CT material decomposition with contrast agents: Single or multiple spectral photon-counting CT scans? A simulation study.

Purpose: With the widespread introduction of dual energy computed tomography (DECT), applications utilizing the spectral information to perform material decomposition became available. Among these, a popular application is to decompose contrast-enhanced CT images into virtual non-contrast (VNC) or virtual non-iodine images and into iodine maps. In 2021, photon-counting CT (PCCT) was introduced, which is another spectral CT modality.

Fluoromethyl Triflate and Fluoromethyl Fluorosulfonate: Easily Accessible and Powerful Fluoromethylation Reagents.

Fluoromethyl triflate (superfluoromethyl, SFM, FHCOSOCF) and fluoromethyl fluorosulfonate (magic fluoromethyl, MFM, FHCOSOF) are two easily synthesized, highly effective and non-ozone depleting fluoromethylation reagents. They are analogous to the well-known and widely used methylation reagents HCOSOCF and HCOSOF. Both SFM and MFM have been fully characterized by multinuclear NMR spectroscopy (H, C, O, F, S).

A geminal antimony(iii)/phosphorus(iii) frustrated Lewis pair.

The geminal Lewis pair (FC)SbCHP(Bu) (1) was prepared by reacting (FC)SbCl with LiCHP(Bu). Despite its extremely electronegative pentafluoroethyl substituents, the neutral 1 exhibits a relatively soft acidic antimony function according to the HSAB concept (hard-soft acid-base). These properties lead to a reversibility in the binding of CS to 1, as observed by VT-NMR spectroscopy, while no reaction with CO is observed.

-Phenylene-bridged phosphorus/silicon Lewis pairs.

A series of five -phenylene-bridged phosphorus-silicon Lewis pairs was synthesized, with phosphorus bearing isopropyl groups while the substituents at the silicon atom vary (-CH, -Cl, -F). Possible interactions between Lewis acid and base were investigated both experimentally (NMR, XRD) and theoretically to determine the influence of the different substituents. Calculated -interaction energies (OIEs) show a stabilizing interactions between the acidic and basic units which were also found for the - and -interaction energies (MIEs and PIEs, respectively), indicating stabilization resulting not from direct acid-base interaction but from electronic interactions through the ring.

Reactivity of Oxygen-Bridged Geminal Al/P and Si/P Frustrated Lewis Pairs towards Heterocumulenes.

The two oxygen-bridged geminal frustrated Lewis pairs (FLP) tBu P-O-AlBis (Bis=CH(SiMe ) ; 1) and tBu P-O-Si(C F ) (2) were reacted with the heterocumulenes PhNCO, PhOCN, PhNCS, CS and PhNSO as well as SO . With isocyanate and cyanate, both 1 and 2, form addition products under formation of five-membered rings. With CS , isothiocyanate and sulfinylaniline, only 1 forms stable adducts, whereas 2 shows reactivity towards sulfinylaniline, but the product decomposed after a few minutes.