Kalle Nättinen

Complexation behaviour of hexadentate ligands possessing N2O4 and N2O2S2 cores: differential reactivity towards Co(II), Ni(II) and Zn(II) salts and structures of the products

Reactions of divalent metal salts of Co, Ni and Zn with 1,2-di(salicylaldimino-o-phenylthio)ethane (H2L1) and 1,2-di(naphthaldimino-o-phenylthio)ethane (H2L2), having N2O2S2 cores, and 1,2-di(O-salicylaldimino-o-hydroxyphenyl)ethane (H2L3), having a N2O4 core, have been explored. Out of the three ligands and the nine products obtained from the corresponding reactions, two ligands and seven products were crystallographically characterized. However, all the ligands and the products were characterized by analytical and spectral methods. Reaction of H2L1 and H2L2 with Co(II) salts results in oxidative cleavage of the C–S bond to produce a Co(III) product bound to two dissimilar tridentate ligands formed as a result of the cleavage. The reaction of H2L1 and H2L2 with Co(III)acac in the presence of methanolic NaOH also shows cleavage of the C–S bond to give compounds similar to those obtained by reacting H2L1 and H2L2 with Co(II) salts in the absence of additional external base. However, the reaction of Co(II) salt with H2L3 did not lead to any C–O bond cleavage; rather it produced an octahedral Co(II) complex of the hexadentate H2L3. Reactions of all these three ligands with Ni(II) salt resulted in octahedral complexes of the corresponding hexadentate ligands. In the case of Zn(II), while H2L3 with a N2O4 core resulted in an octahedral complex, H2L1 and H2L2, both with a N2O2S2 core, produced pseudo-octahedral complexes whose Zn–S bond lengths are rather long. The conformations of both the 5-membered and 6-membered chelate rings formed in the products were evaluated. The extent of distortion exhibited in the geometry of these octahedral complexes was computed and appropriately compared.

Reaction of complex ligands: Part 95. Chromium tricarbonyl complexes of polysubstituted naphthohydroquinones: regioselective synthesis via [3+2+1]-benzannulation and haptotropic rearrangement

Abstract A series of polysubstituted naphthohydroquinoid tricarbonyl chromium complexes were prepared by chromium mediated [3+2+1]-benzannulation of Fischer-type carbene complexes with alkynes. The kinetics and the thermodynamic data of the η 6 -η 6 -haptotropic rearrangements were investigated by in-situ NMR spectroscopy. The free activation energies Δ G # range from 23 to 26 kcal mol −1 and only slightly depend on the bulk and the donor/acceptor properties of the substituents. Equilibrium of metal migration was observed for naphthohydroquinone complexes bearing methoxy substituents at the non-hyroquinoid ring (ring A). In complexes bearing methyl groups or only hydrogen substituents at ring A the haptotropic rearrangement is irreversible. An NMR study suggests that the rearrangements of menthyloxy substituted tricarbonyl chromium complexes in hexafluorobenzene occurs intramolecularly. The two diastereomers of complex 19 show different rate constants for the metal shift which is the first example of kinetic data differing for the rearrangement of a ML n -fragment in two diastereomeric compounds.

Chloride–hydrogen interactions of picolinic, nicotinic and isonicotinic acid chloride hydrochlorides in the crystalline state

The crystal structures of the three isomers of the chemically labile pyridinecarboxylic acid chloride hydrochlorides were analyzed in order to study the weak interactions of the chloride anion with hydrogens. The chloride anions in the crystal structure of 1a have a slightly distorted square-planar interaction sphere with four hydrogens in the equatorial plane (plane of the molecule) with Cl−⋯H distances varying from 2.041(1) nA n[NH+⋯Cl−] to 2.933(1) nA n[CH⋯Cl−]. Nicotinic and isonicotinic acid chloride hydrochloride 1b and 1c show that chloride anion has a crucial role in the formation of bridged dimeric structures. The crystal lattices of 1b and 1c manifest similar herring-bone packing patterns. The chloride anions of 1b and 1c have slightly deformed planar interaction geometries to five and six hydrogens, respectively, with Cl−⋯H distances varying from 2.334(1) and 2.385(4) nA n[NH+⋯Cl−] to 2.781(3) and 2.833(6) nA n[CH⋯Cl−] in 1b and 1c, respectively. The difference in the packing of the isomers was attributed to Cl−⋯C contacts in 1a and on the other hand to end-to-end intermolecular interactions of the dimers of 1b and 1c, which could not exist with herring-bone packing of 1a. The moisture sensitive crystals of 1a, 1b, and 1c were obtained by sublimation of the compounds by heating in vacuo.

