Polymeric materials exhibit an extraordinary range of mechanical responses (Figure 1a), which depend on the chemical and physical structure of the polymer chains. 3 Polymers are broadly categorized as thermoplastic, thermoset, or elastomer. Thermoplastic polymers consist of linear or branched chains and can be amorphous or semicrystalline. The mechanical response of thermoplastic polymers is highly influenced by the molecular mass, chain entanglements, chain alignment, and degree of crystallinity. Thermosetting polymers consist of highly cross-linked three-dimensional networks. The mechanical properties of these amorphous polymers depend on the molecular mass and the cross-link density. Elastomers (e.g., rubber) are highly deformable elastic networks that are lightly cross-linked by chemical or physical junctions. Mary M. Caruso (center) was born and raised in Tampa, FL. She received a B.S. degree in Chemistry from Elon University (Elon, NC) in 2006, where she worked under the direction of Prof. Karl D. Sienerth. Her research included the synthesis and electrochemical characterization of a novel palladium complex. She is currently pursuing her Ph.D. in Organic Chemistry at the University of Illinois at Urbana-Champaign under the guidance of Prof. Jeffrey S. Moore and Prof. Scott R. White. Her research interests include the development of new catalyst-free self-healing polymers, microencapsulation, and mechanical testing of bulk polymers. Douglas A. Davis (second from left) was born in Martin, TN. In 2004, he received his B.S. degree in Chemistry from the University of Tennessee, Knoxville, where he worked on surface enhanced Raman spectroscopy (SERS) in an electrospray plume with Professors Charles Feigerle and Kelsey Cook. He joined Prof. Jeffrey Moore's group at the University of Illinois, Urbana-Champaign in 2005 to pursue his Ph.D. in Organic Chemistry. His current research interests include designing and synthesizing mechanophores, which can be induced to undergo chemical reactions with mechanical force. Qilong Shen (third from left) was born in 1974 in Zhejiang Province, China. He received his B.S. degree in Chemistry (1996) from Nanjing University, China, and his M.S. in Chemistry (1999) from Shanghai Institute of Organic Chemistry, the Chinese Science Academy, China, under the supervision of Prof. Long Lu. After a two-year stay at the University of Massachusetts at Dartmouth with Prof. Gerald B. Hammond, he moved to Yale University, where he received his Ph.D. under the guidance of Prof. John F. Hartwig in 2007. He is currently a postdoctoral researcher with Prof. Jeffrey S. Moore at University of Illinois at Urbana-Champaign. His research interests include the discovery, development, and understanding of new transition metal-catalyzed reactions, and the mechanochemistry of polymers.

A mild, palladium-catalyzed coupling of aryl halides with ammonia or lithium amide to form primary arylamines as the major product is described. These reactions occurred with excellent selectivity for formation of the primary arylamine over formation of the diarylamine (9.5:1 to over 50:1 ratios of arylamine to diarylamine). In addition, the first organopalladium complex with a terminal -NH2 ligand has been isolated. This complex reductively eliminates to form arylamines.

A general catalytic system for the coupling of aryl halides and sulfonates with thiols based on the use of the CyPF-t-Bu ligand (1) is reported. The reactions catalyzed by complexes of 1 occur in excellent yields with broad scope and exhibit extraordinary turnover numbers and high tolerance of functional groups. Turnover numbers usually exceed those of previous catalysts by 2 or 3 orders of magnitude. In addition, the reactions of aryl tosylates with alkane thiols to form aryl sulfides are reported for the first time. Finally, the synthesis of a diarylsulfide from two bromoarenes was accomplished using a hydrogen sulfide surrogate.

We describe a systematic study of the scope and relationship between ligand structure and activity for a highly efficient and selective class of catalysts for the amination of heteroaryl and aryl chlorides, bromides and iodides containing sterically hindered chelating alkylphosphines. In the presence of this catalyst, aryl and heteroaryl chlorides, bromides and iodides react with many primary amines in high yields with part-per-million quantities of palladium precursor and ligand. Many reactions of primary amines with both heteroaryl and aryl chlorides, bromides and iodides occur to completion with 0.0005-0.05 mol % catalysts. A comparison of the reactivity of this catalyst for coupling of primary amines at these loadings is made with catalysts generated from hindered monophosphines and carbenes, and these data illustrate the benefits of chelation. Thus, these complexes constitute a fourth-generation catalyst for the amination of aryl halides, whose activity complements catalysts based on monophosphines and carbenes.

Sulfur and friends: A new electrophilic hypervalent iodine reagent 1 has been developed for direct trifluoromethylthiolation. A variety of nucleophiles, including β‐ketoesters, aldehydes, amides, aryl or vinyl boronic acids, and alkynes, reacted with 1 under mild conditions to give the corresponding trifluoromethylthiolated compounds in good to excellent yields.

During the past decade, the palladium-catalyzed amination of aryl halides has become a principal method to form the CÀN bonds of aromatic amines. [1][2][3][4] Although current catalysts are capable of coupling a wide range of amines with aryl halides, reactions with these catalysts have several limitations: the catalysts have short lifetimes in the reactions of primary amines with chloroarenes, even when conducted with the most recently developed, highly active catalysts containing basic, hindered alkylmonophosphines; [5][6][7][8][9][10][11][12][13][14][15] the reactions of primary alkyl amines with heteroaryl chloride reagents, which are important for the synthesis of biologically active molecules, have limited scope and require large amounts of catalyst; [7,8,11,13,[15][16][17][18][19][20] and the reactions of primary alkyl amines with chloroarenes that possess common protic functional groups have not been described.We now report on catalysts that can overcome these limitations. Our approach, which is based upon the selection of ligands that combine steric hindrance, strong electron donation, and tight chelation, leads to a catalyst that simultaneously possesses long lifetimes and displays high activity for reactions of primary nitrogen nucleophiles with chloropyridines. Many of the reactions occur with part-permillion quantities of catalyst and with turnover numbers that exceed those of previous catalysts by two or more orders of magnitude.To identify the factors that would improve catalyst lifetime over that of current catalysts, we studied the reactions of primary amines and pyridine with aryl palladium(ii) halide complexes and bisphosphine palladium(0) complexes bearing a basic, hindered alkyl monophosphine.[ [*] Q.

A new, electrophilic trifluoromethylthiolating reagent, N-trifluoromethylthiosaccharin, was developed and can be synthesized in two steps from saccharin within 30 minutes. N-trifluoromethylthiosaccharin is a powerful trifluoromethylthiolating reagent and allows the trifluoromethylthiolation of a variety of nucleophiles such as alcohols, amines, thiols, electron-rich arenes, aldehydes, ketones, acyclic β-ketoesters, and alkynes under mild reaction conditions.

A copper-catalyzed trifluoromethylation of aryl- and alkenylboronic acids with Togni's reagent was described. The reaction proceeded in good to excellent yields for a range of different substrates including heteroarylboronic acids and substrates with a variety of functional groups under mild reaction conditions.