Penerapan Model Pembelajaran Atraktif Berbasis Multiple Intelligences Tentang Pemantulan Cahaya pada Cermin

Penelitian ini bertujuan untuk mengetahui efektivitas penerapan model pembelajaran atraktif berbasis multiple intelligences dalam meremediasi miskonsepsi siswa tentang pemantulan cahaya pada cermin. Pada penelitian ini digunakan bentuk pre-eksperimental design dengan rancangan one group pretest-post test design. Alat pengumpulan data berupa tes pilihan ganda dengan reasoning. Hasil validitas sebesar 4,08 dan reliabilitas 0,537. Siswa dibagi menjadi lima kelompok kecerdasan, yaitu kelompok linguistic intelligence, mathematical-logical intelligence, visual-spatial intelligence, bodily-khinestetic intelligence, dan musical intelligence. Siswa membahas konsep fisika sesuai kelompok kecerdasannya dalam bentuk pembuatan pantun-puisi, teka-teki silang, menggambar kreatif, drama, dan mengarang lirik lagu. Efektivitas penerapan model pembelajaran multiple intelligences menggunakan persamaan effect size. Ditemukan bahwa skor effect size masing-masing kelompok berkategori tinggi sebesar 5,76; 3,76; 4,60; 1,70; dan 1,34. Penerapan model pembelajaran atraktif berbasis multiple intelligences efektif dalam meremediasi miskonsepsi siswa. Penelitian ini diharapkan dapat digunakan pada materi fisika dan sekolah lainnya

Surface Plasmon Response for Anisotropic Silver Particles with Dimensions Below the Electrostatic Limit

A seeded process based on the staged addition of sodium borohydride and hydroquinone with silver nitrate was used to form aqueous nanocolloids consisting of a mixture of quasi-spherical and tabular structures. All of the dimensions for these particles were less than the 40 nm limit that marks the transition in spherical particles from a single surface plasmon peak to a broad multipolar signal. Despite the size being below the electrostatic limit, the small tabular particles retained the unique shape of the optical response seen with particles that are large with respect to the optical wavelength. This retention of response shape across the transition from electrostatic to electrodynamic conditions stands in marked contrast to the large change in response seen with spherical particles. The results are explained with respect to the geometry of the resultant induced electrical field across the particles

Ostwald Ripening in Metallic Nanoparticles: Stochastic Kinetics

This paper looks at the factors that control Ostwald ripening in a bimodal silver nanocolloid system containing tabular particles having one dimension equal to or less than 5 nm. The test system was based on a seeded process using the staged addition of sodium borohydride and hydroquinone (HQ) to silver nitrate. The result was a blend of 20 nm spheres and 30 nm/4–5 nm nanodiscs. The mixture of morphologies allows for a greater differentiation in free energy stability between particles and consequently an accelerated rate of ripening. The rate of the ripening process is shown to be heavily dependent on the relative amount of spherical receptor particles as well as on the presence of hydroquinone as a redox catalyst. A stochastic model is proposed for stepwise adatom kinetics

Noninnocent Behavior of Bidentate Amidophosphido [NP]^2– Ligands upon Coordination to Copper

The synthesis and preliminary coordination chemistry of two new redox-active bidentate ligands containing amido and phosphido donors are described. Treatment of the [RNP]2– (R = Ph, 2,4,6-trimethylphenyl) ligands with CuCl2 and PMe3 results in a dimeric copper­(I) P–P coupled product via ligand oxidation. The intermediate of this reaction is proposed to involve a ligand radical generated via oxidation of the [RNP]2– ligand by copper­(II), and the existence of such an intermediate is probed using computational methods. Significant radical character on the phosphorus atoms of the alleged [RNP]•–/copper­(I) intermediate leads to P–P radical coupling

Use of a Bidentate Ligand Featuring an <i>N</i>‑Heterocyclic Phosphenium Cation (NHP⁺) to Systematically Explore the Bonding of NHP⁺ Ligands with Nickel

A novel bidentate ligand featuring an <i>N</i>-heterocyclic phosphenium cation (NHP⁺) linked to a phosphine side arm is used to explore the coordination chemistry of NHP⁺ ligands with nickel. Direct P–Cl bond cleavage from a chlorophosphine precursor [PP]-Cl (<b>1</b>) by Ni­(COD)₂ affords the asymmetric bimetallic complex [Cl₂Ni­(μ-PP)₂Ni] (<b>2</b>) via a nonoxidative process. Abstraction of the halide with either NaBPh₄ or K­[B­(C₆F₅)₄] prior to metal coordination to form the free phosphenium ligand [PP]⁺ <i>in situ</i>, followed by coordination to Ni­(COD)₂, afforded the halide-free Ni⁰ complexes [(PP)­Ni­(COD)] [B­(C₆F₅)₄] (<b>4</b>) and [(PP)­Ni­(COD)]­[BPh₄] (<b>5</b>). Chloride abstraction from <b>1</b> is problematic in the presence of a PF₆^– counterion, however, as evident by the formation of [(PP)­Ni­(PP-F)]­[PF₆] (<b>3</b>). The COD ligand in <b>5</b> can be readily displaced with PMe₃ or PPh₃ to afford [(PP)­NiL₂]­[BPh₄] (L = PMe₃ (<b>6</b>), PPh₃ (<b>7</b>)). Complexes <b>2</b>–<b>7</b> feature planar geometries about the NHP⁺ phosphorus atom and unusually short Ni–P distances, indicative of multiple bonding resulting from both P → Ni σ donation and Ni → P π backbonding. This bonding description is supported by theoretical studies using natural bond orbital analysis

