Neutral intramolecular hydrogen-bonded bases

Zhixin Tian; Alireza Fattahi; Lev Lis; Steven R. Kass

Neutral intramolecular hydrogen-bonded bases

Zhixin Tian, Alireza Fattahi, Lev Lis, Steven R. Kass

Research output: Contribution to journal › Article › peer-review

Abstract

B3LYP/aug-cc-pVDZ computations were carried out on polyamines with up to seven amino groups. The gas-phase proton affinities of these compounds are 219.6 (1-BuNH₂), 238.6 (H₂NCH₂CH₂CH ₂CH₂NH₂), 252.8 [(H₂NCH ₂CH₂CH₂)₂CHNH₂], 261.3 [(H₂NCH₂CH₂CH₂) ₃CNH ₂ (1)], and 288.5 kcal mol^-1 [(H₂NCH ₂CH₂CH(NH₂)CH₂CH₂) ₃CNH₂]. These results indicate that the tetraamine is near the top of the basicity scale and the heptaamine is more basic than any neutral organic compound which has been measured to date. A gas-phase equilibrium acidity determination between 1 and DBU also was carried out, and PA(1) = 256.2 ± 2.1 kcal mol^-1 was obtained. This demonstrates that multiple intramolecular hydrogen bonds can greatly increase basicities, and represents a new motif for designing super bases.

Original language	English (US)
Pages (from-to)	41-45
Number of pages	5
Journal	Croatica Chemica Acta
Volume	82
Issue number	1
State	Published - Jun 2009

Keywords

Computations
Gas-phase basicity
Hydrogen-bonding
Super bases

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title = "Neutral intramolecular hydrogen-bonded bases",

abstract = "B3LYP/aug-cc-pVDZ computations were carried out on polyamines with up to seven amino groups. The gas-phase proton affinities of these compounds are 219.6 (1-BuNH2), 238.6 (H2NCH2CH2CH 2CH2NH2), 252.8 [(H2NCH 2CH2CH2)2CHNH2], 261.3 [(H2NCH2CH2CH2) 3CNH 2 (1)], and 288.5 kcal mol-1 [(H2NCH 2CH2CH(NH2)CH2CH2) 3CNH2]. These results indicate that the tetraamine is near the top of the basicity scale and the heptaamine is more basic than any neutral organic compound which has been measured to date. A gas-phase equilibrium acidity determination between 1 and DBU also was carried out, and PA(1) = 256.2 ± 2.1 kcal mol-1 was obtained. This demonstrates that multiple intramolecular hydrogen bonds can greatly increase basicities, and represents a new motif for designing super bases.",

keywords = "Computations, Gas-phase basicity, Hydrogen-bonding, Super bases",

author = "Zhixin Tian and Alireza Fattahi and Lev Lis and Kass, {Steven R.}",

year = "2009",

month = jun,

language = "English (US)",

volume = "82",

pages = "41--45",

journal = "Croatica Chemica Acta",

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publisher = "Croatian Chemical Society",

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TY - JOUR

T1 - Neutral intramolecular hydrogen-bonded bases

AU - Tian, Zhixin

AU - Fattahi, Alireza

AU - Lis, Lev

AU - Kass, Steven R.

PY - 2009/6

Y1 - 2009/6

N2 - B3LYP/aug-cc-pVDZ computations were carried out on polyamines with up to seven amino groups. The gas-phase proton affinities of these compounds are 219.6 (1-BuNH2), 238.6 (H2NCH2CH2CH 2CH2NH2), 252.8 [(H2NCH 2CH2CH2)2CHNH2], 261.3 [(H2NCH2CH2CH2) 3CNH 2 (1)], and 288.5 kcal mol-1 [(H2NCH 2CH2CH(NH2)CH2CH2) 3CNH2]. These results indicate that the tetraamine is near the top of the basicity scale and the heptaamine is more basic than any neutral organic compound which has been measured to date. A gas-phase equilibrium acidity determination between 1 and DBU also was carried out, and PA(1) = 256.2 ± 2.1 kcal mol-1 was obtained. This demonstrates that multiple intramolecular hydrogen bonds can greatly increase basicities, and represents a new motif for designing super bases.

AB - B3LYP/aug-cc-pVDZ computations were carried out on polyamines with up to seven amino groups. The gas-phase proton affinities of these compounds are 219.6 (1-BuNH2), 238.6 (H2NCH2CH2CH 2CH2NH2), 252.8 [(H2NCH 2CH2CH2)2CHNH2], 261.3 [(H2NCH2CH2CH2) 3CNH 2 (1)], and 288.5 kcal mol-1 [(H2NCH 2CH2CH(NH2)CH2CH2) 3CNH2]. These results indicate that the tetraamine is near the top of the basicity scale and the heptaamine is more basic than any neutral organic compound which has been measured to date. A gas-phase equilibrium acidity determination between 1 and DBU also was carried out, and PA(1) = 256.2 ± 2.1 kcal mol-1 was obtained. This demonstrates that multiple intramolecular hydrogen bonds can greatly increase basicities, and represents a new motif for designing super bases.

KW - Computations

KW - Gas-phase basicity

KW - Hydrogen-bonding

KW - Super bases

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M3 - Article

AN - SCOPUS:68049129470

SN - 0011-1643

VL - 82

SP - 41

EP - 45

JO - Croatica Chemica Acta

JF - Croatica Chemica Acta

IS - 1

ER -

Neutral intramolecular hydrogen-bonded bases

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