The scope and limitations of the alkylation of [closo-B12(OH)12]2- using a series of fourteen alkyl and aralkyl halides and two p-toluenesulfonic acid esters in the presence of N,N-diisopropylethylamine have been investigated. The dodecaalkoxy-closo-dodecaborate products, [closo-B12(OR)12]2-, and their hypercloso two-electron oxidation products have been explored. The species [closo-B12(OR)12]2- containing 26 cage-bonding electrons may undergo two reversible, sequential, one-electron oxidation processes, producing a 25-electron radical anion and a 24-electron neutral species. Several oxidizing reagents were investigated for the chemical oxidation of [closo-B12(OR)12]2- and [hypercloso-B12(OR)12]- to [hypercloso-B12(OR)12]. Both FeCl3.6H2O and K3Fe(CN)6 in 90/5/5 ethanol/acetonitrile/H2O were found to be the reagents of choice. The reverse reaction leading from the neutral species to the radical anion and subsequently to the dianion was achieved using sodium borohydride in ethanol. A variety of alkoxyl derivatives have been synthesized by heating the reactants for extended periods of time in acetonitrile at the reflux temperature. The use of elevated reaction temperatures attained by employing moderate argon pressure (autoclave) over the reaction mixture led to drastic reductions in reaction times and increased efficiency. X-ray diffraction studies of substituted dodecabenzyl ether derivatives proved that 2(2-) has approximate Ih symmetry while hypercloso-2, -3, -9, -11, -12, and -13 have approximate D3d point group symmetry due to Jahn-Teller distortion from Ih.

Pegylated immunonanoparticles can be synthesized with bifunctional PEG derivatives that bridge the nanoparticle and the targeting MAb. This novel formulation may enable the targeted delivery of small molecules, protein drugs, and gene medicines.

A family of η 5 -CpFe(CO) 2 -substituted closo-carboranes was synthesized and characterized, including cyclic voltammetry measurements. Like the previously reported bimetallic compound 1,12-[η 5 -CpFe(CO) 2 ] 2 -1,12-C 2 B 10 H 10 (8), 1,10-[η 5 -CpFe(CO) 2 ] 2 -1,10-C 2 B 8 H 8 (9) produces two dissimilar and irreversible one-electron oxidations within the same range, suggesting that it also exhibits through-cage electronic communication between iron centers. Structures determined by X-ray diffraction studies are reported for 1-[η 5 -CpFe(PPh 3 )(CO)]-1,12-C 2 B 10 H 11 (5), 1,12-[η 5 -CpFe(CO) 2 ] 2 -1,12-C 2 B 10 H 10 (8), and 1,10-[η 5 -CpFe(CO) 2 ] 2 -1,10-C 2 B 8 H 8 (9).

No abstract

A boron-rich, water-soluble porphyrin conjugate was synthesized by coupling of two carboranyl alcohols with 2-chlorophenoxyphosphorus dichloride, followed by conjugation to an amine-functionalized tetraphenyl-porphyrin via an amide linkage.

No abstract

No abstract

Enantioselective syntheses Enantioselective syntheses O 0031Asymmetric Oxazaborolidine-Catalyzed Reduction of Prochiral Ketones with N-tert-Butyl-N-trimethylsilylamine-borane. -The title reagent is reported as an efficient borane source under conditions A). -(HUERTAS, R. E.; CORELLA, J. A.; SODERQUIST*, J. A.; Tetrahedron Lett. 44 (2003) 24, 4435-4437; Dep. Chem., Univ. Puerto Rico, Rio Piedras 00931, P. R.; Eng.) -Mais 36-027