title: ESIMS targeted synthesis of novel {Pt2S2} derivatives

authors: Fortney-Zirker, Ryland

subjects: Inorganic Chemistry

abstract: Electrospray ionisation mass spectrometry (ESIMS) was used to investigate ring-
opening reactions of several epoxides with the nucleophilic dinuclear PtII
complexes
[Pt2(μ-E)2(PPh3)4] (E = S, 1a; Se, 1b) and several activated cyclopropanes, N -
tosylaziridine, and thiirane with 1a. Epoxides cyclohexene oxide, styrene oxide,
epibromohydrin, and 2,2-dimethyloxirane were found to undergo ring-opening when
reacted with 1a and derivatives [Pt2(μ-S)(μ-S C6H10OH)(PPh3)4]BPh4 (5[BPh4],
[Pt2(μ-S)(μ-S C8H8OH)(PPh3)4]BETI (6[BETI]), [Pt2(μ-S CH2CH(OH)CH2 μ-S)-
(PPh3)4][PF6]2 (3[PF6]2), and [Pt2(μ-S)(μ-S CH2C(Me)2OH)(PPh3)4]BPh4 (7 [BPh4])
were respectively isolated and structurally characterised with 31P{1H} and 195Pt nu-
clear magnetic resonance (NMR) spectroscopy, and for 5, 3 and 7 single crystal X-
ray diffraction (XRD) studies. 6 was found to be a mixture of isomers, and crystals
suitable for a single crystal XRD experiment were not obtained. Both styrene oxide
and epibromohydrin underwent ring-opening when reacted with 1b and the respec-
tive derivatives [Pt2(μ-Se)(μ-Se C8H8OH)(PPh3)4]+ and [Pt2(μ-Se CH2CH(OH)-
CH2 μ-Se)(PPh3)4]2+ were characterised by ESIMS. The fully substituted epoxide
2,3-dimethyl-2,3-epoxybutane did not undergo ring-opening when treated with 1a
in refluxing methanol for several hours. 5,6-Epoxy-5,6-dihydro-[1,10]-phenanthro-
line resulted in ring-opening when reacted with 1a however the resulting deriva-
tive [Pt2(μ-S)(μ-S C12H8N2O)(PPh3)4]+ (8) was found to decompose readily in
solution. Cyclopropanes cyclopropyl methyl ketone and trans-1,2-dibenzoylcyclo-
propane did not undergo ring-opening when reacted with 1a. The more activated
2,2,3,3-tetracyanocyclopropane and diethylcyclopropane-1,2-dicarboxylate both re-
i
sulted in ring-opening when reacted with 1a resulting in the isolation of deriva-
tives [Pt2(μ-S)(μ-S C(CN)2)(PPh3)4] (12) and [Pt2(μ-S)(μ-S C2H4CH(CO2Et)2)-
(PPh3)4]BETI (11[BETI]) respectively which were structurally characterised by het-
eronuclear NMR spectroscopy (12 31P{1H}, 195Pt{1H}; 11 1H, 31P{1H}) and single
crystal XRD studies. 12 was found to have a carbanionic center and is proposed
to result from an intramolecular rearrangement of the initially formed [Pt2(μ-S)(μ-
S C(CN)2C(CN)2CH3)(PPh3)4]+ (31). Bromomethylcyclopropane did not result
in ring-opening when reacted with 1a, however alkylation resulted in [Pt2(μ-S)(μ-
S CH2C3H5)(PPh3)4]+ (10) which was isolated as 10[BPh4] and structurally char-
acterised by 31P{1H}-NMR spectroscopy and single crystal XRD. 10[BPh4] did not
undergo ring-opening when refluxed in methanol. N -tosylaziridine resulted in the
ring-opened derivative [Pt2(μ-S)(μ-S C2H4NHtosyl)(PPh3)4]+ (13) when reacted
