Aboriginal Child Welfare

As the relationships between Canada’s Aboriginal peoples and the state undergo changes, the issue of Child Welfare is in the foreground; for it is around the well being, education and care of Aboriginal children that much of the painful historical relationship between First Nations and Canadian government has been played out. In this paper we consider the major issues in Canadian Aboriginal child welfare, drawing upon an extensive review and synthesis of current theory and research. Although there is an abundance of material available concerning Aboriginal child welfare, much of it exists outside mainstream academic child welfare literature. Some of the salient work on Aboriginal child welfare is contained in the justice literature and much is contained in evaluation reports, operational reviews, submissions to government bodies and in oral stories and testimony. Our goal has been to cull these sources in order to present a coherent understanding of Aboriginal child welfare issues that encompasses history, theoretical analysis, politics, visions, realities, education, evaluation and aspirations

Aboriginal Child Welfare

As the relationships between Canada’s Aboriginal peoples and the state undergo changes, the issue of Child Welfare is in the foreground; for it is around the well being, education and care of Aboriginal children that much of the painful historical relationship between First Nations and Canadian government has been played out. In this paper we consider the major issues in Canadian Aboriginal child welfare, drawing upon an extensive review and synthesis of current theory and research. Although there is an abundance of material available concerning Aboriginal child welfare, much of it exists outside mainstream academic child welfare literature. Some of the salient work on Aboriginal child welfare is contained in the justice literature and much is contained in evaluation reports, operational reviews, submissions to government bodies and in oral stories and testimony. Our goal has been to cull these sources in order to present a coherent understanding of Aboriginal child welfare issues that encompasses history, theoretical analysis, politics, visions, realities, education, evaluation and aspirations

Bimetallic Cobalt–Dinitrogen Complexes: Impact of the Supporting Metal on N₂ Activation

Expanding a family of cobalt bimetallic complexes, we report the synthesis of the Ti­(III) metalloligand, Ti­[N­(<i>o-</i>(NCH₂P­(^<i>i</i>Pr)₂)­C₆H₄)₃] (abbreviated as TiL), and three heterobimetallics that pair cobalt with an early transition metal ion: CoTiL (<b>1</b>), K­(crypt-222)­[(N₂)­CoVL] (<b>2</b>), and K­(crypt-222)­[(N₂)­CoCrL] (<b>3</b>). The latter two complexes, along with previously reported K­(crypt-222)­[(N₂)­CoAlL] and K­(crypt-222)­[(N₂)­Co₂L], constitute an isostructural series of cobalt bimetallics that bind dinitrogen in an end-on fashion, i.e. [(N₂)­CoML]⁻. The characterization of <b>1</b>–<b>3</b> includes cyclic voltammetry, X-ray crystallography, and infrared spectroscopy. The [CoTiL]^0/– reduction potential is extremely negative at −3.20 V versus Fc⁺/Fc. In the CoML series where M is a transition metal, the reduction potentials shift anodically as M is varied across the first-row period. Among the [(N₂)­CoML]⁻ compounds, the dinitrogen ligand is weakly activated, as evidenced by N–N bond lengths between 1.110(8) and 1.135(4) Å and by N–N stretching frequencies between 1971 and 1995 cm^–1. Though changes in ν_N₂ are subtle, the extent of N₂ activation decreases across the first-row period. A correlation is found between the [CoML]^0/– reduction potentials and N₂ activation, where the more cathodic potentials correspond to lower N–N frequencies. Theoretical calculations of the [(N₂)­CoML]⁻ complexes reveal important variations in the electronic structure and Co–M interactions, which depend on the exact nature of the supporting metal ion, M

Bimetallic Cobalt–Dinitrogen Complexes: Impact of the Supporting Metal on N₂ Activation

