Anellated Heterophospholes and Phospholides and Analogies with Related Non-Phosphorus Systems

Bansal, Rani; Heinicke, Joachim

doi:10.1021/cr000434c

Cited by 117 publications

(46 citation statements)

References 227 publications

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“…It is based on addition of organolithium species at the phosphorus-carbon double bond, which has also been reported for other types of P=C compounds. [5] In continuation of our research on carbo-and heterocyclically anellated azaphospholes and azaphospholides, [6,7] we have observed competition between addition of tert-butyllithium at the double bond of the P=CH-NR group and CH-lithiation with bulky N-alkylated 1,3-benzazaphos-A C H T U N G T R E N N U N G pholes; [8] we report here on sterically and polarity-controlled formation of P=CLi-NR and/or (E)-tBuP-CHLi-NR species, Supporting information for this article is available on the WWW under http://www.chemeurj.org/ or from the author: NMR data for 3 b-5 b, formed by lithiation of 1 b in THF, tables with detailed X-ray structural data for 6 b, 11 b, and 12 b, 13 C NMR spectra of the reported compounds.…”

Section: Introductionmentioning

confidence: 90%

Sterically and Polarity‐Controlled Reactions of tBuLi with PCH‐NR Heterocycles: Novel Heterocyclic P‐ and P,O‐Ligands and Preliminary Tests in Transition‐Metal Catalysis

Aluri¹,

Kindermann²,

Jones³

et al. 2008

Chemistry A European J

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(1R)-1,3-Benzazaphospholes 1 a-c, P=CH-NR heterocycles of the indole type, react with tBuLi in two ways, depending on the steric demand of the N-substituent and the polarity of the medium. The presence of small N-alkyl groups induces CH-deprotonation in the 2-position to give hetaryllithium reagents 2 a and 2 b, whereas bulky N-substituents and nonpolar solvents change the reactivity towards addition at the P=C bond. The preferred regioselectivity is tert-butylation at phosphorus, occurring with excellent diastereoselectivity for trans-adducts 3 b and 3 c, but the inverse tert-butylation at C2 to 5 b was also observed. N-Neopentyl groups, with intermediate steric demand, give rise to formation of mixtures in ethers but allow switching either to selective CH lithiation in THF/KOtBu or to addition in pentane. Bulkier N-adamantyl groups always cause preferred addition. Protonation, silylation, and carboxylation were used to convert the P=CLi-NR, (E)-tBuP-CHLi-NR, and LiP-CH(tBu)-NR species into the corresponding sigma(2)-P or sigma(3)-P compounds 4 b and 6 a,b, 7 b,c, or 8 b-10 b with additional N and/or O donor sites. Slow diffusion-controlled air oxidation of 10 b led to the meso-diphosphine 11 b. Preferred eta(1)-P coordination was shown for an [Rh(cod)Cl] complex 12 b, and the potential of the new ligands 4 b and 7 b in catalysis was demonstrated by examples of Pd-catalyzed C-N coupling and Ni-catalyzed ethylene oligomerization (TON>6300). Crystal structures of 6 b, 11 b, and 12 b are presented.

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Section: Introductionmentioning

confidence: 90%

Sterically and Polarity‐Controlled Reactions of tBuLi with PCH‐NR Heterocycles: Novel Heterocyclic P‐ and P,O‐Ligands and Preliminary Tests in Transition‐Metal Catalysis

Aluri¹,

Kindermann²,

Jones³

et al. 2008

Chemistry A European J

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“…[12] Several quantum chemical studies have been performed to shed light on the nature of the chemical bonding in, and stabilization of, these compounds, including general principles and trends. [13] We have a longstanding interest in compounds containing twofold-coordinated (σ 2 ) group 15 [14] and group 14 elements [15,16] stabilized in delocalized π-systems, and in the influence of anellation on the stability and ligand properties of these σ 2 -element heterocycles. This includes a series of neutral non-anellated (1a), benzo-(2a) and naphtho-anellated NHGe compounds (3a), and also heterocyclic pyridoand quinoxaline-anellated NHGe compounds.…”

Section: Introductionmentioning

confidence: 99%

Transition Metal Complexes of N‐Heterocyclic Germylenes

et al. 2008

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The five-membered N-heterocyclic germylenes (NHGe) 1a-3a, with or without benzo or naphtho anellation, react with [Mo(CO) 3 (cht)] (cht = 1,3,5-cycloheptatriene) to form the fac-[(NHGe) 3 Mo(CO) 3 ] complexes 1b-3b. Similarly, [Ni(bnNHGe) 4 ] was obtained from the benzo-anellated germylene (bnNHGe) and Ni(1,5-cod) 2 ; attempts to synthesize less electron-rich complexes with mono-or divalent transition metals failed. The CO valence vibrations in the IR spectra of 1b-3b, together with their short Ge II -Mo bonds (as determined by X-ray crystallography), hint at the weak donor and good π-acceptor properties of the ligands. Quantum chemical studies on the benzo-anellated germylene, which are supported by the good correlation between calculated

