Nitrogen-Capped π-Prismands:  Syntheses and Conformational Analyses

Kunze, Andreas; Bethke, Sabine; Gleiter, Rolf; Röminger, Frank

doi:10.1021/ol991360y

“…The copper-nitrogen distances are expanded with regard to copper(i) amine complexes (average [a] X = S for 4, 7-9, 11; X = Se for 5; X = O for 6. value 2.18 Å) [26] but comparable to those reported for 2·Cu + (2.11 Å). [9] The distance Cu-S (2.52 Å) is longer than those reported in other thioether-Cu I complexes (2.25-2.30 Å). [27] The molecular structure of 5·Cu + is isomorphous to that of 4·Cu + .…”

Section: (C) Formation Of Metal Complexesmentioning

confidence: 90%

“…These values are about 0.2 Å larger than those reported for 2·Ag + . [9] In the case of 7·Ag + it was possible to measure the wave number for the stretching vibration of the triple bond (ν = 2281 and 2206 cm -1 ). These values are shifted towards lower energy as compared to the free ligand (ν = 2293 and 2231 cm -1 ) which is evidence for an interaction between the metal and the triple bonds.…”

Section: (C) Formation Of Metal Complexesmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

Koschabek

¹

,

Gleiter

²

,

Röminger

³

2006

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The syntheses of seven bridgehead diazabicycloalkanes are reported. The bridges are represented by either a thioether chain and two 3‐hexyne units (4 and 6–8), one selenoether chain and two 3‐hexyne units (5), or one dithioether chain and two 4,4′‐diethylbiphenyl units (9, 10). X‐ray investigations reveal for 4–10 the in/in conformation at the bridgehead nitrogen atoms. Reactions with CuI triflate yield the endohedral CuI complexes of 4–6. Endohedral complexes of 6, 7, and 10 were isolated with silver triflate. X‐ray investigations and spectroscopic studies on the metal complexes reveal interactions between the metal ion and the nitrogen‐, chalcogen‐, and π‐units. In addition to the bicyclic systems 4–10 we synthesized the tripodal systems 28–33 in a one‐pot reaction. In the cases of 28 and 33 we were able to isolate the corresponding AgI complexes. X‐ray studies show an interaction between the metal ion and the nitrogen atom and one double bond of each of the three adjacent phenyl rings. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…Gleiter et al reported that torsional motion in related nitrogen-based systems is frozen out at À20 8C and the rotation of the p systems ceases at À82 8C. [20] [ 1 H NMR spectroscopy. The robustness of the [As 2 L 3 ] assembly is exciting for several reasons.…”

mentioning

confidence: 99%

Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex

Vickaryous

¹

,

Herges

²

,

Johnson

³

2004

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The self-assembly of supramolecular coordination compounds has resulted in structures with a diverse range of properties, shapes, sizes, and stoichiometries, including helicates (M 2 L 2 , M 2 L 3 , etc.), triangles (M 3 L 3 ), squares (M 4 L 4 ), rings (e.g., M 6 L 6 ), and polyhedra (M 4 L 4 , M 4 L 6 , M 6 L 6 , M 8 L 12 , etc.).[1] These assemblies almost exclusively contain metals with square-planar, tetrahedral or octahedral coordination geometries. Metals that can exhibit more peculiar coordination geometries have typically been avoided as components for a supramolecular design strategy, [2] most likely because of their variable coordination spheres. Herein we describe a supramolecular design strategy for forming arsenic-based assemblies, which relies on the self-assembly of arsenic(iii) with thiol ligands-and hence the reversibility and lability of arsenic-sulfur bonds-and we report the first member of this class, [As 2 L 3 ] (H 2 L = a,a'-dimercapto-para-xylene). The design strategy incorporates the unusual, yet predictable trigonal-pyramidal coordination geometry of As III featuring a stereochemically active lone pair when coordinated by sulfurbased ligands (Figure 1 a). [3][4][5][6] We selected arsenic(iii) as a design component because of its unusual coordination geometry and a general lack of specific and powerful chelators for this highly toxic ion. [7] Arsenic compounds are legendary for their toxicity, and hydrated As III is recognized as a known human carcinogen. Arsenic is abundant in the earths crust and is all-toofrequently present as an environmental health hazard; [8][9][10] however, specific chelators for environmental and in vivo remediation and sensing applications are lacking. Furthermore, the stereochemically active lone pair of As III adds a novel feature to the targeted supramolecular assemblies: for instance, lone pairs directed into the cavity would provide a unique soft, Lewis-basic cavity environment (Figure 1 b). [11] Figure 1 illustrates the design strategy for forming C 3h -symmetric [As 2 L 3 ] assemblies, which is based on rigid, twofold symmetric dithiols capable of acting as bridging ligands. Dithiol ligand H 2 L[12] (Scheme 1) was the initial bridging ligand investigated, because it is easily prepared and thiolates show a well-known affinity for As III .[12] Using a ligand such as H 2 L allows for two possible orientations of the arsenic lone pairs: into or out of the cavity of the complex. Molecular models (CAChe, MM3) indicated that the lone pairs would be directed into the cavity with an AsÀAs distance of about 6 . [13] H 2 L, synthesized by a literature procedure, [12] forms a yellowish white solid in 52 % yield when treated with stoichiometric amounts of AsCl 3 and KOH in THF/methanol mixtures. The product has very simple 1 H and 13 C NMR spectra, indicative of formation of the desired high-symmetry C 3h complex, and the parent ion peak [H{As 2 L 3 }] + is present in the electrospray ionization mass spectrum. Interestingly, [As 2 L 3 ] also forms in the absence of any...

