Synthesis of 1,4-diazabicyclo[2.2.2]octane

Double intramolecular cyclization of N,N-bis(2-chloroethyl)-N-N-bis(2-cyanoethyl)ethylenediamine leads to 1,4-bis(2-cyanoethyl)-1,4-diazoniabicyclo[2.2.2]octane dichloride, which undergoes decyanoethylation to 1,4-diazabicyclo[2.2.2]octane when it is heated. The structures of the compounds were confirmed by their IR and PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 548–550, April, 1978.     

catena‐Poly[1,4‐dihydroxy‐1,4‐diazoniabicyclo[2.2.2]octane [aquatri‐μ‐chlorido‐trichloridodicuprate(II)]]

The title compound, {(C₆H₁₄N₂O₂)[Cu₂Cl₆(H₂O)]}_n, consists of 1,4‐dihydroxy‐1,4‐diazoniabicyclo[2.2.2]octane dications and one‐dimensional inorganic anionic {[Cu₂Cl₆(H₂O)]²⁻}_n chains in which both five‐coordinate [CuCl₃(H₂O)]⁻ and five‐coordinate [CuCl₃]⁻ units exist. These two distinct type of unit are linked together by one chloride ion and are bridged across centres of inversion to further units of their own type through two chloride ions, giving rise to novel polymeric zigzag chains parallel to the c axis. The chains are connected by O—H...Cl hydrogen bonds to produce R₂⁴(16) ring motifs, resulting in two‐dimensional layers parallel to the ac plane. These layers are linked into a three‐dimensional framework with the organic cations via O—H...Cl hydrogen bonds. Hydrogen bonding between the chains, and between the chains and the organic cations, provides stability to the crystal structure.     

Halogen‐bonded adduct of 1,2‐dibromo‐1,1,2,2‐tetrafluoroethane and 1,4‐diazabicyclo[2.2.2]octane

Halogen bonding is an intermolecular interaction capable of being used to direct extended structures. Typical halogen‐bonding systems involve a noncovalent interaction between a Lewis base, such as an amine, as an acceptor and a halogen atom of a halofluorocarbon as a donor. Vapour‐phase diffusion of 1,4‐diazabicyclo[2.2.2]octane (DABCO) with 1,2‐dibromotetrafluoroethane results in crystals of the 1:1 adduct, C₂Br₂F₄·C₆H₁₂N₂, which crystallizes as an infinite one‐dimensional polymeric structure linked by intermolecular N...Br halogen bonds [2.829 (3) Å], which are 0.57 Å shorter than the sum of the van der Waals radii.     

The 1:1 adduct of 5‐methylbenzene‐1,3‐diol (orcin) and 1,4‐di­aza­bicyclo­[2.2.2]­octane

In the title adduct, C₆H₁₂N₂·C₇H₈O₂, the orcin and 1,4‐di­aza­bi­cyclo­[2.2.2]­octane moieties are held together by O—H⋯N hydrogen bonds. One‐dimensional chiral hydrogen‐bonded chains are formed along the b axis. Neighbouring chains are held together principally by van der Waals interactions and are interrelated by translation, resulting in a chiral layer.     

Bis[4‐(trimethylammonio)phenyl] disulfide diiodide acetone solvate

The title compound, C₁₈H₂₆N₂S₂²⁺·2I⁻·2C₃H₆O, is an intermediate in the design of the zwitterionic thiolate 4‐(trimethylammonio)benzenethiolate (Tab), in which a pair of aryl‐substituted S atoms are linked by a covalent bond. The central S—S bond length is 2.020 (3) Å and the C_ar—S—S—C_ar torsion angle is −84.1 (2)°. The crystal structure is stabilized by nonclassical hydrogen bonds which occur as intramolecular C—H...I interactions and intermolecular C—H...S and C—H...O contacts. In the crystal structure, both the dication and the two symmetrically independent iodide counter‐anions are located on twofold crystallographic axes, whereas the acetone solvent molecule occupies a general position.     

The synthesis of 2,6,7‐trioxa‐1,4‐diphosphabicyclo[2.2.2]octane revisited: the synthesis of 2,6,7‐triphenyl‐2N,6N,7N‐triaza‐1,4‐diphosphabicyclo[2.2.2]octane and the synthesis of 1λ5‐phosphiranol

We report herein a reliable synthesis of P(OCH₂)₃P in a study aimed at understanding the factors that control its formation. We also report the serendipitous synthesis of the novel phosphiranol (CH₂)₂PO₂H and the synthesis of P(PhNCH₂)₃P in good yield. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:114–117, 2001     

catena‐Poly­[1,4‐diazo­niabicyclo­[2.2.2]­octane [silver(I)‐tri‐μ‐thio­cyanato‐κ6S:S]]

The title compound, {(C₆H₁₄N₂)[Ag(NCS)₃]}_n, is a polymeric silver(I) complex. The Ag^I atom is hexacoordinated by the S atoms of six thio­cyanate anions, with each thio­cyanate S atom acting in a bridging mode to link the Ag atoms together. The unique Ag^I atom lies at a cell origin and has crystallo­graphically imposed symmetry. The diazonia[2.2.2]octane molecule lies about a site with imposed symmetry with the unique N atom on a threefold axis. The S and N atoms of the thio­cyanate ligands sit on a mirror plane and a threefold axis, respectively. The crystal structure consists of one‐dimensional chains, which are stabilized by N—H⋯N hydrogen bonds to form a three‐dimensional network.     

