Books
in black and white
Main menu
Home About us Share a book
Books
Biology Business Chemistry Computers Culture Economics Fiction Games Guide History Management Mathematical Medicine Mental Fitnes Physics Psychology Scince Sport Technics
Ads

The porphyrin handbook - Kadish K.M.

Kadish K.M. The porphyrin handbook - Academic press, 2000. - 368 p.
Download (direct link): kadishsmishgulilard2000.djvu
Previous << 1 .. 34 35 36 37 38 39 < 40 > 41 42 43 44 45 46 .. 240 >> Next

behavior from 71.5 to 120 C and 65 to 154.5 C, respectively. The
zinc(II) complex underwent a crystal-to-crystal phase transition at 44
C, followed by an observed melting point at 55.5 C and a clearing point
at 125.5 C. X-ray diffraction experiments furnished an intercolumnar
distance of 23.6 A for the Zn, Ni, and Cu materials. A slightly small
inter-columnar distance of 22.8 A was observed for the cobalt complex.
2. Tetra-substituted Porphyrins
An investigation of the photophysics of 5,10,15,20-tetra-kis(4-rc-
pentadecylphenyl)porphyrin, ((4-n-C 15H31 )PP), produced the second
porphyrin liquid-crystal material to be well-documented in the literature
and the first to utilize a tetraphenylporphyrin core (Figure ).13 Three
mesogenic phases were reported; melting of the crystalline phase was
observed upon heating at 27 C, a second mesomorphic transition followed
at 56 C, onset of the third mesophase was noted at 65.5 C and the
material cleared to an isotropic liquid at 134.5 C. A correlation
between the photoconductive properties of the material as part of an
electrochemical cell and the phase transitions of free-base porphyrin
{H2[T(4-rc-Ci5H3I)PP]} was found. Discontinuities in the photocurrent and
dark-current were observed at the phase transitions (Figures 7 and 8).
The third-order nonlinear susceptibilities of benzene solutions of M[T(4-
rc-CI5H3I)PP], where M = H2, Co, Ni, Cu, Zn or V = 0, were studied using
the degenerate four-wave mixing (DFWM) technique. The x(3> value for all
samples was determined to
41 / Porphyrin Materials Chemistry
47
Table 2. Mesomorphism of the Octa-Substituted Porphyrins
Compound Transition T/c Reference
H2[(OC4H9)OEP] K-I 154 5
Zn[(OC4Hc,)OEP] K-D 159 5
D-I 164
H2[(OC6H,,)OEP] K-D 111 5
Zn[(OC6H,3)OEP] K-D 114 5
D-I 181
H2[(OC8Hl7)OEP] K-D 84 5
D-I 89
Zn[(OC8Hl7)OEP] K-D 107 5
D-I 162
Cu[(OC8H17)OEP] K-D 84 5
D-I 132
Pd[(OC8Hl7)OEP] K-D 89 5
D-I 123
Cd[(OC"H,7)OEP] K-D 103 5
D-I 136
Zn[(OC|oH2l)OEP] K-D 86 5
D-I 142
Zn[(OC8H 17)OECNP] K-D 61 5
D-I 147
Zn[(0C"Hl7)0EN02P] K-D 85 5
D-I 140
Zn[(OC8H 17)OEP] / Zn K-D 93 5
[(OCioH2,)OEP] (1:1)
D-I 118
H2[(02C4H9)0EP] K-D 178 6
D-I 222
Zn[(02C4H9)0EP] K-D 184 6
D-I 273
H2[(02C6H13)0EP] K-D 59 6
D-D' 132
D'-I 220
Zn[(02C6Hl3)0EP] K-D 61 6
D-D' 136
D'-I 232
H2[(02C8H|7)0EP] K-D 96 6
D-D' 99
D'-I 166
Zn[(02C8Hl7)0EP] K-D 91 6
D-D' 101
D'-I 208
" Abbreviations: = crystalline phase. D --- discotic columnar phase.
1 - isotropic fluid.
be on the order of ~ 10 - 11 esu calculated at 532 nm.14 Two mesomorphic
phases were observed for a similar species
5,10,15,20-tetrakis(4-"-dodecylphenyl)porphyrin. Phase
Previous << 1 .. 34 35 36 37 38 39 < 40 > 41 42 43 44 45 46 .. 240 >> Next