The time is ripe: A general theoretical framework based on force-transformed potential energy surfaces rationalizes the intriguing results of recent experiments in emerging field covalent mechanochemistry.

We present a theoretical study on the role played by aliphatic polymer chains in transduction of external forces to mechanophores being at heart force spectroscopy and sonication experiments. Upon introducing rigorous approach rooted catastrophe theory, we demonstrate that rupture cis 1,2-disubstituted benzocyclobutene features remarkable dependence, including odd-even effects, length attached chains. This unexpected finding is furthermore rationalized establishing correlation between local...

Quantum mechanical and quantum mechanical/molecular calculations in conjunction with continuum solvation models have been used to analyze CH-pi interactions model systems of aryl- alkyl-aromatic interactions, as well a folding system designed study those interactions. High level reproduced accurately the interaction both alkyl- aryl-based systems. Dispersion effects dominate interaction, but electrostatics term is also relevant for aryl Theoretical were examine influence determining...

The X-ray crystal structures, magnetic susceptibilities from 2 to 300 K, and theoretical analyses of the magnetism for 1D trinuclear azido Cu(II) carboxylate complexes [Cu(1.5)(hnta)(N(3))(2)(H(2)O)](n) (1) [Cu(3)(hnta)(4)(N(3))(2)(H(2)O)(3)] (2), respectively, where hnta is 6-hydroxynicotinate, are described. Although both exhibit strong ferromagnetic coupling, discrete complex exhibits long-range ordering, while very similar system 1 does not. Density functional calculations provided...

A theoretical approach is proposed to accurately calculate the LS–HS energy gap of SCO complexes in solid state.

Iron(II) complexes of the [Fe(II)(1-bpp2)](2+) type (1-bpp = 2,6-di(pyrazol-1-yl)pyridine) have been intensively investigated in context crystal engineering switchable materials because their spin-crossover (SCO) properties dramatically depend on counterions. Here, by means DFT + U calculations at molecular and solid state levels we provide a rationale for different SCO behaviour BF4(-) ClO4(-) salts parent complex; former features Fe(II) with regular coordination geometry undergoes spin...

The thermal spin crossover (SCO) phenomenon refers to an entropy-driven transition in some materials based on d6-d9 metal complexes. While its molecular origin is well known, intricate SCO behaviours are increasingly common, which the occurs concomitantly e.g. phase transformations, solvent absorption/desorption, or order-disorder processes. computational modelling of such cases challenging, as it requires accurate state energies solid state. Density Functional Theory (DFT) best framework,...

Organic radicals have been consistently regarded as promising building blocks for the next generation of applied materials. Here, we discuss insight gained from computational modelling into their magnetism and phase transitions.

The cluster [Ni6(H2L)2(HL1)2(N3)8]·2C2H5OH·2H2O [1·2C2H5OH·2H2O], featuring four fused defective cubanes, has been obtained via azido-bridge-driven dimerization of two phenolate-centered trinuclear Ni3 fragments.

The chemical reactions of a family tetradentate pyridyl/imine ligands, L1, L2, and L3 (L1=[ N, N'-bis(2-pyridinylmethylene)]ethane-1,2-diamine; L2=[ N'-bis(pyridin-2-yl)benzylidene]ethane-1,2-diamine; L3=[ N'-bis(2-pyridinylmethylene)]propane-1,3-diamine), with Ni (II) in the presence various pseudohalides (N3(-), SCN(-), NCO(-)) have served to prepare six different complexes, [Ni 2(L1)2(N3)2](ClO4)2.H2O (1), 2(L2)2(N3)2](ClO4)2 (2), [Ni2(L2)2(NCS)4] (3), [Ni2(L2)2(NCO) 2](ClO4)2 (4),...

Abstract Die Zeit ist reif : Eine allgemeingültige theoretische Beschreibung auf der Grundlage von krafttransformierten Potentialflächen erklärt die Resultate aktueller Experimente im aufstrebenden Feld kovalenten Mechanochemie. magnified image

The role played by polyethylene-like oligomers in transducing external tensile forces to benzocyclobutene mechanophores is investigated computationally. It demonstrated that the oligomer chains do indeed exert a notable influence on force dependence of activation energies both conrotatory and disrotatory ring-opening processes cis 1,2-disubstituted benzocyclobutene. This opens doorway tuning properties mechanoresponsive materials not only changing mechanophore itself, but also tailoring...

Based on a combined theoretical–experimental study, we propose that substituted m-phenylene ligands (m-N-Φ-N) can act as tuneable strong ferromagnetic couplers connecting CuII ions; new complex presenting bridge with J close to +15 cm−1 has been suggested and synthesized.

The mechanism of the magnetic interaction in pyridyl-verdazyl radical:hydroquinone (pyvd:hq) molecular co-crystal is important as it has been suggested to originate by a unique "mediated through-space" interaction. This was proposed magnetically connect two nonadjacent radicals within pi stack, where adjacent pile up head-over-tail orientation. connection made through third radical sitting between previous mediated radicals. Given relevance this proposal, we decided reinvestigate properties...

Forcing the issue: By exploring force-transformed potential energy surfaces of both cis and trans 1,2-disubstituted benzocyclobutene, we unravel mechanism force-induced ring-opening. The expected conrotatory process reactant leading to E,Z product is only observed at very small forces, whereas disrotatory ring-opening yields E,E dienes larger which shown be a concerted process.

Complete active space self‐consistent field theory (CASSCF) calculations and subsequent second‐order perturbation treatment (CASPT2) are discussed in the evaluation of spin‐states energy difference (Δ H elec ) a series seven spin crossover (SCO) compounds. The reference values have been extracted from combination experimental measurements DFT + U calculations, as recent article (Vela et al., Phys Chem 2015, 17, 16306). It is definitely proven that critical IPEA parameter used CASPT2 Δ , key...

The magnetic properties of molecule-based magnets are commonly rationalized by considering only a single nuclear configuration the system under study (usually an X-ray crystal structure). Here, means computational study, we compare results obtained using such static approach with those explicitly accounting for thermal fluctuations, and uncover serious limitations perspective when dealing crystals whose radicals undergo wide-amplitude motions. As proof concept, these illustrated magnetically...

The spin transition of Fe(II) complexes is the subject intensive synthetic and computational efforts. In this manuscript, we analyze crossover (SCO) [Fe(E-dpsp)2]2+ (1), which features a depending on cocrystallizing solvent molecules. Whereas use acetone results in hysteretic at ∼170 K, propylene carbonate (PC) permanent diamagnetic signal up to 300 K. By means DFT+U+D2 calculations solid state material, unravel reasons for such different behavior. Our allow us ascribe relatively low...

Abstract Controlling the electronic states of molecules is a fundamental challenge for future sub-nanoscale device technologies. π-conjugated bi-radicals are very attractive systems in this respect as they possess two energetically close, but optically and magnetically distinct, states: open-shell antiferromagnetic/paramagnetic closed-shell quinoidal diamagnetic states. While it has been shown that possible to statically induce one ground state or other by chemical design, external dynamical...