High‐Tc Enantiomeric Ferroelectrics Based on Homochiral Dabco‐derivatives (Dabco=1,4‐Diazabicyclo[2.2.2]octane)

1,4‐Diazabicyclo[2.2.2]octane (dabco) and its derivatives have been extensively utilized as building units of excellent molecular ferroelectrics for decades. However, the homochiral dabco‐based ferroelectric remains a blank. Herein, by adding a methyl (Me) group accompanied by the introduction of homochirality to the [H₂dabco]²⁺ in the non‐ferroelectric [H₂dabco][TFSA]₂ (TFSA=bis(trifluoromethylsulfonyl)ammonium), we successfully designed enantiomeric ferroelectrics [R and S‐2‐Me‐H₂dabco][TFSA]₂. The two enantiomers show two sequential phase transitions with transition temperature (T_c) as high as 405.8 K and 415.8 K, which is outstanding in both dabco‐based ferroelectrics and homochiral ferroelectrics. To our knowledge, [R and S‐2‐Me‐H₂dabco][TFSA]₂ are the first examples of dabco‐based homochiral ferroelectrics. This finding opens an avenue to construct dabco‐based homochiral ferroelectrics and will inspire the exploration of more eminent enantiomeric molecular ferroelectrics.     

Mononuclear and dinuclear bromide–nitrite cadmium(II) complexes with related 1,4‐diazabicyclo[2.2.2]octane ligands

The title compounds, di‐μ‐bromido‐bis[bromido(1‐carboxymethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane‐κN⁴)(nitrito‐κ²O,O′)cadmium(II)] dihydrate, [Cd₂Br₄(C₈H₁₅N₂O₂)₂(NO₂)₂]·2H₂O, (I), and aquabromido(1‐cyanomethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane‐κN⁴)bis(nitrito‐κ²O,O′)cadmium(II) monohydrate, [CdBr(C₈H₁₄N₃)(NO₂)₂(H₂O)]·H₂O, (II), are two‐dimensional hydrogen‐bonded metal–organic hybrid complexes. In (I), the complex is situated on a centre of inversion so that each symmetry‐related Cd^II atom is coordinated by two bridging Br atoms, one monodentate Br atom, one chelating nitrite ligand and one organic ligand, yielding a significantly distorted octahedral geometry. The combination of O—H...O and O—H...Br hydrogen bonds produces centrosymmetric R₆⁶(16) ring motifs, resulting in two‐dimensional layers parallel to the ab plane. In contrast, the complex molecule in (II) is mononuclear, with the Cd^II atom seven‐coordinated by two bidentate nitrite groups, one N atom from the organic ligand, one monodentate Br atom and a water O atom in a distorted pentagonal–bipyramidal environment. The combination of O—H...O and O—H...Br hydrogen bonds produces R₅⁴(14) and R₃³(8) rings which lead to two‐dimensional layers parallel to the ac plane.     

Above Room Temperature Organic Dielectric Switchable Material: Diprotonated 1,4‐Diazabicyclo[2.2.2]octane Shifts between Two Pyruvic Acids

A pure organic single crystal, [H₂dabco] · [PA]₂ ([H₂dabco]²⁺ = diprotonated 1,4‐diazabicyclo‐[2.2.2]octane, PA = pyruvic acid), was synthesized and its dielectric property was studied. [H₂dabco] · [PA]₂ owns a distinctive architecture composed of discrete hydrogen‐bonded trimeric units, of which one [H₂dabco]²⁺ cation bridged by two PA^– anions through N–H ··· O hydrogen bonding. The switchable property around 348 K was revealed by crystal structure studies between low and high dielectric states. In the high temperature phase, the [H₂dabco]²⁺ cation presents itself in a rotationally disordered state and lies at the symmetric center of the trimer. In the room temperature phase, it is frozen in an ordered state and shifts toward a PA^– anion at one end along the hydrogen bond.     

Conformation perturbation of p-sulfonatocalix[5]arene via complexation of 1,4-diazabicyclo[2.2.2]octane

A novel conformation of p-sulfonatocalix[5]arene has been established in the solid state with two calixarenes organised in a 'bis-molecular capsule' shrouding two di-protonated DABCO molecules and two water molecules within.     