Bimetallic complexes from amphoteric Group 13/15 ligands: Syntheses and X-ray crystal structures

Bimetallic, pentel-bridged complexes of the type [(dmap)Me2M-E(SiMe3)2-M(CO)n] (M=Al, Ga; E=P, As, Sb; M=Cr, Fe, Ni; DMAP=4-(dimethylamino)pyridine) are formed by reactions of DMAP-coordinated monomeric Group 13/15 compounds [(dmap)Me2M-E(SiMe3)2] with the transition metal complexes [(Me3N)Cr(CO)5], [Fe3(CO)12], and [Ni(CO)4]. For the first time, this reaction offers a general pathway to compounds containing a Group 13 metal and a transition metal bridged by a pentel atom. Complexes prepared in this way were characterized by IR and multinuclear NMR spectroscopy and by single-crystal X-ray structure analysis. Their electronic and structural properties are discussed in detail. The Group 13/15 ligands are very weak acceptors, which is likely to be due to the electropositive Group 13 metal, and the complexes feature comparatively long pentel-transition metal bonds. In addition, the synthesis and structural characterization of the parent DMAP-coordinated gallanes [(dmap)Me2Ga-E(SiMe3)2] (E=P, As) are reported.

Synthesis, thermal properties and X-ray structural study of weak C–H⋯OC hydrogen bonding in aliphatic polyester dendrimers

Dendritic polyester compounds based on polyol with three, four and six reactive hydroxy groups as a molecular core, chloroacetyl chloride (or bromoacetyl bromide) and sodium metal enolate were prepared by a simple two-step synthetic procedure. The compounds were characterised by using the NMR and MS techniques, and the thermal properties were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The structures of the crystalline compounds were determined by X-ray single crystal diffraction. Detailed analysis of the structures showed that the self-complementarity of the molecules together with a multitude of weak C–H⋯OC hydrogen bonding results in crystalline dodecamethyl and dodecaethyl esters 9a and 9b, whereas slight modification in the structure of nonaethyl ester 8 renders it viscous oil.

Unusual interaction extended between the pyranose ring oxygen and Zn(II) center in the complexes derived from 4,6-O-butylidene/ethylidene-N-(α-hydroxynaphthylidene/o-hydroxybenzylidene)-β-d-glucopyranosylamine: Evidence for a pseudo-bicapped tetrahedral complex of Zn(II) based on the crystal structure

Abstract The Zn(II) complexes of 4,6-O-butylidene/ethylidene-N-(α-hydroxynaphthylidene/o-hydroxybenzylidene)-β- d -glucopyranosylamine have been synthesized and characterized using spectral and analytical methods and structure for one of the products was established. The geometry of the complexes vary from unusual distorted trigonal bipyramidal to pseudo-bicapped tetrahedron depending upon the extent of binding of pyranose ring oxygens to the Zn(II) ion, as evidenced from crystal structures. Such interaction is also reflected on the optical rotation and CD spectral properties of these complexes in solution.

Methyl 3',4',5'-trimethoxybiphenyl-4-carboxylate

In the title compound, C17H18O5, the dihedral angle between the benzene rings is 31.23u2005(16)°. In the crystal, the molecules are packed in an antiparallel fashion in layers along the a axis. In each layer, very weak C—H⋯O hydrogen bonds occur between the methoxy and methyl ester groups. Weak C—H⋯π interactions between the 4′- and 5′-methoxy groups and neighbouring benzene rings [methoxy-C–ring centroid distances = 4.075 and 3.486u2005Å, respectively] connect the layers.

Calcium dicaesium silver thio­cyanate dihydrate

The title compound, CaCs2[Ag2(SCN)6]*2H2O, forms a continuous structure where the Ag atoms form chains with S atoms in the c-axis direction. The chains are bonded together through Cs and Ca atoms. The crystal water of the structure is bonded to the Ca atoms, which lie on centers of symmetry.

4,4′-[Thio­phene-2,5-diylbis(ethyne-2,1-di­yl)]dibenzonitrile

In the solid state, the title compound, C22H10N2S, forms centrosymmetric dimers by pairs of non-classical C—H⋯S hydrogen bonds linking approximately coplanar molecules. The benzene ring involved in this interaction makes a dihedral angle of only 7.21u2005(16)° with the thiophene ring, while the other benzene ring is twisted somewhat out of the plane, with a dihedral angle of 39.58u2005(9)°. The hydrogen-bonded dimers stack on top of each other with an interplanar spacing of 3.44u2005Å. C—H⋯N hydrogen bonds link together stacks that run in approximately perpendicular directions. Each molecule thus interacts with 12 adjacent molecules, five of them approaching closer than the sum of the van der Waals radii for the relevant atoms. Optimization of the inter-stack contacts contributes to the non-planarity of the molecule.

cis-Diazido­[bis­(diphenyl­phosphino)methane-κ2P,P′]ruthenium(II) dichloro­methane 0.42-solvate

The title compound, [Ru(N3)2(C25H22P2)2] or cis-[Ru(N3)2(dppm)2] [dppm is bisxad(diphenylxadphosphino)methane], was obtained unexpectedly from our attempts to prepare new ruthenium molxadecular wires using organic bridging ligands. Both the azido ligands show a triple bond adjacent to the metal.