with 1a and was isolated as 13[PF6] and structurally characterised by 31P{1H}-NMR
spectroscopy and single crystal XRD. Thiirane appeared to rapidly undergo ring-
opening when reacted with 1a however only polymeric decomposition species were
detected by ESIMS. The previously reported reaction of 1a and 2-chloro-N -methyl-
pyridinium iodide (14[I]) was reexamined. Salts of 14 sans iodide were synthesized
using alkylating agents trimethyloxonium tetrafluoroborate or dimethyl sulfate giv-
ing 14[BF4] or 14[CH3SO4] respectively. The reaction of 1a and 14 was found to
result in the dicationic complex [Pt2(μ-S)(μ-S C6H7N)(PPh3)4]2+ (2) which was
isolated as the bis-hexafluorophosphate salt 2[PF6]2 and structurally characterised
with 31P{1H}-NMR spectroscopy, 195Pt{1H}-NMR spectroscopy, and single crystal
XRD. The 2-mercapto-N -methylpyridinium ligand in 2 was proposed to be an ex-
cellent leaving group and the reaction of 2 with excess bromide resulted in the isola-
tion of the mixed-bridged complex [Pt2(μ-S)(μ-Br)(PPh3)4]BPh4 (16[BPh4]) which
was structurally characterised with 31P{1H}-NMR spectroscopy and single crystal
XRD. The thiols N -acetylcysteamine, 2-mercapto-1-methylimidazole, and 2-amino-
thiophenol were reacted with 2 to give [Pt2(μ-S)(μ-S C2H4NHC( O)CH3)(PPh3)4]+
(38), [Pt2(μ-S)(μNS-S C3H2N2CH3)(PPh3)4]+ (17), and [Pt2(μ-S)(μ-S C6H4NH2)-
ii
(PPh3)4]+ (39) respectively which were isolated as 38[BF4], 17[BETI], and 39[BF4].
17[BETI] was structurally characterised (31P{1H}-NMR spectroscopy, 195Pt{1H}-
NMR spectroscopy, single crystal XRD) and found to contain a novel 6-membered
Pt-S-Pt-S-C-N heterocycle. 38 was characterised using NMR spectroscopy (1H, 13C,
31P{1H}, and 195Pt{1H}). 39 was characterised using 31P{1H}-NMR spectroscopy.
2 was reacted with selenourea resulting in the detection by ESIMS of the mixed-
bridged [Pt2(μ-S)(μ-Se)(PPh3)4]+ (23) which decomposed over the course of several
days to 1a and 1b. When the diaryldichalcogenides Ph2Se2, Ph2Te2, di-4-ethoxy-
phenyl-ditelluride were reduced with hydrazine to the corresponding chalcogeno-
late anion and reacted with 2, substitution of the 2-mercapto-N -methylpyridinium
zwitterion resulted and mixed-bridged derivatives [Pt2(μ-S)(μ-E R)(PPh3)4]+ (E-
R = Se-Ph, 18; Te-Ph, 47; Te-C6H4-OEt, 19) detected by ESIMS. 18[BF4] and
19[BF4] were isolated and structurally characterised with heteronuclear NMR spec-
troscopy (31P{1H}-NMR, 195Pt{1H}-NMR) and single crystal XRD. A bridging hy-
drazine species was observed when reacting 2 with hydrazine reduced diaryldichalco-
genides, and the reaction between 2 and hydrazine was found to result in [Pt2-
(μ-S)(μ-NH NH2)(PPh3)4]+ (21) which was isolated as 21[BPh4] and structurally
characterised with 31P{1H} and 195Pt{1H}-NMR spectroscopy

