Cage bridged

Dussart, Y. Harding, C. Dalgaard, P. McKenzie, C. Kadirvelraj, R. McKee, V. Nelson, J. Cascade chemistry in azacryptand cages bridging carbonates and methylcarbonates, J. Chem. Soc., Dalton Trans. 2002, 1704-1713. 

XIX is composed of two eleven-vertex e/oso-clusters linked by an inter-cage bridging dppp ligand, as shown in the illustration. This conclusion is supported by mass spectrometry, which shows the correct molecular ion, [M], centered at 1718.9 a.m.u., with an isotopic distribution which conforms to the calculated values for the proposed formulation of XIX. 

The center-drive mechanism and feed launder are usually supported by a walkway that extends across one-half or the whole diameter of the basin. Devices having drive mechanisms and rakes supported by a tmss across the diameter of the thickener are referred to as bridge machines. The bridge thickeners usually do not exceed 25—45 m in diameter. In thickeners with larger diameters, the drive mechanism is supported by a central column or pier and the rates are driven and supported by a drive cage. The sediment is discharged into an aimular trench around the bottom of the column. 

The most recent development in the starting of squirrel-cage induction motors is the introduction of the electronic soft-start. This principle has been derived from variable-frequency speed controllers using switched Thyristor or power transistor bridges. The supply sine wave is chopped so that a reduced voltage and frequency is applied to the motor.These are gradually increased so that the motor speed rises in a controlled manner, with the starting current limited to any chosen value. 

Forty-four amino acid module characterized by three internal disulfide bridges and an octahedrical cage for a calcium ion. Complement-type repeats are found in many cell surface proteins and form the ligand-binding domain of receptors of the LDL receptor gene family. 

A crystal-structure determination on [Ni(PhCH2CS2)2] showed evidence of a Ni-Ni bond (Ni—Ni distance, 256 pm) in a bridging, acetate-cage, binuclear complex (363). Each nickel atom is 5-coordinate and is in a tetragonally distorted, square-pyramid spectroscopic evidence for a Ni-Ni bond has been obtained (364). The polarized crystal spectra showed more bands than predicted for a mononuclear, diamagnetic, square-planar nickel(Il), and the spectra are indicative of substantial overlap of the d-orbitals between the two nickel atoms. The bis(dithiobenzation)nickeKII) complex was found to exhibit unusual spectrochemical behavior (365). 

In compound 91 the diborahexasiloxane ring system 89 can be identified, which has been expanded to a three-dimensional structure by an additional (R2Si0)20 fragment bridging now, in contrast to compound 90, two boron atoms [127], This cage can be obtained in yields of 45% from tetraphenyldisiloxanediol and boric acid when reacted in a 6 1 stoichiometry. The molecule contains a... 

Borasiloxane 92 with boron and silicon atoms at alternate corners and the general formula B4Si40io for the central cage is composed of two dib-oratetrasiloxane rings, that are joined by two Si-O-Si bridges [129]. Unlike the related and extensively studied silasesquioxanes 93 (Fig. 25), in which the silicon atoms can be substituted by various combinations of group 13 and 15 elements [137], this molecule contains alternately three-coordinate boron and four-coordinate silicon corner sites. 

Some related examples with BR2 monocapped ligands are also known [181] and one of these molecules, 129, assembles to an interesting supramolecular structure, in which the cobalt(III) ions in a methylcobaloxime unit are coordinated to the pyridine residues of the bridging B(py)(OMe) group (Fig. 34). The dinuclear complex forms a large rectangular cage that is limited by the two pyridine residues and the cobaloxime moieties. The two pyridine... 

Li Q, Walter EC, van der Veer WE, Murray BJ, Newberg JT, Bohannan EW, Switzer JA, Hemminger JC, Penner RM (2005) Molybdenum disulfide nanowires and nanoribbons by electrochemical/chemical synthesis. J Phys Chem B 109 3169-3182 Tenne R, Homyonfer M, Feldman Y (1998) Nanoparticles of layered compounds with hollow cage structures (inorganic fuUerene-like structures). Chem Mater 10 3225-3238 Shibahara T (1993) Syntheses of sulphur-bridged molybdenum and tungsten coordination compounds. Coord Chem Rev 123 73-147... 

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