Porphyrins and metalloporphyrins as field-responsive materials

Chen, Chin-Ti

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https://hdl.handle.net/2142/21859 Copy

Description

Title

Porphyrins and metalloporphyrins as field-responsive materials

Author(s)

Chen, Chin-Ti

Issue Date

1992

Doctoral Committee Chair(s)

Kenneth S. Suslick

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Chemistry, Inorganic
• Chemistry, Organic

Language

eng

Abstract

• {\it Part I}. {\it Metalloporphyrin coordination polymers}. One-dimensional coordination polymers of metalloporphyrins with non-symmetric bridging ligands have been synthesized as candidates for molecular ferroelectric materials. These include the iron(II) porphyrinate polymer: \lbrack Fe$\sp{\rm II}$(TPP)(pyCN)\rbrack$\sb\infty$ (where TPP = 5,10,15,20-tetraphenylporphyrinate(2$-$); pyCn = 4-cyanopyridine); iron(III) porphyrinate polymers: \lbrack Fe$\sp{\rm III}$(TPP)(4-MeIm)\rbrack$\sb\infty$, \lbrack Fe$\sp{\rm III}$(TPP)(4-PhIm)\rbrack$\sb\infty$, \lbrack Fe$\sp{\rm III}$(TPP)(pyCO$\sb2$)\rbrack$\sb\infty$, \lbrack Fe$\sp{\rm III}$(TPP)(OpyCO$\sb2$)\rbrack$\sb\infty$, and \lbrack Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$ (where 4-MeIm = 4-methylimidazolate; 4-PhIm = 4-phenylimidazolate; pyCO$\sb2\sp-$ = pyridine-4-carboxylate; OpyCO$\sb2\sp-$ = pyridine-4-carboxylate N-oxide; ImPhO$\sp-$ = 4-(imidazol-1-yl)phenoxide); tin(IV) porphyrinate polymers: \lbrack Sn$\sp{\rm IV}$(TPP)(ntp)\rbrack$\sb\infty$ and \lbrack Sn$\sp{\rm IV}$(TPP)(cnp)\rbrack$\sb\infty$ (where ntp = nitroterephthalate; cnp = 4-carboxyl-2-nitrophenoxide). The single-crystal X-ray structures were solved for \lbrack Fe$\sp{\rm II}$(TPP)(pyCN)\rbrack$\sb\infty$, \lbrack Fe$\sp{\rm III}$(TPP)(pyCO$\sb2$)\rbrack$\sb\infty$, \lbrack Fe$\sp{\rm III}$(TPP)(OpyCO$\sb2$)\rbrack$\sb\infty$, and Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$. The chain alignment of the bridging ligand is disordered in \lbrack Fe$\sp{\rm II}$(TPP)(pyCN)\rbrack$\sb\infty$, anti-parallel in \lbrack Fe$\sp{\rm III}$(TPP)(pyCO$\sb2$)\rbrack$\sb\infty$ and \lbrack Fe$\sp{\rm III}$(TPP)(OpyCO$\sb2$)\rbrack$\sb\infty$, but polar in \lbrack Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$. \lbrack Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$ crystallizes in a non-centrosymmetric space group, $Pna2\sb1$.
• Pressed pellets of \lbrack Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$ gave no detectable ferroelectric hysteresis in polarization. Calculations based on the crystal structure of \lbrack Fe$\sp{\rm III}$(TPP)(ImPhO)\rbrack$\sb\infty$ shows that the bulky structure of the porphyrin ring significantly limits the magnitude of the spontaneous polarization.
• {\it Part II}. {\it Push-pull porphyrins as nonlinear optical materials}. ``Push-pull'' porphyrins, $\rm H\sb2(a\sb{x}n\sb{4-x}Por),$ (where x = 1--4; a = {\it p\/}-aminophenyl; n = {\it p\/}-nitrophenyl; Por = 5,10,15,20-substituted porphyrin) has been synthesized and characterized by various physical methods. Their second-order non-linear optical properties have been measured by the EFISH technique giving substantial $\beta$ in the range 10 to 30 $\times$ 10$\sp{-30}$ {\it esu\/} (1.91 $\mu$m, CHCl$\sb3$).
• Moderate to strong solvatochromic effects have been observed in several {\it cis\/} isomers of ``push-pull'' porphyrins, H$\sb2$({\it cis\/}-a$\sb2$n$\sb2$Por), H$\sb2$\lbrack{\it cis\/}-(Ocda)n$\sb2$Por\rbrack, and H$\sb2$\lbrack{\it cis\/}-h$\sb2$(Ocdpy)$\sb2$Por\rbrack(I)$\sb2$ \lbrack where Ocda = {\it p\/}-(N-octadecylamino)phenyl; h = {\it p\/}-hydroxyphenyl; Ocdpy = {\it p\/}-(N-octadecyl)pyridiniumyl\rbrack. $\sp1$H NMR can detect the non-symmetric ring current in {\it cis\/} isomers of ``push-pull'' porphyrins. The relative polarization of the $\pi$-electron cloud can be ordered as H$\sb2$\lbrack{\it cis\/}$\sb2$-h$\sb2$(Ocdpy)$\sb2$Por\rbrack$\sp{2+}$ $\sim$ H$\sb2$\lbrack{\it cis\/}-m$\sb2$(Mpy)$\sb2$Por\rbrack$\sp{2+}$ $>$ H$\sb2$\lbrack{\it cis\/}-(Ocda)$\sb2$n$\sb2$Por\rbrack \ $>$ H$\sb2$({\it cis\/}-a$\sb2$n$\sb2$Por) $>$ H$\sb2$({\it cis\/}-h$\sb2$py$\sb2$Por) $\sim$ H$\sb2$({\it cis\/}-m$\sb2$py$\sb2$Por) $>$ H$\sb2$\lbrack{\it cis\/}-({\it s\/}-Clprmd)$\sb2$n$\sb2$Por\rbrack\ $\sim$ H$\sb2$\lbrack{\it cis\/}-(Ocdmd)$\sb2$n$\sb2$Por\rbrack \ (where Mpy = {\it p\/}-N-methylpyridiniumyl; py = 4-pyridyl; m = {\it p\/}-methoxyphenyl; {\it s\/}-Clprmd = {\it p\/}-({\it s\/}-2-chloropropinoylamido)phenyl; Ocdmd = {\it p\/}-octadecanoylamidophenyl\rbrack.
• The isotherms of amphiphilic porphyrins, {\it i.e.\/}, H$\sb2$\lbrack(Ocdmd)$\sb{\rm x}$n$\sb{\rm 4-x}$Por\rbrack, were studied. We found that porphyrins with one or two aliphatic substituents (x = 1 or 2) adopt a perpendicular orientation to the water surface with the mean molecular area ($A\sb0$) less than 120 \AA$\sp2$; those with three or four aliphatic substituents (x = 3 or 4) have a parallel orientation to the water surface with $A\sb0$ larger than 190 \AA$\sp2$. $A\sb0$ of H$\sb2$\lbrack{\it cis\/}-(Ocdmd)$\sb2$n$\sb2$Por\rbrack, H$\sb2$\lbrack{\it cis\/}-(Ocda)n$\sb2$Por\rbrack, and H$\sb2$\lbrack{\it cis\/}-h$\sb2$(Ocdpy)$\sb2$Por\rbrack(NO$\sb3)\sb2$, was found to be 112 $\pm$ 5, 108 $\pm$ 5, and 142 $\pm$ 5 \AA$\sp2$, respectively, in Langmuir films.

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Copyright 1992 Chen, Chin-Ti

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