A5102951664- Magnetism in coordination complexes
- X-ray Diffraction in Crystallography
- Metal complexes synthesis and properties
- Crystallization and Solubility Studies
- Metal-Catalyzed Oxygenation Mechanisms
- Metalloenzymes and iron-sulfur proteins
- Porphyrin and Phthalocyanine Chemistry
- Electron Spin Resonance Studies
- Lanthanide and Transition Metal Complexes
- Crystallography and molecular interactions
- Inorganic Chemistry and Materials
- Polyoxometalates: Synthesis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Organometallic Compounds Synthesis and Characterization
- Spectroscopy Techniques in Biomedical and Chemical Research
- Bone Tissue Engineering Materials
- Organic and Molecular Conductors Research
- Radioactive element chemistry and processing
- Spectroscopy and Chemometric Analyses
- Nanocluster Synthesis and Applications
- Hemoglobin structure and function
- Crystal Structures and Properties
- Quantum and electron transport phenomena
- Inorganic and Organometallic Chemistry
- Vanadium and Halogenation Chemistry
New York University
2003-2024
Eastern Michigan University
2005
University of California, San Diego
2005
Stanford Synchrotron Radiation Lightsource
2005
Stanford University
2005
University of Delaware
1997-2000
Massachusetts Institute of Technology
1983-1986
Princeton University
1983
Raman spectra were acquired on ox femur samples treated with hydrazine to remove the organic components of bone. A large increase in signal-noise ratio mineral spectrum resulted from exposure surface and removal fluorescent matrix. The effect treatment matrix has been reinvestigated shown be slight basis second derivative FTIR data. This is first time that this high resolution technique applied biological minerals.
The aim of this study was to determine the effects 38% silver diamine fluoride (SDF) on carious lesions human deciduous teeth. Ten extracted incisors with caries were collected and treated SDF. After treatment, teeth sectioned through center lesion. extent sliver precipitation examined using quantitative backscattered electron scanning microscopy (qBSE-SEM), energy-dispersive X-ray spectroscopy (EDX), micro-computed tomography (micro-CT). qBSE-SEM images revealed that particles could...
The crossover between thermally assisted and pure quantum tunneling has been studied in single crystals of high spin (S = 10) uniaxial molecular magnet Mn12 using micro-Hall-effect magnetometry. Magnetic hysteresis relaxation experiments have used to investigate the energy levels that determine magnetization reversal as a function magnetic field temperature. These demonstrate occurs narrow ( approximately 0. 1 K) or broad temperature interval depending on magnitude transverse anisotropy axis.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of the "pocket" porphyrinsJames P. Collman, John I. Brauman, Terrence J. Collins, Brent L. Iverson, George Lang, Roger B. Pettman, Jonathan Sessler, Marc A. WaltersCite this: Am. Chem. Soc. 1983, 105, 10, 3038–3052Publication Date (Print):May 1, 1983Publication History Published online1 May 2002Published inissue 1 1983https://pubs.acs.org/doi/10.1021/ja00348a018https://doi.org/10.1021/ja00348a018research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTResonance Raman spectra of (dioxygen)(porphyrinato)(hindered imidazole)iron(II) complexes: implications for hemoglobin cooperativityMarc A. Walters, Thomas G. Spiro, Kenneth S. Suslick, and James P. CollmanCite this: J. Am. Chem. Soc. 1980, 102, 22, 6857–6858Publication Date (Print):October 15, 1980Publication History Published online1 May 2002Published inissue 15 October 1980https://doi.org/10.1021/ja00542a037RIGHTS & PERMISSIONSArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModels of amide-cysteine hydrogen bonding in rubredoxin: between amide and benzenethiolate [(CH3)3NCH2CONH2]2[Co(SC6H5)4].cntdot.1/2CH3CN [(CH3)3NCH2CONH2][SC6H5]Marc Anton Walters, John C. Dewan, Caroline Min, Shirley PintoCite this: Inorg. Chem. 1991, 30, 12, 2656–2662Publication Date (Print):June 1, 1991Publication History Published online1 May 2002Published inissue 1 June...
Infrared absorption spectra of polycrystalline fluor- and hydroxyapatite are transformed to their second derivatives for resolution enhancement. It is observed that although the symmetry lattice lower than fluorapatite, nearly congruent. The data samples analysed on basis single crystal Raman infrared dichroism spectra. number vibrational bands in exceed predicted by factor group analysis. "excess" assigned vibrations expected be active previously reported these two minerals. This can...
Sulfur K-edge X-ray absorption spectroscopy of a hydrogen-bonded elongated [Fe4S4]2+ cube is reported. The data show that this synthetic less covalent than normal compressed with no hydrogen bonding. DFT calculations reveal the observed difference in electronic structure has significant contributions from both cluster distortion and Fe4S4 structures are found to have different spin topologies (i.e., orientation delocalized Fe2S2 subclusters which antiferromagnetically coupled each other). It...
