0000000000182688
AUTHOR
Jani Moilanen
Role of Weak Hydrogen Bonds and Halogen Bonds in 5-Halo-1,3-dimethyluracils and Their Cocrystals : A Combined Experimental and Computational Study
Seven single crystals containing either N,N-dimethyluracil (DMHU) or one of its 5-halogenated derivatives (DMXU; X = F, Cl, Br, I) were prepared using N,N-dimethylformamide as the crystallization solvent. Single crystal X-ray diffraction and quantum chemical calculations carried out at the spin component scaled local MP2 level of theory were then used to study the intramolecular halogen and nonconventional hydrogen bonds present in the structures. The results were compared to and contrasted with the previously reported data for uracil and its halogenated derivatives. In particular, the intermolecular interactions in DMIU were compared to the halogen and hydrogen bonds in 5-iodouracil that, …
α-Aminophosphonates, Phosphinates, and Phosphine Oxides as Extraction and Precipitation Agents for Rare Earth Metals, Thorium, and Uranium : A Review
α-Aminophosphonates, -phosphinates, and -phosphine oxides are a group of organophosphorus compounds that were investigated as extraction agents for rare earth (RE) metals and actinoids for the first time in the 1960s. However, more systematic investigations of their extraction properties towards REs and actinoids were not started until the 2010s. Indeed, recent studies have shown that these α-amino-functionalized compounds can outperform the commercial organophosphorus extraction agents in RE separations. They have also proven to be very efficient extraction and precipitation agents for recovering Th and U from RE concentrates. These actinoids coexist with REs in some of the commercially im…
Simultaneous Endo- and Exo-Complex Formation of Pyridine[4]arene Dimer with Neutral and Anionic Guests
The formation of complexes between hexafluorophosphate (PF6−) and tetraisobutyloctahydroxypyridine[4]arene has been thoroughly studied in the gas phase (ESI‐QTOF‐MS, IM‐MS, DFT calculations), in the solid state (X‐ray crystallography), and in chloroform solution (1H, 19F, and DOSY NMR spectroscopy). In all states of matter, simultaneous endo complexation of solvent molecules and exo complexation of a PF6− anion within a pyridine[4]arene dimer was observed. While similar ternary complexes are often observed in the solid state, this is a unique example of such behavior in the gas phase. peerReviewed
Reaction Mechanism of an Intramolecular Oxime Transfer Reaction: A Computational Study
Density functional theory (PBE0/def2-TZVPP) calculations in conjunction with a polarizable continuum model were used to assess the mechanism of the intramolecular oxime transfer reaction that leads to the formation of isoxazolines. Different diastereomers of the intermediates as well as different oximes (formaldehyde and acetone oxime) were considered. The computed reaction profile predicts the water-addition and -expulsion steps as the highest barriers along the pathway, a conclusion that is in line with the experimental evidence obtained previously for these reactions. peerReviewed
Triplet-State Position and Crystal-Field Tuning in Opto‐Magnetic Lanthanide Complexes : Two Sides of the Same Coin
Lanthanide complex‐based luminescence thermometry and single‐molecule magnetism are two effervescent research fields, owing to the great promise they hold from an application standpoint. The high thermal sensitivity achievable, their contactless nature, along with sub‐micrometric spatial resolution make these luminescent thermometers appealing for accurate temperature probing in miniaturized electronics. To that end, single‐molecule magnets (SMMs) are expected to revolutionize the field of spintronics, thanks to the improvements made in terms of their working temperature – now surpassing that of liquid nitrogen – and manipulation of their spin state. Hence, the combination of such opto‐magn…
Paramagnetic aluminium β-diketiminate
The β-diketiminate ligand framework is shown to undergo reduction to form a neutral main group radical stabilized by spiroconjugation of the unpaired electron over the group 13 element centre. The synthesized paramagnetic complex was characterized by EPR spectroscopy and computational chemistry. peerReviewed
Weak Interactions between Trivalent Pnictogen Centers: Computational Analysis of Bonding in Dimers X3E···EX3 (E = Pnictogen, X = Halogen)
The nature of weak interactions in dimers X3E···EX3 (E = N−Bi, X = F−I) was investigated by wave function and density functional theory (DFT)-based methods. Out of the 20 systems studied, 10 are found to be bound at the CP-MP2 and LMP2 levels of theory. Detailed partition of the interaction energy into different components revealed that dispersion is the primary force holding the dimers together but there also exists an important ionic component whose contribution increases with increasing halogen size. As expected, standard density functionals fail to describe bonding in the studied systems. However, the performance of DFT methods can be easily improved via empirical dispersion correction …
Counterintuitive Mechanisms of the Addition of Hydrogen and Simple Olefins to Heavy Group 13 Alkene Analogues
