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

Nickel-Templated Replacement of Phosphine Substituents in a Tetradentate Bis(amido)bis(phosphine) Ligand

The replacement of phosphine substituents in nickel-bound PNNP ligands is reported as an alternative method for preparing multidentate phosphine ligands with alkyl substituents. Treatment of the previously reported bis­(phosphide) complex {K­(THF)x}22Ph[PNNP]Ni (2) with 2 equiv of MeI, iPrI, and 1,3-dibromoethane formed alkyl-substituted complexes 2Ph,2Me[PNNP]Ni (3), 2Ph,2iPr[PNNP]Ni (4), and 2Ph,propylene[PNNP]Ni (5), respectively. The stereoselectivity (racemic vs meso) of these reactions can be controlled by varying the reaction temperature. The racemic mixtures of products with the new alkyl substituents in an anti configuration were favored at lower temperatures, whereas a larger proportion of meso compounds was acquired at higher temperatures. Further treatment of 3 with KH resulted in selective elimination of the remaining phenyl groups rather than the methyl substituents, affording bis­(methylphosphide) complex {K­(THF)x}22Me[PNNP]Ni (6). Subsequent treatment of 6 with additional MeI formed 4Me[PNNP]Ni (7), in which all four phenyl groups were replaced with methyl substituents. As a proof of concept, demetalation of the ligand from 7 was achieved using aqueous KCN to form a free dimethylphosphine-substituted ligand H24Me[PNNP] (8), and 8 was subsequently coordinated to a different metal, using PdCl2 to form 4Me[PNNP]Pd (9). Unlike the clean elimination of phenyl substituents from 3, the reactions of KH with 4 and 5 exhibited competitive elimination of both alkyl and phenyl substituents and/or attenuated reactivity

Coordinating Anions: (Phosphino)tetraphenylborate Ligands as New Reagents for Synthesis

Anionic, electron-releasing phosphines that incorporate a borate counteranion within the ligand framework are promising reagents for organometallic catalysis. This report describes the synthesis of a new class of monodentate tertiary phosphines built upon the commonly employed tetraphenylborate anion. These new phosphines are highly stable and strongly electron-releasing and readily coordinate transition metals. Moreover, they are promising reagents for catalysis, as demonstrated by their ability to promote the Suzuki cross-coupling of aryl chloride substrates

Coordinating Anions: (Phosphino)tetraphenylborate Ligands as New Reagents for Synthesis

Anionic, electron-releasing phosphines that incorporate a borate counteranion within the ligand framework are promising reagents for organometallic catalysis. This report describes the synthesis of a new class of monodentate tertiary phosphines built upon the commonly employed tetraphenylborate anion. These new phosphines are highly stable and strongly electron-releasing and readily coordinate transition metals. Moreover, they are promising reagents for catalysis, as demonstrated by their ability to promote the Suzuki cross-coupling of aryl chloride substrates

Comparative Studies with Zwitterionic Platinum(II) Bis(pyrazolyl)borate and 2,2‘-Bipyridylborate Complexes

