Sławomir Szafert

TiIV and Mov complexes with diesters. The crystal structure of [o-C6H4(CO2CH2CH2Ph)2Cl4Ti], [C2O4(CH2CH2Ph)2Cl4Ti] and [o-C6H4(CO2Et)2Cl3MoO] · C6H6

The crystal structures of [o-C6H4(CO2CH2CH2Ph)2Cl4Ti] (I), in the presence of activators a good catalyst for olefin polymerization, [C2O4(CH2CH2Ph)2Cl4Ti] (II) and [o-C6H4(CO2Et)2Cl3MoO] (III), have been determined by X-ray diffraction methods and refined by a full-matrix least-squares technique to R = 0.036, 0.041 and 0.055 for 2775, 2437 and 2776 independent non-zero reflections for I, II and III, respectively. The crystals of I are triclinic, space group P1 with two molecules in a unit cell of dimensions a = 10.475(8), b = 10.078(9), c = 13.683(9) A, α = 88.75(7) β = 72.65(6) γ = 66.95(7)°. The crystals of II are monoclinic, space group P21/c, with four molecules in a cell with a = 10.045(8), b = 21.032(22), c = 13.193(9) A, β = 128.91(6)°. The titanium atoms in I and II are octahedrally coordinated by four chlorine and two carbonyl oxygen atoms of coordinated o-diester molecules in the cis position. The crystals of III are triclinic, space group P1, with two molecules in a unit cell of dimensions a = 9.722(12), b = 8.073(12), c = 15.683(21) A, α = 83.46(9), β = 75.81(9), γ = 67.74(9)°. Three Cl atoms, one oxo oxygen and two O atoms of the carbonyl groups form a distorted octahedron around the molybdenum atom. The chelate ligand atoms and the titanium atom in I or molybdenum atom in III form a seven-membered ring which is five-membered in II.

Reactions of TiCl4 with diesters. Crystal structures of [CH2(CO2Et)2Cl4Ti] and [C2H4(CO2CH2CH2OPh)2Cl4Ti]

Direct reactions of TiCl4 with diethyl malonate in n-hexane or with bis(2-phenoxoethyl) succinate in toluene yield the crystalline compounds [CH2(CO2Et)2Cl4Ti] (1) and [C2H4(CO2CH2CH2OPh)2Cl4Ti] (2), respectively. The crystal structures of both complexes have been determined by a single crystal X-ray diffraction study, and refined by full-matrix least-squares techniques to an R of 0.034 and 0.038 for 1575 and 1490 independent non-zero reflections for 1 and 2, respectively. Crystals of 1 are monoclinic, space group P21/c, Z = 4, a = 7.716(10), b = 18.21(2), c = 12.384(10) A, β = 127.29(8)°. Crystals of 2 are triclinic, space group P1, Z = 2, a = 8.680(12), b = 10. 178(11), c = 14.398(15) A, α = 78.45 (9), β = 74.16(9), γ = 88.45(9)°. The titanium atoms in 1 and 2 are octahedrally-coordinated by four chlorine atoms and two carbonyl oxygen atoms of coordinated diester molecules. The titanium atoms and the chelate ligand atoms form the six-membered ring in 1 and the seven-membered ring in 2.

A Versatile and Highly Efficient Method for 1‐Chlorination of Terminal and Trialkylsilyl‐Protected Alkynes

A highly efficient one-pot procedure for the preparation of 1-chloroalkynes and 1-chlorobutadiynes from terminal and trialkylsilyl-protected precursors is reported. This convenient reaction, proceeding under mild conditions, utilizes N-chlorosuccinimide as the chlorinating agent and tolerates a range of functional groups.

