On the microstructure and symmetry of apparently hexagonal BaAl2O4

The P6₃ (a=2a_p, b=2b_p, c=c_p) crystal structure reported for BaAl₂O₄ at room temperature has been carefully re-investigated by a combined transmission electron microscopy and neutron powder diffraction study. It is shown that the poor fit of this P6₃ (a=2a_p, b=2b_p, c=c_p) structure model for BaAl₂O₄ to neutron powder diffraction data is primarily due to the failure to take into account coherent scattering between different domains related by enantiomorphic twinning of the P6₃22 parent sub-structure. Fast Fourier transformation of [0 0 1] lattice images from small localized real space regions (∼10 nm in diameter) are used to show that the P6₃ (a=2a_p, b=2b_p, c=c_p) crystal structure reported for BaAl₂O₄ is not correct on the local scale. The correct local symmetry of the very small nano-domains is most likely orthorhombic or monoclinic.     

[4+2] Cycloaddition reactions of 4-sulfur-substituted 2-pyridones with electron-deficient dienophiles

[4+2] Cycloaddition reactions of 4-(phenylthio)-1-tosyl-2-pyridone (6a) and 4-(phenylsulfonyl)-1-tosyl-2-pyridone (6b) with electron-deficient dienophiles 7 (N-methylmaleimide, N-phenylmaleimide, and methyl acrylate) gave new isoquinuclidine products 8-10. The N-tosyl group of 6a and 6b was also efficiently converted to N-alkyl derivatives 6c-f, which showed different stereoselectivity toward reactions with dienophiles 7. Several other dienophiles 15 (dimethyl acetylenedicarboxylate, methyl vinyl ketone, ethyl vinyl ether, and methyl methacrylate) were found not to react with 6a or 6b, but led to the formation of tosyl migration products 4-(phenylthio)-O-tosyl-pyridinol (16a) and 4-(phenylsulfonyl)-O-tosyl-2-pyridinol (16b), respectively. The reactivity, regioselectivity, and stereoselectivity of the cycloaddition reactions were also compared with semi-empirical calculations.     

Reactivity of 2,3-bis(2-pyridyl)pyrazine with [Re2(CO)8(CH3CN)2]: Molecular structures of [Re2(CO)8(C14H10N4)] and [Re2(CO)8(C14H10N4)Re2(CO)8]

The reaction of the labile compound [Re₂(CO)₈(CH₃CN)₂] with 2,3-bis(2-pyridyl)pyrazine in dichloromethane solution at reflux temperature afforded the structural dirhenium isomers [Re₂(CO)₈(C₁₄H₁₀N₄)] (1 and 2), and the complex [Re₂(CO)₈(C₁₄H₁₀N₄)Re₂(CO)₈] (3). In 1, the ligand is σ,σ′-N,N′-coordinated to a Re(CO)₃ fragment through pyridine and pyrazine to form a five-membered chelate ring. A seven-membered ring is obtained for isomer 2 by N-coordination of the 2-pyridyl groups while the pyrazine ring remains uncoordinated. For 2, isomers 2a and 2b are found in a dynamic equilibrium ratio [2a]/[2b]  =  7 in solution, detected by ¹H NMR (−50 °C, CD₃COCD₃), coalescence being observed above room temperature. The ligand in 3 behaves as an 8e-donor bridge bonding two Re(CO)₃ fragments through two (σ,σ′-N,N′) interactions. When the reaction was carried out in refluxing tetrahydrofuran, complex [Re₂(CO)₆(C₁₄H₁₀N₄)₂] (4) was obtained in addition to compounds 1-3. The dinuclear rhenium derivative 4 contains two units of the organic ligand σ,σ′-N,N′-coordinated in a chelate form to each rhenium core. The X-ray crystal structures for 1 and 3 are reported.     

Calix[4]quinones. Part 4: The ClO2 oxidation of calix[4]arene dialkyl ethers

Except for the special case of calix[4]arene diethyl ether 1, the chlorine dioxide oxidation of dialkyl ethers 2-5 yielded only the corresponding calix[4]diquinone dialkyl ethers 8-11. Chlorine dioxide oxidation of calix[4]arene diethyl ether 1 produced two isomeric products 6 and 7, which were stable enough to be isolated by column chromatography. However, a slow conformational interconversion between isomeric pair 6 and 7 was observed at room temperature, and the equilibrium was reached after 400 h at 18 °C with an amount of 5:3 in favor of syn-isomer.     

Cyclopentadienyl tungsten complexes with thiocarboxylate and thiosulfonate ligands: Structures of CpW(CO)3SCOPh and CpW(CO)3SSO2-4-C6H4Cl

Treatment of the hydrosulfido tungsten complex CpW(CO)₃SH with acid chlorides (RCOCl) or sulfonyl chlorides (RSO₂Cl) affords CpW(CO)₃SCOR (1) [R = Me (a), CH₂Cl (b), Ph (c), 4-C₆H₄NO₂ (d)] and CpW(CO)₃SSO₂R (2) [R = Me (a), Ph (b), 4-C₆H₄Cl (c), 4-C₆H₄NO₂ (d)], respectively. The novel complexes, 1 and 2, were fully characterized by elemental analyses, IR and ¹H NMR spectroscopy. The solid state structures of CpW(CO)₃SCOPh (1c) and CpW(CO)₃SSO₂-4-C₆H₄Cl (2c) were determined by an X-ray crystal structure analysis.     