text: ESIMS targeted synthesis of novel {Pt2S2} derivatives Electrospray ionisation mass spectrometry (ESIMS) was used to investigate ring-
opening reactions of several epoxides with the nucleophilic dinuclear PtII
complexes
[Pt2(μ-E)2(PPh3)4] (E = S, 1a; Se, 1b) and several activated cyclopropanes, N -
tosylaziridine, and thiirane with 1a. Epoxides cyclohexene oxide, styrene oxide,
epibromohydrin, and 2,2-dimethyloxirane were found to undergo ring-opening when
reacted with 1a and derivatives [Pt2(μ-S)(μ-S C6H10OH)(PPh3)4]BPh4 (5[BPh4],
[Pt2(μ-S)(μ-S C8H8OH)(PPh3)4]BETI (6[BETI]), [Pt2(μ-S CH2CH(OH)CH2 μ-S)-
(PPh3)4][PF6]2 (3[PF6]2), and [Pt2(μ-S)(μ-S CH2C(Me)2OH)(PPh3)4]BPh4 (7 [BPh4])
were respectively isolated and structurally characterised with 31P{1H} and 195Pt nu-
clear magnetic resonance (NMR) spectroscopy, and for 5, 3 and 7 single crystal X-
ray diffraction (XRD) studies. 6 was found to be a mixture of isomers, and crystals
suitable for a single crystal XRD experiment were not obtained. Both styrene oxide
and epibromohydrin underwent ring-opening when reacted with 1b and the respec-
tive derivatives [Pt2(μ-Se)(μ-Se C8H8OH)(PPh3)4]+ and [Pt2(μ-Se CH2CH(OH)-
CH2 μ-Se)(PPh3)4]2+ were characterised by ESIMS. The fully substituted epoxide
2,3-dimethyl-2,3-epoxybutane did not undergo ring-opening when treated with 1a
in refluxing methanol for several hours. 5,6-Epoxy-5,6-dihydro-[1,10]-phenanthro-
line resulted in ring-opening when reacted with 1a however the resulting deriva-
tive [Pt2(μ-S)(μ-S C12H8N2O)(PPh3)4]+ (8) was found to decompose readily in
solution. Cyclopropanes cyclopropyl methyl ketone and trans-1,2-dibenzoylcyclo-
propane did not undergo ring-opening when reacted with 1a. The more activated
2,2,3,3-tetracyanocyclopropane and diethylcyclopropane-1,2-dicarboxylate both re-
i
sulted in ring-opening when reacted with 1a resulting in the isolation of deriva-
tives [Pt2(μ-S)(μ-S C(CN)2)(PPh3)4] (12) and [Pt2(μ-S)(μ-S C2H4CH(CO2Et)2)-
(PPh3)4]BETI (11[BETI]) respectively which were structurally characterised by het-
eronuclear NMR spectroscopy (12 31P{1H}, 195Pt{1H}; 11 1H, 31P{1H}) and single
crystal XRD studies. 12 was found to have a carbanionic center and is proposed
to result from an intramolecular rearrangement of the initially formed [Pt2(μ-S)(μ-
S C(CN)2C(CN)2CH3)(PPh3)4]+ (31). Bromomethylcyclopropane did not result
in ring-opening when reacted with 1a, however alkylation resulted in [Pt2(μ-S)(μ-
S CH2C3H5)(PPh3)4]+ (10) which was isolated as 10[BPh4] and structurally char-
acterised by 31P{1H}-NMR spectroscopy and single crystal XRD. 10[BPh4] did not
undergo ring-opening when refluxed in methanol. N -tosylaziridine resulted in the
ring-opened derivative [Pt2(μ-S)(μ-S C2H4NHtosyl)(PPh3)4]+ (13) when reacted
with 1a and was isolated as 13[PF6] and structurally characterised by 31P{1H}-NMR
spectroscopy and single crystal XRD. Thiirane appeared to rapidly undergo ring-
opening when reacted with 1a however only polymeric decomposition species were
detected by ESIMS. The previously reported reaction of 1a and 2-chloro-N -methyl-
pyridinium iodide (14[I]) was reexamined. Salts of 14 sans iodide were synthesized
using alkylating agents trimethyloxonium tetrafluoroborate or dimethyl sulfate giv-
ing 14[BF4] or 14[CH3SO4] respectively. The reaction of 1a and 14 was found to
result in the dicationic complex [Pt2(μ-S)(μ-S C6H7N)(PPh3)4]2+ (2) which was
isolated as the bis-hexafluorophosphate salt 2[PF6]2 and structurally characterised
with 31P{1H}-NMR spectroscopy, 195Pt{1H}-NMR spectroscopy, and single crystal
XRD. The 2-mercapto-N -methylpyridinium ligand in 2 was proposed to be an ex-
cellent leaving group and the reaction of 2 with excess bromide resulted in the isola-
tion of the mixed-bridged complex [Pt2(μ-S)(μ-Br)(PPh3)4]BPh4 (16[BPh4]) which
was structurally characterised with 31P{1H}-NMR spectroscopy and single crystal
XRD. The thiols N -acetylcysteamine, 2-mercapto-1-methylimidazole, and 2-amino-
thiophenol were reacted with 2 to give [Pt2(μ-S)(μ-S C2H4NHC( O)CH3)(PPh3)4]+
(38), [Pt2(μ-S)(μNS-S C3H2N2CH3)(PPh3)4]+ (17), and [Pt2(μ-S)(μ-S C6H4NH2)-
ii
(PPh3)4]+ (39) respectively which were isolated as 38[BF4], 17[BETI], and 39[BF4].
17[BETI] was structurally characterised (31P{1H}-NMR spectroscopy, 195Pt{1H}-
NMR spectroscopy, single crystal XRD) and found to contain a novel 6-membered
Pt-S-Pt-S-C-N heterocycle. 38 was characterised using NMR spectroscopy (1H, 13C,
31P{1H}, and 195Pt{1H}). 39 was characterised using 31P{1H}-NMR spectroscopy.
2 was reacted with selenourea resulting in the detection by ESIMS of the mixed-
bridged [Pt2(μ-S)(μ-Se)(PPh3)4]+ (23) which decomposed over the course of several
days to 1a and 1b. When the diaryldichalcogenides Ph2Se2, Ph2Te2, di-4-ethoxy-
phenyl-ditelluride were reduced with hydrazine to the corresponding chalcogeno-
late anion and reacted with 2, substitution of the 2-mercapto-N -methylpyridinium
zwitterion resulted and mixed-bridged derivatives [Pt2(μ-S)(μ-E R)(PPh3)4]+ (E-
R = Se-Ph, 18; Te-Ph, 47; Te-C6H4-OEt, 19) detected by ESIMS. 18[BF4] and
19[BF4] were isolated and structurally characterised with heteronuclear NMR spec-
troscopy (31P{1H}-NMR, 195Pt{1H}-NMR) and single crystal XRD. A bridging hy-
drazine species was observed when reacting 2 with hydrazine reduced diaryldichalco-
genides, and the reaction between 2 and hydrazine was found to result in [Pt2-
(μ-S)(μ-NH NH2)(PPh3)4]+ (21) which was isolated as 21[BPh4] and structurally
characterised with 31P{1H} and 195Pt{1H}-NMR spectroscopy