Direct synthesis of butadiynyl-substituted pyrroles under solvent- and transition metal-free conditions

The work describes a convenient and highly efficient C–H butadiynylation of substituted pyrroles with the use of 1-halobutadiynes. The method requires only a simple grinding of substrates in a mortar under mild, solvent- and transition metal-free conditions and constitutes the first example of pyrrole butadiynylation via cross-coupling reaction with the use of 1-halobutadiynes. The scope of this mechanochemical approach covers 4,5,6,7-tetrahydro-1H-indole, its N-substituted derivatives and 2-phenylpyrrole and on the other hand ester and phenyl end-capped 1-halobutadiynes including chlorides, bromides and iodides. Interestingly, the method has proven effective also for weak electron withdrawing aryl substituted 1-halobutadiynes what has not been yet achieved for 1-haloacetylenes. Such reactivity was unexpected in the view of the literature data and opened a gate to the plethora of substrates for organic synthesis including syntheses of pharmaceuticals. An X-ray analysis of two coupling products is also presented.

Novel organic–inorganic hybrids based on T8 and T10 silsesquioxanes: synthesis, cage-rearrangement and properties

In this paper, we present a simple approach for the synthesis of well-defined macromolecules based on precisely isolated amino- and amido-functionalized octa T8 and deca T10 silsesquioxanes (SQs). Here, we show that reorganization of the siloxane cage-like core (T8 → T10) can be easily performed, including isolation of intermediates, and cage rearrangement achieved by using Bronsted superacid, trifluoromethanesulfonic acid (CF3SO3H). Moreover, T10-like SQs can be obtained in a one-step reaction by alkoxysilane condensation in trifluoromethanesulfonic acid conditions. The resulting decamers of amine-SQ and an amido-functionalized derivative containing long alkyl chains are reported for the first time in the literature. The non-fluorinated amido derivatives due to their lamellar-like nature and specific packing can serve as transparent hydrophobic coatings in various industrial applications. The obtained compounds were fully characterized using FT-IR, UV-vis, multinuclear NMR (1H, 13C, 29Si), DOSY NMR, TG-DTA, DSC, HR-MS, TEM, EDS and elemental analysis.

Polynuclear aggregation of cobalt and manganese dichlorides. Synthesis, properties and structures of monomeric [CoCl2(tmen)], ionic [Co3(µ3-Cl)2(µ-Cl)3(tmen)3][BPh4], polymeric MnCl2·tmen and tetranuclear [Mn4-(µ-Cl)6Cl2(tmen)4](tmen = Me2NCH2CH2NMe2)

The complexes [CoCl2(tmen)]1, [Co3(µ3-Cl)2(µ-Cl)3(tmen)3][BPh4]·[CoCl2(tmen)]2, MnCl2·tmen 3 and [Mn4(µ-Cl)6Cl2(tmen)4]4(tmen = Me2NCH2CH2NMe2) have been synthesized and structurally characterized by X-ray diffraction. The crystals of 1 consist of the tetrahedral [CoCl2(tmen)] molecules. The structure of the co-crystallite 2 is composed of two independent species, ionic [Co3(µ3-Cl)2(µ-Cl)3(tmen)][BPh4] and molecular [CoCl2(tmen)]. In the first compound the trinuclear [Co3(µ3-Cl)2(µ-Cl)3(tmen)3]+ cations consist of triangulo-{Co3Cl3} units defined by three cobalt atoms with three bridging chloride atoms in the same plane. The remaining two µ3-chloride atoms are symmetrically placed above and below the molecular plane. The polymeric chain of compound 3 is formed by six-co-ordinate manganese(II) centres linked by double chloride bridges. Two nitrogen atoms from the co-ordinate tmen complete the octahedral co-ordination of the manganese. The crystals of compound 4 consist of tetranuclear molecules in which two internal six-co-ordinate and two peripheral five-co-ordinate Mn atoms are linked by double chloride bridges. The natures of the ligand and solvent as key factors promoting the particular aggregation of the cobalt and manganese dichlorides is discussed.

