title: Using ESI-MS to investigate the organometallic compound Cp₂Ti(SC₆H₄CO₂) and closely related compounds

authors: Song, Kai

subjects: ESI-MS

abstract: This thesis reports investigations on the electrospray ionisation mass spectrometric (ESI-MS) behaviour of some metallocene complexes of titanium and molybdenum. The ESI-MS behaviour of titanocene dichloride (Cp₂TiCl₂) compound, which is has shown of interest as an anticancer agent was investigated. Cp₂TiCl₂ was dissolved in various solvents and spectra were recorded at various capillary exit voltages from 60 V to 250 V. Bis(ethylcyclopentadienyl) dichloridotitanium(IV) was also studied via ESI-MS. Results indicated clearly some main species like [Cp₂TiH]⁺, [Cp₂Ti(OCH₃)]⁺ and [Cp₂Ti(OCH₃)₂+H]⁺ were observed. When the capillary exit voltage was greater than 150 V species containing two Ti centres like [Cp₄Ti₂(OCH₃)₂Cl]⁺, [Cp₄Ti₂(OCH₃)₃Cl+H]⁺ and [(Cp₂Ti(OCH₃)₂+H⁺)₂+Cl]⁻ disappeared and titanocene(III) species [Cp₂Ti(CH₃OH)]⁺ was observed which indicated reduction of titanium(IV) during ESI-MS analysis. Larger ions which contain three or more Ti centres were not observed. 

The main focus of this thesis was to investigate the chemistry and characterisation of the organometallic compound bis(cyclopentadienyl) thiosalicylatotitanium(IV) (Cp₂Ti(tsal) tsal = SC₆H₄CO₂). A further experiment was done to run the spectrum of a mixed solution of Cp₂TiCl₂ and Cp₂Ti(tsal) in CH₃OH to investigate the possibility of the tsal ligand bridging two Cp₂Ti centres. Characterisation of Cp₂Ti(tsal) using ESI mass spectrometry in the presence of added alkali metal salts and the reactivity of Cp₂Ti(tsal) towards soft electrophile was also studied.

At the same time, a new complex bis(ethylcyclopentadienyl) thiosalicylatotitanium(IV) ((EtCp)₂Ti(tsal)) was synthesised and studied by ESI-MS. Comparison of the ESI-MS spectra of Cp₂Ti(tsal) with those of (EtCp)₂Ti(tsal) was used to confirm the identity of some unknown species. This new complex was characterised by elemental analysis, melting point, nuclear magnetic resonance (NMR) and infra-red (IR) spectroscopy.

Finally the molybdocene dichloride (Cp₂MoCl₂) compound was studied by ESI-MS. The closely related compound bis(cyclopentadienyl) thiosalicylatomolybdenum(IV)  (Cp₂Mo(tsal)) was synthesised and characterised by ESI-MS, melting point, NMR and IR spectroscopy. Less species can be observed in the Mo system than in the Ti system. Most species in the Mo system contained a Cl ligand.

text: Using ESI-MS to investigate the organometallic compound Cp₂Ti(SC₆H₄CO₂) and closely related compounds This thesis reports investigations on the electrospray ionisation mass spectrometric (ESI-MS) behaviour of some metallocene complexes of titanium and molybdenum. The ESI-MS behaviour of titanocene dichloride (Cp₂TiCl₂) compound, which is has shown of interest as an anticancer agent was investigated. Cp₂TiCl₂ was dissolved in various solvents and spectra were recorded at various capillary exit voltages from 60 V to 250 V. Bis(ethylcyclopentadienyl) dichloridotitanium(IV) was also studied via ESI-MS. Results indicated clearly some main species like [Cp₂TiH]⁺, [Cp₂Ti(OCH₃)]⁺ and [Cp₂Ti(OCH₃)₂+H]⁺ were observed. When the capillary exit voltage was greater than 150 V species containing two Ti centres like [Cp₄Ti₂(OCH₃)₂Cl]⁺, [Cp₄Ti₂(OCH₃)₃Cl+H]⁺ and [(Cp₂Ti(OCH₃)₂+H⁺)₂+Cl]⁻ disappeared and titanocene(III) species [Cp₂Ti(CH₃OH)]⁺ was observed which indicated reduction of titanium(IV) during ESI-MS analysis. Larger ions which contain three or more Ti centres were not observed. 

The main focus of this thesis was to investigate the chemistry and characterisation of the organometallic compound bis(cyclopentadienyl) thiosalicylatotitanium(IV) (Cp₂Ti(tsal) tsal = SC₆H₄CO₂). A further experiment was done to run the spectrum of a mixed solution of Cp₂TiCl₂ and Cp₂Ti(tsal) in CH₃OH to investigate the possibility of the tsal ligand bridging two Cp₂Ti centres. Characterisation of Cp₂Ti(tsal) using ESI mass spectrometry in the presence of added alkali metal salts and the reactivity of Cp₂Ti(tsal) towards soft electrophile was also studied.

At the same time, a new complex bis(ethylcyclopentadienyl) thiosalicylatotitanium(IV) ((EtCp)₂Ti(tsal)) was synthesised and studied by ESI-MS. Comparison of the ESI-MS spectra of Cp₂Ti(tsal) with those of (EtCp)₂Ti(tsal) was used to confirm the identity of some unknown species. This new complex was characterised by elemental analysis, melting point, nuclear magnetic resonance (NMR) and infra-red (IR) spectroscopy.

