Unequivocal evidence for sidearm participation in crystalline lariat ether complexes

Fronczek, Frank R.; Gatto, Vincent J.; Schultz, Rose Ann; Jungk, Steven J.; Colucci, William J.; Gandour, Richard D.; Gokel, George W.

doi:10.1021/ja00360a031

Cited by 55 publications

(9 citation statements)

References 3 publications

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“…We notice for all transition metals under study that the extraction yield is practically the same for 4 with a side-arm bearing a functionalised donor-group and 6 without a donorgroup in a side-arm. Indeed, we can conclude here, contrary to the literature, [19][20][21][22] that the complexation was due to the bipyrazole nitrogens without contribution of a side arm.…”

Section: Liquid-liquid Extraction Of Individual Cationscontrasting

confidence: 99%

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New functionalised C,C-bipyrazoles. Synthesis and cation binding properties

Attayibat

Radi

Lekchiri

et al. 2006

Journal of Chemical Research

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The synthesis of two new C,C-bipyrazoles ligands with a side-arm bearing a functionalised donor-group is reported. The complexation properties of these compounds towards bivalent metal ions (Hg 2+ , Cd 2+ , Pb 2+ , Cu 2+ , Zn 2+ ) and alkaline metal ions (Li + , Na + , K + ) was studied by a liquid-liquid extraction process and the extracted cation percentage was determined by atomic absorption measurements.

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Section: Liquid-liquid Extraction Of Individual Cationscontrasting

confidence: 99%

“…[19][20][21] Furthermore, structures with side arms attached at a nitrogen (N-pivot lariat ethers) instead of a carbon (C-pivot lariat ethers) have stronger binding properties because of greater flexibility, allowing the donor site to have the best binding position. 22…”

Section: Resultsmentioning

confidence: 99%

New functionalised C,C-bipyrazoles. Synthesis and cation binding properties

Attayibat

Radi

Lekchiri

et al. 2006

Journal of Chemical Research

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“…Peak Na + binding occurs when six oxygen atoms are present irrespective of how the donor atoms are arranged: The macroring may be 12-, 15-, or 18-membered and the side arm that complements it may contain one, two, or three oxygen atoms. Proof that the binding array is indeed three dimensional is found in the K + complexes of N-2-[2-(2-methoxyethoxy)ethoxy]ethylmonoaza-12-crown-4, IV, and N-(2-methoxyethyl)monoaza-18-crown-6, V (21). Complex IV· K + has the unique "cal abash" structure we have previously reported (22) (Figure 2).…”

Section: Cation Binding By Monoaza Lariat Etherssupporting

confidence: 67%

Cation Effects on Solvents, Ligands, and Nucleophiles

Gokel

Echegoyen

Arnold

et al. 1987

Advances in Chemistry

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Macrocyclic polyether compounds having one (lariat ethers) or two (bibracchial lariat ethers, BiBLEs) donor-group-bearing side arms exhibit Na+-, K+-, NH4+-, and Ca 2+ -binding affinities and selec tivities different from those of the unsubstituted macrocycles. Mac rocycles utilizing a nitrogen atom as the point of attachment (pivot atom) show generally higher flexibility and binding strength than compounds having the sidearm(s) attached at a carbon (carbon pivot). The more flexible and less polar compounds favor K + over the more charge-dense cations irrespective of hole size. The cation bind ing involves both the macroring and the side arms. This fact is demonstrated for solutions as well as the solid state. Ν-pivot BiBLEs can be prepared by a very convenient single-step cyclization or by a two-step approach that is more conventional but that affords high yields of product. Both lariat ethers and BiBLEs can be electrochemically "switched" to alter the cation-binding affinities and strengths.

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“…[7][8][9] Furthermore, structures with side arms attached at a nitrogen (N-pivot lariat ethers) instead of a carbon (C-pivot lariat ethers) have stronger binding properties because of greater flexibility, allowing the donor site to have the best binding position. 10…”

mentioning

confidence: 99%