Deprotonated diindolylmethanes as dianionic analogues of scorpionate bis(pyrazolyl)borate ligands: synthesis and structural characterization of representative titanocene and zirconocene complexes

Mason, Mark R.; Ogrin, Doug; Fneich, Bassam N.; Barnard, Thomas S.; Kirschbaum, Kristin

doi:10.1016/j.jorganchem.2004.09.003

Cited by 15 publications

(5 citation statements)

References 27 publications

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“…Structural data has been reported for poly(indol-2-yl)methanes bonded through the indole N atom to main-group elements from group 13 (B, Al, and Ga) (Fneich et al, 2018;Song et al, 2012;Kingsley et al, 2010), group 14 (Si) (Mason, 2003), and group 15 (P and Sb) (Mason, 2003;Mallov et al, 2012). Similar bonding patterns have been reported for group 4 metals (Ti and Zr) (Mason, Fneich et al, 2003;Mason, 2003;Mason et al, 2005). Motivation for this may be driven by the reduction in -donating ability of the indolyl amido compared to compounds where the lone pair is not part of a -system.…”

Section: Introductionsupporting

confidence: 52%

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

et al. 2019

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Four 2,2 0 -bisindolylmethanes (BIMs), a useful class of polyindolyl species joined to a central carbon, were synthesized using salicylaldehyde derivatives and simple acid catalysis; these are 2- (IId). BIMs (IIa) and (IIb) were characterized crystallographically as the dimethyl sulfoxide (DMSO) disolvates, i.e. C 26 H 24 N 2 OÁ2C 2 H 6 OS and C 25 H 20 Cl 2 N 2 OÁ2C 2 H 6 OS, respectively. Both form strikingly similar one-dimensional hydrogen-bonding chain motifs with the DMSO solvent molecules. BIM (IIa) packs into double layers of chains whose orientations alternate every double layer, while (IIb) forms more simply packed chains along the a axis. BIM (IIa) has a remarkably long c axis.

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Section: Introductionsupporting

confidence: 52%

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

et al. 2019

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“…In general, Cp 2 ZrCl 2 is an excellent precursor for the preparation of organozirconium alkyls and amides . The chloro group in 4 can also be replaced by other groups.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Structural Characterization, and Reactivity of Group 4 Metallacarboranes Containing the Ligand [Me₂C(C₅H₄)(C₂B₉H₁₀)]³⁻

et al. 2008

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The new inorganic/organic hybrid π ligand [Me2C(C5H4)(C2B9H10)]3− was prepared via a selective deboration of Me2C(C5H5)(C2B10H11) with piperidine in ethanol. Treatment of its sodium salt with MCl4(THF)2 gave the mixed-sandwich complexes [{η5:η5-Me2C(C5H4)(C2B9H10)}MCl2][Na(DME)3] (M = Zr (4), Hf (5)). Complex 4 reacted with C5H5Na, KCH2Ph, or NaNH(C6H3-2,6-Pr i 2) to afford {[η5:η2-Me2C(C5H4)(C2B9H10)]Zr(η5-C5H5)(μ-Cl)}{Na(DME)2} (7), [{η5:η5-Me2C(C5H4)(C2B9H10)}ZrCl(CH2C6H5)][Na(DME)3] (8), or [η5:η5-Me2C(C5H4)(C2B9H10)]Zr(NHC6H3Pr i 2)(THF) (9), respectively. Both 7 and 8 were stable, and no NaCl elimination was observed upon heating the toluene solution. In the presence of excess MAO (methylalumoxane), complexes 4, 5, and 8 were very active catalysts for ethylene polymerization. All complexes were fully characterized by various spectroscopic techniques and elemental analyses. Some were further confirmed by single-crystal X-ray analyses.

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“…Deprotonated 2,2′-bis(indolyl)methanes (henceforth: bis(indolyl)s) would accordingly represent appropriate candidates for multidentate indolyl-based ligands, and several bis(indolyl) complexes have already been reported. − However, since the early work by Mason et al in 2003 and 2005, progress of the coordination chemistry of bis(indolyl) ligands toward group 4 transition metals has somewhat stalled. Recently, our group found that the indolyl nitrogen atoms of bis(indolyl) ligands can adopt rare pyramidalized coordination geometries .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

et al. 2019

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Indolyl is the anionic species obtained from the deprotonation of the N–H group of indole. Group 4 transition-metal complexes that carry indolyl-based polydentate ligands represent promising homogeneous catalysts for, e.g., olefin polymerization, hydroamination, and nitrogen-fixation reactions due to the weak π-donation and electron-withdrawing properties, as well as the low basicity of indolyl. In this study, we systematically investigated the synthesis and structures of titanium and zirconium complexes that carry deprotonated 2,2′-bis(indolyl)methane ligands (henceforth: bis(indolyl) ligands) and two diethylamido ligands. We found that the coordination geometry of the indolyl nitrogen atom in such bis(indolyl) ligands is affected by the steric impact of the substituents attached to the central aromatic ring. Moreover, we examined the dynamics of such bis(indolyl) ligands in solution for the corresponding zirconium complexes, and the mechanism was discussed in conjunction with DFT calculations. The results of this study suggest that bis(indolyl) ligands may also serve as coordinatively flexible ancillary ligands, and indicate the feasibility of an expansion from bis(indolyl) to bis(indolyl)-donor ligands.

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Deprotonated diindolylmethanes as dianionic analogues of scorpionate bis(pyrazolyl)borate ligands: synthesis and structural characterization of representative titanocene and zirconocene complexes

Cited by 15 publications

References 27 publications

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

Synthesis, Structural Characterization, and Reactivity of Group 4 Metallacarboranes Containing the Ligand [Me₂C(C₅H₄)(C₂B₉H₁₀)]³⁻

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

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Deprotonated diindolylmethanes as dianionic analogues of scorpionate bis(pyrazolyl)borate ligands: synthesis and structural characterization of representative titanocene and zirconocene complexes

Cited by 15 publications

References 27 publications

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

Synthesis and crystal structures of some bis(3-methyl-1H-indol-2-yl)(salicyl)methanes

Synthesis, Structural Characterization, and Reactivity of Group 4 Metallacarboranes Containing the Ligand [Me2C(C5H4)(C2B9H10)]3−

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

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Synthesis, Structural Characterization, and Reactivity of Group 4 Metallacarboranes Containing the Ligand [Me₂C(C₅H₄)(C₂B₉H₁₀)]³⁻