Some platinum(II) complexes derived from aromatic alkynes

Several trans‐platinum(II) complexes, of the type R′? {Pt(PBu₃)₂}? R″? {Pt(PR₃)₂}? R′, where R′ and R″ are groups derived from a series of aromatic alkynes and diynes, have been prepared and characterized. Extensive spectroscopic data for these and other known related complexes are presented. A more precise structural study of trans‐Pt(C≡CC₆H₄C≡CPh)₂(PBu₃)₂ (cf. Z. Kristallogr. 1998; 213: 483) is reported. Copyright © 2002 John Wiley & Sons, Ltd.     

Examining Elementary School Science Achievement Gaps Using an Organizational and Leadership Perspective

There is the tendency to explain away successful urban schools as indicative of the heroic efforts by a tireless individual, effectively blaming schools that underperform for a lack of grit and dedication. This study reports the development of a research instrument (School Science Infrastructure, or SSI) and then applying that tool to an investigation of equitable science performance by elementary schools. Our efforts to develop a science‐specific instrument to explore associations between school‐level variables and equitable science performance are informed by James Coleman's tripartite notion of social capital: the “wealth” of organizations is encompassed within their social norms, informational channels, and reciprocating relationships. Grounded in school effectiveness research and social capital theory, the instrument that we report on here is a valid and reliable tool to support meso‐level investigations of factors contributing to school variations in science achievement.     

(Salen)tin complexes: syntheses, characterization, crystal structures, and catalytic activity in the formation of propylene carbonate from CO(2) and propylene oxide

A series of (salen)tin(II) and (salen)tin(IV) complexes was synthesized. The (salen)tin(IV) complexes, (salen)SnX(2) (X = Br and I), were prepared in good yields via the direct oxidation reaction of (salen)tin(II) complexes with Br(2) or I(2). (Salen)SnX(2) successfully underwent the anion-exchange reaction with AgOTf (OTf = trifluoromethanesulfonate) to form (salen)Sn(OTf)(2) and (salen)Sn(X)(OTf) (X = Br). The (salen)Sn(OTf)(2) complex was easily converted to any of the dihalide (salen)SnX(2) compounds using halide salts. All complexes were fully characterized by (1)H NMR spectroscopy, mass spectrometry, and elemental analysis, while some were characterized by (13)C, (19)F, and (119)Sn NMR spectroscopy. Several crystal structures of (salen)tin(II) and (salen)tin(IV) were also determined. Finally, both (salen)tin(II) and (salen)tin(IV) complexes were shown to efficiently catalyze the formation of propylene carbonate from propylene oxide and CO(2). Of the series, (3,3',5,5'-Br(4)-salen)SnBr(2), 3i, was found to be the most effective catalyst (TOF = 524 h(-)(1)).     

Deterministic entanglement of photons in two superconducting microwave resonators

Quantum entanglement, one of the defining features of quantum mechanics, has been demonstrated in a variety of nonlinear spinlike systems. Quantum entanglement in linear systems has proven significantly more challenging, as the intrinsic energy level degeneracy associated with linearity makes quantum control more difficult. Here we demonstrate the quantum entanglement of photon states in two independent linear microwave resonators, creating N-photon NOON states (entangled states |N0> + |0N>) as a benchmark demonstration. We use a superconducting quantum circuit that includes Josephson qubits to control and measure the two resonators, and we completely characterize the entangled states with bipartite Wigner tomography. These results demonstrate a significant advance in the quantum control of linear resonators in superconducting circuits.