Noninnocent Behavior of Bidentate Amidophosphido [NP]^2– Ligands upon Coordination to Copper

The synthesis and preliminary coordination chemistry of two new redox-active bidentate ligands containing amido and phosphido donors are described. Treatment of the [^RNP]^2– (R = Ph, 2,4,6-trimethylphenyl) ligands with CuCl₂ and PMe₃ results in a dimeric copper­(I) P–P coupled product via ligand oxidation. The intermediate of this reaction is proposed to involve a ligand radical generated via oxidation of the [^RNP]^2– ligand by copper­(II), and the existence of such an intermediate is probed using computational methods. Significant radical character on the phosphorus atoms of the alleged [^RNP]^•–/copper­(I) intermediate leads to P–P radical coupling

Coordination of an N-Heterocyclic Phosphenium Containing Pincer Ligand to a Co(CO)₂ Fragment Allows Oxidation To Form an Unusual N-Heterocyclic Phosphinito Species

A tridentate pincer ligand featuring a central N-heterocyclic phosphenium (NHP+) donor has been coordinated to a Co­(CO)2 fragment to generate the Co NHP complex [PPP]­Co­(CO)2 (2). The NHP unit adopts an unusual pyramidal geometry with a relatively long Co–P distance, suggesting a stereochemically active nonbonding phosphorus lone pair. Interestingly, treatment of 2 with trimethylamine N-oxide affords [P­(PO)­P]­Co­(CO)2 (3), in which the Co-bound central phosphorus donor has been oxidized to an unprecedented N-heterocyclic phosphinito species. The bonding and electronic properties of these complexes are discussed in the context of DFT and NBO computational data

Interaction and Activation of Carbon–Heteroatom π Bonds with a Zr/Co Heterobimetallic Complex

Single-electron transfer from the ZrIVCo–I heterobimetallic complex (THF)­Zr­(MesNPiPr2)3Co-N2 (1) to benzophenone was previously shown to result in the isobenzopinacol product [(Ph2CO)­Zr­(MesNPiPr2)3Co-N2]2 (4) via coupling of two ketyl radicals. Thermolysis of 4 led to cleavage of the CO bond to generate a Zr/Co μ-oxo species featuring an unusual terminal CoCPh2 carbene linkage (3). In this work monomeric ketyl radical complexes have been synthesized, and the reactivity of these compounds has been explored. The electronic preference for the formation of a ketyl radical complex or a coordination complex has been investigated computationally. Furthermore, thione substrates were allowed to react with 1, generating new complexes that bind the thione to the Co rather than undergoing single-electron transfer (12, 14). The preference of thiones to coordinate to Co can be overridden if the Co is ligated by CO, in which case a thioketyl radical complex forms (13) analogous to 4. The reaction between 1 and imines resulted in N–H bond activation, affording a μ-methyleneamido Co–H complex (16) that can undergo cyclometalation and loss of H2 (15)

Coordination of an N-Heterocyclic Phosphenium Containing Pincer Ligand to a Co(CO)₂ Fragment Allows Oxidation To Form an Unusual N-Heterocyclic Phosphinito Species

A tridentate pincer ligand featuring a central N-heterocyclic phosphenium (NHP+) donor has been coordinated to a Co­(CO)2 fragment to generate the Co NHP complex [PPP]­Co­(CO)2 (2). The NHP unit adopts an unusual pyramidal geometry with a relatively long Co–P distance, suggesting a stereochemically active nonbonding phosphorus lone pair. Interestingly, treatment of 2 with trimethylamine N-oxide affords [P­(PO)­P]­Co­(CO)2 (3), in which the Co-bound central phosphorus donor has been oxidized to an unprecedented N-heterocyclic phosphinito species. The bonding and electronic properties of these complexes are discussed in the context of DFT and NBO computational data

Interaction and Activation of Carbon–Heteroatom π Bonds with a Zr/Co Heterobimetallic Complex

Single-electron transfer from the ZrIVCo–I heterobimetallic complex (THF)­Zr­(MesNPiPr2)3Co-N2 (1) to benzophenone was previously shown to result in the isobenzopinacol product [(Ph2CO)­Zr­(MesNPiPr2)3Co-N2]2 (4) via coupling of two ketyl radicals. Thermolysis of 4 led to cleavage of the CO bond to generate a Zr/Co μ-oxo species featuring an unusual terminal CoCPh2 carbene linkage (3). In this work monomeric ketyl radical complexes have been synthesized, and the reactivity of these compounds has been explored. The electronic preference for the formation of a ketyl radical complex or a coordination complex has been investigated computationally. Furthermore, thione substrates were allowed to react with 1, generating new complexes that bind the thione to the Co rather than undergoing single-electron transfer (12, 14). The preference of thiones to coordinate to Co can be overridden if the Co is ligated by CO, in which case a thioketyl radical complex forms (13) analogous to 4. The reaction between 1 and imines resulted in N–H bond activation, affording a μ-methyleneamido Co–H complex (16) that can undergo cyclometalation and loss of H2 (15)