Magnetically induced ring currents in metallocenothiaporphyrins

The magnetically induced current-density susceptibility tensor (CDT) of the lowest singlet and triplet states of the metallocenothiaporphyrins, where the metal is V, Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru, or Rh, have been studied with the gauge-including magnetically induced currents (GIMIC) method. The compounds containing V, Mn, Co, Tc or Rh were studied as cations because the neutral molecules have an odd number of electrons. The calculations show that the aromatic nature of most of the studied molecules follows the Huckel and Baird rules of aromaticity. CDT calculations on the high-spin states of the neutral metallocenothiaporphyrins with V, Mn, Co, Tc or Rh also shows that these molecules follow a unified extended Huckel and Baird aromaticity orbital-count rule stating that molecules with an odd number of occupied conjugated valence orbitals are aromatic, whereas molecules with an even number of occupied conjugated orbitals are antiaromatic.Peer reviewe

Metal- and Ligand-Supported Reduction of the {Fe₂S₂} Cluster as a Path to Formation of Molecular Group 13 Element Complexes {Fe₂S₂M} (M = Al, Ga)

The first examples of molecular cluster complexes with the Fe₂S₂(CO)₆ moiety covalently bound to the group 13 elements Al and Ga have been synthesized and characterized. The complexes [(Cp*M)­Fe₂(μ₃-S)₂(CO)₆] with M = Al (<b>1</b>), Ga (<b>2</b>) have been synthesized by the reduction of [Fe₂S₂(CO)₆] by the corresponding M­(I) complexes [AlCp*]₄ and [GaCp]. Analogously, upon reduction of [Fe₂S₂(CO)₆] by a Ga­(II) complex, [(dpp-Bian)­Ga]₂ (dpp-Bian = 1,2-bis­{(2,6-diisopropylphenyl)­imino}­acenaphthene), the compound [((dpp-Bian)­Ga)­Fe₂(μ₃-S)₂(CO)₆] (<b>3</b>) is formed. The M atoms in <b>1</b> and <b>2</b> are coordinated by the two S atoms; thus, the fragment Fe₂S₂(CO)₆ is considered to be dianionic. The Cp* moiety is bound differently to the Al (η⁵) and Ga (η²) atoms, which can be rationalized on the basis of DFT calculations showing different orbital structures for the analogous compounds. In compound <b>3</b> the Ga atom is coordinated by the two S atoms as well; therefore, the fragment Fe₂S₂(CO)₆ is considered to be dianionic, while the Bian ligand is radical anionic, as confirmed by the structure, EPR spectra, and DFT. The redox-active Bian ligand thus takes part in the reduction of the Fe₂S₂ cluster and changes its formal charge (−2 → −1), along with the Ga center (+2 → +3). Analogously to <b>3</b>, the Al complex [((dpp-Bian)­Al)­Fe₂(μ₃-S)₂(CO)₆] (<b>4</b>) is formed in solution and detected by EPR, but it is not stable enough to be crystallized. In contrast to the case for <b>1</b> and <b>2</b>, the calculated molecular and electronic structures of <b>3</b> and <b>4</b> are similar

Ligand-Induced Intramolecular Redox Diversity in Titanium Complexes with Acenaphthene-1,2-diimine

