Session WOB. There are 5 abstracts in this session.

Session: Materials 1, time: 10:45-11:10
Solid-state NMR Studies of Graphene-based Systems and Nano-mole-scale Protein Solid-state NMR using Ultra-fast MAS
Yoshitaka Ishii
Tokyo Institute of Technology, Yokohama, Japan
This work involves two separate topics on solid-state NMR (SSNMR) applications to graphene-related nano-materials and ongoing progress of protein SSNMR using ultra-fast MAS. First, we discuss SSNMR structural studies on graphene-based nano materials such as two-dimensional (2D) graphitic carbon nitride. In the second topic, we discuss resolution and sensitivity enhancement in 1H and 13C biomolecular SSNMR under ultra fast magic angle spinning (UFMAS) conditions (≥ 80 kHz) in a high magnetic field (1H frequency: 750-900 MHz). Additional topics involving novel cross-polarization schemes and SSNMR studies of amyloid cross-propagation may be briefly discussed.

Session: Materials 1, time: 11:10-11:35
Polarization for the Unpolarizable, Calculation for the Uncalculable
Lyndon Emsley
EPFL, Lausanne, Switzerland
We will discuss new approaches to determining structures in materials that have so far been difficult to address using high-resolution multi-dimensional NMR methods.

Specifically, we will address the challenge of how to obtain enhanced sensitivity in bulk inorganic materials, which are often difficult to study because of prohibitively long T1s. We will describe an approach to significantly increase NMR sensitivity, and we demonstrate it with examples.

We will also address the problem of how to achieve high throughput calculation of structural constraints for molecular solids, enabling rapid DNP enhanced NMR crystallography.

Session: Materials 1, time: 11:35-11:50
Room-temperature optical 13C hyperpolarization in powdered diamond
Ashok Ajoy1; Kristina Liu1; Emanuel Druga1; Xudong Lv1; Raffi Nazaryan1; Ben Safvati1; Daniel Arnold1; Grace Li1; Arthur Lin1; Priyanka Raghavan1; Jeffrey Reimer1; Dieter Suter2; Carlos Meriles3; Alexander Pines1
1UC Berkeley, Berkeley, CA; 2TU Dortmund, Dortmund, Germany; 3CUNY, New York, NY
Nitrogen Vacancy (NV) centers in diamond are an attractive platform for dynamic nuclear polarization of nuclear spins, particular because they are electronic spins can be optically polarized at room temperature with modest laser powers. In the quest towards NV driven DNP, nanodiamond powder is particularly attractive: they have large surface areas, and one could arrange for a close physical contact between the polarized NVs and external nuclear spins.

We have developed a method to optically hyperpolarize diamond powder, obtaining high bulk 13C polarization (>0.1%) in 5-200um microcrystals comparable to the best results in single crystals. The technique is remarkably simple, and employs optical DNP at low-fields.

Session: Materials 1, time: 11:50-12:05
Correlating structure, dynamics and optoelectronics properties of donor-acceptor conjugated polymers
Manjunatha Reddy G. N.; Martin Seifrid; Thuc-Quyen Nguyen; Guillermo Bazan; Bradley Chmelka
University of California Santa Barbara, Santa Barbara, USA
Rigid and flexible components of donor-acceptor conjugated polymers and polymer:fullerene bimolecular nanocomposites adopt different structures, which can be correlated to different optical and electronic properties. Compositional and structural heterogeneities associated with these materials persist upon synthesis, post-synthesis modification and device fabrication processes, and ultimately influence the charge carrier properties through mechanisms that are poorly understood. We combine in situ and ex situ solid-state NMR spectroscopy techniques with X-ray scattering and DFT calculations to measure and understand compositions and structures of conjugated polymers consisting of different backbone and sidechain moieties, and correlate these results with the optoelectronic properties. In particular, we discuss the feasibility of dynamic-nuclear-polarization surface-enhanced NMR spectroscopy for the characterization of bulk and thin film conjugated polymers.

Session: Materials 1, time: 12:05-12:20
Spatial Distribution of Organic Functionalities Supported on Silica Surface: Exploration by Conventional and DNP-Enhanced Homonuclear SSNMR Experiments
Takeshi Kobayashi1; Dilini Singappuli-Arachchige1, 2; Zhuoran Wang1; Igor I. Slowing1; Marek Pruski1
1Ames Laboratory, Iowa State University, Ames, IA; 2Department of Chemistry, Iowa State University, Ames, IA
Using the 2D 1H-1H, 13C-13C and 29Si-29Si homonuclear correlation measurements, we developed, for the first time, a coherent description of the distribution of organic functionalities attached on the surface of mesoporous silica nanoparticles. The DNP-enhanced 29Si‒29Si double-quantum/single-quantum experiments revealed that the functionalities introduced by co-condensation form clusters and are less homogeneously distributed than those attached by grafting. The 1H‒1H triple-quantum/single-quantum experiments revealed similar degree of clustering in the samples with different amounts of functionalities introduced via co-condensation. These results suggest that a portion of organosilane precursors self-condense quickly after being injected into the mother liquor. The spatial distribution of different types of functionalities on the surface of bifunctional system was also studied by DNP-enhanced 13C‒13C single-quantum/single-quantum experiments under natural abundance.