Finally the molybdocene dichloride (Cp₂MoCl₂) compound was studied by ESI-MS. The closely related compound bis(cyclopentadienyl) thiosalicylatomolybdenum(IV)  (Cp₂Mo(tsal)) was synthesised and characterised by ESI-MS, melting point, NMR and IR spectroscopy. Less species can be observed in the Mo system than in the Ti system. Most species in the Mo system contained a Cl ligand.

year: 2019

title: Market uncertainty, market sentiment, and the post-earnings announcement drift

authors: Bird, Ron

subjects: anomalies

abstract: Post-earnings announcement drift (PEAD) which was first identified over 40 years ago seems to be as much alive today as it ever was. Numerous attempts have been made to explain its continued existence. In this paper we provide evidence to support a new explanation: that the PEAD is a reflection of the level of market uncertainty and sentiment that prevails during the post-announcement period. The overriding conclusion from our analysis is that both uncertainty and sentiment play a central role in determining investor behaviour and it is this behaviour that ultimately determines the pricing that is observed in financial markets.

text: Market uncertainty, market sentiment, and the post-earnings announcement drift Post-earnings announcement drift (PEAD) which was first identified over 40 years ago seems to be as much alive today as it ever was. Numerous attempts have been made to explain its continued existence. In this paper we provide evidence to support a new explanation: that the PEAD is a reflection of the level of market uncertainty and sentiment that prevails during the post-announcement period. The overriding conclusion from our analysis is that both uncertainty and sentiment play a central role in determining investor behaviour and it is this behaviour that ultimately determines the pricing that is observed in financial markets.

year: 2013

title: The Application of Critical Discourse Theory: A Criterion-Referenced Analysis of Reports Relating to Language Revitalisation in Australia and New Zealand

authors: Lewis, Roger Brian

subjects: te reo Māori

abstract: The discipline of language policy and planning (LPP) is often proposed as a viable tool for language revitalisation. However, the conventional paradigm upon which LPP is based is inadequate for such an inherently political, contentious and problematic area of social policy, and does not address the hegemonic and counter-hegemonic discourse that is at the very core of language revitalisation efforts. It is therefore argued here that LPP needs to be explicitly underpinned by critical discourse theory (CDT) if it is to be of genuine use to those involved in language revitalisation efforts, particularly to grass roots language activists. Following an introductory chapter which provides a background to the research and a rationale for it (Chapter 1), there is a critical review of selected literature on LPP and CDT, a review which ends by proposing a list of criteria which, it is argued, can be used to determine the extent to which discourse that is intended to be counter-hegemonic adheres to the principles of effective counter-hegemonic discourse as outlined in the literature on CDT (Chapter 2). In the following three chapters (Chapters 3, 4 & 5), these criteria are applied to the analysis of three recent reports that have a direct bearing on indigenous language revitalisation in Australia (Our Land Our Languages) and New Zealand (Ko Aotearoa Tēnei and Te Reo Mauriora). The first of these reports is found to adhere very closely to the criteria; the second less so; the third almost not at all. The different ways in which each of these reports has been received would tend to support the hypothesis that, other things being equal, the more closely a text of this type conforms to the criteria - that is, the more closely it is aligned to the fundamental principles of effective counter-hegemonic discourse as outlined in CDT - the more likely it is to be positively received and, therefore, to represent an effective challenge to the existing hegemony. The overall conclusion is that CDT can not only assist language activists by providing a basis for determining how successful counter-hegemonic discourse is likely to be in achieving its aims but has the potential to provide LPP with a secure theoretical foundation (Chapter 6).

text: The Application of Critical Discourse Theory: A Criterion-Referenced Analysis of Reports Relating to Language Revitalisation in Australia and New Zealand The discipline of language policy and planning (LPP) is often proposed as a viable tool for language revitalisation. However, the conventional paradigm upon which LPP is based is inadequate for such an inherently political, contentious and problematic area of social policy, and does not address the hegemonic and counter-hegemonic discourse that is at the very core of language revitalisation efforts. It is therefore argued here that LPP needs to be explicitly underpinned by critical discourse theory (CDT) if it is to be of genuine use to those involved in language revitalisation efforts, particularly to grass roots language activists. Following an introductory chapter which provides a background to the research and a rationale for it (Chapter 1), there is a critical review of selected literature on LPP and CDT, a review which ends by proposing a list of criteria which, it is argued, can be used to determine the extent to which discourse that is intended to be counter-hegemonic adheres to the principles of effective counter-hegemonic discourse as outlined in the literature on CDT (Chapter 2). In the following three chapters (Chapters 3, 4 & 5), these criteria are applied to the analysis of three recent reports that have a direct bearing on indigenous language revitalisation in Australia (Our Land Our Languages) and New Zealand (Ko Aotearoa Tēnei and Te Reo Mauriora). The first of these reports is found to adhere very closely to the criteria; the second less so; the third almost not at all. The different ways in which each of these reports has been received would tend to support the hypothesis that, other things being equal, the more closely a text of this type conforms to the criteria - that is, the more closely it is aligned to the fundamental principles of effective counter-hegemonic discourse as outlined in CDT - the more likely it is to be positively received and, therefore, to represent an effective challenge to the existing hegemony. The overall conclusion is that CDT can not only assist language activists by providing a basis for determining how successful counter-hegemonic discourse is likely to be in achieving its aims but has the potential to provide LPP with a secure theoretical foundation (Chapter 6).

year: 2014