R-allyl)M(arene)] + complexes (M ) Pd, Ni; R ) H, CH 3 , Cl; arene ) mesitylene, hexamethylbenzene) have been synthesized via halide abstraction from the corresponding allyl halide dimers, [(allyl)MX] 2 , using either AgSbF 6 in the case of M ) Pd or NaB(Ar f ) 4 (Ar f ) 3,5-(CF 3 ) 2 C 6 H 3 ) in the case of M ) Ni. The [(allyl)Ni(mesitylene)] + and [(2-methallyl)Ni(hexamethylbenzene)] + salts have been characterized by single-crystal X-ray diffraction. The arene ligands in the Pd species are highly labile. The mesitylene ligand in the [(2-R-allyl)Pd(mesitylene)] + complexes is rapidly displaced at temperatures as low as -120 °C by olefins and alkynes (ethylene, tert-butylethylene, cyclopentene, cyclohexene, cyclooctene, 2-butyne) to yield the bis-olefin or bis-alkyne complexes, which have been characterized by NMR spectroscopy. [(allyl)Pd(mesitylene)] + undergoes rapid degenerate exchange with free mesitylene at low temperatures (∆G q ) 10.2 kcal/mol). The arene ligand of the Ni complexes is less labile. Displacement of mesitylene from [(allyl)Ni(mesitylene)] + by excess diethyl ether at 25 °C yields [(allyl)Ni(Et 2 O) 2 ] + . Reaction of the [(2-R-allyl)Ni(mesitylene)] + complexes (R ) H, CH 3 ) with R-olefins at 25 °C yields new allyl complexes plus propene (when R ) H) or isobutylene (when R ) CH 3 ). A mechanism involving intramolecular hydrogen migration is proposed to account for these transformations.

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N-(2-(Pyridin-2-yl)­ethyl)­benzenesulfonamide derivatives and 1,1,1-trifluoro-N-(2-(pyridin-2-yl)­ethyl)­methane­sulfonamide (1–4), along with three-legged piano stool Cp*IrIIICl complexes (5–11) (Cp* = pentamethyl­cyclopentadienyl) bearing pyridinesulfonamide ligands with varying electronic parameters, were synthesized. These ligands and air-stable complexes were characterized by 1H and 13C­{1H} NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Precatalysts, 5–11, were assessed for transfer hydrogenation of aryl, diaryl, dialkyl, linear, cycloaliphatic, and α,β-unsaturated ketones, diones, β-ketoesters, and a biomass-derived substrate with 2-propanol, using 1 mol % precatalyst. Catalysis was also efficient using a 0.1 mol % loading. Remarkably, all catalysis experiments can be conducted in air without dried and degassed substrates, and basic additives and halide abstractors are not required for high activity in transfer hydrogenation. Control experiments and a mercury poisoning experiment support a homogeneous catalyzed pathway. Overall, the fastest reactions are observed using electron-poor substrates and precatalysts bearing electron-rich ligands.

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Polymerizations of 1,3-dienes using in situ generated catalyst [(2-methallyl)Ni][B(Ar F ) 4 ], 6, (Ar F ¼ 3,5-bis(trifluoromethyl)phenyl) as well as [(2-methallyl)Ni(mes)][B(Ar F ) 4 ], 14, (mes ¼ mesitylene) are reported. Highly sensitive complex 6 polymerizes butadiene (BD) at -30 C to yield polybutadiene with a M n of ca. 10 K and 94% cis-1,4-enchainment while less reactive isoprene (IP) was polymerized at 23 C to yield polyisoprene with M n ca. 7 K. Complex 6 was also shown to polymerize a functionalized diene, 2,3-bis(4-trifluoroethoxy-4oxobutyl)-1,3-BD, to polymer with M n ¼ 113 K. The stable and readily isolated arene complex 14 initiates BD and IP polymerizations at somewhat higher temperatures relative to 6 and delivers polymers with higher molecular weights. Complex [(allyl)Ni(mes)][B(Ar F ) 4 ], 13, catalyzes polymerization of styrene to yield polystyrene with high conversion, M n 's ¼ ca. 6 K and MWD ¼ 2. The p-benzyl complex [(g 3 -1-methylbenzyl)Ni(mes)] [B(Ar F ) 4 ], 19, was detected as an intermediate following chain transfer by in situ NMR studies.

The synthesis and characterization of (COD)Rh(I) and (NBD)Rh(I) (COD = cyclooctadiene; NBD = norbornadiene) chloride complexes containing the 2-(dicyclohexylphosphino)biphenyl (PCy 2 -biPh) ligand are reported. Abstraction of the halide with Na(BAr F ) 4 yields cationic Rh(I) complexes [(NBD)Rh(PCy 2 biPh)][B(Ar F ) 4 ] (2) and [(COD)Rh(PCy 2 biPh)][B(Ar F ) 4 ] ( 7) (Ar F = 3,5-bis(trifluoromethyl)phenyl). In complex 2, the pendent arene of the ligand is coordinated in an η 2 -fashion to rhodium. Complex 7 exists in two configurations that were characterized by low-temperature NMR spectroscopy. One structure is analogous to 2 with η 2 -coordination of the arene, and the other exhibits η 6 -coordination. These structures interconvert on the NMR time scale at room temperature. Addition of H 2 to complex 2 yields the Rh(III) dihydride complex [(PCy 2 biPh)RhH 2 ][B(Ar F ) 4 ] (5), while the addition of H 2 to 7 generates the Rh(I) olefin complex [(COE)Rh(PCy 2 biPh)][B(Ar F ) 4 ] (8). In both 5 and 8, the pendent arene of the ligand is bound η 6 to Rh. Benzene hydrogenation to cyclohexane using 2 as a catalyst precursor is described. Poisoning experiments indicate that heterogeneous rhodium is likely to be the active catalyst in this arene hydrogenation reaction.

An innovative, three-year seminar program was developed for undergraduates at The College of New Jersey (TCNJ) that supplements the core chemistry curriculum by teaching the auxiliary skills necessary for life as a professional chemist. Advising, good laboratory practice, and information literacy are the strategic components of this program that function as building blocks to support sequential learning objectives and outcomes for students while enriching the chemistry program at TCNJ. Although the seminar program model is not unique to the TCNJ campus, this program has novel components, including a strong faculty-embedded-librarian partnership, a three-year approach that builds new skills onto the foundation of those previously acquired, a mentoring relationship between faculty and students that is reinforced by sustained faculty interaction, a peer mentor component that builds throughout the students’ time at TCNJ, and assessment of knowledge retention at the start of each course. Details pertaining to the components of the program, the impact of the program as evidenced by assessment outcomes, along with student views on how the program influenced their learning skills, and future directions are described.