3-Amino- and 3-acylamido-2-phosphonopyridines: synthesis by Pd-catalyzed P-C coupling, structure and conversion to pyrido[b]-anellated PC-N heterocycles

Palladium catalyzed cross-coupling of 3-amino- and 3-acylamido-2-bromopyridines 1a-f with triethyl phosphite allowed the synthesis of 3-amino- and 3-acylamido pyridine-2-phosphonic acid diethyl esters 2a-f, whereas nickel catalysts, although providing access to related anilido-2-phosphonates, proved inactive. Reduction of the aminophosphonate 2a with LiAlH₄ afforded 3-amino-2-phosphinopyridine (3a), which was cyclocondensed with dimethylformamide dimethyl acetal (DMFA) via phosphaalkene intermediates 4a to the novel pyrido[b]-anellated 1,3-azaphosphole 5a. Reaction of amidophosphonates 2b-f with LiAlH₄ did not result in the expected reductive cyclization, as shown by closely related anilido-2-phosphonates, but led to product mixtures containing N-secondary 3-amino-2-phosphinopyridines 3b-f as the main or major component. The conversion of 3b,d,e with DMFA to 5b,d,e provides first examples of N-substituted pyrido[b]-anellated azaphospholes. Structures were confirmed by multinuclear NMR and X-ray crystallography (for 2c, 3b).     

Structure and microstructure of the high pressure synthesised misfit layer compound [Sr2O2][CrO2]1.85

The strontium chromium oxide [Sr₂O₂][CrO₂]_1.85 misfit layer compound has been synthesised at high-pressure and high-temperature conditions. Electron diffraction patterns and high-resolution transmission electron microscopy images along [001] show the misfit character of the different layers composing the structure with a supercell along the incommensurate parameter b≈7b₁≈13b₂. The modulated crystal structure has been refined within the superspace formalism against single-crystal X-ray diffraction data, employing the (3+1)-dimensional superspace group C′nmb(0σ₂0)0 0 s. The compound has a composite structure with lattice parameters a₁=5.182(1) Å, b₁=5.411(1) Å, c₁=18.194(3) Å for the first, SrO, subsystem and the same a and c, but with b₂=2.925(1) Å for the second, CrO₂, subsystem. The layer stacking is similar to that of orthorhombic PbS(TiS₂)_1.18, but with a much stronger intersubsytem bonding in the case of the oxide. The intersubsystem lattice mismatch is mainly handled by displacement modulations of the Sr atoms, correlated with modulations of the valence, the coordination and the anisotropic displacement parameters.     

Hydroxy- and boronic-acid-functionalized carbosilanes: Synthesis and solid state structure of Si(C6H4-4-SiMe2((CH2)3OH))4

Consecutive synthesis methodologies for the preparation of carbosilanes (Ph)(Me)Si((CH₂)₃B(OH)₂)₂ (2), Si(C₆H₄-4-SiMe₂((CH₂)₃B(OH)₂))₄ (5), (Ph)(Me)Si((CH₂)₃OH)₂ (3), and Si(C₆H₄-4-SiMe_3−n((CH₂)₃OH)_n)₄ (6a, n = 1; 6b, n = 2; 6c, n = 3) are reported. Boronic acids 2 and 5 are accessible by treatment of (Ph)(Me)Si(CH₂CHCH₂)₂ (1) or Si(C₆H₄-4-SiMe₂(CH₂CHCH₂))₄ (4a) with HBBr₂·SMe₂ followed by addition of water, while 3 and 6 are available by the hydroboration of 1 or Si(C₆H₄-4-SiMe_3−n(CH₂CHCH₂)_n)₄ (4a, n = 1; 4b, n = 2; 4c, n = 3) with H₃B·SMe₂ and subsequent oxidation with H₂O₂.The single molecular structure of 6a in the solid state is reported. Representative is that 6a crystallized in the chiral non-centrosymmetric space group P2₁2₁2₁ forming 2D layers due to intermolecular hydrogen bond formation of the HO functionalities along the crystallographic a and c axes.     

Reactions of P4S10 and pyPS2Cl with N,N′-diphenylurea and N,N′-diphenylthiourea

The reaction of P₄S₁₀ (1) with N,N′-diphenylurea (PhNH)₂CO (2) results in new heterocyclic compounds: the pyridinium salt of 1,3-diphenyl-2-sulfido-2-thioxo-1,3-diaza-2λ⁵-phosphetidine (3) (with a P–N–C–N cycle) and the pyridinium salt of 1,4-diphenyl-2,5-disulfido-2,5-dithioxo-1,4-dithiadiaza-2λ⁵,5λ⁵-diphosphinane (4), containing the (P–S–N)₂ cycle and the cyclic thiophosphates [pyH]₂[P₂S₈] (5), [pyH]₂[P₂S₇] (6) and [pyH]₃[P₃S₉] (7). A similar reaction, but carried out with N,N′-diphenylthiourea (PhNH)₂CS (8), leads to the formation of 4 and 6. pyPS₂Cl (9), used as an alternative starting material, also yields compounds 3, 4, 5, and further [pyH][PS₂Cl₂] (10) and S₈ after reaction with 2. Compound 3 reacts with Pd(CH₃COO)₂, with the formation of the complex [Pd(Ph₂N₂COPS₂)₂] (11). The crystal structures of 3 and 7 were determined by single-crystal X-ray diffraction.     

