title: Rapid acquisition of wideline MAS solid-state NMR spectra with fast MAS, proton detection, and dipolar HMQC pulse sequences.
abstract: The solid-state NMR spectra of many NMR active elements are often extremely broad due to the presence of chemical shift anisotropy (CSA) and/or the quadrupolar interaction (for nuclei with spin I > 1/2). These NMR interactions often give rise to wideline solid-state NMR spectra which can span hundreds of kHz or several MHz. Here we demonstrate that by using fast MAS, proton detection and dipolar hetero-nuclear multiple-quantum (D-HMQC) pulse sequences, it is possible to rapidly acquire 2D spectra which correlate1H chemical shifts to the indirectly detected wideline MAS powder patterns of dipolar coupled hetero-nuclei. The D-HMQC pulse sequence enables broadband excitation of the wideline hetero-nuclear NMR spectrum and provides higher sensitivity by detecting the narrower and more sensitive1H NMR signal. This approach is demonstrated for the rapid acquisition of 2D1H detected195Pt solid-state NMR spectra of cisplatin and transplatin and the71Ga solid-state NMR spectrum of a self-assembled Ga coordination polymer of unconfirmed structure. This approach should be broadly applicable for the rapid acquisition of wideline MAS solid-state NMR spectra of moderately abundant NMR nuclei.
authors.affiliation: Iowa State University, Department of Chemistry, Ames, IA 50011, USA. arossini@iastate.edu and US DOE Ames Laboratory, Ames, Iowa 50011, USA.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Rossini
authors.affiliation: Iowa State University, Department of Chemistry, Ames, IA 50011, USA. arossini@iastate.edu and US DOE Ames Laboratory, Ames, Iowa 50011, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hanrahan
authors.affiliation: US DOE Ames Laboratory, Ames, Iowa 50011, USA and Iowa State University, Materials Science and Engineering Department, Ames, IA 50011, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Thuo