Herein, we report a class of molecular spherical nucleic acid (SNA) nanostructures. These nano-sized single molecules are synthesized from T polyoctahedral silsesquioxane and buckminsterfullerene C scaffolds, modified with 8 and 12 pendant DNA strands, respectively. These conjugates have different DNA surface densities and thus exhibit different levels of nuclease resistance, cellular uptake, and gene regulation capabilities; the properties displayed by the C SNA conjugate are closer to those of conventional and prototypical gold nanoparticle SNAs. Importantly, the C SNA can serve as a single entity (no transfection agent required) antisense agent to efficiently regulate gene expression. The realization of molecularly pure forms of SNAs will open the door for studying the interactions of such structures with ligands and living cells with a much greater degree of control than the conventional polydisperse forms of SNAs.

We have synthesized a series of stimuli-responsive brush polymers by grafting azide-terminated side chains onto a self-immolative, alkyne-bearing poly(benzyl ether) backbone, which is prepared by anionic polymerization of quinone methide-based monomers. Upon exposure to a decapping reagent (Pd(0) or F−), these brush polymers undergo an irreversible degradation cascade from head to tail to yield individual side chains. It is observed that several factors affect the depolymerization kinetics, including solvent polarity, type of counterion, the rate of the decapping chemistry, and interestingly, the rigidity of the side chains.

Cu-catalyzed synthesis of 3-etherified azaspiro[4.5]trienones from N-arylpropiolamides and ethers is presented using TBHP oxidant. This is achieved through C(sp 3 )-H functionalization, ipso-carbocyclization and dearomatization, and this method represents a new example of alkyne oxidative 1,2-difunctionalization with an ipso-aromatic carbon and a C(sp 3 )-H bond by simultaneously forming two new carboncarbon bonds.

A novel metal-free oxidative 1,2-alkylarylation of unactivated alkenes with the α-C(sp(3))-H bonds of acetonitriles for the synthesis of 5-oxo-pentanenitriles is presented. In the presence of TBPB (tert-butyl peroxybenzoate), a variety of α-aryl allylic alcohols underwent the 1,2-alkylarylation reaction with acetonitriles, giving 5-oxo-pentanenitriles in good to excellent yields. This method proceeds via the C(sp(3))-H oxidative coupling with the C-C double bond and 1,2-aryl-migration, and represents a new access to acyclic molecules through metal-free oxidative alkene 1,2-alkylarylation.

A new approach, the alternating slice-wise diagonalization (ASD) method, is developed for three-way data resolution. First, based on the least squares principle and the constraints inherent in the resolution of the trilinear model, a criterion, the slice-wise diagonalization (SD) loss, is proposed for trilinear analysis of three-way data. This criterion provides a natural way to avoid the two-factor degeneracy, which is difficult to handle for the PARAFAC algorithm. Second, by alternatingly minimizing the SD loss, a procedure is developed for identifying the parameters of the trilinear model. Experimental results show that the resolved profiles of chemical meaning are very stable with respect to the component number provided that the number is chosen to be equal to or greater than the actual one. This enables the ASD method to achieve resolution without concern about the actual component number. This approach is different from the traditional ones, since the determination of the actual component number is a critical step for conventional chemometric resolution techniques. Moreover, the convergence rate of the algorithm for the ASD method is much higher than that of the PARAFAC algorithm.