Synthesis and Study of Zirconium Viologen Phosphonate Thin Films Containing Colloidal Platinum

Abstract

Structural control is a key element in the design of molecular materials with desirable bulk properties. An approach that has attracted attention recently is the use of tetravalent metal phosphonates [e.g., M(03PRP03), M = M4+, R = organic group] for the construction and design of molecular materials.1•2 These structures are reminiscent of Langmuir-Blodgett (LB) multilayers.3 Unlike LB films, the inorganic layers of metal phosphonate (MP) thin films have very strong bonding, resulting in films that are stable for long periods. MP thin films are prepared by sequential treatment of a substrate with aqueous solutions of zirconium and a bisphosphonic acid.23•4-6 Ellipsometric4-*' and X-ray measurements,lf>4b as well as electronic spectroscopy,23 show that this incremental growth technique leads to uniform metal phosphonate thin films. MP films have been used as chiral molecular sieves,7 dielectric layers,5 and chemical sensors,13 as well as to align chromophores for nonlinear opticsld•6 and study photoinduced electron transfer in layered materials.lb•2 The

Control of Structural Order in Self-Assembled Zirconium Alkylphosphonate Films

“…In contrast, metal alkylphosphonates can be adsorbed as strongly bound monolayer films on a variety of different substrates by a simple two-step procedure, consisting of dipping an appropriately functionalized substrate alternately into solutions of a suitable metal ion (e.g., Zr 4+ , Hf 4+ , Zn 2+ , Cu 2+ ) and of a long-chain alkylphosphonic acid. Using α,ω-biphosphonic acids in the second step opened up a simple, repetitive procedure for the fabrication of multilayer films with precisely controllable thickness and layer sequence, which has been exploited over the past decade for a number of different applications , including nonlinear optical materials, − electroluminescent devices, immobilization of biomolecules, or solar energy storage devices based on photoinduced electron-transfer reactions. − …”

Engineering coordination polymers towards applications

“…Photolysis of the white crystalline solids results in the formation of a blue bipyridinium radical cation, followed by oxidation of a halide anion to the radical. The phosphonate groups are assumed to bridge the zirconium atoms to a 2D lamellae, the biphosphonate then bridges between lamellae, the exact structure being unknown 92,303. From a water or dmf solution of1 ∞ {[Zn(H 2 O) 2 (4,4Ј-bipy)(L 65 ) 2 ](NO 3 ) 2 ؒ1.75(L 65 )ؒ0.25(4,4Ј-bipy)ؒ4.45H 2 O} nanofibers were obtained in an electrospinning process 304.…”

Photofunctional Layered Materials

“…12) [206]. Energytransfer among naphthyl-, anthryl-, and pyrenylalkylammonium bound to zirconium phosphate and photoinduced electron transfer from 5,10,15,20-tetrakis (4-phosphonophenyl)porphyrin to N,N 0 -bis(3-phosphonopropyl)-4,4 0 -bipyridinium organized in Zr phosphonate-based self-assembled multilayers have been reported [207][208][209]. The layered structure plays an important role in organizing reactants to control the reaction.…”