Supramolecular structures of cadmium(II) coordination polymers: a new class of ligands formed by linking tripodal tris(pyrazolyl)methane units.

The new ligands C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2) (pz = pyrazolyl ring), 1 (ortho), 2 (meta), and 3 (para), that can potentially bond two or more metal centers were obtained in a single step from the reaction of the appropriate dibromoxylene, 2 equiv of tris-2,2,2-(1-pyrazolyl)ethanol, and excess NaH. Although the arrangement of the tris(pyrazolyl)methane units in the solid-state structures of 1 and 3 are similar, the orientation of these groups with respect to the phenyl ring are different, with 1 showing a twisted structure and 3 a stepped structure. The reaction of [Cd(2)(THF)(5)][BF(4)](4) with the appropriate ligand yields each of the three coordination polymers of the formula [C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2)Cd](BF(4))(2)](n), 4 (ortho), 5 (meta), and 6 (para). In the solid-state structures of all three each tris(pyrazolyl)methane unit is tridentate, with each ligand bonded to two different cadmium(II) atoms, forming a coordination polymer containing 6-coordinate, pseudooctahedral cadmium(II) centers. Polymers 4 and 5 form wavelike chains whereas 6 is arranged in a stepped structure similar to the free ligand. The different connecting patterns of each ligand lead to very different supramolecular structures, structures organized by the BF(4)(-) groups through weak C-H...F hydrogen bonds. Crystallographic information: 1 is monoclinic, P2(1)/n, a = 16.3157(13) A, b = 8.5880(6) A, c = 21.9227(17) A, alpha = gamma = 90 degrees, beta = 100.134(2) degrees, Z = 4; 3 is monoclinic, P2(1)/n, a = 9.1965(9) A, b = 12.9185(12) A, c = 12.7306(12) A, alpha = gamma = 90 degrees, beta = 104.099(2) degrees, Z = 2; 4 is triclinic, P1, a = 10.7877(19) A, b = 12.582(2) A, c = 15.409(3) A, alpha =103.860(4) degrees, beta = 94.123(4) degrees, gamma = 92.573(4) degrees, Z = 2; 6 is monoclinic, C2/c, a = 23.023(3) A, b = 12.2588(14) A, c = 18.119(2) A, alpha = gamma = 90 degrees, beta = 121.281(2) degrees, Z = 4.

Control of the stereochemical impact of the lone pair in lead(II) tris(pyrazolyl)methane complexes. Improved preparation of Na[B[3,5-(CF3)2C6H3]4].

The reaction of Pb(acac)2 with 2 equiv of [H(Et2O)2][B[3,5-(CF3)2C6H3]4] (HBAr(f)) in CH2Cl2 followed by addition of 2 equiv of either HC(pz)3 or HC(3,5-Me2pz)3 (pz = pyrazolyl ring) leads to the formation of [Pb[HC(pz)3]2][B[3,5-(CF3)2C6H3]4]2 (1) and [Pb[HC(3,5-Me2pz)3]2][B[3,5-(CF3)2C6H3]4]2 (2), respectively. The cation in 1 has a distorted octahedral structure with a stereochemically active lone pair on lead(II). In contrast, the cation in 2 is trigonally distorted octahedral with the lone pair on the lead(II) clearly stereochemically inactive. The driving force for this cation to have a stereochemically inactive lone pair is that in this geometric arrangement the interligand distances between adjacent 3-position methyl groups are close to 4.0 A, the sum of the van der Waals radii of two methyl groups. To facilitate this chemistry, the synthesis of Na[B[3,5-(CF3)2C6H3]4], needed to prepare HBAr(f), has been dramatically improved. The main change is to add NaBF4 to the reaction mixture before forming the Grignard from the reaction of magnesium and 3,5-(CF3)2C6H3Br. The Grignard reacts with the NaBF4 as it forms, reducing the danger of explosion and leading to a higher isolated yield of the product. Crystallographic information: 1 is triclinic, P1, a = 13.0133(6) A, b = 17.2210(7) A, c = 24.7634(11) A, alpha = 71.7300(10) degrees, beta = 82.3630(10) degrees, gamma = 70.5120(10) degrees, Z = 2; 2 is triclinic, P1, a = 12.756(4) A, b = 13.469(4) A, c = 17.160(5) A, alpha = 82.454(7) degrees, beta = 89.904(8) degrees, gamma = 72.995(7) degrees, Z = 1.

A novel delta-subdivision proteobacterial lineage from the lower ocean surface layer.

A small-subunit ribosomal RNA (16S rRNA) gene lineage (SAR324) affiliated with the delta-subdivision of the class Proteobacteria (DP) was discovered in a 16S rRNA gene clone library prepared from a water sample collected from 250 m in the western Sargasso Sea. This clone library of nearly full-length amplicons of bacterial 16S rRNA genes has been the subject of previous studies aimed at identifying bacteria that inhibit the lower ocean surface layer. The novel lineage was identified by randomly sequencing clones that did not hybridize to oligonucleotide probes specific for several abundant bacterioplankton groups identified in previous studies. Phylogenetic analysis indicated that SAR324 was most closely affiliated with the DP, although it showed no specific relationship to any DP 16S rRNA genes in databases. Eight of the clones in the library of 148 clones were identified as members of the SAR324 lineage by hybridization to an oligonucleotide probe specific for SAR324. Subsequent hybridizations showed that the SAR324 group is stratified in the lower surface layer of both the Atlantic and Pacific Oceans, with maxima between 160 and 500 m. The repeated discovery of sequences belonging to different gene clusters with similar distributions in this region of the water column suggests that microbial communities in the lower surface layer may be functionally specialized.

Effect of docking on health, blood cells and metabolites and growth of Dorset lambs.

Docking by knife or elastrator had no sustained effect on growth of lambs 0 to 8 wk postpartum. However, during the 2 wk period postdocking, growth of lambs was limited or depressed, regardless of whether lambs were docked by knife at 14, 28 or 42 d of age. Blood hematocrit and hemoglobin were decreased (P less than .01) 1 d after docking by knife and 14 d after docking by elastrator. Neither method of docking proved superior. Regardless of whether lambs were docked by knife or elastrator, tail tissue was destroyed and became necrotic. Numbers of white blood cells increased (P less than .01) in response to docking. This necessitates that lambs be observed often through 2 wk postdocking and that medical treatment be administered when needed.