Structures of Ruthenium-modified Pseudomonas aeruginosa Azurin and [Ru(2,2’-bipyridine)_2(imidazole)_2)]SO_4•10H_2O

The crystal structure of Ru(2,2'-bipyridine)_2(imidazole)(His83)azurin (RuAz) has been determined to 2.3 Å ¬resolution by X-ray crystallography. The spectroscopic and thermodynamic properties of both the native protein and [Ru(2,2'-bipyridine)_2(imidazole)_2]^(2+) are maintained in the modified protein. Dark-green RuAz crystals grown from PEG 4000, LiNO_3, CuCl_2 and Tris buffer are monoclinic, belong to the space group C2 and have cell parameters a = 100.6, b = 35.4, c = 74.7 Å and β = 106.5°. In addition, [Ru(2,2'-bipyridine)_2(imidazole)_2]SO_4•10H_2O was synthesized, crystallized and structurally characterized by X-ray crystallography. Red-brown crystals of this complex are monoclinic, space group P2_1/n, unit-cell parameters a = 13.230 (2), b = 18.197 (4), c = 16.126 (4) Å, β = 108.65 (2)°. Stereochemical parameters for the refinement of Ru(2,2'-bipyridine)_2(imidazole)(His83) were taken from the atomic coordinates of [Ru(2,2'-bipyridine)_2(imidazole)_2]^(2+). The structure of RuAz confirms that His83 is the only site of chemical modification and that the native azurin structure is not perturbed significantly by the ruthenium label

Linear-Chain Structures of Platinum(II) Diimine Complexes

The structures of three linear-chain platinum(II) diimine complexes have been determined [Pt···Pt, Å]:  Pt(bpm)Cl_2·0.5(nmp) (3) [3.411(1), 3.371(1)], Pt(phen)(CN)_2 (6) [3.338(1), 3.332(1)], and Pt(bpy)(NCS)_2 (7) [3.299(2)] (bpm = 2,2‘-bipyrimidine, phen = 1,10-phenanthroline, bpy = 2,2‘-bipyridine, nmp = 1-methyl-2-pyrrolidinone). The Pt···Pt distances in these and in seven related compounds range from 3.24 to 3.49 Å. While we find evidence of interligand interactions influencing these structures, the Pt···Pt bonds are the most important of the stacking forces. The metal−metal distances are generally consistent with an electronic structural model in which σ-donor/π-acceptor ligands strengthen Pt···Pt bonding interactions (for example, the Pt···Pt distances in 3 are 0.04 and 0.08 Å shorter than in the bpy analogue). We have also found that the yellow form of Pt(dmbpy)(NCO)_2 (1b) (4,4‘-dimethyl-2,2‘-bipyridine) has a columnar structure; however, in contrast to the linear-chain form (1), which is orange, the Pt atoms are well separated (>4.9 Å). Interestingly, the yellow form is 7% denser than the orange form; this result is consistent with the concept that directed intermolecular interactions give rise to lower density polymorphs. Crystal data:  (3) monoclinic, C2/m (No. 12), a = 12.668(4) Å, b = 15.618(6) Å, c = 6.704(3) Å, β = 93.43(3)°, Z = 4; (6) orthorhombic, Pbca (No. 61), a = 38.731(13) Å, b = 18.569(3) Å, c = 6.628(1) Å, Z = 16; (7) orthorhombic, Pbcm (No. 57), a = 10.349(3) Å, b = 19.927(5) Å, c = 6.572(3) Å, Z = 4; (1b) monoclinic, C2/c (No. 15), a = 17.313(4) Å, b = 12.263(3) Å, c = 14.291(4) Å, β = 114.00(2)°, Z = 8

A Bis(pyrazolyl)(bipyridyl)platinum Complex

(4,4' -Dimethyl-2,2'-bipyridyl)bis(3,5-dimethylpyrazolium) platinum(II) 0.5-tetrahydrofuran solvate monohydrate, [Pt(C_5H_7N_2MC_(12)H_(12)-N2)].0.5C_4H_80.H_2O, M_r = 623.65, monoclinic, P2_1/n, ɑ = 8.625 (2), b = 20.593 (8), c = 14.451(4) Å, β = 90.32 (2)°, v = 2566.7 (14) Å^3, Z = 4, D_x = 1.61 g cm^(-3), λ(Mo Kɑ)= 0.71073 Å, μ = 55.50 cm^(-1), F(000) = 1232, room temperature, R = 0.0387 for 2874 reflections with F_o^2 > 3σ(F_o^2). The square-planar Pt complex has normal Pt-N(bipyridyl) bonds [2.009 (8) Å] and slightly short Pt-N(pyrazolyl) bonds [1.983 (7) Å]. The ligand molecules have normal distances and angles; the planes of the pyrazolyl ligands are twisted by about 60° to the bipyridyl-Pt plane, with the closest contacts between the pyrazolyls being -3.3 Å (Cl4···N5 and C19···N3)

The red form of [Re(phen)(CO)_3(H_2O)]CF_3SO_3•H_2O

The coordination geometry of the cations in the red form of aquatricarbonyl(1,10-phenanthroline-N, N')rhenium(I) trifluoromethanesulfonate hydrate, [Re(C_(12)H_8N_2)(CO)_3- (H_2O)]CF_3SO_3•H_2O, is approximately octahedral, with a facial arrangement of the linearly coordinated carbonyl ligands. The phenanthroline (phen) ligands interleave to form a columnar r-stacked structure

Mixed versus Focused Resistance Training during an Australian Football Pre-Season

The purpose of this investigation was to determine the effect of a focused versus mixed-methods strength-power training plan on athletes undertaking high volumes of concurrent training. Fourteen junior elite male Australian football players were randomly assigned into either the focused or mixed group. Both training groups undertook a sequenced training intervention consisting of a four-week mesocycle emphasising heavy strength followed by a four-week mesocycle of high velocity emphasis. Training differed between groups by way of the degree of emphasis placed on the targeted attribute in each cycle and occurred during the preseason. Testing occurred pre- and post-training and consisted of the unloaded and loaded (+20 kg) countermovement jump (CMJ). Focused training elicited practical (non-trivial) improvements in flight time to contraction ratio (FT:CT) (g = 0.45, ±90% confidence interval 0.49) underpinned by a small reduction in contraction time (g = −0.46, ±0.45) and a small increase in braking (g = 0.36, ±0.42) and concentric phase mean force (g = 0.22, ±0.39). Conversely, the mixed group demonstrated an unchanged FT:CT (g = −0.13, ±0.56). Similar respective changes occurred in the loaded condition. Preferential improvements in FT:CT occur when a greater focus is placed on a targeted physical quality in a sequenced training plan of junior elite Australian football players during preseason training

Bostonia: The Boston University Alumni Magazine. Volume 12

Founded in 1900, Bostonia magazine is Boston University’s main alumni publication