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“…[17] Herein we report as imple access to annulated 1,3,4-azadiphospholes with aw idely tunable p-conjugated electronic structure, which have,i nc ontrast to well-studied diazaphospholes, [18] only rarely been investigated before. [19] These new compounds may find applications in electronic devices or chemical sensors.…”

mentioning

confidence: 99%

“…Thef ive-membered heterocycles VII-IX are special because they are formed in reactions between carboxylic acid chloride derivatives,RC(= X)Cl (X = NR, O, S) with two (OCP) À anions,but only one is fully included while the other serves as source of a" P À "i on after loss of CO. [17] Herein we report as imple access to annulated 1,3,4-azadiphospholes with aw idely tunable p-conjugated electronic structure, which have,i nc ontrast to well-studied diazaphospholes, [18] only rarely been investigated before. [19] These new compounds may find applications in electronic devices or chemical sensors.…”

mentioning

confidence: 99%

“…Hydrogen atoms and solvent molecules are omitted for clarity;i n(a), only the coordinating oxygen atoms of DME are shown. (5), C2-C3 1.415(6), C3-C4 1.341(6), C4-C5 1.426(6), C5-C6 1.418(6), C6-N1 1.428(5), C5-C7 1.395(6), C7-C8 1.369(6), C8-C9 1.385(7), C9-C10 1.376(6), C10-C6 1.407(6);c)Si[1b]: P1-P2 2.1038(7), P2-C2 1.7274 (19),C 2-N1 1.406(2), N1-C1 1.386(2), C1-O1 1.341(2), C1-P1 1.7344 (18), C2-C3 1.425(3), C3-C4 1.342(3), C4-C5 1.432(3), C5-C6 1.416(2), C6-N1 1.440(2), C5-C7 1.401(3), C7-C8 1.368(3), C8-C9 1.387(3), C9-C10 1.384(3), C10-C6 1.395(3).…”

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confidence: 99%

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Annulated 1,3,4‐Azadiphospholides: Heterocycles with Widely Tunable Optical Properties

2017

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Phosphorus heterocycles find applications in the synthesis of p-conjugated compounds and as precursors for optoelectronic materials such as organic light-emitting diodes (OLEDs), electronic switches,a nd transistors.Ahigh-yield, one-pot synthesis of anionic annulated 1,3,4-azadiphospholides from Na(OCP) and 2-chloropyridines is presented. The synthesis proceeds without the use of transition metals and tolerates aw ide range of substrates.C yano-substituted compounds are especially deeply colored and have absorption maxima which range from l max = 525 to 596 nm. The optical properties are dominated by the spatial separation of an electron acceptor and donor unit within one molecule (pushpull chromophore). The anionic 1,3,4-azadiphospholides are silylated to neutral siloxy compounds with astrong blue-shifted absorption. This reaction can be reversed by addition of fluoride ions,w hich allows fluoride ions to be detected in optically lowc oncentrations.Numerous p-conjugated molecules have astrong impact in the studies of new organic semiconductors and materials,such as dyes in lasers, [1] sensors,l ight emitting diodes, [2] and components for solar cells.[3] Introduction of main group elements in the extended p-systems such as sulfur, [4] boron, [5] silicon, [6] arsenic, [7] and phosphorus [8] allow the physical and electronic properties to be tuned.[9] Unsaturated molecules with low-valent s 2 ,l 3 -phosphorus centers have at endencyt o oligomerize and/or form cage-compounds,l imiting their application.[10] But several successful attempts to use R 2 C= PR and RCPm onomers for the synthesis of conjugated polymers were reported. [11] Compared to the C = C p-bond, the P = Cdouble bond is significantly weaker and the gap between the p (HOMO) and p*(LUMO) orbitals of the C = Pb ond is much smaller. [9g, 12] Phosphorus-containing p-conjugated heterocycles are often easier to handle, [8] and sodium phosphaethynolate,N a(OCP), proved to be av ersatile building block for those (see selected examples in Scheme 1). )o r[ 2 + +4] cycloadditions (VI [15] ), respectively,w hich are likewise formed by incorporating ac omplete (OCP) À anion into the cycle.[14c]Thef ive-membered heterocycles VII-IX are special because they are formed in reactions between carboxylic acid chloride derivatives,RC(= X)Cl (X = NR, O, S) with two (OCP) À anions,but only one is fully included while the other serves as source of a" P À "i on after loss of CO.[17] Herein we report as imple access to annulated 1,3,4-azadiphospholes with aw idely tunable p-conjugated electronic structure, which have,i nc ontrast to well-studied diazaphospholes, [18] only rarely been investigated before. [19] These new compounds may find applications in electronic devices or chemical sensors.We first further improved the synthesis of Na(OCP), which can now be very easily prepared on aseveral-hundred gram scale in high yield by simply exposing as olution of NaOtBu and dimethylcarbonate in THF to PH 3 (Scheme 2).[20] Subsequently,N a(OCP) was reacted with various 2...

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Anellated Heterophospholes and Phospholides and Analogies with Related Non-Phosphorus Systems

Cited by 117 publications

References 227 publications

Sterically and Polarity‐Controlled Reactions of tBuLi with PCH‐NR Heterocycles: Novel Heterocyclic P‐ and P,O‐Ligands and Preliminary Tests in Transition‐Metal Catalysis

Sterically and Polarity‐Controlled Reactions of tBuLi with PCH‐NR Heterocycles: Novel Heterocyclic P‐ and P,O‐Ligands and Preliminary Tests in Transition‐Metal Catalysis

Transition Metal Complexes of N‐Heterocyclic Germylenes

Annulated 1,3,4‐Azadiphospholides: Heterocycles with Widely Tunable Optical Properties

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