Reaction of FcC[triple bond, length as m-dash]CC(O)R (Fc = ferrocenyl) with Ru3(CO)12 leading to unexpected nitro-group reduced ruthenoles and 1,2-CO-inserted triruthenium clusters.

Lei Xu,Weiqiang Zhang,Guofang Zhang,Shasha Li,Ziwei Gao,Liping Jiang

doi:10.1039/c8ra04548h

Abstract

The reaction of Ru3(CO)12 with ferrocene-containing alkynyl ketones FcCCC(O)R (Fc = ferrocenyl; R = Ph (1); 2-thienyl (2); 4-CH3O–Ph (3); 4-NH2–Ph (4); 4-NO2–Ph (5); ferrocenyl (6)) proceeds in toluene with the formation of triruthenium clusters (1a–6a), ruthenoles (1b–5b, 5c and 1d–5d) and unexpected 1,2-CO-inserted triruthenium clusters (1c–4c). 1a–6a were isolated from the reaction of Ru3(CO)12 with one equivalent of 1–6, respectively. Ruthenoles 1b–5b, 5c and 1d–5d were collected by adding 1–5 to the corresponding 1a–5a in a molar ratio of 1 : 1, respectively. Unexpectedly, the nitro group in one of the two phenyl rings in both 5c and 5d molecules was reduced to an amino group, while their ruthenole skeletons are retained. When 1–4 were added to the corresponding 1a–4a in a molar ratio of 1 : 1, respectively, the unusual triruthenium clusters (1c–4c) were isolated, involving 1,2-insertion of a terminal coordinated carbonyl between two CC units of the ynone molecules. No reaction between 6a and 6 was observed. And the familiar cyclotrimerization products were not found. All new compounds were characterized by NMR, FT-IR, and MS-ESI and most of them were structurally confirmed by single crystal X-ray diffraction. The results suggested that the ferrocenyl groups in the 1,3-ynones exhibit strong electron and steric effects on the reaction process and product distribution during their reactions with Ru3(CO)12.

Highlights

Ru3(CO)[12] as a potent catalyst precursor has attracted great interest of researchers due to its unique activity in homogeneous catalytic reactions.[1]
A er slow cooling, the unreacted Ru3(CO)[12] was ltered and recovered, the solvents were removed and the residues were chromatographed on silica gel with dichloromethane and it was found that a mixture of ruthenium clusters was obtained
An electron-withdrawing group at the carbonyl side of an alkynyl ketone is bene cial to the formation of normal ruthenoles b, c and d; while an electrondonating group favors the production of normal ruthenoles b and d, but disfavors the formation of ruthenole c; the larger steric hindrance and electron-donating effect of two ferrocenyl groups in 6 prefers only the formation of 6a

Summary

Introduction

Ru3(CO)[12] as a potent catalyst precursor has attracted great interest of researchers due to its unique activity in homogeneous catalytic reactions.[1]. Compared with the studied 1,3-diphenylprop-2yn-1-one derivatives,[17] the reactions of the ferrocenecontaining 1,3-ynones 1–6 with Ru3(CO)[12] afforded unexpected 1,2-CO-inserted p-coordinated triruthenium clusters (1c–4c), the head-to head ruthenoles (5c and 5d) with reduction of half of the nitro groups into amino groups.

Results

Conclusion