A series of the chlorido and alkoxychlorido titanium complexes of the general formula (dpp-Bian)Ti(OiPr)nCl3–n, where dpp-Bian = 1,2-bis[(2,6-iPr2C6H3)imino]acenaphthene n = 0 (2), 1 (3), 2 (4), as well as (dpp-Bian)Ti(OiPr)2 (5) and (dpp-Bian)Ti(OiPr)Cl3 (3-Cl), were isolated and characterized using single-crystal X-ray diffraction analysis and spectroscopic studies combined with density functional theory (DFT) calculations. In the solid state, compounds 2–4 reveal a square–pyramidal geometry at the metal center supported with monoanionic dpp-Bian, whereas 3-Cl with a neutral diimine ligand and 5 bearing a dianionic enebisamide dpp-Bian show, respectively, an octahedral and tetrahedral coordination surrounding the metal ion. Paramagnetic complexes 2–4 exhibit electron paramagnetic resonance spectra in both toluene solution and solid state, confirming the transfer of spin density from the metal ion to the dpp-Bian ligand as the number of alkoxy groups increases. The increase in polarity of the Ti–N bonds in the row 2 3 4 contributes to enhanced stability of the metal complexes with respect to O-donor molecules. Thus, in tetrahydrofuran (THF), compounds 2 and 3 undergo reversible solvolysis, whereas complex 4 is stable. The charge and spin density distributions as well as molecular orbital energies in 2–4 were analyzed on the basis of DFT calculations which also provided information on the electronic transition energies, absorption band assignments, and thermodynamic parameters of the reactions between the complexes and THF

Intramolecularly group 15 stabilized aryltellurenyl halides and triflates

The preparation of a series of functionalized peri-substituted acenaphthyl compounds 6-Ph2E-Ace-5-Br (1, E = As; 2, E = Sb), 6-Ph2As-Ace-5-TeMes (3), 5-I-Ace-6-TeMes (4), 6-Ph2Sb-Ace-5-TeMes (5), (6-Ph2P-Ace-5)2Te (6), [6-R2E-Ace-5-Te]X (7, E = P, R = Ph, X = Cl; 8, E = P, R = i-Pr, X = Cl; 9, E = P, R = i-Pr, X = Br; 10, E = P, R = i-Pr, X = I; 11, E = P, R = i-Pr, X = ½ (TeI6); 12, E = P, R = i-Pr, X = I3; 13, E = P, R = Ph, X = O3SCF3; 14, E = As, R = Ph, X = O3SCF3; 15, E = Sb, R = Ph, X = O3SCF3) and [6-PhSb-Ace-5-TeMes]O3SCF3 (16) was reported (Ace = acenaphthyl). The synthesis of 7-15 was either achieved by salt metathesis reaction of 5-i-Pr2P-Ace-6-Li with TeCl2∙TMTU (8), TeBr2∙TMTU (9) and TeI4 (10 + 11) or by the aryl cleavage reaction of 6-R2E-Ace-5-TeMes (E = P, As, Sb; R = Ph, i-Pr) with HgCl2 (7), I2 (12) and HO3SCF3 (13-15). The reaction of 5 with triflic acid gave also rise to the formation of [6-PhSb-Ace-5-TeMes]O3SCF3 (16). All compounds have been characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Complementary DFT studies including relaxed potential energy scans (PES) and subsequent topological analysis of the resulting electron and pair densities according to the AIM and ELI-D partitioning schemes are performed for the aryltellurenyl chlorides [6-Ph2P-Ace-5-Te]Cl, [8-Me2N-Nap-1-Te]Cl and [8-Me2P-Nap-1-Te]Cl in the gas phase and in MeCN solution, whereby the Te-Cl distances were systematically varied. The same analyses were carried out for the fully optimized [6-R2E-Ace-5-Te]+ cations (E = P, As, Sb) and compared to those of the previously studied intermolecularly stabilized [R3ETeMes]+ cations (E = P, As, Sb).</p