Expanding a family of cobalt bimetallic complexes, we report the synthesis of the Ti­(III) metalloligand, Ti­[N­(<i>o-</i>(NCH₂P­(^<i>i</i>Pr)₂)­C₆H₄)₃] (abbreviated as TiL), and three heterobimetallics that pair cobalt with an early transition metal ion: CoTiL (<b>1</b>), K­(crypt-222)­[(N₂)­CoVL] (<b>2</b>), and K­(crypt-222)­[(N₂)­CoCrL] (<b>3</b>). The latter two complexes, along with previously reported K­(crypt-222)­[(N₂)­CoAlL] and K­(crypt-222)­[(N₂)­Co₂L], constitute an isostructural series of cobalt bimetallics that bind dinitrogen in an end-on fashion, i.e. [(N₂)­CoML]⁻. The characterization of <b>1</b>–<b>3</b> includes cyclic voltammetry, X-ray crystallography, and infrared spectroscopy. The [CoTiL]^0/– reduction potential is extremely negative at −3.20 V versus Fc⁺/Fc. In the CoML series where M is a transition metal, the reduction potentials shift anodically as M is varied across the first-row period. Among the [(N₂)­CoML]⁻ compounds, the dinitrogen ligand is weakly activated, as evidenced by N–N bond lengths between 1.110(8) and 1.135(4) Å and by N–N stretching frequencies between 1971 and 1995 cm^–1. Though changes in ν_N₂ are subtle, the extent of N₂ activation decreases across the first-row period. A correlation is found between the [CoML]^0/– reduction potentials and N₂ activation, where the more cathodic potentials correspond to lower N–N frequencies. Theoretical calculations of the [(N₂)­CoML]⁻ complexes reveal important variations in the electronic structure and Co–M interactions, which depend on the exact nature of the supporting metal ion, M

Heterobimetallic Complexes That Bond Vanadium to Iron, Cobalt, and Nickel

Zero-valent iron, cobalt, and nickel were installed into the metalloligand V­[N­(<i>o</i>-(NCH₂P­(ⁱPr)₂)­C₆H₄)₃] (<b>1</b>, VL), generating the heterobimetallic trio FeVL (<b>2</b>), CoVL (<b>3</b>), and NiVL (<b>4</b>), respectively. In addition, the one-electron-oxidized analogues [FeVL]­X ([<b>2</b>^<b>ox</b>]­X, where X^– = BPh₄ or PF₆) and [CoVL]­BPh₄ ([<b>3</b>^<b>ox</b>]­BPh₄) were prepared. The complexes were characterized by a host of physical methods, including cyclic voltammetry, X-ray crystallography, magnetic susceptibility, electronic absorption, NMR, electron paramagnetic resonance (EPR), and Mössbauer spectroscopies. The CoV and FeV heterobimetallic compounds have short M–V bond lengths that are consistent with M–M multiple bonding. As revealed by theoretical calculations, the M–V bond is triple in <b>2</b>, <b>2</b>^<b>ox</b>, and <b>3</b>^<b>ox</b>, double in <b>3</b>, and dative (Ni → V) in <b>4</b>. The (d–d)¹⁰ species, <b>2</b> and <b>3</b>^<b>ox</b>, are diamagnetic and exhibit large diamagnetic anisotropies of −4700 × 10^–36 m³/molecule. Complexes <b>2</b> and <b>3</b>^<b>ox</b> are also characterized by intense visible bands at 760 and 610 nm (ε > 1000 M^–1 cm^–1), respectively, which correspond to an intermetal (M → V) charge-transfer transition. Magnetic susceptibility measurements and EPR characterization establish <i>S</i> = ¹/₂ ground states for (d–d)⁹ <b>2</b>^<b>ox</b> and (d–d)¹¹ <b>3</b>, while (d–d)¹² <b>4</b> is <i>S</i> = 1 based on Evans’ method

Heterobimetallic Complexes That Bond Vanadium to Iron, Cobalt, and Nickel

Zero-valent iron, cobalt, and nickel were installed into the metalloligand V­[N­(<i>o</i>-(NCH₂P­(ⁱPr)₂)­C₆H₄)₃] (<b>1</b>, VL), generating the heterobimetallic trio FeVL (<b>2</b>), CoVL (<b>3</b>), and NiVL (<b>4</b>), respectively. In addition, the one-electron-oxidized analogues [FeVL]­X ([<b>2</b>^<b>ox</b>]­X, where X^– = BPh₄ or PF₆) and [CoVL]­BPh₄ ([<b>3</b>^<b>ox</b>]­BPh₄) were prepared. The complexes were characterized by a host of physical methods, including cyclic voltammetry, X-ray crystallography, magnetic susceptibility, electronic absorption, NMR, electron paramagnetic resonance (EPR), and Mössbauer spectroscopies. The CoV and FeV heterobimetallic compounds have short M–V bond lengths that are consistent with M–M multiple bonding. As revealed by theoretical calculations, the M–V bond is triple in <b>2</b>, <b>2</b>^<b>ox</b>, and <b>3</b>^<b>ox</b>, double in <b>3</b>, and dative (Ni → V) in <b>4</b>. The (d–d)¹⁰ species, <b>2</b> and <b>3</b>^<b>ox</b>, are diamagnetic and exhibit large diamagnetic anisotropies of −4700 × 10^–36 m³/molecule. Complexes <b>2</b> and <b>3</b>^<b>ox</b> are also characterized by intense visible bands at 760 and 610 nm (ε > 1000 M^–1 cm^–1), respectively, which correspond to an intermetal (M → V) charge-transfer transition. Magnetic susceptibility measurements and EPR characterization establish <i>S</i> = ¹/₂ ground states for (d–d)⁹ <b>2</b>^<b>ox</b> and (d–d)¹¹ <b>3</b>, while (d–d)¹² <b>4</b> is <i>S</i> = 1 based on Evans’ method