year: 2024-10-18

title: Geodesic Geometry of Black Holes

authors: Slezakova, Gabriela

subjects: geodesic

abstract: The study of geodesics is of intrinsic significance in the study of the geometry of space-time. In this thesis null, space-like and
time-like geodesics are studied in the case of the space-times of Schwarzschild, Reissner-Nordstrouml;m and Kerr black holes. These
space-times have been investigated with varying degrees of thoroughness in many articles and some books. However, there are some significant gaps in these treatments and the central aim of this thesis is to fill these gaps where necessary. Moreover, the following topics are covered for the first time.
1. In Chapter 4 a thorough treatment of the space-like geodesics of the Schwarzschild solutions has been given. These geodesics are the trajectories of Tachyons (faster than light particles) and are
treated in a complete manner. This has been done by obtaining exact solutions and solving them numerically.
2. In Part II all solutions for geodesics for a
Reissner-Nordstrouml;m black hole have been given in complete detail, i.e. time-like, null and space-like geodesics and orbit of a charged particle.
3. In Chapter 14 all solutions for geodesics in the equatorial plane of a Kerr black hole have been given in complete detail, i.e. time-like, null and space-like geodesics.
4. The study of special types of non-equatorial geodesics for a Kerr black hole have been given in complete detail, i.e. time-like (Chapter 17), null (Chapter 15) and space-like (Chapter 16). This has been done in order to distinguish the qualitatively different types of solutions.

Calculation of the explicit formulas, which describe these geodesics, as well as numerically computed diagrams representing the geodesics have been incorporated in these studies. The following subjects have been also treated:
5.  Solutions for the geodesics in Reissner-Nordstrouml;m black holes with |Q_*| gt;= M, which are black holes with one (|Q_*| = M) or no horizon (|Q_*|gt; M) (Chapter 8).
6. Solutions of geodesics in extreme and fast Kerr black holes, i.e. black holes with a = M (extreme) and a gt; M (fast). As in the case of |Q_*| gt; M, fast black holes have naked singularities (Chapter 14).
7. Some general observations about orbit types of the Kerr black holes regarding relationships between parameters such as angular momentum, energy, Carter constant and mass and angular momentum of black holes (Chapter 13).
8. Some corrections to errors found in the literature.

While it has not been possible to cover all different cases which occur for possible relations amongst the parameters specifying a
general black hole, interesting geodesics have, however, been studied and a more thorough  presentation of the properties of geodesics has now been given.

