Modulation of Electronic Couplings within Ru2–Polyyne Frameworks

Dimers of [Ru2(Xap)4] bridged by 1,3,5-hexatriyn-diyl (Xap are 2-anilinopyridinate and its aniline substituted derivatives), [Ru2(Xap)4]2(μ-C6) (1), were prepared. Compounds 1 reacted with 1 equiv of tetracyanoethene (TCNE) to yield the cyclo-addition/insertion products [Ru2(Xap)4]2{μ-CCC(C(CN)2)–C...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2011-09, Vol.133 (38), p.15094-15104
Main Authors: Xi, Bin, Liu, Isiah P.-C, Xu, Guo-Lin, Choudhuri, Mohommad M. R, DeRosa, Maria C, Crutchley, Robert J, Ren, Tong
Format: Article
Language:English
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Summary:Dimers of [Ru2(Xap)4] bridged by 1,3,5-hexatriyn-diyl (Xap are 2-anilinopyridinate and its aniline substituted derivatives), [Ru2(Xap)4]2(μ-C6) (1), were prepared. Compounds 1 reacted with 1 equiv of tetracyanoethene (TCNE) to yield the cyclo-addition/insertion products [Ru2(Xap)4]2{μ-CCC(C(CN)2)–C(C(CN)2)CC} (2) and 1 equiv of Co2(dppm)(CO)6 to yield the η2-Co2 adducts to the middle CC bond, [Ru2(Xap)4]2(μ-C6)(Co2(dppm)(CO)4) (3). Voltammetric and spectroelectrochemical studies revealed that (i) two Ru2 termini in 1 are sufficiently coupled with the monoanion (1 –) as a Robin–Day class II/III mixed valence species; (ii) the coupling between two Ru2 is still significant but somewhat weakened in 3; and (iii) the coupling between two Ru2 is completely removed by the insertion of TCNE in 2. The attenuation of electronic couplings in 2 and 3 was further explored with both the X-ray diffraction study of representative compounds and spin-unrestricted DFT calculations.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja204813h