Cooperative intramolecularly hydrogen-bonded motif in the structure of 2:2 complex of TBD with 4-nitrocatechol

S. W. Ng; P. Naumov; S. Chantrapromma; S. S.S. Raj; H. K. Fun; A. R. Ibrahim; G. Wojciechowski; B. Brzezinski

doi:10.1016/S0022-2860(01)00432-X

Cooperative intramolecularly hydrogen-bonded motif in the structure of 2:2 complex of TBD with 4-nitrocatechol

S. W. Ng, P. Naumov, S. Chantrapromma, S. S.S. Raj, H. K. Fun, A. R. Ibrahim, G. Wojciechowski, B. Brzezinski

Chemistry

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

Abstract

In the crystal of the 2:2 complex of 1,5,7-triazabicyclo[4.4.0]dec-5-ene with 4-nitrocatechol the proton from 1-hydroxyl group of 4-nitrocatechol moiety is transferred to TBD to form ion-pair; two adjacent ion-pairs are linked across a center of inversion. The structure exhibits a cooperative, intramolecularly hydrogen-bonded motif. The hydrogen bonds are relatively long and, and they display only minor proton polarizability. The structure of the complex is retained in chloroform solution, as shown by FT-IR and ¹H NMR measurement; in acetonitrile, the compound partially dissociates. The partial dissociation is implied by the presence of free cations, and also by that of the (O···H···O)^- hydrogen bonds formed between two monodeprotonated 4-nitrocatechol molecules.

Original language	English (US)
Pages (from-to)	139-145
Number of pages	7
Journal	Journal of Molecular Structure
Volume	569
Issue number	1-3
DOIs	https://doi.org/10.1016/S0022-2860(01)00432-X
State	Published - Jul 19 2001

Keywords

1,5,7-Triazabicyclo[4.4.0]dec-5-ene
Cooperative hydrogen bonds
Crystal structure
FT-IR spectroscopy
H NMR spectroscopy
Intramolecular hydrogen bonds
Strong N-base

ASJC Scopus subject areas

Analytical Chemistry
Spectroscopy
Organic Chemistry
Inorganic Chemistry

Access to Document

10.1016/S0022-2860(01)00432-X

Cite this

@article{32a8b7e073124fa187996159b749a6ff,

title = "Cooperative intramolecularly hydrogen-bonded motif in the structure of 2:2 complex of TBD with 4-nitrocatechol",

abstract = "In the crystal of the 2:2 complex of 1,5,7-triazabicyclo[4.4.0]dec-5-ene with 4-nitrocatechol the proton from 1-hydroxyl group of 4-nitrocatechol moiety is transferred to TBD to form ion-pair; two adjacent ion-pairs are linked across a center of inversion. The structure exhibits a cooperative, intramolecularly hydrogen-bonded motif. The hydrogen bonds are relatively long and, and they display only minor proton polarizability. The structure of the complex is retained in chloroform solution, as shown by FT-IR and 1H NMR measurement; in acetonitrile, the compound partially dissociates. The partial dissociation is implied by the presence of free cations, and also by that of the (O···H···O)- hydrogen bonds formed between two monodeprotonated 4-nitrocatechol molecules.",

keywords = "1,5,7-Triazabicyclo[4.4.0]dec-5-ene, Cooperative hydrogen bonds, Crystal structure, FT-IR spectroscopy, H NMR spectroscopy, Intramolecular hydrogen bonds, Strong N-base",

author = "Ng, {S. W.} and P. Naumov and S. Chantrapromma and Raj, {S. S.S.} and Fun, {H. K.} and Ibrahim, {A. R.} and G. Wojciechowski and B. Brzezinski",

note = "Funding Information: In the IR spectrum of the complex in acetonitrile solution ( cm cm cm cm . This is corroborated by the ; only a broad signal (8.50–6.50 ppm) corresponding to the NH and OH protons is observed. Fig. 2c ), the presence of the ν (CN) band at 1647 −1 with a shoulder at 1629 −1 demonstrates that the protonated TBD molecule is partially separated from the anion. The partial dissociation from the complex is supported by the broadened band at 3340 −1 corresponding to the ν (NH) vibrations of almost free species; a medium-intensity continuous absorption is observed in the in the region 1800–500 −1 . The continuous absorption arises from probably two homoconjugated OH⋯O − ⇌ − O⋯HO hydrogen bonds that are formed between the two mono-deprotonated 4-nitrocatechol molecules. The equilibrium is shown in Scheme 2 1 H NMR spectrum ( Table 5 ) ",

