Ligand-tetrahydrofuran coupling in chelated aluminum phosphinates

Synthesis, Characterization, and Stability of Dealkylated Salen-Supported Aluminum Phosphates

Three salen aluminum bromide compounds salen(^tBu)AlBr (1) (salen = N,N'-ethylenebis(3,5-di-tert-butylsalicylideneimine)), salpen(^tBu)AlBr (2) (salpen = N,N'-propylenebis(3,5-di-tert-butylsalicylideneimine)), and salophen(^tBu)AlBr (3) (salophen = N,N'-o-phenylenenebis(3,5-di-tert-butylsalicylideneimine) were evaluated for their potential use as dealkylation agents with a series of organophosphates. These reactions led to the aluminum phosphate compounds containing six-coordinate aluminum centers and hydrolytically stable P-O-C bonds: 4 = [salen(^tBu)AlOP(O)(OMe)₂]_n, 5 = [salen(^tBu)AlOP(O)(OEt)₂]_n, 6 = [salen(^tBu)AlOP(O)(OPh)₂]_n, 7 = [salophen(^tBu)AlOP(O)(OMe)₂]_n, 8 = [salpen(^tBu)AlOP(O)(OⁱPr)₂]₂, 9 = (salen(^tBu)AlO)₃PO, 10 = (salpen(^tBu)AlO)₃PO, 11 = (salophen(^tBu)AlO)₃PO. All the compounds were characterized by ¹H, ¹³C, ²⁷Al, and ³¹P NMR, IR, and mass spectrometry. Furthermore, compounds 4-8 were structurally characterized by single-crystal X-ray diffraction. The potential hydrolysis of these compounds was modeled with 4 and demonstrated the unique stability of the final product and ease of isolation.

Lewis acid-assisted detection of nerve agents in water

The five-coordinate compound, Salen((t)Bu)Al(Ac), prepared in situ from Salen((t)Bu)AlBr and NH4Ac, forms Lewis acid-base adducts in aqueous solution with the G-type nerve agents, Sarin and Soman, and the VX hydrolysis product, ethylmethylphosphonate (EMPA). The resulting compounds, [Salen((t)Bu)Al(NA)](+)[Ac] (-) (with NA = Sarin, Soman, and EMPA) are sufficiently stable to be identified by ESI-MS. Molecular ion peaks were detected for every compound with little or no fragmentation. The distinctive MS signatures for the [Salen((t)Bu)Al(NA)](+) compounds provide a new technique for identifying nerve agents from aqueous solution. The energetics of the displacement of Ac(-) by the nerve agents to form [Salen((t)Bu)Al(NA)](+)[Ac](-) were determined computationally.

A Novel Organophosphorus Hybrid with Excellent Thermal Stability: Core-Shell Structure, Hybridization Mechanism, and Application in Flame Retarding Semi-Aromatic Polyamide

An organophosphorous hybrid (BM@Al-PPi) with unique core-shell structure was prepared through hybridization reaction between boehmite (BM) as the inorganic substrate and phenylphosphinic acid (PPiA) as the organic modifier. Fourier transform infrared spectra (FTIR), solid state (31)P and (27)Al magic angle spinning nuclear magnetic resonance, X-ray diffraction, and element analysis were used to investigate the chemical structure of the hybrids, where the microrod-like core was confirmed as Al-PPi aggregates generated from the reaction between BM and PPiA, and those irregular nanoparticles in the shell belonged to residual BM. Compared with the traditional dissolution-precipitation process, a novel analogous suspension reaction mode was proposed to explain the hybridization process and the resulting product. Scanning electronic microscopy further proved the core-shell structure of the hybrids. BM exhibited much higher initial decomposition temperature than that of Al-PPi; therefore, the hybrid showed better thermal stability than Al-PPi, and it met the processing temperature of semi-aromatic polyamide (HTN, for instance) as an additive-type flame retardant. Limiting oxygen index and cone calorimetric analysis suggested the excellent flame-retardant performance and smoke suppressing activity by adding the resulting hybrid into HTN.

Aluminum complexes based on pyridine substituted alcohols: synthesis, structure, and catalytic application in ROP

2,6-Bis(hydroxyalkyl)pyridines were used in the synthesis of Al complexes. The structure of the ligand determines the complex nature. Compounds were used as initiators of lactone ROP.

Evidence of the Facile Hydride and Enolate Addition to the Imine Bond of an Aluminum−Salophen Complex

The isolation of complexes 2 and 3, unambiguously characterized by single-crystal X-ray diffraction, demonstrates that nucleophilic additions to the aluminum-coordinated imino bond of salophen complex 1 can be achieved under very mild conditions.