Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism Page: 4 of 51
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yellow in the case of (Me3Si)C5H4, (Me3Si)2C5H3, (Me3Si)3C5H2 and (Me3C)3C5H2, while the others are
orange or red.
Table 1. Characterization data for substituted maganocenes
compound (Cp') color m.p. ( C) Tsub ( C) a Mn-C (ave) (A) 1H NMR (S)
C5HS amber 172-173 2.41
MeC5H4 amber 62-64
C5Me5 orange 292 90-95 2.1le
Me3CC5H4 red 59-60 40-50 2.14' 13 (3100)
Me3SiC5H4 yellow < 25 92-93b 2.389 13 (524)
1,3-(Me3C)2C5H3 red 145-146 55-60 2.13' 15 (2700)
1,3-(Me3Si)2C5H3 ivory 90-91 50-55 2.37' 12 (980)
1,2,4-(Me3C)3C5H2 light 308-309 90-95 2.43' 15 (2810)
1,2,4-(Me3Si)3C5H2 ivory 286-288 70-80 2.40' 10 (1050),
1,3-(Me3C)(Me3Si)C5H3 orange 106-107 50-60 20 (2500)
a sublimation temperature in diffusion pump vacuum; distillation temperature in diffusion pump
vacuum at 92-93 C; ' Recorded in benzene-d6 at 20 C. Chemical shifts of the Me3E (E= Si or C)
resonances in ppm. Line width at half-peak height (Hz) is given in parentheses. Methine resonances are
not observed in tetra- and hexasubstituted manganocenes. d Averaged Mn-C distance of the il5-
coordinated Cp-ring. Ref. 18. e Ref. 16.' This work. 9 Ref. 19.
Solid State Crystal Structures. The crystal structures of [(Me3Si)2C5H3]2Mn, [(Me3Si)3C5H2]2Mn,
[(Me3C)C5H4]2Mn, [(Me3C)2C5H3]2Mn and [(Me3C)3C5H2]2Mn are determined at low temperature (see
Table 2 for details), while that of [(Me3Si)C5H4]2Mn was reported some years ago. 9 Thus, the solid
state structures of the manganocenes described in this paper are known, except for the mixed-ring
metallocene [(Me3C)(Me3Si)C5H3]2Mn; several attempts to grow suitable crystals for an X-ray
diffraction study either by slow sublimation or crystallization failed. The ORTEP diagrams are given in
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Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N. Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism, article, April 17, 2008; Berkeley, California. (digital.library.unt.edu/ark:/67531/metadc933976/m1/4/: accessed November 15, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.