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“…[20,23] The self-assembly strategy allows for increased yields in the macrobicyclization reaction and is a proof of principle of the design strategy to form arsenic-based supramolecular assem- Zuschriften blies from simple, identical starting compounds. The success of this strategy augurs well for the formation of larger arsenicbased capsules resulting from expanded two-and threefold symmetric ligands.…”

mentioning

confidence: 99%

Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex

Vickaryous

¹

,

Herges

²

,

Johnson

³

2004

View full text Add to dashboard Cite

The self-assembly of supramolecular coordination compounds has resulted in structures with a diverse range of properties, shapes, sizes, and stoichiometries, including helicates (M 2 L 2 , M 2 L 3 , etc.), triangles (M 3 L 3 ), squares (M 4 L 4 ), rings (e.g., M 6 L 6 ), and polyhedra (M 4 L 4 , M 4 L 6 , M 6 L 6 , M 8 L 12 , etc.).[1] These assemblies almost exclusively contain metals with square-planar, tetrahedral or octahedral coordination geometries. Metals that can exhibit more peculiar coordination geometries have typically been avoided as components for a supramolecular design strategy, [2] most likely because of their variable coordination spheres. Herein we describe a supramolecular design strategy for forming arsenic-based assemblies, which relies on the self-assembly of arsenic(iii) with thiol ligands-and hence the reversibility and lability of arsenic-sulfur bonds-and we report the first member of this class, [As 2 L 3 ] (H 2 L = a,a'-dimercapto-para-xylene). The design strategy incorporates the unusual, yet predictable trigonal-pyramidal coordination geometry of As III featuring a stereochemically active lone pair when coordinated by sulfurbased ligands (Figure 1 a). [3][4][5][6] We selected arsenic(iii) as a design component because of its unusual coordination geometry and a general lack of specific and powerful chelators for this highly toxic ion. [7] Arsenic compounds are legendary for their toxicity, and hydrated As III is recognized as a known human carcinogen. Arsenic is abundant in the earths crust and is all-toofrequently present as an environmental health hazard; [8][9][10] however, specific chelators for environmental and in vivo remediation and sensing applications are lacking. Furthermore, the stereochemically active lone pair of As III adds a novel feature to the targeted supramolecular assemblies: for instance, lone pairs directed into the cavity would provide a unique soft, Lewis-basic cavity environment (Figure 1 b). [11] Figure 1 illustrates the design strategy for forming C 3h -symmetric [As 2 L 3 ] assemblies, which is based on rigid, twofold symmetric dithiols capable of acting as bridging ligands. Dithiol ligand H 2 L[12] (Scheme 1) was the initial bridging ligand investigated, because it is easily prepared and thiolates show a well-known affinity for As III .[12] Using a ligand such as H 2 L allows for two possible orientations of the arsenic lone pairs: into or out of the cavity of the complex. Molecular models (CAChe, MM3) indicated that the lone pairs would be directed into the cavity with an AsÀAs distance of about 6 . [13] H 2 L, synthesized by a literature procedure, [12] forms a yellowish white solid in 52 % yield when treated with stoichiometric amounts of AsCl 3 and KOH in THF/methanol mixtures. The product has very simple 1 H and 13 C NMR spectra, indicative of formation of the desired high-symmetry C 3h complex, and the parent ion peak [H{As 2 L 3 }] + is present in the electrospray ionization mass spectrum. Interestingly, [As 2 L 3 ] also forms in the absence of any...

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Nitrogen-Capped π-Prismands: Syntheses and Conformational Analyses

Cited by 19 publications

References 19 publications

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex

Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex

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Nitrogen-Capped π-Prismands: Syntheses and Conformational Analyses

Cited by 19 publications

References 19 publications

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

Arsenic–π Interactions Stabilize a Self‐Assembled As2L3 Supramolecular Complex

Arsenic–π Interactions Stabilize a Self‐Assembled As2L3 Supramolecular Complex

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Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex

Arsenic–π Interactions Stabilize a Self‐Assembled As₂L₃ Supramolecular Complex