TY - JOUR
T1 - Anion-π interactions as controlling elements in self-assembly reactions of Ag(I) complexes with π-acidic aromatic rings
AU - Schottel, Brandi L.
AU - Chifotides, Helen T.
AU - Shatruk, Mikhail
AU - Chouai, Abdellatif
AU - Pérez, Lisa M.
AU - Bacsa, John
AU - Dunbar, Kim R.
PY - 2006/5/3
Y1 - 2006/5/3
N2 - Reactions of 3,6-bis(2′-pyridyl)-1,2,4,5-tetrazine (bptz) and 3,6-bis(2′-pyridyl)-1,2-pyridazine (bppn) with the AgX salts (X = [PF 6], [AsF6]-, [SbF6]-, and [BF4]-) afford complexes of different structural motifs depending on the π-acidity of the ligand central ring and the outer-sphere anion. The bptz reactions lead to the polymeric {[Ag(bptz)][PF 6]}∞ (1) and the dinuclear compounds [Ag2(bptz) 2(CH3CN)2][PF6]2 (2) and [Ag2(bptz)2(CH3CN)2][AsF 6]2 (3), as well as the propeller-type species [Ag 2(bptz)3][AsF6]2 (4) and [Ag 2(bptz)3]-[SbF6]2 (5a and 5b). Reactions of bppn with AgX produce the grid-type structures [Ag 4(bppn)4][X]4 (6-9), regardless of the anion present. In 6-9, π-π stacking interactions are maximized, whereas multiple and shorter (therefore stronger) anion-π interactions between the anions and the tetrazine rings are established in 1-5b. These differences reflect the more electron-rich character of the bppn pyridazine ring as compared to the bptz tetrazine ring. The evidence gleaned from the solid-state structures was corroborated by density functional theory calculations. In the electrostatic potential maps of the free ligands, a higher positive charge is present in the bptz as compared to the bppn central ring. Furthermore, the electrostatic potential maps of 3, 4, and 5b indicate an electron density transfer from the anions to the π-acidic rings. Conversely, upon addition of the [AsF 6]- ions to the cation of 7, there is negligible change in the electron density of the central pyridazine ring, which supports the presence of weaker anion-π interactions in the bppn as compared to the bptz complexes. From the systems studied herein, it is concluded that anion-π interactions play an important role in the outcome of self-assembly reactions.
AB - Reactions of 3,6-bis(2′-pyridyl)-1,2,4,5-tetrazine (bptz) and 3,6-bis(2′-pyridyl)-1,2-pyridazine (bppn) with the AgX salts (X = [PF 6], [AsF6]-, [SbF6]-, and [BF4]-) afford complexes of different structural motifs depending on the π-acidity of the ligand central ring and the outer-sphere anion. The bptz reactions lead to the polymeric {[Ag(bptz)][PF 6]}∞ (1) and the dinuclear compounds [Ag2(bptz) 2(CH3CN)2][PF6]2 (2) and [Ag2(bptz)2(CH3CN)2][AsF 6]2 (3), as well as the propeller-type species [Ag 2(bptz)3][AsF6]2 (4) and [Ag 2(bptz)3]-[SbF6]2 (5a and 5b). Reactions of bppn with AgX produce the grid-type structures [Ag 4(bppn)4][X]4 (6-9), regardless of the anion present. In 6-9, π-π stacking interactions are maximized, whereas multiple and shorter (therefore stronger) anion-π interactions between the anions and the tetrazine rings are established in 1-5b. These differences reflect the more electron-rich character of the bppn pyridazine ring as compared to the bptz tetrazine ring. The evidence gleaned from the solid-state structures was corroborated by density functional theory calculations. In the electrostatic potential maps of the free ligands, a higher positive charge is present in the bptz as compared to the bppn central ring. Furthermore, the electrostatic potential maps of 3, 4, and 5b indicate an electron density transfer from the anions to the π-acidic rings. Conversely, upon addition of the [AsF 6]- ions to the cation of 7, there is negligible change in the electron density of the central pyridazine ring, which supports the presence of weaker anion-π interactions in the bppn as compared to the bptz complexes. From the systems studied herein, it is concluded that anion-π interactions play an important role in the outcome of self-assembly reactions.
UR - http://www.scopus.com/inward/record.url?scp=33646553020&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646553020&partnerID=8YFLogxK
U2 - 10.1021/ja0606273
DO - 10.1021/ja0606273
M3 - Article
C2 - 16637658
AN - SCOPUS:33646553020
SN - 0002-7863
VL - 128
SP - 5895
EP - 5912
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 17
ER -