In continuation with the previous research work carried out with axially ligated Zirconium(IV)p- methoxy-meso-tetraphenylporphyrin[Zr(p-OCH 3 TPP)(Y)(X) [Y = acac and X = different phenolates] here we have undertaken to synthesize meso-tetra(p-methylphenyl) porphinatozirconium (IV) acetylacetonatophenolates containing different phenols as axial ligands i. e. [Zr(p-CH 3 TPP)(Y)(X)] [Y=acac and X=different phenolates] by the reaction of meso-tetra(p-methylphenyl)porphyrin (p- CH 3 H 2 TPP) with Zirconium(IV)acetylacetonate (Zr(acac) 4 ) and different phenols at 200-220°C. The separation and isolation of these compounds were achieved through chromatographic methods and their characterization were done by Electronic absorption spectra, IR spectra, 1 H NMR,
less intense and appear at or below 350 nm. The optical absorption spectral data of Zr(IV) metal derivatives containing acetylacetonate (acac) and different phenolates as an axial ligand in chloroform is shown in the (Table 2). It is observed from the tables that the Zr(IV) metal derivatives of (p- OCH 3 TPP) with phenolates as an axial ligand show hypso-chromic shift (blue-shift) and variation in intensities of absorption bands when compared to their respective free base porphyrins (H 2 TPP), due to incorporation of the metal ion alongwith phenolate in the porphyrin rings. When a comparative study of optical absorption spectral data of Zr(p-OCH 3 TPP)(Y)(X), (Y = acac and X = different phenolates as an axial ligand) in chloroform is done with respect to Zr(H 2 TPP)(Y)(X), a slight bathochromic shift (Red shift) i.e., to longer wavelength is observed because of the presence –OCH 3 group at the para position of the meso- phenyl rings of por phyrin moiety. The optical absorption spectra of Zr(IV) metal derivatives of different porphyrins with different phenolates as an axial ligand show one soret band i.e. B(0, 0), two Q bands i.e., Q(0, 0), Q(1, 0) and one shoulder Q(2, 0). The order of absorbance of B and Q bands of axially ligated Zr(IV) metal derivatives of different porphyrins is B(0, 0) > Q(0, 0) > Q(1, 0) > Q(2, 0). When a comparative study is done among the axially ligated Zr(IV) porphyrins, with different phenolates attached to Zr(IV) metal atom , those having electron donating groups in phenolates have slightly red shifted B and Q bands while those having electron withdrawing groups in phenolates have blue shifted B and Q bands. When the optical absorption spectra of the compounds of Zr(p-OCH 3 TPP)(Y)(Y) is recorded in different solvents (Table 3) and spectra
square-grid network. In acetylacetonato(pyca)copper(II) perchlorate monohydrate (Zhong et al., 1990), which has a similar bidentate coordination mode to the title compound, the Cu—O and Cu—N distances are 2.008 (6) and 1.992 (3) Å, respectively. Interestingly, in this case the perchlorate anions occupy axialpositions, with Cu—O distances of 2.543 (9) and 2.871 (4) Å, and each perchlorate anion bridges two adjacent copper centers to form extended chains. S2. Experimental
position: the Fe atom and one of the carbonyl groups lie on the twofold axis. The Fe atom has an almost undistorted trigonal- bipyramidal coordination environment. The trans-phosphine ligands are in axialpositions, the PFeP unit being almost linear [PÐFeÐP 178.86 (3) ; FeÐP 2.2113 (4) AÊ] and orthogonal to
a hexacoordinated Si atom located on a crystallographic centre of inversion. The coordination of the Si atom can be described as a slightly distorted octahedron, with the 3- picoline ligands in the equatorial plane and the two H atoms occupying axialpositions. It is remarkable that (I) is not isomorphous with its analogue where the Br ÿ ions are
Because the wave of muscle activation travels down the body faster than the wave of lateral displacement, the phase of the muscle length change (strain) cycle in which red muscle is active also varies along the body. This observation led to research that focused on quantifying red muscle activity and shortening at different axialpositions; specifically, studies examined the EMG/strain phase relationship. A common trend that has emerged among teleosts is that red muscle activation typically occurs during muscle lengthening (from 0 to 90° of the strain cycle) and offset occurs during muscle shortening (typically 100–250°) (Altringham and Ellerby, 1999). This pattern enhances positive power production in cyclic contractions of fish muscle (Altringham and Johnston, 1990). In addition, in many teleosts there is a decrease in the duration of muscle activation towards the tail, a shift in the EMG/strain phase at more posterior locations such that onset occurs relatively earlier in the strain cycle (Williams et al., 1989; van Leeuwen et al., 1990; Rome et al., 1993; Wardle and Videler, 1993; Jayne and Lauder, 1995b; Hammond et al., 1998; Shadwick et al., 1998; Ellerby and Altringham, 2001; Knower et al., 1999), and a rostrocaudal increase in strain amplitude.
