Bromination Studies in the 5,10-Dihydrophenazasiline Series

Gilman, Henry; Zuech, Ernest A.

doi:10.1021/jo01067a110

Cited by 15 publications

(13 citation statements)

References 3 publications

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“…In this case, the phosphine arm was first installed by direct formation of a P–C bond, followed by introduction of the aldehyde functionality and, in the last step, condensation of two monophosphinated, benzaldehyde derivatives of di- tolyl -amine with the desired diamine. First, the monophosphinated intermediate 2 (δ P = −13.8 ppm) was prepared in 79% isolated yield by reacting bis(2-bromo-4-methylphenyl)amine with two equivalents of n BuLi at −40 °C, followed by quenching the dilithiated intermediate with one equivalent of i Pr 2 PCl . Lithium–halogen exchange and addition of dimethylformamide gave the desired aldehyde 3 in high isolated yield (87%; δ P = −8.8 ppm).…”

Section: Resultsmentioning

confidence: 99%

Binuclear Palladium Complexes Supported by Bridged Pincer Ligands

Herbert

Ozerov

2011

Organometallics

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A series of binucleating ligands each containing two tridentate pincer sites based on a central, monoanionic aryl (C) donor flanked by neutral phosphinito (P) and imino (N) donors, [(PCN)-(CH2) n -(PCN)] (1), or a central, monoanionic amido (N) flanked by neutral phosphine (P) and imino donors (N), [(PNN)-(CH2) n -(PNN)] (4), are presented. The metalating sites were linked through the condensation of two equivalents of m-hydroxybenzaldehyde or the purposively built asymmetric diarylamine [(H)N(2-C(O)H-4-Me-C6H3)(2-P(iPr)2-4-Me-C6H3)] (3) with primary α,ω-diamines (1,2-diaminoethane, n = 2; 1,4-diaminobutane, n = 4), which simultaneously constructed the imino arms and bridged the pincer cores. Ligands 1 and 4 were then used in the synthesis of neutral, square-planar palladium(II) complexes 5 and 6, [(PCN-C n )Pd2X2, (PNN-C n )Pd2X2; n = 2, 4; X = Cl, OAc, OTf]. The difference in the trans influence of the central donor was demonstrated through X-ray crystal structures of 5b-Cl, (PCN-C4)Pd2Cl2, and 6b-Cl, (PNN-C4)Pd2Cl2. The (PNN-C n )Pd2X2 complexes (6) proved to be redox-active, presumably via oxidation of the ligand, and cyclic voltammetry illustrated the extent to which electronic communication between the two pincer sites is mediated by the length of the bridge between them. (PCN-C n )Pd2OTf2 (5-OTf) and (PNN-C n )Pd2OTf2 (6-OTf) complexes reacted with hydride donors such as Et3SiH or β-hydride-containing alkoxides such as NaOiPr to generate bridging-hydride monocations [(PCN)Pd-H-Pd(PCN)-C n ][OTf] (5-H, n = 2, 4) and [(PNN)Pd-H-Pd(PNN)-C2][OTf] (6a-H), where the supported Pd–Pd separation was also found to be affected by the bridge length. In the case of the (CH2)4-bridged (PNN-C4)PdOTf (6b-OTf), a bridging-hydride monocation was not observed. Instead, the formation of [(PN(H)N)Pd-Pd(PNN)-C4][OTf] (6b-H), protonated at the amido N of the ligand with a direct Pd(I)–Pd(I) bond, was recorded.

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Section: Resultsmentioning

confidence: 99%

Binuclear Palladium Complexes Supported by Bridged Pincer Ligands

Herbert

Ozerov

2011

Organometallics

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“…17 The same dibromo-substituted amine precursor was used in each preparation. 25 The key step in the syntheses of the unsymmetrical ligands 1 and 2 is to add the dialkylchlorophosphine first, prior to the addition of the diphenylchlorophosphine, due to the higher electrophilic character of the diphenylchlorophosphine. If the order of addition is reversed, mixtures of products including the symmetrically-substituted ligands are formed.…”

Section: Synthesis and Characterization Of Unsymmetrical Ligands 1 Andmentioning

confidence: 99%

“…The starting bis(2-bromo-4-methylphenyl)amine was prepared according to the literature procedure. 25 NMR spectra were obtained at room temperature on a Bruker AMX 250 MHz spectrometer or on a Bruker AC 250 MHz spectrometer with a Tecmag MacSpect upgrade. All chemical shifts are reported in (d) ppm with 1 H and 13 C spectra referenced to tetramethylsilane or to their respective residual solvent peaks.…”

Section: Experimental General Proceduresmentioning

confidence: 99%

Unsymmetrical RPNPR′ pincer ligands and their group 10 complexes

2011

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Two new unsymmetrical (R)PNP(R')-type pincer ligands based on a bis(tolyl)amine framework have been synthesized and characterized by a variety of techniques, including X-ray crystallography. These ligands have been coordinated to Ni, Pd, and Pt precursors to provide a number of well-characterized group 10 halides. Conversion of these metal halides to metal hydrides was accomplished using borohydride reagents, or by direct interaction of the ligand with the zerovalent metal precursor. The insertion of oxygen into these hydrides in an attempt to prepare metal hydroperoxides has been examined; however, we were unable to obtain stable and isolable hydroperoxide species.

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“…The synthesis of N -aryl-substituted PNP ligand precursors is straightforward (Scheme ). A brominated precursor, o -dibromo- p -ditolylamine ( 1 ), was prepared by the slow addition of Br 2 to a cold solution of p -ditolylamine in glacial acetic acid . Subsequently, compound 1 was subjected to a N–C Ullman coupling − with iodonaphthalene or o -iodotoluene to yield 2a and 2b , respectively, as confirmed by 1 H NMR spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

“…All solvents were stored over molecular sieves in a N 2 -filled glovebox. Compound 1 was prepared according to a previously published literature procedure . All other chemicals were used as received.…”

Section: Experimental Sectionmentioning

confidence: 99%

Aryl and Benzyl C–H Activation of N-Substituted PNP Ligands

Vilanova

Iluc

2016

Organometallics

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The synthesis of the N-aryl-substituted PNP proligands H(PN naph P) (N-di(2-diisopropylphosphine-4-methylphenyl)naphthylamine) and H(PN tol P) (N-di(2-diisopropylphosphine-4methylphenyl)-o-tolylamine) is reported. The corresponding iridium(III) complexes, [(PN naph P)Ir(H)Cl], [(o-methyl-PN tol P)Ir-(H)Cl], [(o-aryl-PN tol P)Ir(H)Cl], [(PN naph P)Ir(H) 2 ], [(o-methyl-PN tol P)Ir(H) 2 ], and [(o-aryl-PN tol P)Ir(H) 2 ], were also synthesized and structurally characterized, along with reaction intermediates, demonstrating various ligand coordination modes.

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Bromination Studies in the 5,10-Dihydrophenazasiline Series

Cited by 15 publications

References 3 publications

Binuclear Palladium Complexes Supported by Bridged Pincer Ligands

Binuclear Palladium Complexes Supported by Bridged Pincer Ligands

Unsymmetrical RPNPR′ pincer ligands and their group 10 complexes

Aryl and Benzyl C–H Activation of N-Substituted PNP Ligands

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