Imaging for early differential diagnosis of parkinsonism

The Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged for financial support. The energy decomposition and deformation electron density analyses were carried out within the framework of the Project 14-13-00832 supported by the Russian Science Foundation.The preparation of a series of functionalized peri-substituted acenaphthyl compounds 6-Ph2E-Ace-5-Br (1, E = As; 2, E = Sb), 6-Ph2As-Ace-5-TeMes (3), 5-I-Ace-6-TeMes (4), 6-Ph2Sb-Ace-5-TeMes (5), (6-Ph2P-Ace-5)2Te (6), [6-R2E-Ace-5-Te]X (7, E = P, R = Ph, X = Cl; 8, E = P, R = i-Pr, X = Cl; 9, E = P, R = i-Pr, X = Br; 10, E = P, R = i-Pr, X = I; 11, E = P, R = i-Pr, X = ½ (TeI6); 12, E = P, R = i-Pr, X = I3; 13, E = P, R = Ph, X = O3SCF3; 14, E = As, R = Ph, X = O3SCF3; 15, E = Sb, R = Ph, X = O3SCF3) and [6-PhSb-Ace-5-TeMes]O3SCF3 (16) was reported (Ace = acenaphthyl). The synthesis of 7-15 was either achieved by salt metathesis reaction of 5-i-Pr2P-Ace-6-Li with TeCl2∙TMTU (8), TeBr2∙TMTU (9) and TeI4 (10 + 11) or by the aryl cleavage reaction of 6-R2E-Ace-5-TeMes (E = P, As, Sb; R = Ph, i-Pr) with HgCl2 (7), I2 (12) and HO3SCF3 (13-15). The reaction of 5 with triflic acid gave also rise to the formation of [6-PhSb-Ace-5-TeMes]O3SCF3 (16). All compounds have been characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Complementary DFT studies including relaxed potential energy scans (PES) and subsequent topological analysis of the resulting electron and pair densities according to the AIM and ELI-D partitioning schemes are performed for the aryltellurenyl chlorides [6-Ph2P-Ace-5-Te]Cl, [8-Me2N-Nap-1-Te]Cl and [8-Me2P-Nap-1-Te]Cl in the gas phase and in MeCN solution, whereby the Te-Cl distances were systematically varied. The same analyses were carried out for the fully optimized [6-R2E-Ace-5-Te]+ cations (E = P, As, Sb) and compared to those of the previously studied intermolecularly stabilized [R3ETeMes]+ cations (E = P, As, Sb).PostprintPeer reviewe

N,N′-Fused Bisphosphole: Heteroaromatic Molecule with Two-Coordinate and Formally Divalent Phosphorus. Synthesis, Electronic Structure, and Chemical Properties

The reduction of 6,12-dichloro-1,2,3,4,7,8,9,10-octahydro-6<i>H</i>,12<i>H</i>-[1,2,3]­benzodiazaphospholo­[2,1-<i>a</i>]­[1,2,3]­benzodiazaphosphole (<b>3</b>) by metallic magnesium in tetrahydrofuran (THF) affords the N,N′-fused bisphosphole <b>1</b> in 92% yield. The compound reveals a novel type of 10π-electron heteroaromatic system [NICS(0) = −11.4], containing a two-coordinate and formally divalent phosphorus atom. Compound <b>1</b> possesses a much higher coordination activity than many other diazaphospholes. This is caused by a novel type of complexation to a metal ion wherein the lone phosphorus pairs are not involved in metal coordination. Instead, the 10π-electron heteroaromatic system provides two electrons for P → M bond formation. Polarization of the ligand results in the formation of extended molecular associates or cluster compounds. Complexes of <b>1</b> with mercury dichloride [{(<b>1</b>)₃HgCl}₂(μ₆-Cl)]⁺Cl^– (<b>7</b>) and tin dichlorides [<b>1</b>·SnCl₂(PhMe solvate)] (<b>8a</b>) and [<b>1</b>·SnCl₂] (<b>8b</b>) are, in fact, supramolecular in nature, containing multiple intermolecular short contacts. Crystals of complex <b>8a</b> containing short Sn···Sn packing interactions were converted reversibly to metallic tin after workup with THF. The simple mixing of <b>1</b> and <b>3</b> (1:1) gave a P–P bridging dimeric species prone to easy dissociation. The addition of GeCl₂(diox) to the equimolar mixture of <b>1</b> and <b>3</b> shifted the equilibrium to the formation of a poorly soluble salt-like dimer <b>6</b>, which is, in fact, a stacked 18π-electron dication having a through-space delocalization of π electrons