Een reis zonder wederkeer. Opmerkelijke notities in handschrift Oxford, Bodleian Library, Can. Misc. 278

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Enhancing Strategies for the Assembly of Metal–Organic Systems with Inherent Cavity-Containing Calix[4]arenes

<i>p</i>-Carboxylatocalix­[4]­arenes have recently emerged as useful building blocks in the assembly of both discrete and polymeric coordination compounds. Steric effects of coligands used are now shown to dramatically influence the assembly process, dictating the assembly of one-dimensional (1D)-three-dimensional (3D) systems. Solvothermal techniques have also been found to promote formation of 3D systems with a sterically undemanding coligand

Enhancing Strategies for the Assembly of Metal–Organic Systems with Inherent Cavity-Containing Calix[4]arenes

<i>p</i>-Carboxylatocalix­[4]­arenes have recently emerged as useful building blocks in the assembly of both discrete and polymeric coordination compounds. Steric effects of coligands used are now shown to dramatically influence the assembly process, dictating the assembly of one-dimensional (1D)-three-dimensional (3D) systems. Solvothermal techniques have also been found to promote formation of 3D systems with a sterically undemanding coligand

Molecular Paneling in the Rational Design of Calixarene Coordination Polymers

We demonstrate the design of calixarene coordination polymers by using versatile molecular panels comprising binuclear Co­(II) clusters and <i>p</i>-carboxylatocalix­[4]­arenes linked together with 4,4′-bipyridyls. By variation in the length of the 4,4′-bipyridyl, conformational changes in the calixarene molecule have been observed and the solvent-filled channels within the crystalline solid have been adjusted

Enhancing Strategies for the Assembly of Metal–Organic Systems with Inherent Cavity-Containing Calix[4]arenes

<i>p</i>-Carboxylatocalix­[4]­arenes have recently emerged as useful building blocks in the assembly of both discrete and polymeric coordination compounds. Steric effects of coligands used are now shown to dramatically influence the assembly process, dictating the assembly of one-dimensional (1D)-three-dimensional (3D) systems. Solvothermal techniques have also been found to promote formation of 3D systems with a sterically undemanding coligand

Enhancing Strategies for the Assembly of Metal–Organic Systems with Inherent Cavity-Containing Calix[4]arenes

<i>p</i>-Carboxylatocalix­[4]­arenes have recently emerged as useful building blocks in the assembly of both discrete and polymeric coordination compounds. Steric effects of coligands used are now shown to dramatically influence the assembly process, dictating the assembly of one-dimensional (1D)-three-dimensional (3D) systems. Solvothermal techniques have also been found to promote formation of 3D systems with a sterically undemanding coligand

Side-on Bound Complexes of Phenyl- and Methyl-diazene

Treatment of <i>trans</i>-[FeCl₂(dmpe)₂] with phenylhydrazine and 1 equiv of base afforded the side-on bound phenylhydrazido complex <i>cis</i>-[Fe­(η²-NH₂NPh)­(dmpe)₂]⁺. Further deprotonation of the phenylhydrazido complex afforded the side-on bound phenyldiazene complex <i>cis</i>-[Fe­(η²-HNNPh)­(dmpe)₂] as a mixture of diastereomers. Treatment of <i>cis</i>-[RuCl₂(dmpe)₂] with phenylhydrazine or methylhydrazine afforded the end-on bound phenylhydrazine or methylhydrazine complexes <i>cis</i>-[RuCl­(η¹-NH₂NHR)­(dmpe)₂]⁺ (R = Ph, Me). Treatment of the substituted hydrazine complexes with base afforded the side-on bound phenylhydrazido complex <i>cis</i>-[Ru­(η²-NH₂NPh)­(dmpe)₂]⁺ as well as the phenyldiazene and methyldiazene complexes <i>cis</i>-[Ru­(η²-HNNR)­(dmpe)₂] (R = Ph, Me). <i>cis</i>-[RuCl­(η¹-NH₂NHR)­(dmpe)₂]⁺ (R = Ph, Me), <i>cis</i>-[M­(η²-NH₂NPh)­(dmpe)₂]⁺ (M = Fe, Ru) and <i>cis</i>-[Ru­(η²-HNNPh)­(dmpe)₂] were characterized structurally by X-ray crystallography. <i>cis</i>-[Ru­(η²-HNNPh)­(dmpe)₂] is the first side-on bound phenyldiazene complex to be structurally characterized. In the structure of <i>cis</i>-[Ru­(η²-HNNPh)­(dmpe)₂], the geometry of the coordinated diazene fragment is significantly nonplanar (CNNH angle 137°) suggesting that the complex is probably better described as a Ru­(II) metallodiaziridine than a Ru(0) diazene π-complex

Exploratory studies into 3<i>d</i>/4<i>f</i> cluster formation with fully bridge-substituted calix[4]arenes^*

<p>Calix[4]arenes are extremely versatile ligands that are capable of supporting the formation of a wide variety of polymetallic clusters of paramagnetic metal ions. One can exert influence over cluster formation through alteration of the calix[4]arene framework and subsequent ‘expansion’ of the lower-rim polyphenolic binding site. The present contribution investigates cluster formation with calix[4]arenes substituted at all four methylene bridge positions with furan moieties. Two known cluster types have been isolated with this ligand, the structures of which lend insight into factors that may ultimately preclude the formation of mixed-metal species.</p

Pyridine Directed Assembly of Di-<i>O</i>-Alkyl-tris-<i>p</i>-Carboxylatocalix[4]arenes

Crystallization of four di-<i>O</i>-alkyl-tris-<i>p</i>-carboxylatocalix­[4]­arenes from a series of pyridine derivatives has been carried out to investigate the effect of introducing alkyl groups around the pyridine guest/template. Where single crystals were obtained, for 12 of 24 possible structures, in all but one case the calixarenes assemble with the pyridine derivative into hydrogen-bonded head-to-head dimers within extended bilayer or nanotubular arrays

A distributed fuzzy logic controller for a prosthetic hand / Mohd Yazed Ahmad

A Fuzzy Logic with distributed control monitoring (D S) sy tern i implemented to control multiple degree-of-freedom (DOF) prosthetic fingers. Ther are four fingers with 3-DOF and a thumb with 4-DOF. Five identical microcontrollers programmed with Fuzzy Logic ontroller (FLC) and a ystem Handler are employed to control and monitor the fingers and the thumb to replicate the desired hand action of the grasp, the key pinch, the pulp to pulp pinch, the tripod pinch, and the open hand. Each finger is equipp d with position sensors at the pi ot joints and a tactile-pressure sensor at the fingertip. The finger mo ements are programmed to follow given set points and stopped ,. h ne er an obstacle is encountered and the pressure of the tactile sensor exceeds a specified limit. This allows the fingers and thumb to wrap round an object without crushing it. DC motors with reduced gear heads are used as actuators and they are dri en by H-Bridge sv itches. Input signals to the switches in the form of Pulse Width Modulation (PWM) and direction signals are generated by the microcontroller . The signal r present control action of the FLC. Membership functions of the FLC were tuned and the rule \ ere formed to obtain the desired response. Distributed control is implemented by conn cting all finger microcontrollers to a main microcontroller that can b integrated with the Brain omputer Interface. The o erall system was constructed and te ted successfully to control the prosthetic hand