A Case-Based Decision Support System for Land Development Control

Interest in fiber reinforced polymeric (FRP) composites for structural highway applications has generated the need for reliable techniques which may be used to measure all of the elastic constants of these materials. Mechanical techniques may only be used to measure some of the engineering constants of these anisotropic materials due to the geometry of the pultruded members. Further, mechanical tests are destructive in nature. Ultrasonic techniques are uniquely qualified for the nondestructive measurement of all of the elastic constants of these materials. This paper presents the results of three ultrasonic techniques. The first of these is an immersion technique, similar to that presented by Gieske and Allred [1]. The last two techniques were developed specifically for this research, and implement optical generation and detection of surface acoustic waves for the measurement of some of the elastic constants. The results of the various techniques are compared to each other, as well as to results from mechanical tests

Synthesis and Structure of Platinum Bis(phospholane) Complexes Pt(diphos*)(R)(X), Catalyst Precursors for Asymmetric Phosphine Alkylation

The complexes Pt­((<i>R,R</i>)-Me-DuPhos)­(Ph)­(Cl) (<b>1</b>) and Pt­((<i>R,R</i>)-<i>i</i>-Pr-DuPhos)­(Ph)­(Cl) (<b>2</b>) have been used as catalyst precursors in Pt-catalyzed asymmetric alkylation of secondary phosphines. To investigate structure–reactivity–selectivity relationships in these reactions, analogous complexes with different bis­(phospholane) ligands and/or Pt-hydrocarbyl groups were prepared. Treatment of Pt­(COD)­(R)­(Cl) (R = Me, Ph) with BPE or DuPhos ligands gave Pt­((<i>R,R</i>)-Me-BPE)­(Me)­(Cl) (<b>3</b>), Pt­((<i>R,R</i>)-Ph-BPE)­(Me)­(Cl) (<b>5</b>), Pt­((<i>R,R</i>)-Ph-BPE)­(Ph)­(Cl) (<b>6</b>), and Pt­((<i>R,R</i>)-<i>i</i>-Pr-DuPhos)­(Me)­(Cl) (<b>7</b>). However, treatment of Pt­(COD)­(Me)­(Cl) with (<i>R,R</i>)-Me-FerroLANE gave a mixture of products, which were converted upon heating to Pt­((<i>R,R</i>)-Me-FerroLANE)­(Me)­(Cl) (<b>8</b>). A related mixture formed from Pt­(COD)­(Ph)­(Cl) precipitated <i>trans</i>-[Pt­((<i>R,R</i>)-Me-FerroLANE)­(Ph)­(Cl)]_<i>n</i> (<b>9T</b>), which on treatment with AgOTf followed by LiCl gave <i>cis</i>-Pt­((<i>R,R</i>)-Me-FerroLANE)­(Ph)­(Cl) (<b>9</b>) as the major product. The reaction of Pt­(COD)­(Ph)­(Cl) with (<i>R,R</i>)-Me-BPE gave the dinuclear dication [(Pt­((<i>R,R</i>)-Me-BPE)­(Ph))₂(μ-(<i>R,R</i>)-Me-BPE))]­[Cl]₂ (<b>10</b>) instead of the expected Pt­((<i>R,R</i>)-Me-BPE)­(Ph)­(Cl) (<b>4</b>). The iodide Pt­((<i>R,R</i>)-Me-BPE)­(Ph)­(I) (<b>11</b>) was formed from Pt­(COD)­(Ph)­(I) and BPE but decomposed readily. Treatment of Pt­(COD)­X₂ with (<i>R,R</i>)-Me-BPE gave Pt­((<i>R,R</i>)-Me-BPE)­X₂ (X = Cl (<b>12</b>), I (<b>13</b>)). Reaction of Pt­(COD)­Ph₂ with (<i>R,R</i>)-Me-BPE gave Pt­((<i>R,R</i>)-Me-BPE)­Ph₂ (<b>14</b>), which was protonated with HCl to yield <b>4</b>. Treatment of Pt­((<i>R,R</i>)-Me-DuPhos)­Cl₂ with excess (9-phenanthryl)magnesium bromide gave Pt­((<i>R,R</i>)-Me-DuPhos)­(9-phenanthryl)­(Br) (<b>15</b>), while a similar reaction with excess (6-methoxy-2-naphthyl)­magnesium bromide gave Pt­((<i>R,R</i>)-Me-DuPhos)­Ar₂ (<b>16</b>). Complexes <b>3</b>, <b>4</b>, <b>6</b>–<b>10</b>, and <b>12</b>–<b>14</b> were structurally characterized by X-ray crystallography. Structure–reactivity–selectivity relationships in this series of Pt catalyst precursors were investigated in the catalytic alkylation of the bis­(secondary phosphine) PhHP­(CH₂)₃PHPh with benzyl bromide