Trivalent scandium, yttrium and lanthanide complexes with thia-oxa and selena-oxa macrocycles and crown ether coordination

Complexes of the oxa-thia macrocycles [18]aneO4S2, [15]aneO3S2 and the oxa-selena macrocycle [18]aneO4Se2 (L) of types [MCl2(L)]FeCl4 (M = Sc or Y) were prepared from [ScCl3(thf)3] or [YCl2(THF)5][YCl4(THF)2] and the ligand in anhydrous MeCN, using FeCl3 as a chloride abstractor. The [MI2(L)]I, [LaI3(L)] and [LuI2(L)]I have been prepared from the ligands and the appropriate anhydrous metal triiodide in MeCN. Complexes of type [LaI3(crown)] and [LuI2(crown)]I (crown = 18-crown-6, 15-crown-5) were made for comparison. Use of the metal iodide results in complexes with high solubility compared to the corresponding chlorides, although also with increased sensitivity to moisture. All complexes were characterised by microanalysis, IR, (1)H, (45)Sc and (77)Se NMR spectroscopy as appropriate. X-ray crystal structures are reported for [ScCl2([18]aneO4S2)][FeCl4], [ScI2([18]aneO4S2)]I, [YCl2(18-crown-6)]3[Y2Cl9], [YCl2([18]aneO4S2)][FeCl4], [LaI3(15-crown-5)], [LaI2(18-crown-6)(MeCN)]I, [LuI(18-crown-6)(MeCN)2]I2, [Lu(15-crown-5)(MeCN)2(OH2)]I3, [LaI3([18]aneO4S2)], [LaI([18]aneO4S2)(OH2)]I2, [LaI3([18]aneO4Se2)] and [LuI2([18]aneO4Se2)]I. In each complex all the neutral donor atoms of the macrocycles are coordinated to the metal centre, showing very rare examples of these oxophilic metal centres coordinated to thioether groups, and the first examples of coordinated selenoether donors. In some cases MeCN or adventitious water displaces halide ligands, but not the S/Se donors from La or Lu complexes. A complex of the oxa-tellura macrocycle [18]aneO4Te2, [ScCl2([18]aneO4Te2)][FeCl4] was isolated, but is unstable in MeCN solution, depositing elemental Te. YCl3 and 18-crown-6 produced [YCl2(18-crown-6)]3[Y2Cl9], the asymmetric unit of which contains two cations with a trans-YCl2 arrangement and a third with a cis-YCl2 group

Coordination complexes of the tungsten(VI) oxide fluorides WOF4 and WO2F2 with neutral oxygen- and nitrogen-donor ligands

Abstract[WOF4(MeCN)], prepared from a 1:1 ratio of WF6 and O(SiMe3)2 in MeCN, is a convenient synthon for the preparation of complexes of WOF4 and WO2F2 with neutral N- or O-donor ligands. It reacts with monodentate ligands L (L=OPPh3, OPMe3, dmso, py) in a 1:1 ratio to form [WOF4L], whilst reaction of [WOF4(MeCN)], O(SiMe3)2 and L⿲ (L⿲=OPPh3, py, pyNO, dmso) in 1:1:2 ratio affords [WO2F2L⿲2]. The synthesis of [WO2F2(L-L)] (L-L=Ph2P(O)CH2P(O)Ph2 or 1,10-phenanthroline) are also described. Similar complexes with arsines, thio- or seleno-ethers are not formed by these routes. The complexes have been characterised by microanalysis, IR, 1H and 19F{1H} NMR spectroscopy, and X-ray crystal structures are reported for [WOF4(OPPh3)], [WO2F2(OPPh3)2], [WO2F2{Ph2P(O)CH2P(O)Ph2}] and [WO2F2(pyNO)2]

Synthesis and structure of [CeF4(Me2SO)2]— a rare neutral ligand complex of a lanthanide tetrafluoride

Hydrated cerium(IV) fluoride dissolves in hot dimethylsulfoxide to form yellow [CeF4(Me2SO)2], the X-ray structure of which reveals a chain polymer with eight-coordinate cerium bound to two terminal and four bridging fluorines and two O-bonded Me2SO molecules. The complex was also characterised by IR, 1H and 19F{1H} NMR and UV/visible spectroscopies. Attempts to use [CeF4(Me2SO)2] as a synthon to prepare other complexes with phosphine oxides or 2,2?-bipyridyl were unsuccessful. Thorium(IV) fluoride hydrate does not react with boiling dmso.<br/

Six-coordinate NbF5 and TaF5 complexes with tertiary mono-phosphine and -arsine ligands

The syntheses of the extremely moisture sensitive, neutral [MF5(PR3)] (M = Nb or Ta, R = Me or Ph) and [MF5(AsR?3)] (R? = Me or Et), from reaction of the ligands with MF5 in anhydrous diethyl ether solution are reported. Attempts to isolate analogous complexes with SbMe3 were unsuccessful. The products are characterised by IR and mutinuclear NMR (1H, 19F{1H}, 31P{1H} and 93Nb) spectroscopic studies. These are the first examples of six-coordinate phosphine or arsine complexes of the Group 5 pentafluorides. The ionic species, trans-[MF4(PMe3)2][MF6], are obtained from diethyl ether solution of [MF5(PMe3)] containing excess PMe3 and similarly characterised. All complexes are extremely moisture and oxygen sensitive and decomposed by many common solvents. In solution in toluene the [MF5(PMe3)] (M = Nb or Ta) and [MF5(AsR?3)] are extensively dissociated at ambient temperatures. The [MF5(PPh3)] dissolve in CH2Cl2 with decomposition to form [PPh3H][MF6]. Attempts to isolate phosphine complexes of NbOF3 were unsuccessful

