An official website of the United States government
Abstract In this work, we describe the easy synthesis of mercury complexes with the 1,5,9‐trimesityldipyrromethene (MesDPM) ligand. The compounds were characterized using standard analytic methods such as NMR, IR, as well as UV/Vis spectroscopy. The molecular structures in solid state were determined by single‐crystal X‐ray diffraction analysis (SC‐XRD) experiments. In addition, the199Hg NMR chemical shifts were determined by measurements and quantum chemical calculations.
more »
« less
NMR-guided refinement of crystal structures using 15 N chemical shift tensors
An NMR-guided procedure for refining crystal structures has recently been introduced and shown to produce unusually high resolution structures.
more »
« less
- Award ID(s):
- 2100582
- PAR ID:
- 10520341
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- CrystEngComm
- Volume:
- 26
- Issue:
- 25
- ISSN:
- 1466-8033
- Page Range / eLocation ID:
- 3289 to 3302
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
The gas-phase structures of zinc and cadmium complexes of lysine (Lys) are investigated via a combination of infrared multiple photon dissociation action spectroscopy and ab initio quantum chemical calculations. In order to unambiguously identify the experimentally observed species, [Zn(Lys−H)]+and CdCl+(Lys), the action spectra were compared to linear absorption spectra calculated at the B3LYP level of theory, using 6-311+G(d,p) and def2-TVZP basis sets for the zinc and cadmium systems, respectively. Single point energies were also calculated at the B3LYP, B3P86, MP2, and B3LYP-GD3BJ (accounting for empirical dispersion) levels of theory using larger basis sets. Identification of the experimentally formed isomers is possible through good agreement between infrared multiple photon dissociation action spectra and the theoretically predicted spectra. The [Zn(Lys−H)]+complex adopts a tridentate orientation involving the amino acid backbone amine and deprotonated carboxylic acid groups as well as the side-chain amine group, [Nα,CO−,Nɛ]. The CdCl+(Lys) complex similarly adopts a tridentate chelation involving the amino acid backbone amine and carbonyl groups, as well as the side-chain amine group, [Nα,CO,Nɛ]. In both cases, the identified complexes are the lowest energy gas-phase structures at all levels of theory.more » « less
-
Abstract Multiplex imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) provides exciting opportunities for more precise understanding of biological processes and more accurate diagnosis of diseases by enabling real‐time acquisition of images with improved contrast and spatial resolution in deeper tissues. Today, the number of imaging agents suitable for this modality remains very scarce. In this work, we have synthesized and fully characterized, including theoretical calculations, a series of dimeric LnIII/GaIIImetallacrowns bearing RuIIpolypyridyl complexes,LnRu‐3(Ln=YIII, YbIII, NdIII, ErIII). Relaxed structures ofYRu‐3in the ground and the excited electronic states have been calculated using dispersion‐corrected density functional theory methods. Detailed photophysical studies ofLnRu‐3have demonstrated that characteristic emission signals of YbIII, NdIIIand ErIIIin the NIR‐II range can be sensitized upon excitation in the visible range through RuII‐centered metal‐to‐ligand charge transfer (MLCT) states. We have also showed that these NIR‐II signals are unambiguously detected in an imaging experiment using capillaries and biological tissue‐mimicking phantoms. This work opens unprecedented perspectives for NIR‐II multiplex imaging using LnIII‐based molecular compounds.more » « less
-
The fact that every compact oriented 4-manifold admits spinc structures was proved long ago by Hirzebruch and Hopf. However, the usual proof is neither direct nor transparent. This article gives a new proof using twistor spaces that is simpler and more geometric. After using these ideas to clarify various aspects of four-dimensional geometry, we then explain how related ideas can be used to understand both spin and spinc structures in any dimension.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d4ce00237g