The Fe4S4 complex {(CH3)3NCH2CONH2}2[Fe4S4(tBuS)4] (1) was synthesized to replicate the ferredoxin active site with a subset of its N−H···S hydrogen bonds. two cationic counterions mimic polypeptide backbone (Fd) as amide hydrogen-bond donors sulfur atoms iron−sulfur cluster. X-ray crystallographic data show that organic (Sγ) one tert-butylthiolate ligand and inorganic cluster core serve acceptors. 1 is tetragonally elongated in contrast Fd, which compressed. This first observation an...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen-Bonding and Polar Group Effects on Redox Potentials in Mo[HB(Me2pz)3](NO)(SR)2Jiong Huang, Robert L. Ostrander, Arnold Rheingold, Yiuchong Leung, Marc Anton WaltersCite this: J. Am. Chem. Soc. 1994, 116, 15, 6769–6776Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://pubs.acs.org/doi/10.1021/ja00094a036https://doi.org/10.1021/ja00094a036research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModels of lysine-cysteine hydrogen bonding in metallothionein: between ammonium and benzenethiolate ligands [(C6H11)2NH2]2 [Co(SC6H5)4]Wesley P. Chung, John C. Dewan, M. Anton WaltersCite this: J. Am. Chem. Soc. 1991, 113, 2, 525–530Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 January 1991https://pubs.acs.org/doi/10.1021/ja00002a021https://doi.org/10.1021/ja00002a021research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Electrochemistry of Mo[BH(Me2pz)3](NO)[S(CH2)2CONH(CH2)2S] as a Probe the Effects N-H.cntdot..cntdot..cntdot.S Hydrogen Bonding on Redox PotentialsJiong Huang, Robert L. Ostrander, Arnold Rheingold, Marc Anton WaltersCite this: Inorg. Chem. 1995, 34, 5, 1090–1093Publication Date (Print):March 1, 1995Publication History Published online1 May 2002Published inissue 1 March...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of N-H.cntdot..cntdot..cntdot.S hydrogen bonding in dicyclohexylammonium hexakis(benzenethiolato)dizincate(2-): a model for metallothioneinWesley P. Chung, John C. Dewan, and M. Anton WaltersCite this: Inorg. Chem. 1991, 30, 22, 4280–4282Publication Date (Print):October 1, 1991Publication History Published online1 May 2002Published inissue 1 October...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and cluster interconversion chemistry of a linear trinuclear hexakis(.mu.-benzenethiolato)triiron(II) hexacarbonyl compoundM. Anton Walters John C. DewanCite this: Inorg. Chem. 1986, 25, 27, 4889–4893Publication Date (Print):December 1, 1986Publication History Published online1 May 2002Published inissue 1 December 1986https://pubs.acs.org/doi/10.1021/ic00247a022https://doi.org/10.1021/ic00247a022research-articleACS PublicationsRequest...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTResonance Raman enhancement of imidazole vibrations via charge-transfer transitions pentacyanoiron(III) and imidazolate complexesM. Anton Walters Thomas G. SpiroCite this: Inorg. Chem. 1983, 22, 26, 4014–4017Publication Date (Print):December 1, 1983Publication History Published online1 May 2002Published inissue 1 December 1983https://pubs.acs.org/doi/10.1021/ic00168a039https://doi.org/10.1021/ic00168a039research-articleACS PublicationsRequest reuse...
The complex [(C2H5)4N]Na[Fe(SC6H4NH2-2)4] (1) has been synthesized in order to study the influence of ligand hydrogen bonding on redox potential monomeric iron-sulfur complexes. Compound 1 crystallizes space group P21c, with a = 11.747(4), b 25.058(5), c 12.301(3) Å, β 106.22(2)° and Z 4. related cobalt [(C2H5)4N]2[Co(SC6H4NH2−2)4] (2) was also found crystallize Pccn 12.544(3), 13.920(3), 24.646(15) Åand average MS bond length is 2.341(1) Å 2.295(2) 2. electronic absorption spectrum 2...
Thermal and photo decomposition, particularly of solid samples, have been chronic problems in the field resonance Raman spectroscopy due to absorption by sample very intense tightly focused laser light. Strenuous efforts made minimize damage cooling methods as well beam dispersion. The use spinning cells is also widely practiced order increase time-averaged area irradiation.
The tetrahedral Fe(II) thiolate complex anion [Fe{SCH2CON(CH3)2}4]2- has been synthesized as a model compound of rubredoxin and characterized by X-ray crystallography electrochemistry. Its redox potential, −0.712 V (relative to SCE), is approximately 370 mV more positive than those the analogous [Fe(SCH2CH3)4]2- [Fe(S2-o-xyl)2]2- anions. shift in potential title attributed charge−dipole interaction between amide sulfur. Redox shifts this magnitude are observed among iron−sulfur proteins may...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFacile one-step synthesis of tetrachalcogenotetrairon(2+) (chalcogen = sulfur, selenium) cubane-like centersScott Rutchick, Sunghoon Kim, and M. Anton WaltersCite this: Inorg. Chem. 1988, 27, 9, 1513–1515Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Published inissue 1 1988https://pubs.acs.org/doi/10.1021/ic00282a001https://doi.org/10.1021/ic00282a001research-articleACS PublicationsRequest reuse...