Organically Modified Aluminum Phosphates:  Synthesis and Characterization of Model Compounds Containing Diphenyl Phosphate Ligands

Abstract

Reactions of diphenylphosphoric acid (DPPA) with AlMe3, AlEt3, Al(tBu)3, and boehmite have been studied. The reaction with Al(tBu)3 yields the molecular complex ([(tBu)2AlO2P(OPh)2]2) (1), which in the solid state exists as a centrosymmetric dimer consisting of two four-coordinate Al centers linked by diphenyl phosphate (DPP) bridges. The ligand bite distance Al···Al in 1 is equal to 4.75 Å. Reactions with AlMe3 or AlEt3 lead to polymeric aluminum organophosphates ({Al[O2P(OC6H5)2]3} n ) (2). These polymers were characterized by elemental analysis, in addition to XRD, TGA, FT-IR, SEM, and MAS NMR techniques. The results of MAS NMR and FT-IR studies have shown that Al(OP)6 units are the basic chain building blocks that produce condensed structures. The same type of Al environment was observed in aluminophosphate phase found in the products of the reaction with boehmite. This phase reveals a fibrous structure attributed to the close-packed hexagonal columnar structure consisting of polymeric chains of catena-Al(DPP)3 with the unit cell parameters α = 15.14(4) Å and c = 14.44(3) Å (V = 2870 Å3). The number of molecules in the crystallographic unit (Z) is 3. According to this model the mean diameter of the chain is equal to the parameter α (15.14 Å) while the distance between adjacent Al atoms linked by three phosphate bridges can be estimated as c/3 = 4.81 Å. The latter value matches perfectly the value of the Al···Al distance determined for compound 1.

The orientation-enhancing effect of diphenyl aluminium phosphate nanorods in a liquid-crystalline epoxy matrix ordered by magnetic field

“…4 and 2D-WAXS/SAXS in Figs. 5 and 6a) display the following interference maxima, which can be correlated with the structural features of their components: LCEM: q = 1.4 Å À1 (intense and somewhat broad; corresponds to d = 4.4 Å which can be assigned to the lateral distance of LCEM rods), q = 0.75 Å À1 (weak, d = 8.4 Å), q = 0.49 Å À1 (weak, d = 13 Å, corresponds to the width of the aromatic core), 0.32 Å À1 (weak, second order maximum of the reflection at q = 0.16 Å À1 ), q = 0.16 Å À1 (intense, d = 39 Å, corresponds approximately to the LCEM length); DDM: q = 0.63 Å À1 (weak, d = 10 Å, corresponds approximately to the length of DDM, not prominent in 2D-SAXS), non-characteristic reflections in the range 1.0-2.0 Å À1 ; NR: q = 0.51 Å À1 (d = 12.3 Å; distance between arrays of electron-rich P and Al atoms in the cores of the NR molecules, as assigned in [30] and verified by comparing homologues with different substituents on NR surface in [30] vs. [29]; in the studied case, d = 12.3 Å is also similar to the width of the entire NR molecule), three maxima between q = 1.3 and 1.5 Å À1 (corresponding to regular Al-Al, P-P and other atoms distances along the main axis of the rod-like NR molecule [30]). The intense reflections at q = 1.40 Å À1 (LCEM), 0.51 Å À1 (NR) and q = 0.16 Å À1 (LCEM) were investigated with 2D-WAXS and -SAXS (see Scheme 6), in order to assess the orientation of LCEM and NR.…”

“…3). These crystallites are composed of nanorods (formula: Al[O 2 P(OPh) 2 ] 3 , see Scheme 3) and were synthesized according to the method reported in the literature [29,30]. All the reagents and solvents were commercial products from Sigma-Aldrich, Fluka, or Merck, and were used as received.…”

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

“…Subsequently, selected compositions were cured again but this time with the addition of a nanofiller. Diphenyl aluminum phosphate nanorods (NR) having 100 − 200 nm in diameter and 1 − 5 μm in length, synthesized according to were used as the filler.…”

Low permeability styrene butadiene rubber/boehmite nanocomposites modified with tannic acid

“…1. In the spectrum of BM, the absorption bands approximately 739 cm − 1 (γ as ), 1070 cm −1 (σ s ), 3072 cm − 1 (ν s ) and 3305 cm −1 (σ as ) can be assigned to aluminol groups of BM [11,18]. In addition, the peaks around 478 and 617 cm −1 are associated with the stretching vibrations in the distorted AlO 6 octahedron [19].…”