John B. Goods

Phosphate functionalized graphene with tunable mechanical properties.

The synthesis of a covalently modified graphene oxide derivative with exceptional and tunable compressive strength is reported. Treatment of graphene oxide with triethyl phosphite in the presence of LiBr produces monolithic structures comprised of lithium phosphate oligomers tethered to graphene through covalent phosphonate linkages. Variation of the both phosphate content and associated cation produces materials of various compressive strengths and elasticity.

Study of Two Papyrus Fragments with Fourier Transform Infrared Microspectroscopy

GJW The fragment is predominantly composed of oxidized cellulosic material, which is consistent with old papyrus. The fragment is largely homogenous in chemical composition. We found one anomalous feature that we were unable to identify. We did not observe any major spectral differences between “bare” papyrus and papyrus coated with ink. We did not observe any major spectral differences between the recto and verso sides of the papyrus fragment. The degree of oxidation is similar to that of the John fragment; however, the GJW fragment appears to be slightly less oxidized overall than the John fragment. Oxidation of the fragments is dependent on both their storage conditions and their ages, among other factors.

Hypervalent Iodine for α,α-Dihalogenation

Significance: Functionalization at the α-position of carbonyls represents one of the most versatile and useful types of transformations in organic chemistry. In this paper, the authors describe the use of a hypervalent iodine species to doubly halogenate the α-position of esters with either chlorine or fluorine. Comment: While the chlorination procedure was shown to be broadly functional group tolerant, the need for BF3·OEt2 in the case of fluorination limits the possible functionality in the starting material. The authors report that substrates with labile moieties such as OMe or NHAc decompose upon heating with BF3·OEt2. N2 OR2 O R1 OR2 O R1

Extending Arenes via C–H Activation with Rhodium

Significance: Extending the conjugation length of arenes is of great interest to the materials chemistry community due to the impartation of new electrical and photophysical properties. The previously reported method for rhodium-catalyzed arene homologation was achieved with a boronic acid functionalized substrates (J. Org. Chem. 2011, 76, 2867); in contrast, Pham and Cramer report a C– H functionalization to achieve the same transformation. Comment: While dibutyl alkynes were used most prominently in this paper, the authors were also able to demonstrate that other alkynes, including those bearing aryl groups, could be incorporated. A proposed mechanism for the transformation is included in the paper. R1 R2 R2 [(Cp*RhCl2)2)] (2.5 mol%) Cu(2-ethylhexanoate)2 (200 mol%) (Br5C6)2O (30 mol%) 160 °C, MW, 3 h R1 R2 R2

C–H Arylation with Platinum

Significance: C–H activation in aryl systems finds broad applicability in the construction of conjugated organic materials. This paper reports the use of a platinum catalyst to couple aryl groups pendant on hypervalent iodine to simple arenes via a C–H activation pathway. Comment: The authors have previously reported a similar process using a palladium catalyst (ACS Catal. 2011, 1, 170). However, with the exception of some examples in which the reaction resulted in mixed isomers, the use of a platinum catalyst produced materials with different selectivity than the palladium catalyst, providing two processes with complementary reactivity. [Ar2I]TFA Na2PtCl4 (2.5–5 mol%) TFA or AcOH (0–32 equiv)