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Title: Photochemical behavior of the quadruply metal-metal bonded [Tc 2Cl 8] 2– anion in acetonitrile

Abstract

Here, the photochemical behavior of [Tc 2Cl 8] 2– was investigated in acetonitrile. The speciation of Tc before and after irradiation at 254 nm was performed by UV-visible spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Upon irradiation at 254 nm, [Tc 2Cl 8] 2– was unstable, the scission of the Tc ≡ Tc unit occurred and the complex [TcCl 4(CH 3CN) 2] was identified. The disappearance rate of [M 2Cl 8] 2– (M = Tc, Re) under irradiation has been measured and was ~7.5 time faster for Tc than for Re.

Authors:
 [1];  [2];  [2];  [2];  [3];  [4]
  1. Hunter College of the City Univ. of New York, New York City, NY (United States); Lehman College of the City Univ. of New York, New York City, NY (United States); The Graduate Center of the City Univ. of New York, New York, NY (United States)
  2. Univ. of Nevada, Las Vegas, NV (United States)
  3. Hunter College of the City Univ. of New York, New York City, NY (United States); The Graduate Center of the City Univ. of New York, New York, NY (United States)
  4. Univ. of Nevada, Las Vegas, NV (United States); Argonne National Lab. (ANL), Lemont, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
University of Nevada–Las Vegas; National Institutes of Health (NIH); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1339611
Alternate Identifier(s):
OSTI ID: 1359175
Grant/Contract Number:
AC02-06CH11357; FG02-09ER16097; SC0002456
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Inorganica Chimica Acta
Additional Journal Information:
Journal Volume: 453; Journal Issue: C; Journal ID: ISSN 0020-1693
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; technetium; metal-metal multiple bonds; photochemistry

Citation Formats

Burton-Pye, Benjamin P., Poineau, Frederic, Bertoia, Julie, Czerwinski, Kenneth R., Francesconi, Lynn C., and Sattelberger, Alfred P.. Photochemical behavior of the quadruply metal-metal bonded [Tc2Cl8]2– anion in acetonitrile. United States: N. p., 2016. Web. doi:10.1016/j.ica.2016.09.041.
Burton-Pye, Benjamin P., Poineau, Frederic, Bertoia, Julie, Czerwinski, Kenneth R., Francesconi, Lynn C., & Sattelberger, Alfred P.. Photochemical behavior of the quadruply metal-metal bonded [Tc2Cl8]2– anion in acetonitrile. United States. doi:10.1016/j.ica.2016.09.041.
Burton-Pye, Benjamin P., Poineau, Frederic, Bertoia, Julie, Czerwinski, Kenneth R., Francesconi, Lynn C., and Sattelberger, Alfred P.. Fri . "Photochemical behavior of the quadruply metal-metal bonded [Tc2Cl8]2– anion in acetonitrile". United States. doi:10.1016/j.ica.2016.09.041. https://www.osti.gov/servlets/purl/1339611.
@article{osti_1339611,
title = {Photochemical behavior of the quadruply metal-metal bonded [Tc2Cl8]2– anion in acetonitrile},
author = {Burton-Pye, Benjamin P. and Poineau, Frederic and Bertoia, Julie and Czerwinski, Kenneth R. and Francesconi, Lynn C. and Sattelberger, Alfred P.},
abstractNote = {Here, the photochemical behavior of [Tc2Cl8]2– was investigated in acetonitrile. The speciation of Tc before and after irradiation at 254 nm was performed by UV-visible spectroscopy and electrospray ionization mass spectrometry (ESI-MS). Upon irradiation at 254 nm, [Tc2Cl8]2– was unstable, the scission of the Tc ≡ Tc unit occurred and the complex [TcCl4(CH3CN)2] was identified. The disappearance rate of [M2Cl8]2– (M = Tc, Re) under irradiation has been measured and was ~7.5 time faster for Tc than for Re.},
doi = {10.1016/j.ica.2016.09.041},
journal = {Inorganica Chimica Acta},
number = C,
volume = 453,
place = {United States},
year = {Fri Sep 23 00:00:00 EDT 2016},
month = {Fri Sep 23 00:00:00 EDT 2016}
}

