Organic-Soluble Cyclic and Cage Alkylaluminophosphates: X-ray Crystal Structure of [(tBu)2Al(μ2-O)2P(OSiMe3)2]2

The organic-soluble alkylaluminophosphates [(tBu)2Al(μ2-O)2P(OSiMe3)2]2 (1) and [(tBu)Al(μ2-O)3P(OSiMe3)]4 (2) have been prepared by equimolar reaction of (Me3SiO)3PO with tBu2AlCl and tBuAlCl2, respectively. X-ray crystallography confirms a cyclic Al2P2O4 framework for 1 that is analogous to four-membered-ring secondary building units in some AlPO4 molecular sieves. Similarly, spectroscopic (1H, 13C, 31P NMR; MS) and analytical data suggest that 2 has a cubic Al4P4O12 core analogous to double-four-ring (D4R) secondary building units in AlPO4 materials.