A comparison between the mononuclear platinum complexes of three structurally different monoanionic borato ligands is presented:  [Ph2B(pyrazolyl)2]- ([Ph2B(pz)2], 1), [4-Ph3B(2,2‘-bipyridine)]- ([(4-BPh3)bpy], 2), and [Ph2B(CH2PPh2)2]- ([Ph2BP2], 3). The new bipyridylborate ligand 2 is introduced in this study. The relative trans influence of these ligands has been assessed by comparison of the structural and spectroscopic (NMR) data of the platinum dimethyl complexes [[Ph2B(pz)2]Pt(Me)2][NBu4] (4), [[(4-BPh3)bpy]Pt(Me)2][NBu4] (5), and [[Ph2BP2]Pt(Me)2][ASN] (6). The neutral complexes [Ph2B(pz)2]Pt(Me)(NCCH3) (7), [Ph2B(pz)2]Pt(Me)(CO) (8), [Ph2B(pz)2]Pt(Me)(P(C6F5)3) (9), [(4-BPh3)bpy]Pt(Me)(NCCH3) (10), [(4-BPh3)bpy]Pt(Me)(CO) (11), and [(bpy)Pt(Me)(CO)][BPh4] (12) were prepared, and the carbonyl complexes 8, 11, and 12 provide information pertaining to the relative electron-releasing character of each ligand type. The CO stretching frequencies suggest that the charged borate moiety renders the borato ligands more electron-donating than their neutral analogues. Of the neutral platinum methyl solvento complexes supported by ligands 1, 2, and 3, only those of 1 display very different C−H activation propensities. Upon protonation or methide abstraction in benzene at room temperature, complex 4 rapidly activates two molecules of benzene to generate [[Ph2B(pz)2]Pt(Ph)2][NBu4] (13). Isotopic scrambling of deuterium into methane in C6D6 solvent suggests the intermediacy of a methane σ-adduct in this reaction. The double C−H activation reaction can be halted by addition of acetonitrile to trap the intermediate [Ph2B(pz)2]Pt(Ph)(NCCH3) (14). Complex 3 also displays reactivity toward the benzylic C−H bonds of mesitylene at room temperature to form [Ph2B(pz)2]Pt(pzH)(CH2C6H3(CH3)2) (15) in modest yield

Activation of CO₂ by a Heterobimetallic Zr/Co Complex

At room temperature, the early/late heterobimetallic complex Co(iPr2PNMes)3Zr(THF) has been shown to oxidatively add CO2, generating (OC)Co(iPr2PNMes)2(μ-O)Zr(iPr2PNMes). This compound can be further reduced under varying conditions to generate either the Zr oxoanion (THF)3Na–O–Zr(MesNPiPr2)3Co(CO) or the Zr carbonate complex (THF)4Na2(CO3)-Zr(MesNPiPr2)3Co(CO). Additionally, reactivity of the CO2-derived product has been observed with PhSiH3 to generate the Co-hydride/Zr-siloxide product (OC)(H)Co(iPr2PNMes)3ZrOSiH2Ph

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

Activation of CO₂ by a Heterobimetallic Zr/Co Complex

At room temperature, the early/late heterobimetallic complex Co(iPr2PNMes)3Zr(THF) has been shown to oxidatively add CO2, generating (OC)Co(iPr2PNMes)2(μ-O)Zr(iPr2PNMes). This compound can be further reduced under varying conditions to generate either the Zr oxoanion (THF)3Na–O–Zr(MesNPiPr2)3Co(CO) or the Zr carbonate complex (THF)4Na2(CO3)-Zr(MesNPiPr2)3Co(CO). Additionally, reactivity of the CO2-derived product has been observed with PhSiH3 to generate the Co-hydride/Zr-siloxide product (OC)(H)Co(iPr2PNMes)3ZrOSiH2Ph

Si–H Bond Activation and Dehydrogenative Coupling of Silanes across the Iron–Amide Bond of a Bis(amido)bis(phosphine) Iron(II) Complex

Despite the utility of Si–Si bonds, there are relatively few examples of Si–Si bond formation by base metals. In this work, a four-coordinate iron complex, (PNNP)FeII, is shown to strongly activate the Si–H bonds in primary silanes across the Fe–amide bonds in a metal–ligand cooperative fashion. Upon treatment with excess silane, Si–Si dehydrogenative homocoupling is shown to occur across the Fe–Namide bond without concomitant oxidation and spin state changes at the Fe center

Characterization of the Terminal Iron(IV) Imides {[PhBP<i>^t</i>^Bu₂(pz‘)]Fe^IV⋮NAd}⁺

New hybrid bis(phosphine)(pyrazole)borate tripodal ligands ([PhBPtBu2(pz‘)]-) are reported that support pseudotetrahedral iron in the oxidation states +1, +2, +3, and +4. The higher oxidation states are stabilized by a terminal Fe⋮NR linkage. Of particular interest is the generation and thorough characterization of an S = 1 FeIV⋮NR+ imide cation using this new ligand system. The latter species can be observed electrochemically and spectroscopically, and its solid-state crystal structure is reported