The mechanism of the reaction of olefins and hydrogen with dimetallenes ArMMAr (Ar = aromatic group; M = Al or Ga) was studied by density functional theory calculations and experimental methods. The digallenes, for which the most experimental data are available, are extensively dissociated to gallanediyl monomers, :GaAr, in hydrocarbon solution, but the calculations and experimental data showed also that they react with simple olefins, such as ethylene, as intact ArGaGaAr dimers via stepwise [2 + 2 + 2] cycloadditions due to their considerably lower activation barriers vis-à-vis the gallanediyl monomers, :GaAr. This pathway was preferred over the [2 + 2] cycloaddition of olefin to monomeric…
Theoretical and experimental studies of some main group compounds : from closed shell interactions to singlet diradicals and stable radicals
Acquiring knowledge of different interactions within and between molecules is a fascinating undertaking as it not only deepens our understanding of chemical bonding but also offers insight into electronic structures, molecular properties and the connections between these two. This dissertation combines together three main group chemistry related topics within the aforementioned theme. Research presented in the first third of this dissertation describes wave function and density functional theory studies of weak inter- and intramolecular interactions in pnictogen-based dimers X3Pn···PnX3 (Pn = N-Bi; X = F-I), dithallenes RTlTlR (R = H, Me, tBu, Ph) and octachalcogen dications Ch82+ (Ch = S, …
Strong Exchange Coupling in a Trimetallic Radical-Bridged Cobalt(II)-Hexaazatrinaphthylene Complex
: Reducing hexaazatrinaphthylene (HAN) with potassium in the presence of 18-c-6 produces [{K(18-c-6)}HAN], which contains the S = 1/2 radical [HAN]C ¢ . The [HAN]C ¢ radical can be transferred to the cobalt(II) amide [Co{N- (SiMe3 )2 }2 ], forming [K(18-c-6)][(HAN){Co(N’’)2 }3 ]; magnetic measurements on this compound reveal an S = 4 spin system with strong cobalt–ligand antiferromagnetic exchange and J ¢290 cm¢1 (¢2 J formalism). In contrast, the CoII centres in the unreduced analogue [(HAN){Co(N’’)2}3] are weakly coupled (J ¢4.4 cm¢1 ). The finding that [HAN]C ¢ can be synthesized as a stable salt and transferred to cobalt introduces potential new routes to magnetic materials based on str…
The Nature of Transannular Interactions in E4N4 and E82+ (E = S, Se)
The electronic structures of tetrachalcogen tetranitrides, E4N4, and octachalcogen dications, E82+, and the nature of their intramolecular E···E interactions (E = S, Se) was studied with high-level theoretical methods. The results reveal that the singlet ground states of both systems have a surprisingly large correlation contribution which functions to weaken and therefore lengthen the cross-ring E–E bond. The observed correlation effects are primarily static in E4N4, whereas in E82+ the dynamic part largely governs the total correlation contribution. The presented description of bonding is the first that gives an all-inclusive picture of the origin of cross-ring interactions in E4N4 and E8…
Nature of Bonding in Group 13 Dimetallenes: a Delicate Balance between Singlet Diradical Character and Closed Shell Interactions
The nature of metal−metal bonding in group 13 dimetallenes REER (E = Al, Ga, In, Tl; R = H, Me, tBu, Ph) was investigated by use of quantum chemical methods that include HF, second order Møller−Plesset perturbation theory (MP2), coupled cluster (CCSD(T)), complete active space with (CASPT2) and without (CAS) second order perturbation theory, and two density functionals, namely, B3LYP and M06-2X. The results show that the metal−metal interaction in group 13 dimetallenes stems almost exclusively from static and dynamic electron correlation effects: both dialuminenes and digallenes have an important singlet diradical component in their wave function, whereas the bonding in the heavier diindene…
More electron rich than cyclopentadienyl: 1,2-diaza-3,5-diborolyl as a ligand in ferrocene and ruthenocene analogs
Ruthenium and iron sandwich complexes incorporating cyclopentadienyl analogs with CB2N2− skeletons were characterized. Electrochemical measurements supported by computational studies revealed that in combination with larger metal ions such as Ru the CB2N2− ligand can be more electron-rich than its organic counterpart. peerReviewed
CCDC 1904524: Experimental Crystal Structure Determination
Related Article: Diogo Galico, Riccardo Marin, Gabriel Brunet, Dylan Errulat, Eva Hemmer, Fernando Sigoli, Jani Moilanen, Muralee Murugesu|2019|Chem.-Eur.J.|25|14625|doi:10.1002/chem.201902837
CCDC 986380: Experimental Crystal Structure Determination
Related Article: Luke J. Murphy, Katherine N. Robertson, Scott G. Harroun, Christa L. Brosseau, Ulrike Werner-Zwanziger, Jani Moilanen, Heikki M. Tuononen, Jason A.C. Clyburne|2014|Science|344|75|doi:10.1126/science.1250808
CCDC 2002644: Experimental Crystal Structure Determination
Related Article: Esko Saloj��rvi, Anssi Peuronen, Jani Moilanen, Hannu Huhtinen, Johan Lind��n, Akseli Mansikkam��ki, Mika Lastusaari, Ari Lehtonen|2021|Dalton Trans.|50|15831|doi:10.1039/D1DT01607E
CCDC 2002643: Experimental Crystal Structure Determination
Related Article: Esko Saloj��rvi, Anssi Peuronen, Jani Moilanen, Hannu Huhtinen, Johan Lind��n, Akseli Mansikkam��ki, Mika Lastusaari, Ari Lehtonen|2021|Dalton Trans.|50|15831|doi:10.1039/D1DT01607E
CCDC 868803: Experimental Crystal Structure Determination
Related Article: Jani Moilanen, Javier Borau-Garcia, Roland Roesler and Heikki M. Tuononen|2012|Chem.Commun.|48|8949|doi:10.1039/C2CC34051H
CCDC 2062703: Experimental Crystal Structure Determination
Related Article: Esko Saloj��rvi, Anssi Peuronen, Jani Moilanen, Hannu Huhtinen, Johan Lind��n, Akseli Mansikkam��ki, Mika Lastusaari, Ari Lehtonen|2021|Dalton Trans.|50|15831|doi:10.1039/D1DT01607E