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Thermolysis of [(Cp*RuCO) 2 B 2 H 6 ] (1; Cp* = η 5 -C 5 Me 5 ) with [Ru 3 (CO) 12 ] yielded the trimetallaborane [(Cp*RuCO) 3 (μ 3 -H)BH] (2) and a number of homometallic boride clusters: [Cp * RuCO{Ru(CO) 3 } 4 B] (3 ), [ ( C p * R u ) 2 { R u 2 ( C O ) 8 } B H ] ( 4 ) , a n d [(Cp*Ru) 2 {Ru 4 (CO) 12 }BH] (5). Compound 2 is isoelectronic and isostructural with the triply bridged borylene compounds [(μ 3 -BH)(Cp*RuCO) 2 (μ-CO){Fe(CO) 3 }] (6) and [(μ 3 -BH)(Cp*RuCO) 2 (μ-H)(μ-CO){Mn(CO) 3 }] (7), where the [μ 3 -BH] moiety occupies the apical position. To test if compound 2 undergoes hydroboration reactions with alkynes, as observed with 6, we performed the reaction of 2 with the same set of alkynes under photolytic conditions. However, neither 2 nor 7 undergoes hydroboration to yield a vinyl−borylene complex. On the other hand, thermolysis of 6 with trimethylsilylethylene yielded the novel diruthenacarborane [1,1,7,7,7-(CO) 5 -2,3-(Cp*) 2 -μ-2,3-(CO)-μ 3 -1,2,3-(CO)-5-(SiMe 3 )-pileo-1,7,2,3,4,5-Fe 2 Ru 2 C 2 BH] ( 8). The solid-state X-ray diffraction results suggest that 8 exhibits a pentagonal -bipyramidal geometry with one additional CO capping one of its faces. Cluster 3 is a boride cluster where boron is in the interstitial position of a square-pyramidal geometry, whereas compound 4 can be described as a tetraruthenium boride in which the Ru 4 butterfly skeleton has an interstitial boron atom. Electronic structure calculations of compound 2 employing density functional theory (DFT) generate geometries in agreement with the structure determinations. The existence of a large HOMO−LUMO gap in 2 is in agreement with its high stability. Bonding patterns in the structure have been analyzed on the grounds of DFT calculations. Furthermore, the B3LYP-computed 11 B and 1 H chemical shifts for compound 2 precisely follow the experimentally measured values. All the compounds have been characterized by IR and 1 H, 11 B, and 13 C NMR spectroscopy, and the geometries of the structures were unambiguously established by crystallographic analyses of 2−4 and 8.

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Cost effective, high performance dielectric composites based on polyvinyl alcohol, cellulose fibers and polyaniline were prepared and the dielectric properties were studied as a function of fiber content, fiber dimensions and polyaniline content over a frequency range of 40 Hz to 30 MHz. The short cellulose fibers were size-reduced to micro and nano levels prior to coating with polyaniline. Fiber surface was coated with Polyaniline (PANI) by an in situ polymerization technique in aqueous medium. The composites were then prepared by solution casting method. Short cellulose fiber composites showed a dielectric constant (DEC) of 2.3 x 105 at 40 Hz. For the micro- and nano- cellulose fiber composites the DEC was increased to 4.5 x 105 and 1.3 x 108, respectively. To gain insight into the inflection point of the dielectric data polynomial regression analysis was carried out. The loss tangent of all the composites remained at less than 1.5. Further, AC conductivity, real and imaginary electric moduli of all the composites were evaluated. PVA nanocomposite attained an AC conductivity of 3 S/m. These showed that by controlling the size of the fiber used, it was possible to tune the permittivity and dielectric loss to desired values over a wide range. These novel nanocomposites, combining high dielectric constant and low dielectric loss, can be effectively used in applications such as high-charge storage capacitors.

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Reconfigurable actuators are designed based on chitosan and pNipam which has the capability to attain precise and programmable actuation. The current approach offers a feasible way to fabricate soft actuators with repeatable and reversible actuation.