Escape rooms are physical adventure games where players solve a series of puzzles and riddles. Using clues and hints participants focus on completing a series of tasks within a set time frame. Because participants of escape rooms interact with a variety of challenging problems in an experiential manner they are of interest as active learning tools. To engagingly accommodate a broad audience, however, the puzzles in traditional escape rooms have limited requirements for specialized participant skills or knowledge. In contrast, ChemEscape strives to both engage and have participants enhance and apply discipline specific skills and knowledge during puzzle solution. This is achieved by incorporating opportunities to learn about objectives and hands-on problem-solving skills typical of research-based experiences. Described herein are four hands-on general chemistry puzzles for use in the novel Battle Box design at the grade 4–12 level and first year general chemistry.

The introduction of polymer chemistry in undergraduate science courses is becoming more popular in recent years, introducing content into the relationships between polymer structure and physical properties in a variety of contexts. However, active learning techniques, outside of laboratory experience, for teaching polymer chemistry are extremely limited. The ChemEscape project has successfully integrated escape-room type puzzle design and course specific learning objectives into an interactive learning experience. The novel battle box design, a self-contained puzzle unit, allows for puzzles to be easily transported and applied as a teaching tool in large postsecondary classrooms as well as an outreach tool. Herein, we describe the design and application of a series of new polymer puzzles, focusing on tacticity, elasticity, and hydrophobicity, into the battle box design as well as an all-in-one backdrop design. Puzzles are scaffolded to allow for all learning to be combined in the final puzzle solution as well as a workbook provided for participants to record observations and learning during the puzzles’ solutions.

Examples of unsymmetric diphosphines, especially those with customized secondary coordination spheres, are rare. Herein, we provide an approach towards a Lewis acid-containing analogue of the bulky diphosphine, 1,2-bis(di-tert-butylphosphino)ethane that contains a single boron moiety. The coordination chemistry of this ligand and its allyl precursor have been explored using nickel(0).

Cobalt(I) complexes supported by a series of PC carbene P pincer ligands of varying donicity, differing in the aryl group linking the phosphine arms with the anchoring carbon donor, are described. Addition of the proligands to cobalt bromide results in the formation of a series of cobalt(II) tetrahedral complexes, Ln-1, which serve as excellent precursors to the corresponding PC alkyl P and PC carbene P complexes. The square-planar cobalt PC carbene P complexes L2 R -3-X (X = Cl, Br) are readily synthesized by addition of a bulky aryloxide radical to the corresponding PC alkyl P complex L1-2-Br, via addition of L2 R to ClCo(PPh 3 ) 3 in the presence of trityl radical, or by addition of NaHBEt 3 and trityl radical to isolated L2 R -1. For the L2 NMe2 PC carbene P complexes, salt metathesis reactions with CsOH•H 2 O, LiCH 2 TMS, or LiNH 2 result in the corresponding hydroxo, alkyl, and amine complexes L2 NMe2 -3-R (R = OH, CH 2 TMS, NH 2 ). Reaction of L2 NMe2 -3-OH with benzoic acid affords the κ 2 -O 2 CPh derivative The nature of the carbene bond in either ligand platform and the effects of the X-type capping ligand on the CoC bond are explored using CASSCF and CASPT2 calculations and show that triplet structures are relatively more stable for the less electron donating ligand L1 while singlet Co(I) carbenes dominate for the more electron rich L2 derivatives. For L2 NMe2 complexes, the effect of the trans ligand X was also probed. π donors imbue the carbene with singlet character, while the strongly σ donating alkyl derivative exhibits significant triplet character.

Benzoxaboroles are a class of five-membered hemiboronic acids that recently attracted significant attention as a new pharmacophore on account of their unique structural and physicochemical properties and their ability to interact selectively with biomolecules. Their structural behavior in water and its effect on their physiological properties remain unclear, especially the question of dynamic hydrolytic equilibrium of the oxaborole ring. Herein, we used NMR spectroscopy, in mixed aqueous-organic solvent, to confirm the strong preference for the closed form of benzoxaborole and its six-and seven-membered homologues over the open boronic acid form. Only with the eight-membered homologue does the cyclic form become unfavorable. Using dynamic VT-NMR studies with designed probe compound 20, we demonstrate that the oxaborole ring undergoes rapid hydrolytic ring closing−opening at ambient temperature at a rate of >100 Hz via a mechanism featuring rate-limiting protontransfer steps. This knowledge can help provide a better understanding of the behavior of benzoxaboroles in biological systems. KEYWORDS: Benzoxaborole, boron heterocycles, hydrolysis, ring size, VT-NMR T he benzoxaborole ring system has emerged as a promising pharmacophore on the strength of the recent approval of the antifungal drug tavaborole (2, AN2690) 1 and the potency demonstrated by numerous derivatives against an impressive diversity of target classes (Figure 1).2−8 The parent compound, benzoxaborole (1), was first prepared by Torssell in 1957. 9 It was described as a highly water-soluble and unusually robust boronic acid derivative with great resistance to both acidic and basic aqueous deboronation. At the time, its structure was proposed to be the cyclic monodehydrated form on the grounds of elemental analysis 9 and ebullioscopic molecular weight determination.10 Although the asserted preference for a cyclic hemiboronic structure 1 C over the open form 1 O ( Figure 1, eq 1) is reasonable based on the lability of B−O bonds and the stability of five-membered rings, until this day there appears to exist no published experimental evidence for it aside from mass spectrometry (in the gas phase) and X-ray crystallography (in thesolid form).11 Surprisingly, the structural behavior of 1 in aqueous solutions has never been studied systematically.While studying the chemistry of benzoxaborole (1), Snyder remarked that it "is remarkably resistant to hydrolysis of the link between the alkoxyl group and the boron atom".10 Indeed, we are aware of only two instances where a benzoxaborole derivative was observed in its open form: a specific case involving a stable trifluoroborate derivative that is less prone to cyclize due to the strength of B−F bonds, 12 and the peculiar 7-hydroxymethylated derivative of 1 whose cyclization would lead to a disfavored [5.5] system. 13 Owing to Le Chatelier's Principle, boronic ester formation is intrinsically unfavored in water. Because the balance of bond enthalpy is neutral (O−H and B−O bonds are broken to form simil...