Palladium Porphyrin Containing Zirconium Phosphonate Langmuir−Blodgett Films

Abstract

The substituted tetraphenylporphyrins palladium 5,10,15,20-tetrakis(2′,3′,5′,6′-tetrafluorophenyl-4′-octadecyloxyphosphonic acid)porphyrin ( 16) and palladium 5,10,15-tris(2′,6′dichlorophenyl)-20-(2′,3′,5′,6′-tetrafluorophenyl-4′-octadecyloxyphosphonic acid)porphyrin ( 17) have been studied as Langmuir monolayers and as zirconium phosphonate Langmuir-Blodgett (LB) films. Using a three-step deposition technique, symmetric and alternating zirconium phosphonate bilayers and multilayers were prepared. In these films, the porphyrin constituent resides in the hydrophobic region of the monolayer and the phosphonate substituents bind zirconium ions in the hydrophilic part. Films of the pure porphyrins and of mixtures with octadecylphosphonic acid (OPA) were prepared. Langmuir monolayers were characterized with pressure vs area isotherms and reflectance UV-vis spectroscopy. LB films were studied with transmittance UV-vis and X-ray diffraction. Control over chromophore interaction was achieved by chemical modification of the amphiphiles and by selection of appropriate transfer conditions. For example, reduced aggregation was seen in LB films of the tetraphosphonic acid substituted porphyrin 16 transferred at mean molecular areas (MMA) larger than the area per molecule of the substituted porphyrin. In these films, the porphyrin macrocycles are nonaggregated and oriented parallel to the surface. In contrast, the monophosphonic acid substituted 17 aggregates under all of the deposition conditions studied. The stability of the porphyrin LB films was examined by exposing the films to refluxing chloroform. UV-vis absorbance after immersion in chloroform confirmed conclusions that in films of 17, many of the chromophores are not tethered to the inorganic network and are easily removed, whereas in films of 16, all molecules bind to the zirconium phosphonate extended network, making these films very resilient. CM980636D (48) Petruska, M.; Talham, D. Unpublished results.

Manganese porphyrin multilayer films assembled on ITO electrodes via zirconium phosphonate chemistry: chemical and electrochemical catalytic oxidation activity

“…Consistent with earlier reports [14][15][16][17], we have recently found that stable multilayer films based on a rigid 5,15-functionalized porphyrin bis-phosphonates and related supramolecular assemblies can be prepared on indium-tin oxide (ITO) coated glass slides [18,19]. This method involves the formation of a zirconium layer on the conductive surface and sequential adsorption of porphyrin bisphosphonates and ZrOCl 2 providing multilayer films.…”

Techniques for phosphopeptide enrichment prior to analysis by mass spectrometry

“…A number of studies demonstrated the formation of zirconium phosphonate films on various surfaces because of potential applications in catalysis, sensing, electronics, protein immobilization, and separations (Lee et al, 1988; Putvinski et al, 1990; Hong, Sackett, & Mallouk, 1991; Byrd, Pike, & Talham, 1993; Frey, Hanken, & Corn, 1993; Byrd et al, 1994; Nixon et al, 1999; Clearfield et al, 2000; Kohli & Blanchard, 2000; Kumar & Chaudhari, 2000; Benitez et al, 2002; Nonglaton et al, 2004; Mazur, Krysinski, & Blanchard, 2005). Zr(IV) binds strongly to phosphonate monolayers due to metal ion‐ligand crosslinking (Zr(IV) ions coordinate to more than one phosphonate molecule), (Byrd, Pike, & Talham, 1993; Byrd et al, 1994) and multilayer Zr(IV) phosphonate films can also be prepared (Nixon et al, 1999; Clearfield et al, 2000; Kohli & Blanchard, 2000). With regard to phosphopeptide enrichment, Zhou and co‐workers used zirconium phosphonate monolayers immobilized on porous silicon as phosphopeptide affinity probes for MALDI‐TOF‐MS (Zhou et al, 2006).…”

Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system

“…Indeed, the zirconium phosphonates reported in literatures are a class of versatile materials with promising applications such as catalyst supporters, heavy metal sorbents, as well as proton-conducting materials1819202122. However, there are two key hurdles for the further development of zirconium phosphonate MOFs.…”

“…Compared to zirconium carboxylate MOFs, tetravalent zirconium phosphonates are proposed to possess elevated stabilities owing to the higher p K a values of the phosphonate ligands 17 . Indeed, the zirconium phosphonates reported in literatures are a class of versatile materials with promising applications such as catalyst supporters, heavy metal sorbents, as well as proton-conducting materials 18 19 20 21 22 . However, there are two key hurdles for the further development of zirconium phosphonate MOFs.…”