title: Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes

authors: Henderson, William

subjects: Rhodium

abstract: Reactions of the chloride-bridged dimers [LMCl(μ-Cl)]₂ (M=Rh, Ir; L=Cp*=η⁵-C₅Me₅; M=Ru, L=η⁶-p-cymene) with two mole equivalents of thiosalicylic acid (HSC₆H₄CO₂H, H₂tsal) and excess base gives the dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes [LM(tsal)]₂. Reaction of the complex [Cp*RhCl₂(PPh₂)] with one equivalent of H₂tsal and triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]₂ and the phosphine complex [Cp*Rh(tsal)(PPh₃)]; upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers reveals the expected thiolate-bridged M₂(μ-S)₂ unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]⁺ ions. With added thiosalicylic acid, cations of the type [(LM)₂(Htsal)₃]⁺ were detected in the mass spectra.

text: Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes Reactions of the chloride-bridged dimers [LMCl(μ-Cl)]₂ (M=Rh, Ir; L=Cp*=η⁵-C₅Me₅; M=Ru, L=η⁶-p-cymene) with two mole equivalents of thiosalicylic acid (HSC₆H₄CO₂H, H₂tsal) and excess base gives the dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes [LM(tsal)]₂. Reaction of the complex [Cp*RhCl₂(PPh₂)] with one equivalent of H₂tsal and triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]₂ and the phosphine complex [Cp*Rh(tsal)(PPh₃)]; upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers reveals the expected thiolate-bridged M₂(μ-S)₂ unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]⁺ ions. With added thiosalicylic acid, cations of the type [(LM)₂(Htsal)₃]⁺ were detected in the mass spectra.

year: 2001-04-01

title: A diversity-aware model for majority vote ensemble accuracy

authors: Lim, Nick Jin Sean

subjects: Science & Technology

abstract: Ensemble classifiers are a successful and popular approach for classification, and are frequently found to have better generalization performance than single models in practice. Although it is widely recognized that ‘diversity’ between ensemble members is important in achieving these performance gains, for classification ensembles it is not widely understood which diversity measures are most predictive of ensemble performance, nor how large an ensemble should be for a particular application. In this paper, we explore the predictive power of several common diversity measures and show – with extensive experiments – that contrary to earlier work that finds no clear link between these diversity measures (in isolation) and ensemble accuracy instead by using the ρ diversity measure of Sneath and Sokal as an estimator for the dispersion parameter of a Polya-Eggenberger distribution we can predict, independently of the choice of base classifier family, the accuracy of a majority vote classifier ensemble ridiculously well. We discuss our model and some implications of our findings – such as diversity-aware (non-greedy) pruning of a majority-voting ensemble.

text: A diversity-aware model for majority vote ensemble accuracy Ensemble classifiers are a successful and popular approach for classification, and are frequently found to have better generalization performance than single models in practice. Although it is widely recognized that ‘diversity’ between ensemble members is important in achieving these performance gains, for classification ensembles it is not widely understood which diversity measures are most predictive of ensemble performance, nor how large an ensemble should be for a particular application. In this paper, we explore the predictive power of several common diversity measures and show – with extensive experiments – that contrary to earlier work that finds no clear link between these diversity measures (in isolation) and ensemble accuracy instead by using the ρ diversity measure of Sneath and Sokal as an estimator for the dispersion parameter of a Polya-Eggenberger distribution we can predict, independently of the choice of base classifier family, the accuracy of a majority vote classifier ensemble ridiculously well. We discuss our model and some implications of our findings – such as diversity-aware (non-greedy) pruning of a majority-voting ensemble.

year: 2020

title: Racism and intersections with health services

authors: Cormack, Donna

abstract: WERO webinar hosted by Māori and Indigenous Analysis Ltd & AATEA Solutions.

text: Racism and intersections with health services WERO webinar hosted by Māori and Indigenous Analysis Ltd & AATEA Solutions.

year: 2025-10-07