%0 Journal Article
%A Mason, Mark R.
%A Perkins, Alisa M.
%A Matthews, R. Mark
%A Fisher, James D.
%A Mashuta, Mark S.
%A Vij, Ashwani
%D 1998
%T Synthesis and Characterization of Dimeric, Trimeric, and Tetrameric Gallophosphonates
and Gallophosphates⊥
%U https://acs.figshare.com/articles/journal_contribution/Synthesis_and_Characterization_of_Dimeric_Trimeric_and_Tetrameric_Gallophosphonates_and_Gallophosphates_sup_sup_/3621615
%R 10.1021/ic980132h.s001
%2 https://ndownloader.figshare.com/files/5710257
%K ULM
%K t Bu
%K THF
%K NMR spectroscopy
%K t BuGaO 3 PR
%K t Bu 3 Ga
%K refluxing diglyme
%K OH
%K H 3 PO 4
%K cuboidal Ga 4 P 4 O 12 cores
%K 3 SiNMe 2
%X THF/toluene solutions of phosphonic or phosphoric acids were reacted with tBu3Ga at low temperature to yield
the cyclic dimers [tBu2GaO2P(OH)R]2 (R = Ph, Me, tBu, H, OH; 1−5). Poor crystallinity and variable thermal
stabilities of 1−5 necessitated derivatization with Me3SiNMe2 to yield [tBu2GaO2P(OSiMe3)R]2 (R = Ph, Me,
tBu, H, OSiMe3; 6−10), which were more amenable to purification and characterization. In solution, trans isomers
were predominant for 6 and 7 at ambient temperature, whereas the cis isomer of 8 was predominant. NMR
spectroscopy demonstrated cis−trans interconversion for 6−8 and crossover experiments showed interconversion
to occur by, or be accompanied with, an intermolecular exchange process. Thermolysis of 3 in refluxing toluene
yielded the cluster [(tBuGa)2(tBu2Ga)(O3PtBu)2{O2P(OH)tBu}] (11), which was converted to [(tBuGa)2(tBu2Ga)(O3PtBu)2{O2P(OSiMe3)tBu}] (12) with Me3SiNMe2. Thermolysis of 1−3 in refluxing diglyme, or solid-state
pyrolysis at 250 °C in vacuo, yielded [tBuGaO3PR]4 (R = Ph, tBu, Me; 13−15). The gallophosphate [tBuGaO3P(OSiMe3)]4 (16) was similarly obtained by reaction of tBu3Ga with H3PO4 in refluxing diglyme, followed by
trimethylsilylation with Me3SiNMe2. Compounds 13−16 possess cuboidal Ga4P4O12 cores analogous to double-four-ring secondary building units in the gallophosphates cloverite, gallophosphate-A, and ULM-5. The thermal,
hydrolytic, and oxidative stabilities of 13−16 are discussed, as are observed intermolecular exchange processes.
In addition to characterization of 1−16 by multinuclear (1H, 13C, 31P) NMR spectroscopy, infrared spectroscopy,
mass spectrometry, and elemental analysis, molecular structures for compounds 6, 8, 10, 12, 14, 15, and 16 were
determined by X-ray crystallography.
%I ACS Publications