Michael Braydich - Academia.edu (original) (raw)
Papers by Michael Braydich
: A time dependent scheme is developed for calibration of standard solid state chloride ion probe... more : A time dependent scheme is developed for calibration of standard solid state chloride ion probes to be used in basic hydrogen peroxide solutions. The accuracy of the method is tested and reported. (Author)
Journal of the American Chemical Society, 1985
Inorganic Chemistry, 1983
When Government drawings, specifications, or other data are used for any purpose other than in co... more When Government drawings, specifications, or other data are used for any purpose other than in connection with a definitely Government-related procurement, the United States Government incurs no responsibility or any obligation whatsoever. The fact that the government may have formulated or in any way supplied the said drawings, specifications, or other data, is not to be regarded by implication, or otherwise in any manner construed, as licensing the holder, or any other person or corporation; or as conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. This report is releasable to the National Technical Information Service (NTIS). At NTIS, it will be available to the general public, including foreign nations. This technical report has been reviewed and is approved for publication.
Journal of The American Chemical Society, 1985
The observed splitting between B, and B2 of 0.4 eV is further larger than the calculated spin-orb... more The observed splitting between B, and B2 of 0.4 eV is further larger than the calculated spin-orbit splitting of AEso = 0.18 eV for W2C14(PHJ4 (Table VII). A spin-orbit splitting of 0.4 eV would, according to the discussion in section IIIc, require that the a-orbital is almost pure d, (C12 = 1). We find, however, CI2 = 0.57 in close agreement with the value of CI2 = 0.6 from the SCF-Xa-SW calculations on W2C14(PH3)4.11a V. Concluding Remarks W e have in this study explored the u, T , 6 orbitals, used by Cotton2' to account for the multiple metal-metal bond in binuclear complexes, by calculating the energies for the 2B2g, 2Eu, and 2Al, states of M2(C02H)4+ (M = Cr, Mo, W), corresponding to ionization of one electron out of the u, a , 6 orbitals, respectively, as a function of the metal-metal bond distance RMM. The energies for the three states were calculated in the order E('Bzg) E(2EI) (29) It is argued in ref 1 la where B, and B2 are assigned to the a orbitals that the different shapes of B, and B2 are due to differences in the coupling between the two a orbitals with u, 6 as one spin-orbit component of a will interact with 6 and the other with u. We do not in our full relativistic treatment find any significant coupling between x and u, 6. In fact, such a coupling would only be important if either 6 or u was degenerate in energy with the x orbitals. In ref 1 la a is separated from 6 and u by 2 eV from above and below, respectively. (30) The calculated trend in RMo for the doublet states of the bridged M2(C02R),+ systems, Table I1 and Figure 1, seems not possible to rationalize in terms of changing metal-ligand overlaps with variations in the metal-metal bond distance, as the same trend was calculated for the nonbridged M2C14-(PH3)4C systems, Table VI and Figure 2.-E(2Alg), indicating with out energy-decomposition analysis on several M2C14(PH3)4n+ complexes'Ib of group 6 and group 7 metals. We have found in line with the 6 bond being weaker than the a bond that ionization of one electron out of the a-orbital results in a larger elongation of the metal-metal bond than the ionization of an electron out of the &orbital. The ionization of an electron from the a-orbital does, on the other hand, not change the metal-metal bond distance substantially, and this somewhat surprising result30 is explained in section IIIb. The HFS calculations indicate, in contrast to previous studies4 based on the Xa model, that ionizations from the 6, a , u orbitals occur at lower energy than ionizations from the ligand-based orbitals and that the ionization potentials for u, T are close in energy. W e have attempted to reconcile the H F S results with record photoelectron spectra of tetracarboxylate complexes5~' and other binuclear systems11a with a quadruple metal-metal bond and find that the spectra of W2(C02CF3), and W2C14(PMe3)4 clearly show three bands that can be assigned to the metal-metal bonding orbitals 6, a, u, at lower energy than the first peak due to ionizations from ligand-based orbitals. Acknowledgment. The investigation was supported by the National Sciences and Engineering Research Council of Canada.
Inorganic Chemistry, 1983
Inorg. Chem. metal complexes including Cu. They used a self-consistent charge iteration procedure... more Inorg. Chem. metal complexes including Cu. They used a self-consistent charge iteration procedure to refine Coulomb integrals. We omitted that procedure. While we employed the simplest assumption of direct proportionality of resonance integrals to an average of Coulomb integrals times overlap, Zerner and Gouterman used a more sophisticated relationship. Our extended Huckel energy levels for porphine (Figure 3) show a', as the HOMO with aZu just below. Both are a orbitals. In the energy level scheme obtained by Zerner and Gouterman these levels are reversed. We agree on e, as the porphine LUMO. Their HOMO-LUMO gap is about 2 eV compared to 1.49 eV from our results. More serious differences occur in comparisons of the energy level pattern for the Cuz+ complex of porphine. We found eg (a) as the singly occupied HOMO of the complex with b,, (u) vacant above. Zerner and Gouterman show bl, as the singly occupied HOMO with e, as the LUMO. Both results are consistent with ESR data that has been interpreted as indicating that the odd electron resides primarily on the Conclusions On the basis of simple Huckel results it was previously concluded that B8SI6 would form much weaker complexes than (29) E. M.