Bromostibine complexes of iron(II): hypervalency and reactivity

The halostibine complexes [CpFe(CO)2(SbMe2Br)][CF3SO3] and [CpFe(CO)2(SbMe2Br)][BF4] both contain significant interactions between the anion and the formally neutral Sb(III) ligand, which simultaneously displays Lewis acidic and Lewis basic properties. The unexpected secondary product [CpFe(CO)(Me2BrSb-?-Br-SbBrMe2)] is formed in the presence of excess ligand, the strongly associated Br– anion bridging the two Sb donors to form a four-membered FeSb2Br ring.<br/

A Relic of the Past: Identification, Placement and Review Committees in Ontario’s Education System

The Identification, Placement and Review Committee (IPRC) process has been long established within Ontario special education practice and provincial legislation. Borne out of advocacy for advancing the right to education for children with disabilities, the IPRC process is now being critically explored as to whether the process itself creates an infringement on students’ access and rights to quality education. Drawing on historical and contemporary shifts in education policy and human rights in Ontario, this paper presents the case that the current structure of the IPRC is outdated and may function as a significant barrier to students’ academic futures

Spirituality and Aging: How Worship communities of Older Adults Sustain Their Faith in the Absence of Traditional Ordained Leadership

This thesis considers the ways that older Anglican Christians (greater than 70 years of age) exercise worship in an environment of shared ministry, rather than in one that is led by traditional ordained stipended clergy. It explores the ways that such groups of Christians nurture and draw on their spirit-given gifts to sustain their faith, in the context of ministry of and by all the baptized. Specific attention is given to the model of worship established within the Auckland Diocese of the Anglican Church in Aotearoa/New Zealand and Polynesia (Auckland Diocese) known as Local Shared Ministry Units (LSMU). Interviews with individual members of four LSMUs were carried out, with the resulting comments treated as a collective case study. This methodological approach works well where there are a number of cases (LSMU) and selected units of analysis within each case (worshippers in the ol der adult category). The interview data was then analysed using Grounded Theory as the data analysis approach. The findings from the analysed data indicate that these older adults are still seeking faith formation, generally do not regard themselves as fully formed spiritually, and are using personal prayer in particular to enhance and nourish their faith growth. Also, their present worship environment of the LSMU model plays a large and positive part in their spiritual wellbeing. They feel valued not just as members of their congregations, but as active participants in their own worship activities and thus faith journeys. Enabling people to exercise Christian ministries in their own church environment, in ways that enhance their faith, allowing individual skills and gifts to be developed and used, was regarded by all the respondents in this research as highly valuable. They consistently affirmed how this environment (the LSMU model) enhanced both their personal faith and the overall quality of their worship. However, the challenge to church leadership for supporting this desired worship environment may not entirely be in the power of the worshippers. It may in fact be how the structure which currently affirms a seminary-trained clergy, supporting a vicar-led church model, following fairly strictly determined liturgical protocols can adapt to a genuine empowerment of the worshippers themselves to direct and manage their own worship activities. Therefore, given the increasing numbers of older adults in both the general population and desirably in worship populations, there is a need for church leadership to acknowledge and take note of this phenomenon, in the way strategies are developed to provide satisfactory worship environments in the 21st Century for a growing number of potential worshippers in this older adult group

Short-Term H-alpha Variability in M Dwarfs

We spectroscopically study the variability of H-alpha emission in mid- to late-M dwarfs on timescales of ~0.1-1 hr as a proxy for magnetic variability. About 80% of our sample exhibits statistically significant variability on the full range of timescales probed by the observations, and with amplitude ratios in the range of ~1.2-4. No events with an order of magnitude increase in H-alpha luminosity were detected, indicating that their rate is < 0.05 /hr (95% confidence level). We find a clear increase in variability with later spectral type, despite an overall decrease in H-alpha "activity" (i.e., L_{H-alpha}/L_{bol}). For the ensemble of H-alpha variability events, we find a nearly order of magnitude increase in the number of events from timescales of about 10 to 30 min, followed by a roughly uniform distribution at longer durations. The event amplitudes follow an exponential distribution with a characteristic scale of Max(EW)/Min(EW)}-1 ~ 0.7. This distribution predicts a low rate of ~ 10^{-6} /hr for events with (Max(EW)/Min(EW) > 10, but serendipitous detections of such events in the past suggests that they represent a different distribution. Finally, we find a possible decline in the amplitude of events with durations of > 0.5 hr, which may point to a typical energy release in H-alpha events for each spectral type (E_{H-alpha} ~ L_{H-alpha} x t ~ const). Longer observations of individual active objects are required to further investigate this possibility. Similarly, a larger sample may shed light on whether H-alpha variability correlates with properties such as age or rotation velocity.Comment: Accepted for publication in Ap

The figure of the Devil: Demonic representation in Scottish literature, 1785-1999 with special reference to selected works by five major authors in the Scottish tradition: Burns, Hogg, Stevenson, Spark and Morgan

Abstract Not Provided