year = "2001",

month = jul,

day = "19",

doi = "10.1016/S0022-2860(01)00432-X",

language = "English (US)",

volume = "569",

pages = "139--145",

journal = "Journal of Molecular Structure",

issn = "0022-2860",

publisher = "Elsevier B.V.",

number = "1-3",

}

TY - JOUR

T1 - Cooperative intramolecularly hydrogen-bonded motif in the structure of 2:2 complex of TBD with 4-nitrocatechol

AU - Ng, S. W.

AU - Naumov, P.

AU - Chantrapromma, S.

AU - Raj, S. S.S.

AU - Fun, H. K.

AU - Ibrahim, A. R.

AU - Wojciechowski, G.

AU - Brzezinski, B.

N1 - Funding Information: In the IR spectrum of the complex in acetonitrile solution ( cm cm cm cm . This is corroborated by the ; only a broad signal (8.50–6.50 ppm) corresponding to the NH and OH protons is observed. Fig. 2c ), the presence of the ν (CN) band at 1647 −1 with a shoulder at 1629 −1 demonstrates that the protonated TBD molecule is partially separated from the anion. The partial dissociation from the complex is supported by the broadened band at 3340 −1 corresponding to the ν (NH) vibrations of almost free species; a medium-intensity continuous absorption is observed in the in the region 1800–500 −1 . The continuous absorption arises from probably two homoconjugated OH⋯O − ⇌ − O⋯HO hydrogen bonds that are formed between the two mono-deprotonated 4-nitrocatechol molecules. The equilibrium is shown in Scheme 2 1 H NMR spectrum ( Table 5 )

PY - 2001/7/19

Y1 - 2001/7/19

N2 - In the crystal of the 2:2 complex of 1,5,7-triazabicyclo[4.4.0]dec-5-ene with 4-nitrocatechol the proton from 1-hydroxyl group of 4-nitrocatechol moiety is transferred to TBD to form ion-pair; two adjacent ion-pairs are linked across a center of inversion. The structure exhibits a cooperative, intramolecularly hydrogen-bonded motif. The hydrogen bonds are relatively long and, and they display only minor proton polarizability. The structure of the complex is retained in chloroform solution, as shown by FT-IR and 1H NMR measurement; in acetonitrile, the compound partially dissociates. The partial dissociation is implied by the presence of free cations, and also by that of the (O···H···O)- hydrogen bonds formed between two monodeprotonated 4-nitrocatechol molecules.

AB - In the crystal of the 2:2 complex of 1,5,7-triazabicyclo[4.4.0]dec-5-ene with 4-nitrocatechol the proton from 1-hydroxyl group of 4-nitrocatechol moiety is transferred to TBD to form ion-pair; two adjacent ion-pairs are linked across a center of inversion. The structure exhibits a cooperative, intramolecularly hydrogen-bonded motif. The hydrogen bonds are relatively long and, and they display only minor proton polarizability. The structure of the complex is retained in chloroform solution, as shown by FT-IR and 1H NMR measurement; in acetonitrile, the compound partially dissociates. The partial dissociation is implied by the presence of free cations, and also by that of the (O···H···O)- hydrogen bonds formed between two monodeprotonated 4-nitrocatechol molecules.

KW - 1,5,7-Triazabicyclo[4.4.0]dec-5-ene

KW - Cooperative hydrogen bonds

KW - Crystal structure

KW - FT-IR spectroscopy

KW - H NMR spectroscopy

KW - Intramolecular hydrogen bonds

KW - Strong N-base

UR - http://www.scopus.com/inward/record.url?scp=0035913309&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035913309&partnerID=8YFLogxK

U2 - 10.1016/S0022-2860(01)00432-X

DO - 10.1016/S0022-2860(01)00432-X

M3 - Article

AN - SCOPUS:0035913309

SN - 0022-2860

VL - 569

SP - 139

EP - 145

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

IS - 1-3

ER -

Cooperative intramolecularly hydrogen-bonded motif in the structure of 2:2 complex of TBD with 4-nitrocatechol

Abstract

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this