Insertion of isocyanides into zirconium-alkyl bonds of di-ansa-zirconocene complexes. X-ray molecular structure of Zr{(SiMe2)2(η5−C5H3)2}Cl{η2−C(i−Pr)N(2,6-Me2C6H3)

Novel Metallacycles via Nucleophilic Aminomethylation: 5,5-Bis(cyclopentadienyl)-1,3-diaza-5-zirconacyclohexane and Related Organometallic Heterocycles

“…The assignment of the { 1 H} 13 C NMR resonances of 3a and 3b has been checked by proton-coupled 13 C NMR spectra. An odd numbered, symmetrical multiplet of low intensity at δ 240.0 for 3a and a singlet at δ 239.7 for 3b are consistent with the presence of η 2 -iminoacyl fragments in 3a and 3b . 18b,, The ν(CN) stretching mode is observed at 1618 cm -1 for 3a and at 1625 cm -1 for 3c . Literature values for similar compounds range from 1490 to 1760 cm -1 . − …”

“…Reactions of numerous dicyclopentadienyl zirconium alkyls with different alkyl isocyanides have enabled the isolation and characterization of a large number of η 2 -iminoacyl complexes . Several mechanistic and theoretical studies on this insertion reaction have also been reported, and the “inside” or “outside” coordination of the nitrogen atom in the iminoacyl ligands generated has been extensively studied. 3a,,18a,,20a Zirconaheterocycles have also been studied . In addition, insertion of carbon monoxide into zirconium organyl bonds has attracted much attention and was investigated in detail. , On the basis of these studies, one of the nine relevant orbitals in zirconocene dialkyl complexes occupies the central equatorial position, mutually cis to both alkyl ligands.…”

Multi-insertion Reactions of Isocyanides with Zirconium Amido Silyl Complexes

“…This preferential isocyanide insertion into the Zr−Si bonds in the alkyl silyl system prompted us to study the reactions of the amido analogues (Me 2 N) 3 ZrSiR 3 [SiR 3 = Si(SiMe 3 ) 3 ( 1 ), SiPh 2 Bu t ( 2 )] and (Me 2 N) 2 [(Me 3 Si) 2 N]ZrSi(SiMe 3 ) 3 ( 3 ) with isocyanide. Insertions of isocyanides (RNC) into M−C, − M−N, , and M−Si , bonds of early-transition-metal complexes are well documented; however, there are only a few reports of the reactions of isocyanides with metal complexes containing different reactive ligands. 3e,, The reactions of isocyanides with complexes involving both M−Si and M−N bonds, to our knowledge, have not been investigated. Our amido silyl complexes 1 − 3 offer a unique opportunity to observe the direct competition between silyl and amido ligands in the migration step and to study whether silyl or amido ligand migration is preferred.…”

Synthesis and reactivity of new mixed dicyclopentadienyl Group 4 metal complexes with the doubly bridged bis(dimethylsilanediyl)-cyclopentadiene-(η5-cyclopentadienyl) ligand

“…However di-h 5 -cyclopentadienyl ligands singly bridged by various alkyl [2 -5] and silyl [6][7][8][9][10][11][12][13][14] groups are among the most frequently used systems to bridge dinuclear metal compounds. We have recently reported the use of the 1,1%-2,2%-(dimethylsilanediyl)dicyclopentadienyl ligand to synthesize ansadicyclopentadienyl and bridged homodinuclear monoand di-cyclopentadienyl complexes of the Group 4 and 6 metals [15][16][17][18][19][20]. This and related doubly silyl-bridged ligands have also been used [14,21] to isolate mononuclear and dinuclear Group 4 metal compounds.…”