Experimental and computational studies on the reactivity of a terminal thorium imidometallocene towards organic azides and diazoalkanes

Wenshan Ren; Enwei Zhou; Bo Fang; Guohua Hou; Guofu Zi; De-Cai Fang; Marc D Walter

doi:10.1002/anie.201406191

Experimental and computational studies on the reactivity of a terminal thorium imidometallocene towards organic azides and diazoalkanes

Angew Chem Int Ed Engl. 2014 Oct 13;53(42):11310-4. doi: 10.1002/anie.201406191. Epub 2014 Aug 28.

Authors

Wenshan Ren¹, Enwei Zhou, Bo Fang, Guohua Hou, Guofu Zi, De-Cai Fang, Marc D Walter

Affiliation

¹ Department of Chemistry, Beijing Normal University, Beijing 100875 (China); College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China).

PMID: 25168074
DOI: 10.1002/anie.201406191

Abstract

The reaction of the base-free terminal thorium imido complex [{η(5)-1,2,4-(Me3C)3C5H2}2Th=N(p-tolyl)] (1) with p-azidotoluene yielded irreversibly the tetraazametallacyclopentene [{η(5)-1,2,4-(Me3C)3C5H2}2Th{N(p-tolyl)N=N-N(p-tolyl)}] (2), whereas the bridging imido complex [{[η(5)-1,2,4-(Me3C)3C5H2]Th(N3)2}2{μ-N(p-tolyl)}2][(n-C4H9)4N]2 (3) was isolated from the reaction of 1 with [(n-C4H9)4N]N3. Unexpectedly, upon the treatment of 1 with 9-diazofluorene, the NN bond was cleaved, an N atom was transferred, and the η(2)-diazenido iminato complex [{η(5)-1,2,4-(Me3C)3C5H2}2Th{η(2)-[N=N(p-tolyl)]}{N=(9-C13H8)}] (4) was formed. In contrast, the reaction of 1 with Me3SiCHN2 gave the nitrilimido complex [{η(5)-1,2,4-(Me3C)3C5H2}2Th{NH(p-tolyl)}{N2CSiMe3}] (5), which slowly converted into [{η(5)-1,2,4-(Me3C)3C5H2}{η(5):κ-N-1,2-(Me3C)2-4-CMe2(CH2NN=CHSiMe3)C5H2}Th{NH(p-tolyl)}] (6) by intramolecular C-H bond activation. The experimental results are complemented by density functional theory (DFT) studies.

Keywords: cycloaddition; diazoalkanes; imido complexes; organic azides; thorium.