Influence of Copper Oxidation State on the Bonding and Electronic Structure of Cobalt–Copper Complexes

Heterobimetallic complexes that pair cobalt and copper were synthesized and characterized by a suite of physical methods, including X-ray diffraction, X-ray anomalous scattering, cyclic voltammetry, magnetometry, electronic absorption spectroscopy, electron paramagnetic resonance, and quantum chemical methods. Both Cu­(II) and Cu­(I) reagents were independently added to a Co­(II) metalloligand to provide (py₃tren)­CoCuCl (<b>1</b>-Cl) and (py₃tren)­CoCu­(CH₃CN) (<b>2</b>-CH₃CN), respectively, where py₃tren is the triply deprotonated form of <i>N</i>,<i>N</i>,<i>N</i>-tris­(2-(2-pyridylamino)­ethyl)­amine. Complex <b>2</b>-CH₃CN can lose the acetonitrile ligand to generate a coordination polymer consistent with the formula “(py₃tren)­CoCu” (<b>2</b>). One-electron chemical oxidation of <b>2</b>-CH₃CN with AgOTf generated (py₃tren)­CoCuOTf (<b>1</b>-OTf). The Cu­(II)/Cu­(I) redox couple for <b>1</b>-OTf and <b>2</b>-CH₃CN is reversible at −0.56 and −0.33 V vs Fc⁺/Fc, respectively. The copper oxidation state impacts the electronic structure of the heterobimetallic core, as well as the nature of the Co–Cu interaction. Quantum chemical calculations showed modest electron delocalization in the (CoCu)⁺⁴ state via a Co–Cu σ bond that is weakened by partial population of the Co–Cu σ antibonding orbital. By contrast, no covalent Co–Cu bonding is predicted for the (CoCu)⁺³ analogue, and the d-electrons are fully localized at individual metals

Role of the Metal in the Bonding and Properties of Bimetallic Complexes Involving Manganese, Iron, and Cobalt

A multidentate ligand platform is introduced that enables the isolation of both homo- and heterobimetallic complexes of divalent first-row transition metal ions such as Mn­(II), Fe­(II), and Co­(II). By means of a two-step metalation strategy, five bimetallic coordination complexes were synthesized with the general formula M₁M₂Cl­(py₃tren), where py₃tren is the triply deprotonated form of <i>N</i>,<i>N</i>,<i>N</i>-tris­(2-(2-pyridylamino)­ethyl)­amine. The metal–metal pairings include dicobalt (<b>1</b>), cobalt–iron (<b>2</b>), cobalt–manganese (<b>3</b>), diiron (<b>4</b>), and iron–manganese (<b>5</b>). The bimetallic complexes have been investigated by X-ray diffraction and X-ray anomalous scattering studies, cyclic voltammetry, magnetometry, Mössbauer spectroscopy, UV–vis–NIR spectroscopy, NMR spectroscopy, combustion analyses, inductively coupled plasma optical emission spectrometry, and ab initio quantum chemical methods. Only the diiron chloride complex in this series contains a metal–metal single bond (2.29 Å). The others show weak metal–metal interactions (2.49 to 2.53 Å). The diiron complex is also distinct with a septet ground state, while the other bimetallic species have much lower spin states from <i>S</i> = 0 to <i>S</i> = 1. We propose that the diiron system has delocalized metal–metal bonding electrons, which seems to correlate with a short metal–metal bond and a higher spin state. Multiconfigurational wave function calculations revealed that, indeed, the metal–metal bonding orbitals in the diiron complex are much more delocalized than those of the dicobalt analogue