Variable Peripheral Ligand Donation Tunes Electronic Structure and NIR II Emission in Tetrathiafulvalene Tetrathiolate Diradicaloids.

Near-infrared (NIR) lumiphores are promising candidates for numerous imaging, communication, and sensing applications, but they typically require large, conjugated scaffolds to achieve emission in this low-energy region. Due to the extended conjugation and synthetic complexity required, it is extremely difficult to tune the photophysical properties of these systems for desired applications. Here, we report facile tuning of deep NIR-emitting diradicaloid complexes through simple modification of peripheral ligands. These new lumiphores are rare examples of air-, acid-, and water-stable emissive diradicaloids. We apply a simple Hammett parameter-based strategy to tune the electron donation of the capping ligand across a series of commercially available triarylphosphines. This minor peripheral modification significantly alters the electronic structure, and consequently, the electrochemical, photophysical, and magnetic properties of the tetrathiafulvalene tetrathiolate (TTFtt)-based lumiphores. The resultant ∼100 nm absorption and emission range spans common laser lines and the desirable telecom region (ca. 1260-1550 nm). Furthermore, these lumiphores are sensitive to local dielectrics, distinguishing them as promising candidates for ratiometric imaging and/or barcoding in the deep NIR region.

Structure and Luminescence Studies of Salts of the Helical Dication, [Au2(µ-bis(diphenylphosphine)ethane)2]2+ and Comparison with Salts of [Au2(µ-bis(diphenylphosphine)propane)2]2.

Six salts ([Au2(µ-dppe)2](BF4)2·CHCl3, [Au2(µ-dppe)2](BF4)2·1,2-Cl2C2H4, [Au2(µ-dppe)2](PF6)2·CHCl3, [Au2(µ-dppe)2](PF6)2, [Au2(µ-dppe)2](SbF6)2, and [Au2(µ-dppe)2](OTf)2·2CHCl3), (dppe is bis(diphenylphosphine)ethane) containing the dication, [Au2(µ-dppe)2]2+, have been prepared and structurally characterized by single-crystal X-ray crystallography. Unlike the three-coordinate dppe-bridged dimers, Au2X2(µ-dppe)2 (X = Br, I), which show considerable variation in the distance between the gold(I) ions over the range 3.0995(10) to 3.8479(3) Å in various solvates, the structure of the helical dication, [Au2(µ-dppe)2], in the new salts is remarkably consistent with the Au···Au separation falling in the narrow range 2.8787(9) to 2.9593(5) Å. In the solid state, the six crystals display a green luminescence both at room temperature and at 77 K, which has been assigned as phosphorescence. However, solutions of the dication are not luminescent. Salts containing the analogous dication [Au2(µ-dppp)2](PF6)2 (dppp is bis(diphenylphosphine)propane) have been prepared to determine whether the longer bridging ligand might also twist into a helical shape. These salts include [Au2(µ-dppp)2](OTf)2 (OTf is triflate) and three crystalline forms of [Au2(µ-dppp)2](PF6)2: the solvate [Au2(µ-dppp)2](PF6)2·(CHCl3) and two polymorphs of the unsolvated salt. None of these crystals are luminescent, but all contain a similar dication, [Au2(µ-dppp)2]2+, that contains two nearly parallel, linear P-Au-P groups and a long separation between the gold ions that varies from 5.3409(4) to 5.6613(6)Å.

Bright, Modular, and Switchable Near-Infrared II Emission from Compact Tetrathiafulvalene-Based Diradicaloid Complexes.

Near-infrared (NIR)-emitting molecules are promising candidates for biological sensing and imaging applications; however, many NIR dyes are large conjugated systems which frequently have issues with stability, solubility, and tunability. Here, we report a novel class of compact and tunable fluorescent diradicaloid complexes which are air-, water-, light-, and temperature-stable. These properties arise from a compressed π manifold which promotes an intense ligand-centered π-π transition in the NIR II (1000-1700 nm) region and which subsequently emits at ∼1200 nm. This emission is among the brightest known for monomolecular lumiphores with deep NIR II (>1100 nm) emission, nearly an order of magnitude brighter than the commercially available NIR II dye IR 26. Furthermore, this fluorescence is electrochemically sensitive, with efficient switching upon addition of redox agents. The brightness, stability, and modularity of this system distinguish it as a promising candidate for the development of new technologies built around NIR emission.

Interplay of Electronic and Geometric Structure Tunes Organic Biradical Character in Bimetallic Tetrathiafulvalene Tetrathiolate Complexes.

The synthesis and design of organic biradicals with tunable singlet-triplet gaps have become the subject of significant research interest, owing to their possible photochemical applications and use in the development of molecular switches and conductors. Recently, tetrathiafulvalene tetrathiolate (TTFtt) has been demonstrated to exhibit such organic biradical character in doubly ionized bimetallic complexes. In this article we use high-level ab initio calculations to interrogate the electronic structure of a series of TTFtt-bridged metal complexes, resolving the factors governing their biradical character and singlet-triplet gaps. We show that the degree of biradical character correlates with a readily measured experimental predictor, the central TTFtt C-C bond length, and that it may be described by a one-parameter model, providing valuable insight for the future rational design of TTFtt based biradical compounds and materials.

