Reported are the synthesis and structure of the anionic intermetalloid cluster [Bi12Ni7(CO)4](4-). It was synthesized from the known smaller clusters Bi3Ni4(CO)6(3-), Bi3Ni6(CO)9(3-), and Ni@Bi6Ni6(CO)8(4-) by their aggregation as a result of thermal deligation and oxidation. The new cluster is structurally characterized by single-crystal X-ray diffraction in the compound (K[crypt])4[Bi12Ni7(CO)4] (1), and its presence in solution is confirmed by electrospray mass spectrometry. It can be viewed as composed of a Ni-centered icosahedral core of Bi6Ni6(CO)4 where two diametrically opposed Ni atoms are capped by Bi3 triangles. However, its electron count is rationalized based on a structure made of fused tetrahedra.
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http://dx.doi.org/10.1021/acs.inorgchem.5b01101 | DOI Listing |
Inorg Chem
September 2015
Department of Chemistry and Biochemistry University of Notre Dame, Notre Dame, Indiana 46556, United States.
Reported are the synthesis and structure of the anionic intermetalloid cluster [Bi12Ni7(CO)4](4-). It was synthesized from the known smaller clusters Bi3Ni4(CO)6(3-), Bi3Ni6(CO)9(3-), and Ni@Bi6Ni6(CO)8(4-) by their aggregation as a result of thermal deligation and oxidation. The new cluster is structurally characterized by single-crystal X-ray diffraction in the compound (K[crypt])4[Bi12Ni7(CO)4] (1), and its presence in solution is confirmed by electrospray mass spectrometry.
View Article and Find Full Text PDFJ Phys Chem B
October 2013
Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Korea.
Nitrosylated ferric heme is autoreduced readily to the more stable Fe(II)-NO adduct, but it is stabilized in NO-carrier heme proteins where maintaining the Fe(III) oxidation state is crucial for efficient NO delivery. Density functional theory calculations by Lehnert and co-workers have shown that a NO-bound ferric model heme has a low-spin (LS) Fe(III)-NO(radical) state that might be critical for efficient NO transport by NO-carrier heme proteins. Recently, the elusive LS Fe(III)-NO(radical) state was observed as an electronic intermediate state during geminate rebinding (GR) of NO to ferric myoglobin (Mb(III)).
View Article and Find Full Text PDFJ Phys Chem B
March 2013
Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Korea.
Femtosecond vibrational spectroscopy was used to investigate the photoexcitation dynamics of NO-bound ferric myoglobin (Mb(III)NO) in D2O solution at 294 K after excitation with a 575 nm pulse. The stretching mode of NO in Mb(III)NO consists of a major band at 1922 cm(-1) (97.7%) and a minor band at 1902 cm(-1) (2.
View Article and Find Full Text PDFBiophys J
October 2007
Laboratory of Soft Matter Physics, Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
The infrared (IR) absorption of the amide I band for the loop structure may overlap with that of the alpha-helices, which can lead to the misassignment of the protein secondary structures. A resolution-enhanced Fourier transform infrared (FTIR) spectroscopic method and temperature-jump (T-jump) time-resolved IR absorbance difference spectra were used to identify one specific loop absorption from the helical IR absorption bands of horse heart cytochrome c in D2O at a pD around 7.0.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 1989
Department of Chemistry, University of Pennsylvania, Philadelphia 19104.
The photodissociation of CO from HbCO at ambient temperature is studied by means of a femtosecond IR technique. The bleaching of the FeCO absorption and the appearance of a new IR absorption near that of free CO are both observed at 300 fs after optical excitation. The bleach does not recover on the time scale of a few picoseconds but does recover by approximately 4% within 1 ns, which suggests that a barrier to recombination is formed within a few picoseconds.
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