Effects of Structural Differences on the NMR Chemical Shifts in Isostructural Dipeptides

Title:
Effects of Structural Differences on the NMR Chemical Shifts in Isostructural Dipeptides
Authors:
Altheimer, Benjamin D.; Mehta, Manish A.
Abstract:
Porous crystalline dipeptides have gained recent attention for their potential as gas-storage materials. Within this large class is a group of dipeptides containing alanine, valine, and isoleucine with very similar crystal structures. We report the 13C (carbonyl and Cα) and 15N (amine and amide) solid-state NMR isotropic chemical shifts in a series of seven such isostructural porous dipeptides as well as shift tensor data for the carbonyl and amide sites. Using their known crystal structures and aided by ab initio quantum chemical calculations for the resonance assignments, we elucidate trends relating local structure, hydrogen-bonding patterns, and chemical shift. We find good correlation between the backbone dihedral angles and the Cα1 and Cα2 shifts. For the C1 shift tensor, the δ11 value shifts downfield as the hydrogen-bond distance increases, δ22 shifts upfield, and δ33 shows little variation. The C2 shift tensor shows no appreciable correlation with structural parameters. For the N2 tensor, δ11 shows little dependence on the hydrogen-bond length, whereas δ22 and δ33 both show a decrease in shielding as the hydrogen bond shortens. Our analysis teases apart some, but not all, structural contributors to the observed differences the solid-state NMR chemical shifts.
Citation:
Benjamin D. Altheimer and Manish A. Mehta. April 10, 2014. “Effects of Structural Differences on the NMR Chemical Shifts in Isostructural Dipeptides.” Journal of Physical Chemistry A 118(14): 2618-2628.
Publisher:
American Chemical Society
DATE ISSUED:
2014-04-10
Department:
Chemistry and Biochemistry
Type:
Article
PUBLISHED VERSION:
10.1021/jp411220y
PERMANENT LINK:
http://hdl.handle.net/11282/566868

Full metadata record

DC FieldValue Language
dc.contributor.authorAltheimer, Benjamin D.en
dc.contributor.authorMehta, Manish A.en
dc.date.accessioned2015-08-13T10:35:53Zen
dc.date.available2015-08-13T10:35:53Zen
dc.date.issued2014-04-10en
dc.identifier.citationBenjamin D. Altheimer and Manish A. Mehta. April 10, 2014. “Effects of Structural Differences on the NMR Chemical Shifts in Isostructural Dipeptides.” Journal of Physical Chemistry A 118(14): 2618-2628.en
dc.identifier.issn1089-5639en
dc.identifier.urihttp://hdl.handle.net/11282/566868en
dc.description.abstractPorous crystalline dipeptides have gained recent attention for their potential as gas-storage materials. Within this large class is a group of dipeptides containing alanine, valine, and isoleucine with very similar crystal structures. We report the 13C (carbonyl and Cα) and 15N (amine and amide) solid-state NMR isotropic chemical shifts in a series of seven such isostructural porous dipeptides as well as shift tensor data for the carbonyl and amide sites. Using their known crystal structures and aided by ab initio quantum chemical calculations for the resonance assignments, we elucidate trends relating local structure, hydrogen-bonding patterns, and chemical shift. We find good correlation between the backbone dihedral angles and the Cα1 and Cα2 shifts. For the C1 shift tensor, the δ11 value shifts downfield as the hydrogen-bond distance increases, δ22 shifts upfield, and δ33 shows little variation. The C2 shift tensor shows no appreciable correlation with structural parameters. For the N2 tensor, δ11 shows little dependence on the hydrogen-bond length, whereas δ22 and δ33 both show a decrease in shielding as the hydrogen bond shortens. Our analysis teases apart some, but not all, structural contributors to the observed differences the solid-state NMR chemical shifts.en
dc.language.isoen_USen
dc.publisherAmerican Chemical Societyen
dc.identifier.doi10.1021/jp411220yen
dc.subject.departmentChemistry and Biochemistryen
dc.titleEffects of Structural Differences on the NMR Chemical Shifts in Isostructural Dipeptidesen
dc.typeArticleen
dc.identifier.journalJournal of Physical Chemistry Aen
dc.subject.keywordSolid-state NMRen_US
dc.subject.keywordResidue carbonyl carbonsen_US
dc.subject.keywordX-ray structureen_US
dc.subject.keywordC-13 NMRen_US
dc.subject.keywordAb initio calculationsen_US
dc.subject.keywordShielding tensorsen_US
dc.subject.keywordHydrophobic dipeptidesen_US
dc.subject.keywordSecondary structureen_US
dc.subject.keywordAnisotropy tensorsen_US
dc.subject.keywordCrystalline stateen_US
dc.identifier.volume118en
dc.identifier.issue14en
dc.identifier.startpage2618en
All Items in The Five Colleges of Ohio Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.