Synthesis And Catalysis Of Pyrrolyl-metal Complexes

Pyrrolyl metal compounds exhibited good catalytic effect, such as catalytic olefin polymerization, ring-opening polymerization of lactide and caprolatone. In addition, this kind of compounds were synthesized as cataly sts toward Tishchenko reaction and amidation reactions. Based on the application of this kind of compounds, many pyrrolyl metal compounds have been synthesized. However, the pyrrolyl aluminum compounds were more synthesized for either tridentate pincer type or bidentate pyrrolyl metal compounds, while pyrrolyl zinc compounds were relatively rare. Therefore, here the series of compounds containing pyrrolyl ligands were synthesized by satisfactory C, H, and N microanalysis. And on this basis, a series of pyrrolyl metal compounds were synthesized and characterized by 1H, 13C NMR spectra. The catalytic activity for the cyclotrimerization of isocyanate has been investigated. A detailed description is as follows:Six compounds containing pyrrolyl ligands, C4H2NH(2,5-CH2NC4H8)2, C4H3NH(CH2NHC(CH3)3)-2 (3-1), C4H3NH(CH2NHCH(CH3)2)-2 (3-2), C4 H3NH(CH2NHCH(CH2)5)-2 (3-3), C4H3NH(CH2NHCH3)-2 (3-4), C4H3NH (CH2NHCH2CH3)-2 (3-5), were synthesized by traditional Mannich reaction. The single crystal X-ray structural data and NMR data are go-t in the previous works. Then the corresponding pyrrolyl zinc compounds were synthesized:[{C4H3N(2-CH2NHipr)}ZnEt] (3b), [{C4H3N(2-CH2NH Cy)}ZnEt] (3c), [{C4H3N(2-CH2NHtBu)}ZnEt] (3d), [{C4H3N(2-CH2 NHCH3)}ZnEt] (3e), [{C4H3N(2-CH2NHC2H5)}ZnEt] (3f). In addition, the dimeric substances of tridentate pincer type pyrrolyl lithium, magnesium compounds were synthesized and characterized by 1H,13C NMR spectra. Our group obtained the single crystal X-ray structural data and NMR data except compounds 3e and 3f. All pyrroyl metal compounds exhibited good catalytic activities for the cyclotrimerization of isocyanate. The aromatic isocyanate cyclotrimerized almost quanti tatively to its corresponding aromatic isocya nurate in the presence of lithium compound (2a) at 0.1% mol loading in Et2O at room temperature.