Recess and children with disabilities: A mixed-methods pilot study.

BACKGROUND: It is well-understood that children's social relationships are intrinsically linked to their overall health trajectories. Recess is the only time in the school day that children are free to play and socialize. Yet research on recess consistently indicates that many school playgrounds are challenged by a social landscape that is not conducive to meaningful play. While all children are susceptible to negative social experiences, children with disabilities are at a heightened risk for exclusion and victimization. OBJECTIVE: This study examines this phenomenon specifically within the context of recess. METHOD: Participants included 743 students in grades 4-8 who completed an anonymous on-line survey about their recess experiences. The responses of 44 students with disabilities were highlighted for analysis. MANOVA was used to assess sample differences between children who identified as having a disability and those who did not on self-reported recess enjoyment, affect, victimization and belongingness. Descriptive statistics and qualitative analyses were used to support the findings. RESULTS: Children with disabilities reported more negative affect and victimization and lower positive affect and belongingness. CONCLUSION: Further research is warranted as the results indicate that children with disabilities are more vulnerable than their non-disabled peers during recess. Studies that explore the context of recess may provide further insights as to best practices.

Risk Factors for Problem Gambling in California: Demographics, Comorbidities and Gambling Participation.

While population surveys have been carried out in numerous jurisdictions internationally, little has been done to assess the relative strength of different risk factors that may contribute to the development of problem gambling. This is an important preparatory step for future research on the etiology of problem gambling. Using data from the 2006 California Problem Gambling Prevalence Survey, a telephone survey of adult California residents that used the NODS to assess respondents for gambling problems, binary logistic regression analysis was used to identify demographic characteristics, health-related behaviors, and gambling participation variables that statistically predicted the odds of being a problem or pathological gambler. In a separate approach, linear regression analysis was used to assess the impact of changes in these variables on the severity of the disorder. In both of the final models, the greatest statistical predictor of problem gambling status was past year Internet gambling. Furthermore, the unique finding of a significant interaction between physical or mental disability, Internet gambling, and problem gambling highlights the importance of exploring the interactions between different forms of gambling, the experience of mental and physical health issues, and the development of problem gambling using a longitudinal lens.

Variation in interoperability across clinical laboratories nationwide.

OBJECTIVE: To characterize nationwide variation and factors associated with clinical laboratories': (1) capabilities to send structured test results electronically to ordering practitioners' EHR systems; and (2) their levels of exchange activity, as measured by whether they sent more than three-quarters of their test results as structured data to ordering practitioners' EHR systems. MATERIALS AND METHODS: A national survey of all independent and hospital laboratories was conducted in 2013. Using an analytic weighted sample of 9382 clinical laboratories, a series of logistic regression analyses were conducted to identify organizational and area characteristics associated with clinical laboratories' exchange capability and activity. RESULTS: Hospital-based clinical laboratories (71%) and larger clinical laboratories (80%) had significantly higher levels of capability compared to independent (58%) and smaller laboratories (48%), respectively; though all had similar levels of exchange activity, with 30% of clinical laboratories sending 75% or more of their test results electronically. In multivariate analyses, hospital and the largest laboratories had 1.87 and 4.40 higher odds, respectively, of possessing the capability to send results electronically compared to independent laboratories (p<0.001). Laboratories located in areas with a higher share of potential exchange partners had a small but significantly greater capability to send results electronically and higher levels of exchange activity(p<0.05). CONCLUSION: Clinical laboratories' capability to exchange varied by size and type; however, all clinical laboratories had relatively low levels of exchange activity. The role of exchange partners potentially played a small but significant role in driving exchange capability and activity.

School recess, social connectedness and health: a Canadian perspective.

Children need opportunities to establish positive social connections at school, yet many school playgrounds are challenged by social conflict that can undermine these connections. When children's social needs go unmet, the resultant feelings of loneliness, isolation and self-doubt can cumulatively lead to mental and physical illness. Because recess is typically the only time during the school day that children are free to socialize and play, we propose a more thoughtful way of thinking about it: from the lens of belongingness. Schools are, historically, designed for instruction. We argue, however, that we need to attend to children's social needs at school. We highlight current research from social neuroscience, belonging and social connectedness in order to delineate the pathways between daily school recess and developmental health trajectories. We then consolidate an array of research on play, social interaction and school change to suggest four areas that could benefit from consideration in research, practice and policy: (i) the culture of recess, (ii) the importance of healthy role models on the playground, (iii) the necessity of activities, options and variety during recess and (iv) the significance of space and spatial layout (indoor and outdoor). We bridge our discussion with the conception of health as described in the Ottawa Charter and emphasize the need to build alliances across sectors to assist schools in their efforts to support children's overall health needs.