Abstract:[Zr2Cl4(NPMe3)4(HNPMe3)] · CH3CN, a Phosphorane Iminato Complex with ZrN Double Bonds
The title compound has been prepared from a molten mixture of ZrCl4 with Me3SiNPMe3 in the presence of potassium fluoride and subsequent extraction with acetonitrile. According to the crystal structure determination the zirconium atoms are linked by three μ2‐N atoms of two NPMe3− groups and by the HNPMe3 molecule. Two terminal bounded chlorine atoms and a terminally coordinated NPMe3− ligand complete the distorted octahedral… Show more
“…In both cases the P-N-Zr angles were approaching linearity, being 174.8(4) and 175.2(4)°in 1 and 2, respectively. These are much larger than those reported for the related dimeric ([Zr 2 Cl 4 (NPMe 3 ) 4 (µ-HNPMe 3 )]) (159.3(2), 155.6-(2)°) 15 and trimeric ([Zr 3 Cl 6 (NPMe 3 ) 5 ] + ) (132.9(7), 126.1-(6)°) 16 species. The P-N bond distances of 1.588(5) and 1.569(7) Å, respectively, are typical of those found in other group IV phosphinimide complexes.…”
Section: Resultsmentioning
confidence: 65%
“…The P−N bond distances of 1.588(5) and 1.569(7) Å, respectively, are typical of those found in other group IV phosphinimide complexes . The Zr−N bond distances of 1.902(5) and 1.926(7) Å in 1 and 2 , respectively, are significantly shorter than the Zr−N bond distances found in the dimeric and trimeric species (1.95(2)−2.27(9) Å). − This suggests some degree of Zr−N multiple bond character. 1 ORTEP drawing of 1 .…”
Section: Resultsmentioning
confidence: 66%
“…17 The Zr-N bond distances of 1.902(5) and 1.926(7) Å in 1 and 2, respectively, are significantly shorter than the Zr-N bond distances found in the dimeric and trimeric species (1.95(2)-2.27(9) Å). [15][16][17] This suggests some degree of Zr-N multiple bond character.…”
Zirconium phosphinimide complexes of the form CpZr(NP-t-Bu 3 )Cl 2 (1) and Cp*Zr(NPR 3 )-Cl 2 (R ) i-Pr (2), t-Bu (3)) were readily prepared under ambient conditions via the reaction of [CpZrCl 3 ] n or Cp*ZrCl 3 with the appropriate trialkylphosphinimide lithium salt (R 3 PNLi). A series of derivatives were readily obtained via alkylation or arylation of the above dihalide precursors. These included CpZr(NP-t-Bu 3 )Me 2 (4), Cp*Zr(NPR 3 )Me 2 (R ) i-Pr (5), t-Bu (6)),. Reaction of 17 with the borane B(C 6 F 5 ) 3 yielded the zwitterionic and cationic complexes Cp*Zr(NP-t-Bu 3 )(CH 2 C(CH 3 )C(CH 3 )CH 2 B(C 6 F 5 ) 3 ) (18) and Cp*Zr(NP-t-Bu 3 )(THF)-(CH 2 C(CH 3 )C(CH 3 )CH 2 B(C 6 F 5 ) 3 ) (19). A number of the above compounds were screened for their potential as catalyst precursors in ethylene polymerization. In general, upon activation with methylaluminoxane, the resulting catalysts exhibit low activity. Efforts to understand the deactivation pathway for these zirconium catalysts involved investigating the interactions of catalyst precursors with activators. For example, reaction of 4 with the borane B(C 6 F 5 ) 3 leads to aryl group transfer and formation of catalytically inactive CpZr(NP-t-Bu 3 )(C 6 F 5 ) 2 (20). Interactions with MAO were modeled via reaction with AlMe 3 . The Zr clusters (Cp*Zr) 4 -(µ-Cl) 5 (Cl)(µ-CH) 2 ( 21) and (Cp*Zr) 5 (µ-Cl) 6 (µ-CH) 3 ( 22) were two of the products that were characterized from these reactions. The isolation of 21 and 22 infers that aryl for methyl exchange, ligand abstraction, and C-H bond activation may be catalyst deactivation pathways.
