Inner-sphere oxidation of ternary iminodiacetatochromium(III) complexes involving DL-valine and L-arginine as secondary ligands. Isokinetic relationship for the oxidation of ternary iminodiacetato-chromium(III) complexes by periodate

<p>Abstract</p> <p>Background</p> <p>In this paper, the kinetics of oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺and [Cr^III(HIDA)(Arg)(H₂O)₂]⁺(HIDA = iminodiacetic acid, Val = DL-valine and Arg = L-arginine) were studied. The choice of ternary complexes was attributed to two considerations. Firstly, in order to study the effect of the secondary ligands DL-valine and L-arginine on the stability of binary complex [Cr^III(HIDA)(IDA)(H₂O)] towards oxidation. Secondly, transition metal ternary complexes have received particular focus and have been employed in mapping protein surfaces as probes for biological redox centers and in protein capture for both purification and study.</p> <p>Results</p> <p>The results have shown that the reaction is first order with respect to both [IO₄^-] and the complex concentration, and the rate increases over the pH range 2.62 – 3.68 in both cases. The experimental rate law is consistent with a mechanism in which both the deprotonated forms of the complexes [Cr^III(IDA)(Val)(H₂O)₂] and [Cr^III(IDA)(Arg)(H₂O)₂] are significantly more reactive than the conjugate acids. The value of the intramolecular electron transfer rate constant for the oxidation of [Cr^III(HIDA)(Arg)(H₂O)₂]⁺, <it>k</it>₃(1.82 × 10^-3s^-1), is greater than the value of <it>k</it>₁(1.22 × 10^-3s^-1) for the oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺at 45.0°C and <it>I </it>= 0.20 mol dm^-3. It is proposed that electron transfer proceeds through an inner-sphere mechanism <it>via </it>coordination of IO₄^-to chromium(III).</p> <p>Conclusion</p> <p>The oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺and [Cr^III(HIDA)(Arg)(H₂O)₂]⁺by periodate may proceed through an inner-sphere mechanism via two electron transfer giving chromium(VI). The value of the intramolecular electron transfer rate constant for the oxidation of [Cr^III(HIDA)(Arg)(H₂O)₂]⁺, <it>k</it>₃, is greater than the value of <it>k</it>₁for the oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺. A common mechanism for the oxidation of ternary iminodiacetatochromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH* and ΔS* values for these reactions.</p

Australian chiropractic sports medicine: half way there or living on a prayer?

Sports chiropractic within Australia has a chequered historical background of unorthodox individualistic displays of egocentric treatment approaches that emphasise specific technique preference and individual prowess rather than standardised evidence based management. This situation has changed in recent years with the acceptance of many within sports chiropractic to operate under an evidence informed banner and to embrace a research culture. Despite recent developments within the sports chiropractic movement, the profession is still plagued by a minority of practitioners continuing to espouse certain marginal and outlandish technique systems that beleaguer the mainstream core of sports chiropractic as a cohesive and homogeneous group. Modern chiropractic management is frequently multimodal in nature and incorporates components of passive and active care. Such management typically incorporates spinal and peripheral manipulation, mobilisation, soft tissue techniques, rehabilitation and therapeutic exercises. Externally, sports chiropractic has faced hurdles too, with a lack of recognition and acceptance by organized and orthodox sports medical groups. Whilst some arguments against the inclusion of chiropractic may be legitimate due to its historical baggage, much of the argument appears to be anti-competitive, insecure and driven by a closed-shop mentality.sequently, chiropractic as a profession still remains a pariah to the organised sports medicine world. Add to this an uncertain continuing education system, a lack of protection for the title 'sports chiropractor', a lack of a recognized specialist status and a lack of support from traditional chiropractic, the challenges for the growth and acceptance of the sports chiropractor are considerable. This article outlines the historical and current challenges, both internal and external, faced by sports chiropractic within Australia and proposes positive changes that will assist in recognition and inclusion of sports chiropractic in both chiropractic and multi-disciplinary sports medicine alike