New intermediates for the synthesis of olefin polymerization catalysts: the complexes [M2(µ-Cl)2Cl4(thf)4](M = Ti or V, thf = tetrahydrofuran); crystal structures and properties

The dimeric titanium(III) and vanadium(III) complexes [M2(µ-Cl)2Cl4(thf)4](M = Ti 1 or V 2, thf = tetrahydrofuran) have been prepared by recrystallization of [MCl3(thf)3] from dichloromethane. In the dimers, composed of slightly distorted edge-sharing octahedra, the metal atoms separated by Ti ⋯ Ti and V ⋯ V distances of 3.711 (3) and 3.619(1)A, respectively, are surrounded by two terminal Cl atoms, two oxygen atoms of thf molecules and are linked by two bridging Cl atoms. The geometry around the titanium atoms differs from that around vanadium because the thf molecules and the terminal chlorine atoms are differently located with respect to the bridging chlorine atoms of the M2(µ-Cl)2 unit. High catalytic activity was found for ethylene polymerization by 1.

Synthesis and microstructural properties of the scaffold based on a 3-(trimethoxysilyl)propyl methacrylate–POSS hybrid towards potential tissue engineering applications

The aim of this work was to develop an efficient approach to prepare a macroporous scaffold for sophisticated bone replacement, avoiding a long-lasting and complex methodology. Such a scaffold based on the 3-(trimethoxysilyl)propyl methacrylate–POSS hybrid was synthesized via the reaction of 3-(trimethoxysilyl)propyl methacrylate and the trifluoromethanesulfonate–POSS salt. The results show that the chemical composition, structural dimensions, topography, and microstructural properties of the scaffold fulfill the potential requirements for hard-tissue engineering. The microstructural properties were evaluated with the use of X-ray microcomputed tomography (micro-CT) and nanoindentation tests. The former makes it possible to estimate the geometrical measures of the microstructure (porosity, thickness distribution, etc.), whereas the latter makes it possible to estimate the mechanical properties of the constituents of the material (hardness, stiffness modulus, creep, etc.). The aforementioned laboratory testing methods are modern techniques, currently being developed for materials science, making it possible to determine the microstructural/measures of the analyzed system.

Syntheses of new hexacoordinate germanium(IV) complexes. Crystal structures and properties of [GeCl4(TMEDA)] and [GeCl2(N3)2(TMEDA)]

The simple high-yield syntheses and some characterization of new hexacoordinate [GeCl4(TMEDA)] (1) and [GeCl2(N3)2(TMEDA)] (2) are reported. The crystal structures of neutral 1 and 2 are described. Some electronic, geometrical, and thermodynamic features of 1 and 2 were computationally investigated at the B3LYP density functional level of theory.

Synthesis and characterization of new di- and tetra-meric vanadium intermediates of olefin polymerization catalysts. Crystal structures of [V2(µ-Cl)2Cl4(MeCo2Et)4] and [{VOCl2[CH2(CO2Et)2]}4]·2CH2Cl2

The direct reaction of VCl3 and ethyl acetate yields [V2(µ-Cl)2Cl4(MeCO2Et)4]1. The compound [V2(µ-Cl)2Cl4{CH2(CO2Et)2}2]2 was obtained in dichloromethane via the substitution of MeCO2Et in 1 by ethyl malonate. During crystallization of 2, under the influence of dioxygen and moisture, the tetrameric compound [{VOCl2[CH2(CO2Et)2]}4]·2CH2Cl23 was formed. The crystal structures of 1 and 3 have been determined by single-crystal X-ray diffraction studies. The dimeric compound 1 exhibits six-co-ordinate VIII centres [separated by a V ⋯ V distance of 3.590(1)A] surrounded by two terminal Cl atoms, two carbonyl oxygen atoms of co-ordinated ethyl acetate molecules and linked by two bridging Cl atoms. In the tetrameric species 3, the four vanadium(IV) atoms have equivalent octahedral geometries, being bonded by two mutually cis chlorine atoms, two mutually cis oxygen atoms. High catalytic activity was found for 1, 2 and [V2(µ-Cl)2Cl4(thf)4](thf = tetrahydrofuran).