skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-$${di$$-$o$-$vanillin} dimethyl dichloride

Abstract

The vibrational dynamics of a newly synthesized tetrastannoxane was characterized with a combination of experimental (Raman, IR and tin-based nuclear resonance vibrational spectroscopy) and computational (DFT/B3LYP) methods, with an emphasis on the vibrations of the tin sites. The cytotoxic activity revealed a significant regression selectively against the human pancreatic cell lines.

Authors:
 [1];  [1];  [1];  [2];  [2];  [3];  [4];  [1]
  1. Aligarh Muslim Univ., Aligarh (India). Dept. of Chemistry
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  3. Univ. de Rennes, Rennes (France). Inst. de Physique de Rennes
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1340298
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 18; Journal Issue: 27
Country of Publication:
United States
Language:
English

Citation Formats

Arjmand, F., Sharma, S., Usman, M., Leu, B. M., Hu, M. Y., Toupet, L., Gosztola, David J., and Tabassum, S. Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-${di$-$o$-$vanillin} dimethyl dichloride. United States: N. p., 2016. Web. doi:10.1039/c6cp02914k.
Arjmand, F., Sharma, S., Usman, M., Leu, B. M., Hu, M. Y., Toupet, L., Gosztola, David J., & Tabassum, S. Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-${di$-$o$-$vanillin} dimethyl dichloride. United States. doi:10.1039/c6cp02914k.
Arjmand, F., Sharma, S., Usman, M., Leu, B. M., Hu, M. Y., Toupet, L., Gosztola, David J., and Tabassum, S. 2016. "Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-${di$-$o$-$vanillin} dimethyl dichloride". United States. doi:10.1039/c6cp02914k.
@article{osti_1340298,
title = {Vibrational dynamics (IR, Raman, NRVS) and DFT study of new antitumor tetranuclearstannoxanecluster, Sn(IV)$-$oxo$-${di$-$o$-$vanillin} dimethyl dichloride},
author = {Arjmand, F. and Sharma, S. and Usman, M. and Leu, B. M. and Hu, M. Y. and Toupet, L. and Gosztola, David J. and Tabassum, S.},
abstractNote = {The vibrational dynamics of a newly synthesized tetrastannoxane was characterized with a combination of experimental (Raman, IR and tin-based nuclear resonance vibrational spectroscopy) and computational (DFT/B3LYP) methods, with an emphasis on the vibrations of the tin sites. The cytotoxic activity revealed a significant regression selectively against the human pancreatic cell lines.},
doi = {10.1039/c6cp02914k},
journal = {Physical Chemistry Chemical Physics. PCCP (Print)},
number = 27,
volume = 18,
place = {United States},
year = 2016,
month = 6
}
  • We have used four vibrational spectroscopies--FT-IR, FT-Raman, resonance Raman, and {sup 57}Fe nuclear resonance vibrational spectroscopy (NRVS)--to study the normal modes of the Fe-S cluster in [(n-Bu){sub 4}N]{sub 2}[Fe{sub 4}S{sub 4}(SPh){sub 4}]. This [Fe{sub 4}S{sub 4}(SR){sub 4}]{sup 2-} complex serves as a model for the clusters in 4Fe ferredoxins and high-potential iron proteins (HiPIPs). The IR spectra exhibited differences above and below the 243 K phase transition. Significant shifts with {sup 36}S substitution into the bridging S positions were also observed. The NRVS results were in good agreement with the low temperature data from the conventional spectroscopies.The NRVS spectra weremore » interpreted by normal mode analysis using optimized Urey-Bradley force fields (UBFF) as well as from DFT theory. For the UBFF calculations, the parameters were refined by comparing calculated and observed NRVS frequencies and intensities. The frequency shifts after {sup 36}S substitution were used as an additional constraint. A D{sub 2d} symmetry Fe{sub 4}S{sub 4}S{sub 4} model could explain most of the observed frequencies, but a better match to the observed intensities was obtained when the ligand aromatic rings were included for a D{sub 2d} Fe{sub 4}S{sub 4}(SPh){sub 4} model. The best results were obtained using the low temperature structure without symmetry constraints. In addition to stretching and bending vibrations, low frequency modes between 50 and 100 cm{sup -1} were observed. These modes, which have not been seen before, are interpreted as twisting motions with opposing sides of the cube rotating in opposite directions. In contrast with a recent paper on a related Fe{sub 4}S{sub 4} cluster, we find no need to assign a large fraction of the low frequency NRVS intensity to rotational lattice modes. We also reassign the 430 cm{sup -1} band as primarily an elongation of the thiophenolate ring, with 10% terminal Fe-S stretch character. This study illustrates the benefits of combining NRVS with conventional Raman and IR analysis for characterization of Fe-S centers. DFT theory is shown to provide remarkable agreement with the experimental NRVS data. These results provide a reference point for the analysis of more complex Fe-S clusters in proteins.« less