“…In both cases the P-N-Zr angles were approaching linearity, being 174.8(4) and 175.2(4)°in 1 and 2, respectively. These are much larger than those reported for the related dimeric ([Zr 2 Cl 4 (NPMe 3 ) 4 (µ-HNPMe 3 )]) (159.3(2), 155.6-(2)°) 15 and trimeric ([Zr 3 Cl 6 (NPMe 3 ) 5 ] + ) (132.9(7), 126.1-(6)°) 16 species. The P-N bond distances of 1.588(5) and 1.569(7) Å, respectively, are typical of those found in other group IV phosphinimide complexes.…”
Section: Resultsmentioning
confidence: 65%
“…The P−N bond distances of 1.588(5) and 1.569(7) Å, respectively, are typical of those found in other group IV phosphinimide complexes . The Zr−N bond distances of 1.902(5) and 1.926(7) Å in 1 and 2 , respectively, are significantly shorter than the Zr−N bond distances found in the dimeric and trimeric species (1.95(2)−2.27(9) Å). − This suggests some degree of Zr−N multiple bond character. 1 ORTEP drawing of 1 .…”
Section: Resultsmentioning
confidence: 66%
“…17 The Zr-N bond distances of 1.902(5) and 1.926(7) Å in 1 and 2, respectively, are significantly shorter than the Zr-N bond distances found in the dimeric and trimeric species (1.95(2)-2.27(9) Å). [15][16][17] This suggests some degree of Zr-N multiple bond character.…”
Zirconium phosphinimide complexes of the form CpZr(NP-t-Bu 3 )Cl 2 (1) and Cp*Zr(NPR 3 )-Cl 2 (R ) i-Pr (2), t-Bu (3)) were readily prepared under ambient conditions via the reaction of [CpZrCl 3 ] n or Cp*ZrCl 3 with the appropriate trialkylphosphinimide lithium salt (R 3 PNLi). A series of derivatives were readily obtained via alkylation or arylation of the above dihalide precursors. These included CpZr(NP-t-Bu 3 )Me 2 (4), Cp*Zr(NPR 3 )Me 2 (R ) i-Pr (5), t-Bu (6)),. Reaction of 17 with the borane B(C 6 F 5 ) 3 yielded the zwitterionic and cationic complexes Cp*Zr(NP-t-Bu 3 )(CH 2 C(CH 3 )C(CH 3 )CH 2 B(C 6 F 5 ) 3 ) (18) and Cp*Zr(NP-t-Bu 3 )(THF)-(CH 2 C(CH 3 )C(CH 3 )CH 2 B(C 6 F 5 ) 3 ) (19). A number of the above compounds were screened for their potential as catalyst precursors in ethylene polymerization. In general, upon activation with methylaluminoxane, the resulting catalysts exhibit low activity. Efforts to understand the deactivation pathway for these zirconium catalysts involved investigating the interactions of catalyst precursors with activators. For example, reaction of 4 with the borane B(C 6 F 5 ) 3 leads to aryl group transfer and formation of catalytically inactive CpZr(NP-t-Bu 3 )(C 6 F 5 ) 2 (20). Interactions with MAO were modeled via reaction with AlMe 3 . The Zr clusters (Cp*Zr) 4 -(µ-Cl) 5 (Cl)(µ-CH) 2 ( 21) and (Cp*Zr) 5 (µ-Cl) 6 (µ-CH) 3 ( 22) were two of the products that were characterized from these reactions. The isolation of 21 and 22 infers that aryl for methyl exchange, ligand abstraction, and C-H bond activation may be catalyst deactivation pathways.
“…The finding that [Cp*RhCl 2 ] 2 catalyzes the borylation of alkanes , led us to test reactions catalyzed by a series of Cp*MCl n complexes. Among these complexes, 1 mol % of [Cp*RuCl 2 ] 2 ( 1 ) (2 mol % of Ru) catalyzed the reaction of B 2 pin 2 (pin = pinacolate, eq 1) with octane to form HBpin and 1-octylBpin in quantitative yield after 48 h. With this result in hand, we studied reactions catalyzed by ruthenium complexes possessing structures and oxidation states that are likely to be closer to those of an active catalyst for alkane functionalization.…”
We report the regiospecific, ruthenium-catalyzed borylation of saturated terminal C-H bonds. Alkylboronates were obtained in 78-98% yields. The borylations of alkanes, trialkylamines, protected alcohols, and fluoroalkanes occurred regiospecifically at the methyl group that is least sterically hindered. In contrast to most organometallic C-H activation, the reactions of alkanes occurred in higher yields than the reactions of arenes. Reactions were conducted that probed steric and electronic effects on the alkyl borylation. These reactions showed that the borylation occurred preferentially at the methyl group that is least sterically hindered and most electron-deficient. Ruthenium compounds containing boryl ligands were synthesized, and one was characterized by X-ray crystallography. One of these compounds contained a rare bridging boryl ligand and served as a catalyst precursor for the borylation of octane.
“…Im Gegensatz zu Phosphaniminen R 3 PNR' mit R' = SiMe 3 , Alkyl oder Aryl, von denen nur die g 1 -Koordination bekannt ist [4,5], ko È nnen Phosphanimine R 3 PNH auch als l 2 -Bru È cken-Liganden auftreten. Beispiele sind [Zr 2 Cl 4 (l 2 -NPMe 3 ) 4 (l 2 -HNPMe 3 )] [6] und [Hf 2 (l-Cl)(l-OCMe 3 )(l-HNPMe 3 )(OCMe 3 ) 6 ] [7]. Wir berichten hier u È ber zwei neue Komplexe von Kupfer(I) und Platin(IV), in denen die Phosphanimine Me 3 PNH und Et 3 PNH l 2 -N-Bru È ckenfunktion erfu È llen.…”
Synthesis and Crystal Structures of the Phosphaneimine Complexes [Cu(μ‐HNPEt3)]4(O3S–CF3)4 and [Pt2Me6(μ‐I)2(μ‐HNPMe3)]
The title compounds have been prepared by the reaction of copper(I)triflate with [NiBr(NPEt3)]4 in CH2Cl2 suspension in the presence of water, and by the reaction of [PtMe3I]4 with Me3SiNPMe3 in boiling toluene in the presence of cesium fluoride, respectively. According to the crystal structure determinations the cation of the copper complex forms tetrameric units [Cu(HNPEt3)]44+ with S4 symmetry with Cu–N bond lengths of 191.6 and 192.1 pm. In the platinum complex the platinum atoms are linked by two μ‐I bridging atoms as well as by the μ‐N atom of the HNPMe3 ligand with Pt–N bond lengths of 228.1 and 229.5 pm.
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