History

NMR Spectroscopy investigations started in Bulgaria in 1966 at the Institute of Organic Chemistry, Bulgarian Academy of Sciences. A CW JEOL instrument with working frequency 60 MHz was the first NMR spectrometer installed and it was in use until May 1981. In 1977 and 1978 two more CW NMR spectrometers – Tesla 80 MHz and 60 MHz, respectively, were purchased. The expertise of the scientists contributed to the broader implementation of the method in the country.

During that period several more CW NMR instruments were installed in other research institutions in Bulgaria such as the Technical University of Chemistry, the Faculty of Chemistry at the Sofia University, the Institute of Chemical Technology, the Faculty of Pharmacy at the Medical University and the Faculty of Chemistry at the University of Plovdiv. Most of these instruments are now out of operation and if not, preliminary information only can be obtained.

In 1981 high resolution pulse NMR instrument with cryomagnet was installed in the Institute of Organic Chemistry, Bulgarian Academy of Sciences. The new spectrometer – Bruker WM 250, with a working frequency of 250 MHz, was supplied as part of a project between the Bulgarian Government and UNDP UNESCO for founding a Centre of Phytochemisty. Considerable enhancement of the RTD capacity and capability has been achieved by expanding the research topics and areas and starting new investigations of methodological, analytical and practical aspects. At that time the NMR spectrometer in the Institute of Organic Chemistry with Centre of Phytochemistry was the most up-to date spectrometer in the vast region of the Balkan Peninsula. The improvement of the scientific equipment opened new opportunities for collaboration with industrial partners by offering analytical expertise and services to pharmaceutical, food and cosmetic companies. Application of NMR spectroscopy for identification and quality control of various formulations, intermediates and final products started.

In 1994 the spectrometer cabinet was upgraded to the digital model Avance DRX, which contributed further to the evolution of NMR spectroscopy studies in Bulgaria. The application of 2D NMR spectroscopy and selective 1D experiments have been made routinely available. A new more sensitive (~30%) dual 13C/1H probehead has been put into operation, leading to a considerable speed-up of research and service routine.

In 2005 the Institute of Organic Chemistry with Centre of Phytochemistry together with six academic institutions from the country set up a consortium, which has been awarded financial support in the framework of the Program “Promotion of the Research Potential through Unique Scientific Equipment” launched by the Ministry of Education and Science, Bulgaria. An advanced NMR spectrometer Bruker Avance II+ 600 for investigation of samples in the liquid and solid state was purchased and installed in February 2007 in the Institute in fully refurbished and reconstructed rooms. At the same time the existing Bruker DRX 250 spectrometer was upgraded for gradient work and supplied with more up-to date software. The two spectrometers are integrated in the local network of the Institute, which ensures easy, fast and convenient access for downloading the spectra. In 2009 the infrastructure project “Bulgarian NMR Centre – Development of Advanced and Effective Research Infrastructure for NMR Analysis of Bio- and Nanomaterials “ has been funded from the National Science Fond. The goal of the proposed project is building of an advanced and effective Nuclear Magnetic Resonance Research Infrastructure based on the state-of-the-art research equipment and the integrated knowledge, expertise and research capacity of the Institute of Organic Chemistry with Centre of Phytochemistry, Institute of Polymers, Institute of General and Inorganic Chemistry at the Bulgarian Academy of Sciences and the Chemical Faculty, Sofia University.

Since 2007 the refurbished and upgraded NMR laboratory at the Institute of Organic Chemistry with Centre of Phytochemistry, equipped with two advanced NMR spectrometers has been in a process of transition to a Bulgarian NMR Centre. This NMR Centre possesses highly qualified and experienced staff, involved in a number of research and applied projects and offering service analyses, teaching and training of students and researchers, as well as high scientific expertise for various research, academic and industrial institutions.

Combining research, education and practical application, the Bulgarian NMR centre opens new perspectives for research, development and innovation in the priority areas of the 7th EC framework: Health; Food, Agriculture and Fisheries, Biotechnology; Information & communication technologies (ICT); Nanosciences, nanotechnologies, materials & new production technologies; Energy; Environment and Security. A firm basis for multi- and interdisciplinary projects with scientists and industrial experts from the country and the international scientific community has been founded.

Selected publications of the prominent scientists, that introduced and promoted the methods and applications of NMR spectroscopy in Bulgaria:

Prof. DSc. Stefan Spassov: – S. Spassov “NMR Spectra, Configuration and Conformation of Diastereomers: 3-Substituted 2,3-Diphenylpropanoic Acids and Their Methyl Esters”, Tetrahedron 25 (1969) 3631. – E. Stanoeva, S. Spassov, M. Haimova and B. Kurtev, “Stereochemie der 3,4-Disubstituirten 1,2,3,4-Tetrahydroisochinoline” Chem. Ber 109 (1976) 2972. – S. Spassov, M. Lyapova and M. Ivanova, NMR Spectra and Stereochemistry of Diastereoisomeric 4,5-Diphenylphosphamides. Phosphorus and Sulfur 37 (1988) 199. – G. I. Eneva, S. L. Spassov, M. A. Haimova and J. Sandstroem, “Complete 1H and 13C NMR Assignment for Apramycin, Sisomicin and Some N- and N,O-Polyacetylated Aminoglycosides” Magn. Reson. Chem. 30 (1992) 841. – S. Simova, G. Ivanova and S. L. Spassov, “Alternative NMR Method for Quantitative Determination of Acyl Positional Distribution in Triacylglycerols and Related Compounds” Chem. Phys. Lipids 126 (2003) 167. Prof. DSc. Valentin Dimitrov: – V. S. Dimitrov, “Dynamic NMR: Integral Parameter Sensitivities and Their Use in the Total Line Shape Analysis” J. Magn. Reson. 22 (1976) 71. – V. S. Dimitrov and J. A. Ladd, “A Double – Fitting Procedure for Two-Site Exchange Analysis” J. Magn. Reson. 36 (1979) 401. – E. Kupce, J-M. Nuzillard, V. S. Dimitrov and R. Freeman, “A New Form of Correlation Spectroscopy” J. Magn. Reson. A, 107 (1994) 246. – V. S. Dimitrov and N. G. Vassilev, “Dynamic NMR: A New Procedure for the Estimation of Mixing Times in the 2D EXSY Experiments. A Four Site Exchange System Studied by 1D and 2D EXSY Spectroscopy, Magn. Reson. Chem., 33 (1995) 739 – P. S. Denkova and V. S. Dimitrov, “A Combined Usage of Complete Line Shape Analysis of 1D Spectra Subjected to Reference Deconvolution and Linear Prediction, 2D EXSY Spectra and Double Fitting Method for Studying Chemical Exchange. Application to an Eight Site Exchange System”, Magn. Reson. Chem., 37 (1999) 637.