Journal Article:
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  • Application of pressure (up to 150 kbar, where 1 kbar = 986.9 atm = 0.1 GPa) to solutions of Re{sub 2}X{sub 8}{sup 2{minus}} (X = F, Cl, Br) and Mo{sub 2}Cl{sub 4}(PMe{sub 3}){sub 4} results in smooth, continuous changes in experimental observables related to metal-metal bond length and, for the Re complexes, torsional angle (X-Re-Re-X dihedral angle). Resonance Raman studies show that increasing pressure engenders an increase in the frequency of the metal-metal stretching mode for all of the species studied, and this change is empirically correlated with a decrease in metal-metal bond length. Large red shifts in the energymore » of the {sup 1}({delta} {yields} {delta}*) transitions with increased pressure for Re{sub 2}Br{sub 8}{sup 2{minus}} and Re{sub 2}Cl{sub 8}{sup 2{minus}}, in contrast to the relative insensitivity of Re{sub 2}F{sub 8}{sup 2{minus}} absorption and Mo{sub 2}Cl{sub 4}(PMe{sub 3}){sub 4} fluorescence transitions, imply a tendency for the former complexes to distort torsionally from an eclipsed configuration toward a staggered configuration due to pressure-induced steric repulsion of the chloride and bromide ligands. Integrated absorption intensities further show that, at higher pressures, even Re{sub 2}F{sub 8}{sup 2{minus}} undergoes some torsional distortion, whereas the steric repulsion of adjacent phosphines located at a 90{degree} dihedral angle on opposite Mo atoms prevents Mo{sub 2}Cl{sub 4}(PMe{sub 3}){sub 4} from distorting along the torsional coordinate. 28 refs., 7 figs., 1 tab.« less
  • The electronic structure of the ''quadruply bonded'' Re/sub 2/Cl/sub 8//sup 2 -/ species has been studied by using ab initio wave functions and relativistic effective core potentials. The metal-metal bonding in the ground state is discussed, and the rich spectrum of electronic states below 6 eV (50,000 cm/sup -1/) is treated in detail, including correlation effects and spin-orbit coupling. Highly correlated multiconfiguration wave functions are needed to describe the electrons in the weak delta bond, particularly in the ground /sup 1/A/sub 1g/ state and the excited /sup 1/A/sub 2u/ (calculated 2.8 eV, experimental 1.8 eV), /sup 3/A/sub 2u/ (calculated 0.4more » eV), and 2 /sup 1/A/sub 1g/ (calculated 3.2 eV) states. These excited states involving delta-delta* excitations all undergo torsional distortions to D/sub 4d/ geometries. The nature and relative intensities of weaker transitions involving excitations among the ten 5d orbitals as well as the strong transitions involving the Cl 3p-Re 5d charge-transfer excitations are also discussed.« less
  • This paper reports transient absorption kinetics studies in the 10/sup -11/-10/sup -3/s time range for (Re/sub 2/Cl/sub 8/)/sup 2 -/ (I), (Mo/sub 2/Cl/sub 8/)/sup 4 -/ (II), Mo/sub 2/Cl/sub 4/(CH/sub 3/CN)/sub 4/ (III), and Mo/sub 2/Cl/sub 4/(PBu/sub 3/)/sub 4/ (IV) in solution at room temperature. A detailed description of the optical layout and equipment used to measure the kinetics in the 10/sup -8/-1 s time range following picosecond excitation is also given. Complexes I-III have small steric barriers to rotation about the M-M bond and upon photoexcitation appear to form /sup 1/(sigmasigma*)/sub staggered/ metal-metal charge-transfer (MMCT) states in <20 ps.more » The absorption spectra of /sup 1/(sigmasigma*) MMCT states are shown to have characteristic, strong charge-transfer (CT) bands in the near UV. Complex IV has bulky alkylphosphine groups and should retain its eclipsed geometry in its /sup 1/(sigmasigma*) excited state in noncoordinating solvents. In CH/sub 3/CN, IV undergoes some nuclear relaxation in the /sup 1/(sigmasigma*) state with a rate constant of 10/sup 9/ s/sup -1/. A particularly important result is that in complex IV a nonluminescent transient species is observed at long times (tau approx. 100 ns) following the decay of the /sup 1/(sigmasigma*) MMCT state.« less
  • The new heteronuclear compound Cs/sub 3/MoWCl/sub 8/H has been prepared and shown by x-ray powder diffraction and infrared spectroscopy to have the structure of Cs/sub 3/Mo/sub 2/Cl/sub 8/H. The infrared spectra of salts containing the anions Mo/sub 2/X/sub 8/H/sup 3 -/ (X = Cl, Br) and Mo/sub 2/Cl/sub 8/D/sup 3 -/ were redetermined and found to exhibit two bands in the region 1600 to 1200 cm/sup -1/ for the hydrides and 1120 to 890 cm/sup -1/ for the deuterides. On the basis of band intensities and known geometrical restraints the band of higher frequency was assigned as the symmetric M--H--Mmore » stretch and the band of lower frequency as the asymmetric stretch. Using equations relating frequencies of ..nu..(sym) and ..nu..(asym) to the M--H--M bond angle (..cap alpha..) and the known Mo--Mo distances in Rb/sub 3/Mo/sub 2/Cl/sub 8/H and Cs/sub 3/Mo/sub 2/Br/sub 8/H, values of d(Mo--H) = 1.90 and 1.93 A and ..cap alpha.. = 77.6 and 78.3/sup 0/, respectively, were determined for the Mo/sub 2/Cl/sub 8/H/sup 3 -/ and Mo/sub 2/Br/sub 8/H/sup 3 -/ anions.« less