The preparation of a series of organically functionalized wormhole-motif microspherical MSU-X silicas mesostructures was achieved by a direct synthesis process involving the addition of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) to mildly acidified solutions of a structure-directing nonionic surfactant (Igepal CA-720), followed by fluoride-mediated hydrolysis/cross-linking and surfactant extraction. The influence of organosilane content (MPTMS/TEOS ratio) and synthesis temperature on the framework order, pore structure, and particle size of the resulting mesostructures was investigated. The lattice spacings, pore volumes, and pore diameters were found to systematically increase as a function of increasing synthesis temperature. Although very poorly ordered and microporous when prepared at lower synthesis temperatures, the framework ordering and pore channel diameters of the microspheres dramatically improved when these were synthesized at temperatures above 40-45 °C. Moreover, increasing the synthesis temperature reduced the average particle sizes of the microspheres, although a sudden swelling of the particle sizes was observed in the threshold temperature zone where improved framework order and mesoporosity in the microspheres was evidenced. Incorporation of organic functional groups (MPTMS) inside the structures appeared to have little influence on the structure and morphology of the mesostructures, save for slight lattice and pore diameter contractions upon increasing organosilane group loading. By systematically varying the organosilane content and the synthesis temperature of the microspheres, functional MSU-X materials with accurately fine-tuned pore dimensions and particle diameters could therefore be obtained.

Group 13 metal atoms react with ethers under matrix isolation conditions to give a number of interesting products. This work has been extended to include the reaction of Al atoms with 1,2-epoxybutane (CH(3)CH(2)H(2)) and its isotopomers, 1,2-epoxybutane-1,1-d(2) (CH(3)CH(2)D(2)) and 1,2-epoxybutane-2-d(1) (CH(3)CH(2)H(2)). The paramagnetic species generated in the reaction have been studied by electron paramagnetic resonance (EPR) spectroscopy. Two divalent Al insertion products were spontaneously formed. Species A, with the magnetic parameters a(Al) = 855 MHz, a(H)(1) = 28.8 MHz, a(H)(2) = 13.6 MHz, and g = 2.0014, is the C(1)-O insertion radical CH(3)CH(2). Species B, thought to result from the insertion of Al atoms into the C(2)-O bond, CH(3)CH(2), has the magnetic parameters g = 2.0003, a(Al) = 739 MHz, a(H)(1) = 15.1 MHz, a(H)(2) = 18.5 MHz, and a(H)(1) = 37.8 MHz. Support for these assignments was obtained by comparing the experimental values of the Al and H hyperfine interaction (hfi) with those calculated using a DFT method. At temperatures < 150 K, there is evidence for the formation of the alkyl radical CH(3)CH(2)CH(O(-))CH(2)* due to ring opening at the C(1)-O bond, while at higher temperatures a radical with magnetic parameters similar to those reported for 1-methallyl was detected.

Mesoporous MSU silica microspheres were prepared by the hydrolysis of tetraethoxysilane (TEOS) in mildly acidic aqueous nonionic surfactant solutions in the presence of small amounts (molar percentage up to 1.25% with respect to TEOS) of cationic organotrialkoxysilanes (N-((trimethoxysilyl)propyl)-N,N,N-trimethylammonium chloride, N-((trimethoxysilyl)propyl)-N, N,N-tributylammonium chloride, and N-((trimethoxysilyl)propyl)-ammonium chloride). The incorporation of increasing amounts of cationic organotrialkoxysilanes results in the formation of microspherical MSU silica with increasingly perturbed mesopore structure (bimodal pore size distributions in the 30-120 A ˚range) and increasingly textural morphology. Functionalized derivatives of the microspheres were prepared by the substitution of TEOS with 3-mercaptopropyltrimethoxysilane (MPTMS) in the synthesis mixture. Gold ion adsorption studies were performed on the resulting microspheres, which showed that mildly perturbed microspheres, maintaining an adequate degree of uniformity in their mesopores, had optimal adsorption capacity and improved adsorption kinetics compared with both unperturbed and highly perturbed microspherical mesostructures.

(69/71)Ga atoms were reacted with 1,2-epoxybutane and its isotopomers, 1,2-epoxybutane-1,1-d(2) (CH(3)CH(2)CHOCD(2)) and 1,2-epoxybutane-2-d(1) (CH(3)CH(2)CDOCH(2)), under matrix-isolation conditions. The novel gallaoxetanes CH(3)CH(2)CHCH(2)GaO and CH(3)CH(2)CHCH(2)OGa, resulting from the insertion of the metal atom in the C(1)-O and C(2)-O bonds, respectively, of the 1,2-epoxybutane, were detected by EPR spectroscopy. The Ga and H hyperfine interaction (hfi) values of the gallaoxetanes, calculated using a DFT method, were used to help assign the EPR spectra. A third Ga-centered species, detected at 190 K, underwent spectral changes similar to those of the C(2)-O insertion product upon isotopic substitution of the 1,2-epoxybutane. Although the Ga hfi for this species was 36% smaller than that of the C(2)-O insertion product, the values for the H hfi were similar, suggesting that the carrier of the spectrum was the C(2)-O insertion product where Ga was perturbed by the matrix constraints. The alkyl radical CH(3)CH(2)(•CH)CH(2)OGa, resulting from ring-opening at the C(2)-O bond of 1,2-epoxybutane, was observed at temperatures below 150 K. This radical has been implicated in the formation of the C(2)-O insertion product. The unusually small value found for two of the β-hydrogens of the alkyl radical is discussed.