Thermally stable lead(II) amidinates and guanidinates

The reactions of lithium amidinates and guanidinates [Li(Fiso)] (Fiso = N, N'-bis(2,6-diisopropylphenyl) formamidinate), [Li(Piso)] (Piso = N, N'-bis(2,6-diisopropylphenyl)( tert-butyl) amidinate), [Li(CyG)] (CyG = N, N ''-bis(2,6-diisopropylphenyl)-N', N'-dicyclohexylguanidinate) and [Li(HDG)] (HDG = N, N ''-bis(2,6-diisopropylphenyl)-N'-(2,6diisopropylphenyl) guanidinate) with anhydrous PbCl(2) in THF afforded the amidinate complexes [Pb(Fiso)(2)] 1, and [Pb(Piso)Cl](2) 2, and the guanidinate complexes [Pb(CyG)Cl](2) 3, and [Pb(HDG)Cl](2) 4 in moderate yields. The complexes are thermally stable, 2, 3 and 4 decompose between 163-202 degrees C whilst 1 melts with decomposition to lead metal at 310 degrees C. 2, 3 and 4 are unsymmetrical dimers in the solid state but their NMR data suggested fluxional behaviour in solution. Storing the yellow crystals of [Pb(CyG)Cl](2) 3 for one week in the perfluorinated crystallography oil under air resulted in oxygen incorporation into one isopropyl group of the CyG ligand giving a mixed amidinate-alkoxide dianion (CyGO) and afforded some new colourless crystals of [(CyGO) Pb](2) 5 that were characterised by a X-ray single crystal structure determination

Patterns of Walkability, Transit, and Recreation Environment for Physical Activity

INTRODUCTION: Diverse combinations of built environment (BE) features for physical activity (PA) are understudied. This study explored whether patterns of GIS-derived BE features explained objective and self-reported PA, sedentary behavior, and BMI. METHODS: Neighborhood Quality of Life Study participants (N=2,199, aged 20–65 years, 48.2% female, 26% ethnic minority) were sampled in 2001–2005 from Seattle/King County, WA and Baltimore, MD/Washington, DC regions. Their addresses were geocoded to compute net residential density, land use mix, retail floor area ratio, intersection density, public transit, and public park and private recreation facility densities using a 1-km network buffer. Latent profile analyses (LPAs) were estimated from these variables. Multilevel regression models compared profiles on accelerometer-measured moderate to vigorous PA (MVPA) and self-reported PA, adjusting for covariates and clustering. Analyses were conducted in 2013–2014. RESULTS: Seattle region LPAs yielded four profiles, including low walkable/transit/recreation (L-L-L), mean walkability/transit/recreation (M-M-M), moderately high walkability/transit/recreation (MH-MH-MH), and high walkability/transit/recreation (H-H-H). All measures were higher in the H-H-H than the L-L-L profile (difference of 17.1 minutes/day for MVPA, 146.5 minutes/week for walking for transportation, 58.2 minutes/week for leisure-time PA, and 2.2 BMI points; all p<0.05). Baltimore region LPAs yielded four profiles, including L-L-L, M-M-M, high land use mix, transit, and recreation (HLU-HT-HRA), and high intersection density, high retail floor area ratio (HID-HRFAR). HLU-HT-HRA and L-L-L differed by 12.3 MVPA minutes/day; HID-HRFAR and L-L-L differed by 157.4 minutes/week for walking for transportation (all p<0.05). CONCLUSIONS: Patterns of environmental features explain greater differences in adults’ PA than the four-component walkability index