  • We have used (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the Fe(2)S(2)(Cys)(4) sites in oxidized and reduced [2Fe-2S] ferredoxins from Rhodobacter capsulatus (Rc FdVI) and Aquifex aeolicus (Aa Fd5). In the oxidized forms, nearly identical NRVS patterns are observed, with strong bands from Fe-S stretching modes peaking around 335 cm(-1), and additional features observed as high as the B(2u) mode at approximately 421 cm(-1). Both forms of Rc FdVI have also been investigated by resonance Raman (RR) spectroscopy. There is good correspondence between NRVS and Raman frequencies, but because of different selection rules, intensities vary dramatically between the twomore » kinds of spectra. For example, the B(3u) mode at approximately 288 cm(-1), attributed to an asymmetric combination of the two FeS(4) breathing modes, is often the strongest resonance Raman feature. In contrast, it is nearly invisible in the NRVS, as there is almost no Fe motion in such FeS(4) breathing. NRVS and RR analysis of isotope shifts with (36)S-substituted into bridging S(2-) ions in Rc FdVI allowed quantitation of S(2-) motion in different normal modes. We observed the symmetric Fe-Fe stretching mode at approximately 190 cm(-1) in both NRVS and RR spectra. At still lower energies, the NRVS presents a complex envelope of bending, torsion, and protein modes, with a maximum at 78 cm(-1). The (57)Fe partial vibrational densities of states (PVDOS) were interpreted by normal-mode analysis with optimization of Urey-Bradley force fields. Progressively more complex D(2h) Fe(2)S(2)S'(4), C(2h) Fe(2)S(2)(SCC)(4), and C(1) Fe(2)S(2)(Cys)(4) models were optimized by comparison with the experimental spectra. After modification of the CHARMM22 all-atom force field by the addition of refined Fe-S force constants, a simulation employing the complete protein structure was used to reproduce the PVDOS, with better results in the low frequency protein mode region. This process was then repeated for analysis of data on the reduced FdVI. Finally, the degree of collectivity was used to quantitate the delocalization of the dynamic properties of the redox-active Fe site. The NRVS technique demonstrates great promise for the observation and quantitative interpretation of the dynamical properties of Fe-S proteins.« less
  • We have used {sup 57}Fe nuclear resonance vibrational spectroscopy (NRVS) to study the Fe(S{sub cys})4 site in reduced and oxidized rubredoxin (Rd) from Pyrococcus furiosus (Pf). The oxidized form has also been investigated by resonance Raman spectroscopy. In the oxidized Rd NRVS, strong asymmetric Fe-S stretching modes are observed between 355 and 375 cm{sup -1}; upon reduction these modes shift to 300-320 cm{sup -1}. This is the first observation of Fe-S stretching modes in a reduced Rd. The peak in S-Fe-S bend mode intensity is at {approx}150 cm{sup -1} for the oxidized protein and only slightly lower in the reducedmore » case. A third band occurs near 70 cm{sup -1} for both samples; this is assigned primarily as a collective motion of entire cysteine residues with respect to the central Fe. The {sup 57}Fe partial vibrational density of states (PVDOS) were interpreted by normal mode analysis with optimization of Urey-Bradley force fields. The three main bands were qualitatively reproduced using a D{sub 2d} Fe(SC){sub 4} model. A C{sub 1} Fe(SCC){sub 4} model based on crystallographic coordinates was then used to simulate the splitting of the asymmetric stretching band into at least 3 components. Finally, a model employing complete cysteines and 2 additional neighboring atoms was used to reproduce the detailed structure of the PVDOS in the Fe-S stretch region. These results confirm the delocalization of the dynamic properties of the redox-active Fe site. Depending on the molecular model employed, the force constant KFe-S for Fe-S stretching modes ranged from 1.24 to 1.32 mdyn/Angstrom. KFe-S is clearly diminished in reduced Rd; values from {approx}0.89 to 1.00 mdyn/Angstrom were derived from different models. In contrast, in the final models the force constants for S-Fe-S bending motion, HS-Fe-S, were 0.18 mdyn/Angstrom for oxidized Rd and 0.15 mdyn/Angstrom for reduced Rd. The NRVS technique demonstrates great promise for the observation and quantitative interpretation of the dynamical properties of Fe-S proteins.« less
  • No abstract prepared.