No abstract

No abstract

No abstract

Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social–ecological–technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales. Such holistic urban approaches are rare in practice. A co-design process involving researchers, practitioners and other stakeholders, has progressed such an approach in the Australian context, aiming to also contribute to international knowledge development and sharing. This process has generated three outputs: (1) a shared framework to support more systematic knowledge development and use, (2) identification of barriers that create a gap between stated urban goals and actual practice, and (3) identification of strategic focal areas to address this gap. Developing integrated strategies at broader urban scales is seen as the most pressing need. The knowledge framework adopts a systems perspective that incorporates the many urban trade-offs and synergies revealed by a systems view. Broader implications are drawn for policy and decision makers, for researchers and for a shared forward agenda.

No abstract

No abstract

Triazapentadienides, C(3)F(7)-C(=NR)-N=C(NHR)-C(3)F(7), result from the reaction of primary amines RNH(2) with the fluorinated imine C(3)F(7)-CF=N-C(4)F(9). The aniline derivative (R = Ph) is a weak monoprotic acid in dmso. Its conjugate base exhibits an extensive coordination chemistry. It acts as a bidentate ligand toward the molecular fragments Pd(C(3)H(5)), Rh(c-C(8)H(12)), Ir(c-C(8)H(12)), and Rh(CO)(2). The chelates [C(3)F(7)-C(NPh)-N-C(NPh)-C(3)F(7)](2)M, M = Mg, Mn, Fe, Co, Ni, Cu, Zn, and Pd, were prepared. In the crystallographically characterized Co complex, the metal is 3d(7), S = (3)/(2) and tetrahedrally coordinated. Spin densities at carbon in the C(6)H(5) and C(3)F(7) groups were estimated from the (1)H and (19)F contact shifts. Spin delocalization onto phenyl sp(2) carbons is approximately 10 times greater than onto the fluorinated sp(3) carbons.

3815by N M R spectroscopy due to rapid back reaction with the CO p r o d u d in the photolysis. Studies on Fe(0) complexes of dfepe suggest that the bulky bidentate ligand is able to prevent clustering reactions of unsaturated species.30 Thus, given the substantial Cralkane binding energy in (dfepe)Cr(CO)3(alkane), it seems plausible that this alkane complex could be observed in N M R experiments if it could be generated in the absence of CO or other (30) Brookhart, M.; Chandler, W. A.; Pfister, A. C.; Santini, C. C.; White, P. S. Abstract:The nature of valence trapping is studied for a series of six pphenoxo-bis(N-carboxylate)-bridged FeI1Fe1I1 complexes. The septadentate ligand bimp-binds the two metal ions and provides a phenoxide bridge as well as four imidazole moieties. The X-ray structure of [Fe11Fe111(bimp)(p02CPh)2] (BPh4)2.3/2CH3CN at 295 K is reported. This mixed-valence complex crystallizes in the Pi space group with unit cell parameters of a = 15.995 (4) A, b = 23.475 (4) A, c = 11.464 (4) A, a = 97.57 (l)", @ = 101.74 ( l ) ' , y = 85.22 ( l ) ' , and Z = 2. A total of 11334 unique data with I > 3 4 were refined to values of R = 0.045 and R, = 0.051. The structure shows distinct octahedral (N303) high-spin FelI1 and Fe" ions, with an Fe-Fe distance of 3.440 A. The phenoxide FeIW-Fe"' bridging angle is 115.17 (8)'. The BPh, ions are not symmetrically distributed about the FeI1Fe1I1 cation; they are closer to the FeI1 ion than the FelI1 ion. Sharp 'H NMR signals spanning a chemical shift range of -350 ppm are seen for CD3CN solutions of the Fe"Fe"' complexes. Relative to the 'H NMR timescale these mixed-valence complexes are rapidly transferring electrons in solution. This is due to either rapid intramolecular electron transfer or rapid electron transfer between binuclear complexes. A weak intervalence transfer (IT) electronic absorption band is seen at -1300 nm (e = -200 M-l cm-I) for all six FeI1Fe1I1 complexes in solution. Two quasireversible one-electron wavescorresponding to the FellFell/FellFelll and FellFelll/FelllFelll couples are seen for each complex by cyclic voltammetry. The two waves observed for the Fe"FelI1(bimp) complexes occur at potentials 100-300 mV more negative than those reported for the analogous polypyridyl and benzimidazole complexes. Variable-temperature (5-300 K) magnetic susceptibility data are presented for two of the FellFelll complexes. These data^ were least-squares fit in a matrix diagonalization approac! including the effects of Heisenberg magnetic exchange ( H = -USI.S2), isotropic Zeeman and axial single-ion zero-field (DSz2 -I/3S(S + l)] for both Fe" and Fe"' interactions. Fitting of the data for one sample of [Fe11Fe111(bimp)(fi-02CCH3)2] (C104)2.2H,0, for example, gave parameters of J = -3.4 cm-l, D(Fe") = 0.63 cm-', and g(Fe") = 1.86. There is a S = ground state; however, the S = 3/2, 7/2, and 9/2 excited states are near to the ground state. 57Fe Miissbauer spectroscopy was used to thoroughly examine the temperature dependence of valence detrapping seen for the ...