1‐Phosphabicyclo[3.2.1]octane

1‐Phosphabicyclo[3.2.1]octanes 1‐Phosphabicyclo[3.2.1]octane has been obtained by free‐radical cyclization of (2‐vinyl‐4‐pentenyl)‐phosphane in the presence of AIBN. Another approach to 1‐phosphabicyclo[3.2.1]octanes involves free‐radical cyclization of 2‐methyl‐4‐(2‐propenyl)‐phospholane synthesized by the reaction of [2‐(2‐propenyl)‐4‐pentenyl]‐phosphane with KPH₂/[18]crown‐6 in THF. The bicyclic phosphanes are characterized by reactions with CS₂, selenium, sulfur, NO, CH₃I, and HSO₃F, respectively, structural and analytical data as well as ¹H, ¹³C, ³¹P, ⁷⁷Se NMR spectral measurements. The steric crowding of the phosphanes as complex ligands has been estimated from ³¹P–¹H coupling constants according to the Tolman model. The configuration of the methyl substituents as well as the conformation of the six‐membered ring were determined by NMR parameters (coupling constants, noe's) and proved by X‐ray crystal structure analysis.     

Studies on the reaction of 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone with tribenzylamine and diazabicyclo[2.2.2]octane in acetonitrile solvent

The reaction of chloranilic acid with two nitrogen nucleophiles, tribenzylamine and diazabicyclo[2.2.2]octane has been studied. Careful spectroscopic analysis showed that the product in both cases is a radical ion pair of Q^.-, A^.+ type. Stoichiometry of the complex formed is of 1:1 type. Mechanism of the reaction is proposed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Supramolecular catalytic systems based on alkylated diquaternary 1,4-diazabicyclo[2.2.2]octane derivatives

The micellization and catalytic properties of the diquaternary 1,4-diazabicyclo[2.2.2]octane derivatives, viz., 1-alkyl-4-ethyl-1,4-diazoniabicyclo[2.2.2]octane dibromides (DAD) in water were studied by conductometry, viscosimetry, and spectrophotometry. The critical micelle concentrations and the semiaxial ratio of the micellar aggregates were determined. The character and strength of the effect of the DAD micelles on the alkaline hydrolysis of 4-nitrophenyl alkylchloromethylphosphonates depend on the surfactant and substrate structures, DAD concentration in solution, and temperature. An increase in the hydrophobicity of DAD and phosphonate increases the efficiency of catalysis.     

A new three‐dimensional CdII supramolecular framework constructed from the 1‐[(1H‐tetrazol‐5‐yl)methyl]‐1,4‐diazoniabicyclo[2.2.2]octane ligand

A new tetrazole–metal supramolecular compound, di‐μ‐chlorido‐bis(trichlorido{1‐[(1H‐tetrazol‐5‐yl‐κN²)methyl]‐1,4‐diazoniabicyclo[2.2.2]octane}cadmium(II)), [Cd₂(C₈H₁₆N₆)₂Cl₈], has been synthesized and structurally characterized by single‐crystal X‐ray diffraction. In the structure, each Cd^II cation is coordinated by five Cl atoms (two bridging and three terminal) and by one N atom from the 1‐[(1H‐tetrazol‐5‐yl)methyl]‐1,4‐diazoniabicyclo[2.2.2]octane ligand, adopting a slightly distorted octahedral coordination geometry. The bridging bicyclo[2.2.2]octane and chloride ligands link the Cd^II cations into one‐dimensional ribbon‐like N—H...Cl hydrogen‐bonded chains along the b axis. An extensive hydrogen‐bonding network formed by N—H...Cl and C—H...Cl hydrogen bonds, and interchain π–π stacking interactions between adjacent tetrazole rings, consolidate the crystal packing, linking the poymeric chains into a three‐dimensional supramolecular network.     

DABCO-directed self-assembly of bisporphyrins (DABCO=1,4-diazabicyclo[2.2.2]octane)

Three isomeric zinc bisporphyrins have been prepared by covalently linking together two aminoporphyrins with an isophthalic acid derivative. The porphyrins differ in the substitution pattern on the meso phenyl groups, that is, ortho, meta, or para. Titrations carried out by UV-visible and 1H NMR spectroscopy have been used to map out the stabilities and the stoichiometries of the complexes formed with 1,4-diazabicyclo[2.2.2]octane (DABCO) in chloroform. The ortho- and meta-substituted bisporphyrins form 1:1 intramolecular sandwich complexes. The para-substituted bisporphyrin cannot adopt the cofacial conformation required for this type of complex and forms a higher order 2:2 intermolecular assembly, which is stable over a wide range of DABCO concentrations.