1. catena-Poly[[bis-(μ(2)-1,4,7,10,13,16-hexa-oxacyclo-octa-deca-ne)dipotassium]-μ(2)-iodido-(iodidocadmium)-di-μ(2)-iodido-(iodidocadmium)-μ(2)-iodido]
K Rajarajan, A Pugazhenthi, M Nizammohideen Acta Crystallogr Sect E Struct Rep Online. 2013 Feb 1;69(Pt 2):m125.doi: 10.1107/S1600536813002274.Epub 2013 Jan 31.
The reaction of CdCl(2), 18-crown-6 and KI in water yields the title coordination polymer, [{K(C(12)H(24)O(6))}(2)Cd(2)I(6)](n). The potassium ion lies approximately in the plane of the crown ether, coordinated by all six crown ether O atoms and also by an iodide anion bound to a cadmium atom. A C atom of the crown ether is disordered over two positions with site occupancies of 0.77 (2) and 0.23 (2). Two K(18-crown-6)(+) units are linked by inversion symmetry, forming a [bis-(μ(2)-18-crown-6)dipottasium] system with approximately square-planar K(2)O(2) units. Inversion symmetry also generates the Cd(2)I(6) fragment and the polymeric system is extended along the c axis by the formation of K-I-Cd bridges.
2. Regulation of the biosynthesis of 4,7,10,13,16-docosapentaenoic acid
B S Mohammed , D L Luthria, S P Bakousheva, H Sprecher Biochem J. 1997 Sep 1;326 ( Pt 2)(Pt 2):425-30.doi: 10.1042/bj3260425.
It is now established that fatty acid 7,10,13,16-22:4 is metabolized into 4,7,10,13,16-22:5 as follows: 7,10,13,16-22:4-->9,12,15, 18-24:4-->6,9,12,15,18-24:5-->4,7,10,13,16-22:5. Neither C24 fatty acid was esterified to 1-acyl-sn-glycero-3-phosphocholine (1-acyl-GPC) by microsomes, whereas the rates of esterification of 4, 7,10,13,16-22:5, 7,10,13,16-22:4 and 5,8,11,14-20:4 were respectively 135, 18 and 160 nmol/min per mg of microsomal protein. About four times as much acid-soluble radioactivity was produced when peroxisomes were incubated with [3-14C]9,12,15,18-24:4 compared with 6,9,12,15,18-24:5. Only [1-14C]7,10,13,16-22:4 accumulated when [3-14C]9,12,15,18-24:4 was the substrate, but both 4,7,10,13,16-22:5 and 2-trans-4,7,10,13,16-22:6 were produced from [3-14C]6,9,12,15, 18-24:5. When the two C24 fatty acids were incubated with peroxisomes, microsomes and 1-acyl-GPC there was a decrease in the production of acid-soluble radioactivity from [3-14C]6,9,12,15, 18-24:5, but not from [3-14C]9,12,15,18-24:4. The preferential fate of [1-14C]4,7,10,13,16-22:5, when it was produced, was to move out of peroxisomes for esterification into the acceptor, whereas only small amounts of 7,10,13,16-22:4 were esterified. By using 2H-labelled 9,12,15,18-24:4 it was shown that, when 7,10,13,16-22:4 was produced, its primary metabolic fate was degradation to yield esterified arachidonate. Collectively, the results show that an inverse relationship exists between rates of peroxisomal beta-oxidation and of esterification into 1-acyl-GPC by microsomes. Most importantly, when a fatty acid is produced with its first double bond at position 4, it preferentially moves out of peroxisomes for esterification to 1-acyl-GPC by microsomes, rather than being degraded further via a cycle of beta-oxidation that requires NADPH-dependent 2,4-dienoyl-CoA reductase.
3. catena-Poly[[trans-dichlorocopper(II)-mu-1,4,7,10,13,16-hexathiacyclooctadecane-S1:S10]
A J Blake, V Lippolis, S Parsons, M Schröder Acta Crystallogr C. 2001 Jan;57(Pt 1):36-7.doi: 10.1107/s0108270100014475.
In the title complex, [CuCl2(C12H24S6)]n, the CuCl2 unit and the ligand lie on and about inversion centres, respectively. The coordination geometry at CuII is a tetragonally elongated octahedron with the equatorial positions occupied by two chlorides, Cu-Cl 2.2786 (12) A, and two S donors, Cu-S 2.3710 (13) A. The apical positions of the octahedron are defined by two S donors at distances of 2.8261 (14) A from the metal. The macrocyclic ligand adopts a very puckered and distorted conformation. Eight of the 18 torsion angles are less than 90 degrees and all S-donors are oriented exo to the ring.