text: Geodesic Geometry of Black Holes The study of geodesics is of intrinsic significance in the study of the geometry of space-time. In this thesis null, space-like and
time-like geodesics are studied in the case of the space-times of Schwarzschild, Reissner-Nordstrouml;m and Kerr black holes. These
space-times have been investigated with varying degrees of thoroughness in many articles and some books. However, there are some significant gaps in these treatments and the central aim of this thesis is to fill these gaps where necessary. Moreover, the following topics are covered for the first time.
1. In Chapter 4 a thorough treatment of the space-like geodesics of the Schwarzschild solutions has been given. These geodesics are the trajectories of Tachyons (faster than light particles) and are
treated in a complete manner. This has been done by obtaining exact solutions and solving them numerically.
2. In Part II all solutions for geodesics for a
Reissner-Nordstrouml;m black hole have been given in complete detail, i.e. time-like, null and space-like geodesics and orbit of a charged particle.
3. In Chapter 14 all solutions for geodesics in the equatorial plane of a Kerr black hole have been given in complete detail, i.e. time-like, null and space-like geodesics.
4. The study of special types of non-equatorial geodesics for a Kerr black hole have been given in complete detail, i.e. time-like (Chapter 17), null (Chapter 15) and space-like (Chapter 16). This has been done in order to distinguish the qualitatively different types of solutions.

Calculation of the explicit formulas, which describe these geodesics, as well as numerically computed diagrams representing the geodesics have been incorporated in these studies. The following subjects have been also treated:
5.  Solutions for the geodesics in Reissner-Nordstrouml;m black holes with |Q_*| gt;= M, which are black holes with one (|Q_*| = M) or no horizon (|Q_*|gt; M) (Chapter 8).
6. Solutions of geodesics in extreme and fast Kerr black holes, i.e. black holes with a = M (extreme) and a gt; M (fast). As in the case of |Q_*| gt; M, fast black holes have naked singularities (Chapter 14).
7. Some general observations about orbit types of the Kerr black holes regarding relationships between parameters such as angular momentum, energy, Carter constant and mass and angular momentum of black holes (Chapter 13).
8. Some corrections to errors found in the literature.

While it has not been possible to cover all different cases which occur for possible relations amongst the parameters specifying a
general black hole, interesting geodesics have, however, been studied and a more thorough  presentation of the properties of geodesics has now been given.

year: 2006

title: Anti-racism Allyship Amongst Psychologists and Students in Psychology Training in Aotearoa New Zealand

authors: Tan, Kyle K. H.

abstract: Racism is a well-established social determinant of health, impacting Māori, Pacific, and Asian communities in Aotearoa New Zealand. However, few scholarly studies have focused on racial justice allyship in Aotearoa, particularly within the psychology discipline. This study examines demographic and attitudinal factors associated with anti-racism allyship among psychologists and students in psychology training amidst escalating racist rhetoric and opposition to Māori self-determination in Aotearoa. Drawing data from an online anonymous survey (n = 280), we assessed participants’ responses on three scales: 1) Attitudes towards aspects of Māori (taha Māori); 2) Attitudes towards acknowledging the existence of racism and settler colonialism 3) Anti-racist allyship. Certain demographic groups (Pākehā, Asian, older-aged, male, or those who entered training decades ago) scored lower on these scales, indicating the need for targeted training. Regression analyses showed both ‘Attitudes towards taha Māori’ and ‘Attitudes towards racism and colonisation’ scales were significantly correlated with anti-racist allyship. Our findings call for a sustained investment in training anti-racist psychologists who are competent in providing culturally safe care and capable of challenging racial injustices. Future research is required on the development of a racial justice allyship model across all institutions that train, employ and regulate psychologists in Aotearoa that is informed by Te Tiriti o Waitangi.

text: Anti-racism Allyship Amongst Psychologists and Students in Psychology Training in Aotearoa New Zealand Racism is a well-established social determinant of health, impacting Māori, Pacific, and Asian communities in Aotearoa New Zealand. However, few scholarly studies have focused on racial justice allyship in Aotearoa, particularly within the psychology discipline. This study examines demographic and attitudinal factors associated with anti-racism allyship among psychologists and students in psychology training amidst escalating racist rhetoric and opposition to Māori self-determination in Aotearoa. Drawing data from an online anonymous survey (n = 280), we assessed participants’ responses on three scales: 1) Attitudes towards aspects of Māori (taha Māori); 2) Attitudes towards acknowledging the existence of racism and settler colonialism 3) Anti-racist allyship. Certain demographic groups (Pākehā, Asian, older-aged, male, or those who entered training decades ago) scored lower on these scales, indicating the need for targeted training. Regression analyses showed both ‘Attitudes towards taha Māori’ and ‘Attitudes towards racism and colonisation’ scales were significantly correlated with anti-racist allyship. Our findings call for a sustained investment in training anti-racist psychologists who are competent in providing culturally safe care and capable of challenging racial injustices. Future research is required on the development of a racial justice allyship model across all institutions that train, employ and regulate psychologists in Aotearoa that is informed by Te Tiriti o Waitangi.

year: 2025