ion in four equatorial positions and the two amine (pyrrolidine, prldn) molecules occupy the two axialpositions. The Co III ion has a slightly distorted octahedral coordination geometry. The N atoms of the pyrrolidine axial ligands are involved in hydrogen bonds with the O atoms of the perchlorate anions, forming chains along the a axis.
not ubiquitous, among bony fishes (Gillis, 1998; Altringham and Ellerby, 1999; Coughlin, 2002). Studies have shown differences in patterns of power production and variation in isometric twitch kinetics along the body in several species of bony fish. Slower rates of relaxation [scup S. chrysops (Coughlin et al., 1996); yellowfin tuna T. albacares (Altringham and Block, 1997); largemouth bass M. salmoides (Coughlin, 2000)] and slower rates of activation in the posterior musculature relative to the anterior [rainbow trout O. mykiss (Hammond et al., 1998; Coughlin et al., 2001) have been documented. In contrast, the current study noted no significant differences in the twitch kinetics between anterior and posterior RM in leopard sharks from 15–25°C, or in mako sharks from 20–28°C (Figs·1, 2). Furthermore, in both species there were no significant differences in optimal stimulus duration or phase for work from RM at the two axialpositions (Fig.·5). Consequently, patterns of work and power production as a function of cycle frequency were similar in the anterior and posterior positions for both shark species (Fig.·6). These observations and the consistency in activation duty cycle and phase recorded along the body during steady swimming (Donley and Shadwick, 2003; Donley et al., 2005) all support the hypothesis that contractile properties and thus muscle function is constant along the body in the leopard and mako
this case is tridentate, along with two chloro ligands. The s value is 0.61, conrming a trigonal bipyramidal geometry (Fig. 6 and 7). A structural study of the CSD database revealed that this geometry is not common among the zinc complexes with CN ¼ 5 with the most common geometry for such complexes being square-pyramidal (64%), as was observed for copper complexes with the same coordination number. In this geometry two chloro ligands are located on the equatorial plane along with the N1 atom (Scheme 1) of the HEAC ligand, with the two axialpositions being occupied by the O1 and N2 atoms (Scheme 1). The ethanolic arm of the HEAC does not participate in coordi- nation and is parallel with the equatorial plane, modelled as disordered over two positions. Of the two Cu–N distances, the
octahedral (Table 1), in which sulfate atom O1 and water atom O7 occupy the axialpositions, while the equatorial plane is formed by N1, N2, O5 and O6. Through OÐH O hydrogen bonds, the crystal structure extends into a two-dimensional framework (Fig. 2).
transition metal complex of the novel chelating triazole ligand, 2-(5-amino- 1H-1,2,4-triazol-3-yl)acetic acid (ATAA), to be structurally characterized. In the molecule of the title complex, the nickel(II) cation is located on an inversion centre and is coordinated by two water molecules in axialpositions and two O and two N atoms from two trans-oriented chelating anions of the deprotonated ATAA ligand, forming a slightly distorted octahedron. The trans angles of the octahedron are all 180 due to the inversion symmetry of the molecule. The cis- angles are in the range 87.25 (8)–92.75 (8) . The six-membered chelate ring adopts a slightly twisted boat conformation with puckering parameters Q = 0.542 (2) A ˚ , = 88.5 (2) and ’ = 15.4 (3) . The molecular conformation is
The single-crystal X-ray analysis at 90 K shows a chain structure of 1·1.2nC 2 H 5 OH, of which the axialpositions of the paddlewheel-type dinuclear ruthenium core are occupied by chloro ligands. The ORTEP diagram is shown in Fig. 4 and the selected bond distances and angles are listed in Table 1. There are two crystallographically independent halves of the dinuclear units. Each of the dinuclear units has an inversion centers on the midpoint of the Ru–Ru bond.
