T.
Noll, Bruce C.
Michl, Josef
Uncontrolled Keywords:Sandwich complexes, Boranes, Carborane anions, Alkali metal cations, Cation-π interactions, Crystal structure determination, Carboranes, Noncovalent interactions, Arenes
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:64
Number:6
Page Range:pp. 1001-1012
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19991001UNSPECIFIED
ID Code:1534
Item Type:Article
Deposited On:06 Feb 2009 17:10
Last Modified:06 Feb 2009 16:10

Citation

King, Benjamin T.; Noll, Bruce C.; Michl, Josef (1999) Cation-π Interactions in the Solid State: Crystal Structures of M+(benzene)2CB11Me12- (M = Tl, Cs, Rb, K, Na) and Li+(toluene)CB11Me12-. Collection of Czechoslovak Chemical Communications, 64 (6). pp. 1001-1012. ISSN 0010-0765

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