Jilles J. H. Edema

CHEMICALLY MODIFIED FIELD-EFFECT TRANSISTORS - POTENTIOMETRIC AG+ SELECTIVITY OF PVC MEMBRANES BASED ON MACROCYCLIC THIOETHERS

A chemically modified field-effect transistor (CHEMFET) with satisfactory Ag+ selectivity is described. The potentiometric Ag+ selectivities of CHEMFETs with plasticized PVC membranes based on macrocyclic thioethers have been determined. All the macrocyclic thioethers tested showed silver response and a selectivity towards Ag + and Hg2+ versus other interfering cations. The highest Ag+ selectivity was obtained for a 14-membered cyclic tetrathioether with an exocyclic methylene group.

NOVEL SILICON BISALKOXY COMPLEXES WITH A PSEUDO-ATRANE STRUCTURE - SYNTHESIS AND MOLECULAR-STRUCTURES OF 2,6-DI(2-HYDROXY(2-ADAMANTYL))ETHYLPYRIDINE AND 2,6-DI(2-OXY(2-ADAMANTYLIDINE))ETHYLPYRIDINE DIMETHYLSILICON

Abstract Reaction of 2,6-lutidine with 2 equivalents of n BuLi followed by addition of 2-adamantanone affords the doubly functionalized 2,6-di-(2-oxy (2-adamantylidine))ethylpyridine ( 2a ). Reaction of 2a with Me 2 SiCl 2 gives the pseudo-pentacoordinate 2,6-di-(2-oxy (2-adamantylidine))-ethylpyridinedimethylsilicon ( 4 ). The structures of 2a and 4 have been determined by an X-ray diffraction study.

SYNTHESIS OF THE MACROCYCLIC THIOCROWN ETHERS 1,4,7,10,13,16,19-HEPTATHIAHENEICOSANE (21-S-7) AND 1,4,7,10,13,16,19,22-OCTATHIATETRAEICOSANE (24-S-8)

Abstract The synthesis and characterization of the two macrocyclic sulfides, 1,4,7,10,13,16,19-heptathiaheneicosane (21-S-7) and 1,4,7,10,13,16,19,22-octathiatetraeicosane (24-S-8), are described starting from different combinations of dithiols and dichlorides of differing chain lengths. Cs2CO3, is used for the cyclizations.

Synthesis of mesocyclic and macrocyclic thiacrown ethers containing -SCH2SCH2S- units using thio(bischloromethane)

Abstract Oxidative cleavage of 1,3,5-trithiane 1 by the thionyl chloride is promoted by a catalytic quantity of a Lewis acid like zinc bromide or aluminum chloride and results in the formation of pure thiobis (chloromethane) ( 2 ). This reagent has been successfully employed in the straightforward synthesis of a novel series of thiacrown ethers possessing methylene bridges between the heteroatoms. These molecules have chemical and physical properties that differ considerably in their solubilities from those of their ethylenic or propylenic counterparts.

Pyridinediols as HCI receptors; formation of an unusual pyridine·HCI complex in conjunction with the preparation of Lewis acidic titanium(IV) centres

Reaction of Pyridinediols 1 with TiCl4 affords in one case an unusual dehydration–HCI complexation; in conjunction with these results, reaction of 1 with HCI indicates a strong affinity of these diols for (Lewis) acids.

Boric acid mediated preparation of mesocyclic thiocrown ethers containing xylylene units. Molecular structures of 3,8-dibenzo-1,6-di-thiacyclodecane and 2,5,8-trithia-(9)-p-benzenophane

Reaction of a dithiol with B(OH)3 and base in MeOH followed by reaction with xylylene dibromides proceeds selectively to give the corresponding ortho, meta or para-cyclophanes in good yield (70-86 %). The syntheses of examples of all three types of benzenophanes are discussed. The molecular structures of 3,8-dibenzo-1,6-dithiacyclodecane (8) and 2,5,8-trithia-(9)-p-benzenophane (5) have been determined by X-ray crystallography. Crystal data for 8: space group P2(1)/c with a=8.2745(10), b=4.9330(10), c=16.5500(12) A, beta=100.37 (1)-degrees, Z=2; R=0.043 (R(w)=0.045) for 949 reflections (I>2.5 sigma (I)). Crystal data for 5 (150K): Space group P2(1)/c with a=10.310(1), b=7.430 (1), c=17.681(2) A, beta=113.27(1)-degrees, Z=4; R=0.065 (R(w)=0.065) for 1969 reflections (I>2.5 sigma(I)).

Isolation and characterization of a vanadium ethylidyne complex. The crystal structure of [(Cy2N)2Li(µ3-O)(µ2,η1:η1CMe) an unusual V2LiO cluster

Reaction of VCI2(TMEDA)2[TMEDA =N,N,N′,N′-tetramethylenediannine] with Cy2NH [Cy = cyclohexyl] and BunLi in tetrahydrofuran led to the formation of a complicated mixture of products from which a dinuclear ethylidyne complex [(Cy2N)2V]2(µ3η1-O)(µ2,η1:η1-CMe)1was isolated

CHROMIUM(II) AMIDES - SYNTHESIS AND STRUCTURES

A novel class of mono- and di-meric chromium(II) amides has been prepared and characterized. Reaction of [CrCl2(thf)2](thf = tetrahydrofuran) with 2 equivalents of M(NR2)(R = C6H11, Pri, Ph, or phenothiazinyl; M = Li or Na) allowed the formation of the homoleptic amides [{Cr(µ-NR2)(NR2)}2](R = Ph 1a, C6H111b or Pri1c). The reaction is followed by co-ordination of a Lewis base which, although preserving the Cr2(NR2)2 core, remarkably elongated the Cr ⋯ Cr distance forming [{Cr(µ-NR2)(NR2)L}2](R = Ph, L = thf 2). Facile cleavage to give the square-planar monomeric species [Cr(NR2)L2](R = Ph, L = pyridine 3a, thf 3b; NR2= phenothiazinyl, L = thf 3c) occurred upon treatment with an excess of co-ordinating solvent. Reaction with an excess of M(NR2) led to the formation of anionic chromium(II) square-planar metalates [M2Cr(NR2)4L2](R = Ph, M = Na, L = thf 4a; R = Et, M = Li, L = thf 4b or pyridine 4c). A dimeric species with a very short Cr ⋯ Cr contact [{Cr[N(C5H4N-2)2]2}2]·2dmf (dmf = dimethylformamide)5b has been obtained involving a unique three-centre chelating geometry of the bridging amide ligand. The crystal structures of compounds 1b, 2, 3a, 3c, 4c and 5b have been determined.

Preparation and characterization of [V3Cl5(tmeda)3][V(NPh2)4](tmeda =N,N,N′,N′-tetramethylethylenediamine): a VII–VIII mixed valence complex

Reaction of trans-[VCl2(tmeda)2](tmeda =N,N,N′,N′-tetramethylethylenediamine) with an excess of NaNPh2 led to the formation of the VII–VIII mixed-valence species [V3Cl5(tmeda)3][V(NPh2)4], through an unusual disproportionation reaction.

Chlorobis{2-[(dimethylamino)methyl]phenyl-C1,N}(pyridine)vanadium(III)

The octahedral coordination of the tervalent bis-aryl vanadium complex [VCl(C5H5N)(C9H12N)(2)] is completed by one pyridine and one Cl ligand with a V-Cl distance of 2.395 (2) Angstrom.