NMR

Central NMR Facility

 

 Overview

 

The central NMR facility operates and maintains the NMR spectrometers. Although the primary users of the NMR facility are from the research community within the laboratory, the facility is also open to researchers in other educational institutions and industry.

 

 Mission & Goals

 

To provide state-of-the-art NMR spectroscopic techniques in solution and solid state for scientists in diverse research areas.

 

Competencies

 

- Structural elucidation of organic and bio-organic molecules

 

- Micro structural analysis of polymers

 

- NMR of molecular self assemblies

 

- Solid state NMR of polymers and zeolites and other inorganic materials

 

- NMR of gels

 

- Diffusion by pulse field gradient NMR

 

- Micro imaging

 

- Identification of polymorphs by solid state NMR

 

- NMR instrumentation and maintenance

 

Facilities

 

Solution State: Multi-nuclear and multi-dimensional NMR.

 

Solid State: wide line NMR, Magic Angle Spinning (MAS) and Cross-Polarisation (CP)/MAS, Multiple Quantum (MQ)/ MAS.

 

High Resolution MAS on gels

 

NMR micro imaging

 

BrukerDRX500

 

- A narrow bore spectrometer (52 mm) with 11.1 T magnet

 

Solution State

 

- QNP (P, C, N and H) probe

 

- Broad Band Inverse probe with PFG, capable of handling the full range of nuclei

 

- 10 mm high temperature C probe

 

Solid State

 

- Broad band4mm CP/MAS probe

 

- 4mm HRMAS probe for gels

 

- Doty 4mmXY probe

 

 BrukerMSL-300

 

- Wide bore (89mm) instrument with 7.1 T Magnet

 

- Two solution probes (5mm Hand C, 10mm H/BB)

 

- MAS probe (H/46 - 85 MHz) for high- resolution solid state NMR

 

- Broad Band Wide line probe for static solid state NMR

 

- Micro imaging probe with 5 mm, 10 mm, 15 mm and 20 mm inserts.

 

BrukerAC-200

 

- Narrow bore (52mm) instrument

 

- Equipped with two solution probes (5 mm H, C, P and F, QNP and 5mm H)

 

Glimpses of current research

 

Some of the current focus areas of research include:

 

- Structural elucidation by multi nuclear multi dimensional NMR

 

- Hydration of macromolecules

 

- Characterization of materials in solid state by multinuclear and two dimensional NMR

 

- Polymer surfactant interactions

 

- Molecular self assemblies

 

Proton magnetic resonance imaging in hydrogels

 

 The Proton Magnetic Resonance Imaging techniques provide an elegant method to monitor the phenomenon of volume phase transition in cross-linked hydrogels of poly (N-isopropyl-acrylamide). The images, derived from relaxation and diffusion weighted planar spin-echo experiments, gives insights on the nature of hydration and the motional state of polymer in the fully swollen and collapsed states of the gel. (Polymer, 2000, 41, 4543)

 

3QMAS Al NMR of aluminum hydroxides

 

New methodologies based on solid-state NMR techniques are offered in the characterization of Al environments in synthetic aluminium hydroxides (boehmitebayerite, and gibbsite) as a prelude to phase identification and quantification through 3Q-MAS experiments and quantum chemical calculations. Crystallographically inequivalent aluminiums that build layers of edge-sharing Al (OH) octahedra are unambiguously identified. (J. Am. Chem Soc., 2002,124, 3200)

 

Solid state NMR of molecular self-assemblies

 

 The power of solid state NMR as a technique to study molecular self-assemblies that defy crystallization is demonstrated through the well-known example of cyanuric acid (CA): melamine (MA) assembly, a DNAnucleobase mimic, which forms a network of well-defined robust hydrogen-bonded molecular tape. The NMR approach, based on C, NCP/MAS at natural abundance and H MAS, gives structural information in reliable agreement with that from X-ray technique. (Organic Letters, 2001, 3, 1921)

 

Contact

 

Dr. PR Rajamohanan

National Chemical Laboratory ,

Dr. Homi Bhabha Road ,

Pune 411 008 India

Email :rmohan@dalton.ncl.res.in

Phone :+91-20-2589 3300 (extn 2330, 2075)

Fax :+91-20-2589 3234

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