: A time dependent scheme is developed for calibration of standard solid state chloride ion probe... more : A time dependent scheme is developed for calibration of standard solid state chloride ion probes to be used in basic hydrogen peroxide solutions. The accuracy of the method is tested and reported. (Author)
Journal of the American Chemical Society, 1985
Inorganic Chemistry, 1983
When Government drawings, specifications, or other data are used for any purpose other than in co... more When Government drawings, specifications, or other data are used for any purpose other than in connection with a definitely Government-related procurement, the United States Government incurs no responsibility or any obligation whatsoever. The fact that the government may have formulated or in any way supplied the said drawings, specifications, or other data, is not to be regarded by implication, or otherwise in any manner construed, as licensing the holder, or any other person or corporation; or as conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. This report is releasable to the National Technical Information Service (NTIS). At NTIS, it will be available to the general public, including foreign nations. This technical report has been reviewed and is approved for publication.
Journal of The American Chemical Society, 1985
The observed splitting between B, and B2 of 0.4 eV is further larger than the calculated spin-orb... more The observed splitting between B, and B2 of 0.4 eV is further larger than the calculated spin-orbit splitting of AEso = 0.18 eV for W2C14(PHJ4 (Table VII). A spin-orbit splitting of 0.4 eV would, according to the discussion in section IIIc, require that the a-orbital is almost pure d, (C12 = 1). We find, however, CI2 = 0.57 in close agreement with the value of CI2 = 0.6 from the SCF-Xa-SW calculations on W2C14(PH3)4.11a V. Concluding Remarks W e have in this study explored the u, T , 6 orbitals, used by Cotton2' to account for the multiple metal-metal bond in binuclear complexes, by calculating the energies for the 2B2g, 2Eu, and 2Al, states of M2(C02H)4+ (M = Cr, Mo, W), corresponding to ionization of one electron out of the u, a , 6 orbitals, respectively, as a function of the metal-metal bond distance RMM. The energies for the three states were calculated in the order E('Bzg) E(2EI) (29) It is argued in ref 1 la where B, and B2 are assigned to the a orbitals that the different shapes of B, and B2 are due to differences in the coupling between the two a orbitals with u, 6 as one spin-orbit component of a will interact with 6 and the other with u. We do not in our full relativistic treatment find any significant coupling between x and u, 6. In fact, such a coupling would only be important if either 6 or u was degenerate in energy with the x orbitals. In ref 1 la a is separated from 6 and u by 2 eV from above and below, respectively. (30) The calculated trend in RMo for the doublet states of the bridged M2(C02R),+ systems, Table I1 and Figure 1, seems not possible to rationalize in terms of changing metal-ligand overlaps with variations in the metal-metal bond distance, as the same trend was calculated for the nonbridged M2C14-(PH3)4C systems, Table VI and Figure 2.-E(2Alg), indicating with out energy-decomposition analysis on several M2C14(PH3)4n+ complexes'Ib of group 6 and group 7 metals. We have found in line with the 6 bond being weaker than the a bond that ionization of one electron out of the a-orbital results in a larger elongation of the metal-metal bond than the ionization of an electron out of the &orbital. The ionization of an electron from the a-orbital does, on the other hand, not change the metal-metal bond distance substantially, and this somewhat surprising result30 is explained in section IIIb. The HFS calculations indicate, in contrast to previous studies4 based on the Xa model, that ionizations from the 6, a , u orbitals occur at lower energy than ionizations from the ligand-based orbitals and that the ionization potentials for u, T are close in energy. W e have attempted to reconcile the H F S results with record photoelectron spectra of tetracarboxylate complexes5~' and other binuclear systems11a with a quadruple metal-metal bond and find that the spectra of W2(C02CF3), and W2C14(PMe3)4 clearly show three bands that can be assigned to the metal-metal bonding orbitals 6, a, u, at lower energy than the first peak due to ionizations from ligand-based orbitals. Acknowledgment. The investigation was supported by the National Sciences and Engineering Research Council of Canada.
Inorganic Chemistry, 1983
Inorg. Chem. metal complexes including Cu. They used a self-consistent charge iteration procedure... more Inorg. Chem. metal complexes including Cu. They used a self-consistent charge iteration procedure to refine Coulomb integrals. We omitted that procedure. While we employed the simplest assumption of direct proportionality of resonance integrals to an average of Coulomb integrals times overlap, Zerner and Gouterman used a more sophisticated relationship. Our extended Huckel energy levels for porphine (Figure 3) show a', as the HOMO with aZu just below. Both are a orbitals. In the energy level scheme obtained by Zerner and Gouterman these levels are reversed. We agree on e, as the porphine LUMO. Their HOMO-LUMO gap is about 2 eV compared to 1.49 eV from our results. More serious differences occur in comparisons of the energy level pattern for the Cuz+ complex of porphine. We found eg (a) as the singly occupied HOMO of the complex with b,, (u) vacant above. Zerner and Gouterman show bl, as the singly occupied HOMO with e, as the LUMO. Both results are consistent with ESR data that has been interpreted as indicating that the odd electron resides primarily on the Conclusions On the basis of simple Huckel results it was previously concluded that B8SI6 would form much weaker complexes than (29) E. M.