The one‐step syntheses, X‐ray structures, and spectroscopic characterization of synthetic iron clusters, bearing either inorganic sulfides or thiolate with interstitial carbide motifs, are reported. ...Treatment of iron carbide carbonyl clusters Fen(μn‐C)(CO)mx (n=5,6; m=15,16; x=0,−2) with electrophilic sulfur sources (S2Cl2, S8) results in the formation of several μ4‐S dimers of clusters, and moreover, iron‐sulfide‐(sulfocarbide) clusters. The core sulfocarbide unit {C−S}4− serves as a structural model for a proposed intermediate in the radical S‐adenosyl‐L‐methionine biogenesis of the M‐cluster. Furthermore, the electrophilic sulfur strategy has been extended to provide the first ever thiolato‐iron‐carbide complex: an analogous reaction with toluylsulfenyl chloride affords the cluster Fe5(μ5‐C)(SC7H7)(CO)13−. The strategy described herein provides a breakthrough towards developing syntheses of biomimetic iron‐sulfur‐carbide clusters like FeMoco.
At first glance, CO‐supported iron‐carbide clusters are an appealing synthetic starting point for modeling the carbide‐containing FeMoco cluster. However, these compounds have historically been uncontrollable towards traditional CO→S substitution methods. Demonstrated here is an approach utilizing unconventional electrophilic sulfur reagents to achieve carbide‐containing multi‐sulfide multi‐iron clusters.
Herein we report the synthesis, X-ray structure, and characterization of the title pentairon (molybdo)carbido cluster. The reaction of the pentairon (μ
-carbido) dianion Fe
(μ
-C)(μ
-CO)
(CO)
(1) ...with Mo(CO)
(chpt) (chpt = cycloheptatriene) forms the heterohexanuclear cluster K(benzo-18-crown-6)
Fe
Mo(μ
-C)(μ
-CO)
(CO)
(2). The dianion exhibits a Fe
Mo(μ
-C) core structure supported by three bridging (ν
= 1788 cm
) and terminal (ν
= 1943 cm
) CO ligands. Cluster 2 provides the selective reduction of diphenylacetylene to cis-diphenylethylene via a spectroscopically observed cluster-hydride intermediate (
H NMR: δ -26).
In C
plants, the enzymatic machinery underpinning photosynthesis can vary, with, for example, three distinct C
acid decarboxylases being used to release CO
in the vicinity of RuBisCO. For decades, ...these decarboxylases have been used to classify C
species into three biochemical sub-types. However, more recently, the notion that C
species mix and match C
acid decarboxylases has increased in popularity, and as a consequence, the validity of specific biochemical sub-types has been questioned. Using five species from the grass tribe Paniceae, we show that, although in some species transcripts and enzymes involved in multiple C
acid decarboxylases accumulate, in others, transcript abundance and enzyme activity is almost entirely from one decarboxylase. In addition, the development of a bundle sheath isolation procedure for a close C
species in the Paniceae enables the preliminary exploration of C
sub-type evolution.
The focus of this thesis is an examination of the theological significance of moments of metalepsis within biblical narrative. Metalepsis, as defined by narratologists, is the transgression of the ...normal boundaries between layers of a narrative. Close readings of Job 19:23, Mark 13:14, Luke 16:8 and moments within the Deuteronomic History illustrate the impact of such diegetic muddles, which are also identified in apocalyptic subsummation of the seer, shifts between first and third person narrative voice, and anomalous moments of narrative stage management. These biblical contaminations of narrative thresholds are highly comparable with instances of illusion in visual art, fourth wall breaks in theatre, appeals to the reader in novels and classical apostrophes. They confound the logical separation between spatiotemporal dimensions, lay bare the paradox inherent in representations of the past in the present, and demonstrate the willingness of biblical narrators to include themselves within the frame of their own stories. Hermeneutically, such instances function as a form of narratological self-disclosure and enfold the time of the telling of the story into the horizon of the text. They model and reveal a fundamental supposition pregnant within much biblical narrative – that the world revealed within the text is analogous to or contiguous with the world of the narrator and the reader. Thus, every timeframe conceivable to the narrator is subsumed into biblical representation of reality. Theologically, biblical metalepsis provokes consideration of providence and the meaning of history, of the presence of the divine in the process of reception and of the significance of the self. These themes emerge in the creedal claims of biblical narrators who include themselves within the frame of the text and also assert with assurance the promises of God. In these moments authoritative statements and confessions of the subjectivity of the narrating self are juxtaposed in a model of self-involvement that the reader is invited to reciprocate. The themes outlined above are explored in dialogue with a number of hermeneuticists and theologians including Paul Ricoeur, Søren Kierkegaard and Erich Auerbach, whose explorations of time and narrative, of contemporaneity with Christ and the tyranny of the biblical world view provide context, counterpoint and conceptual background to the notion of readerly self-involvement that is developed throughout this study.
A series of two-page advertisements have appeared in the September and November 2016 issues of the SAMJ, entitled ‘da Vinci Transoral Robotic Surgery (TORS) is a minimally invasive alternative to ...open surgery and full-dose chemoradiation therapy for diseases of the head and neck’. As these advertisements go beyond simply marketing surgical equipment, but seek to influence patients, referring doctors, oncologists and head and neck surgeons on how to treat cancers of the head and neck and sleep apnoea, we have taken the unusual step of writing to the editor of the SAMJ to correct some misconceptions in the advertisement.
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