ligand and two acetate anions (Fig. 1). The tpdaH2 ligand is mer-coordinated, with the peripheral N1 and N5 atoms in the axialpositions and the central N3 atom equatorial. The remaining equatorial positions are occupied by the O atoms of two acetate anions. Selected geometric parameters are listed in Table 1. Atoms O1, O2, O3 and N3 in the equatorial plane of the octahedron are approximately coplanar with the central Ni atom, the maximum deviation from the least-squares plane through all five atoms being 0.0367 (5) A ˚ for atom O2. The three pyridine rings of the tpdaH2 ligand are not coplanar. The dihedral angles between the planes of the central pyridine ring and two peripheral rings are 13.0 (4) and 21.4 (9) . The
The Fe atom in (I) is coordinated in a trigonal–bipyramidal fashion with the phosphine ligand situated in one of the axialpositions. Taking into account the standard uncertainties, the Fe—C bonds are virtually identical, with an average value of 1.776 (7) A ˚ . The P—C bond lengths show expected values. The bond angles correspond to a nearly ideal trigonal–bipyr- amidal coordination mode for iron and to a nearly perfect tetrahedral environment for the P atom.
is formed by one chelating pyrazole–pyridine fragment of the organic ligand and two water molecules. The axialpositions in one octahedron are occupied by a water molecule and a monodentately coordinated perchlorate anion, while those in the other are occupied by a nitrate anion and a disordered perchlorate/nitrate anion with equal site occupancy. The pyrazole–pyridine units of the organic selenide are trans- oriented to each other with a C—Se—C angle of 96.01 (14) .
fashion. Two pyridyl N donor atoms, one from each of two different symmetry related L ligands, complete the octahedral coordination sphere by occupying the axialpositions. The average Cu—O bond length is 2.085 Å, the Cu—N bond distance is 2.1062 (19) Å, and the intrachain distance between successive Cu centers is approximately 15.4 Å. The Cu— O and Cu—N distances are typical (Yang et al. , 2001; Lingafelter & Braun, 1966), and the Cu···Cu distance provides an estimate of the length of L . The octahedrally coordinated Cu 2+ centers are linked into one-dimensional chains by L , with
skeleton, with a trans-decaline backbone constrained by the lactone bridge. The -hydroxy substituent and the methyl group belonging to the two decaline rings are in axialpositions, whereas the other methyl group and the acyl group occupy the sterically preferred equatorial positions. The molecular structure is stabilized by an intramolecular C— H O hydrogen bond. In the crystal, molecules are linked into chains along  by O—H O hydrogen bonds
The two crystallographically independent mercury atoms are located at special positions with site symmetry 2 for Hg1 (Fig. 1) and 1 for Hg2 (Fig. 2), respectively. Both have a distorted octahedral coordination with two short axial bonds to N atoms of pyridine rings, d(HgÐN) = 2.101 AÊ, and four longer equatorial bonds to terminal O atoms of the dichro- mate groups, d(HgÐO) = 2.620 AÊ.
We decided to maintain both sequences, 2D T1-weighted axial and 3D MPRAGE, to increase our sensitivity for the detection of enhancing lesions and to be in agreement with the standard pro- tocol in our department, which includes 2 different T1-weighted sequences after contrast administration. Considering the clinical importance of the postcontrast sequences in this population, we believe that maintaining both sequences is useful in case of patient movement during the MR imaging acquisition. While the 3D MPRAGE is known to have higher spatial resolution compared with 2D sequences, it may have decreased the conspicuity of en- hancement for small lesions in some cases, supporting the com- plementary use of both sequences. 27,28
The new SLD is obtained with the computational flow of SLD shown in Figure 1. In step 1, the initial milling force is calculated by initial milling parameters. In step 2, the deflections of workpiece on the nods at first tool position are calculated; then the average deflection of workpiece at first tool position is obtained. In step 3, the actual radial depth of cutting at first tool position is calculated, and the start angle and the exit angle are also calculated. In step 4, the thickness of the first finished workpiece unit is calculated. In step 5, the FRF of workpiece is calculated after the first milling stage. In step 6, the modal parameters of workpiece are extracted from the FRF of workpiece. In step 7, the milling stability is calculated by modal parameters, start angle and exit angle. Then, the stability lobes diagram of first milling stage is obtained. In step 8, repeat the operations from step 1 to step 7 to calculate the milling stability of the next milling stage. After the milling process is completed, the calculation procedure will stop, where 𝑚 is the number of tool positions. 𝑛 is the number of nodes on contact locations of tool and workpiece. 𝑀 is the sum of tool positions and 𝑁 is the sum of nodes on contact locations of tool and workpiece.