Formation and structural characterization of mercury complexes from Te(R)CH2SiMe3 (R = Ph, CH2SiMe3) and HgCl2

The reaction of HgCl₂ and Te(R)CH₂SiMe₃ [R = CH₂SiMe₃ (1), Ph (2)] in ethanol yielded a mononuclear complex [HgCl₂{Te(R)CH₂SiMe₃}₂] (R = Ph, 3a; R = CH₂SiMe₃, 3b). The recrystallization of 3a or 3b from CH₂Cl₂ produced a dinuclear complex [Hg₂Cl₂(μ-Cl)₂{Te(R)CH₂SiMe₃}₂] (R = Ph, 4a; R = CH₂SiMe₃, 4b). When 3a was dissolved in CH₂Cl₂, the solvent quickly removed, and the solid recrystallized from EtOH, a stable ionic [HgCl{Te(Ph)CH₂SiMe₃}₃]Cl·2EtOH (5a·2EtOH) was obtained. Crystals of [HgCl₂{Te(CH₂SiMe)₂}]·2HgCl₂·CH₂Cl₂ (6b·2HgCl₂·CH₂Cl₂) were obtained from the CH₂Cl₂ solution of 3b upon prolonged standing. The complex formation was monitored by ¹²⁵Te-, and ¹⁹⁹Hg NMR spectroscopy, and the crystal structures of the complexes were determined by single crystal X-ray crystallography.     

Synthesis of novel calix[4]arenes containing organosilicon groups

Metalation of (RSiMe₂)₃CH (1a R = H, 1b R = Me, 1c R = Ph) with lithium diisopropylamide (LDA) or methyllithium in THF gave organolithium reagents (RSiMe₂)₃CLi, which reacted with the formylated calixarene (2), to give the corresponding 5,17-bis[2,2-bis(organosilyl)-1-ethenyl]-25,26,27,28-tetrapropoxycalix[4]arenes (3a, 3b and 3c) via the Peterson olefination. The compounds (RSiMe₂)₃CLi were treated with 25,26,27,28-tetrakis(4-bromobutoxy)calix[4]arene (4) to give 25,26,27,28-tetrakis[4-(tris(dimethylsilyl)methyl)butoxy] calix[4]arene (5a) and 25,26,27,28-tetrakis[4-(tris(trimethylsilyl)methyl)butoxy] calix[4]arene (5b) via nucleophilic substitution reactions. However the compound 25,26,27,28-tetrakis[4-(tris(dimethylphenylsilyl)methyl)butoxy] calix[4]arene (5c) was not obtained, presumably because (PhSiMe₂)₃C- is highly sterically hindered and the reactivity of its derivatives is low. The compound 5a has potential as a core for dendrimers.     

Synthesis and reactivity of para-substituted benzoylmethyltellurium(II and IV) compounds: observation of intermolecular C-H-O hydrogen bonding in the crystal structure of (p-MeOC6H4COCH2)2TeBr2

Bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC₆H₄COCH₂)₂TeBr₂, (Y=H (1a), Me (1b), MeO (1c)) can be prepared either by direct insertion of elemental Te across C_Rf-Br bonds (where C_Rf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (p-YC₆H₄COCH₂)₂Te (Y=H (2a), Me (2b), MeO (2c)). Bis(p-substituted benzoylmethyl)tellurium dichlorides, (p-YC₆H₄COCH₂)₂TeCl₂ (Y=H (3a), Me (3b), MeO (3c)), are prepared by the reaction of the bis(p-substituted benzoylmethyl)tellurides 2a-c with SO₂Cl₂, whereas the corresponding diiodides (p-YC₆H₄COCH₂)₂TeI₂ (Y=H (4a), Me (4b), MeO (4c)) can be obtained by the metathetical reaction of 1a-c with KI, or alternatively, by the oxidative addition of iodine to 2a-c. The reaction of 2a-c with allyl bromide affords the diorganotellurium dibromides 1a-c, rather than the expected triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, ¹H, ¹³C and ¹²⁵Te NMR spectroscopy (solution and solid-state) and in case of 1c also by X-ray crystallography. (p-MeOC₆H₄COCH₂)₂TeBr₂ (1c) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.     

Ullmann coupling reaction of 1,3-bistriflate esters of calix[4]arenes: facile syntheses of monoaminocalix[4]arenes and 4,4′:6,6′-diepithiobis(phenoxathiine)

Treatment of 1,3-bistriflate esters of thiacalix- (6a) and calix[4]arenes 6b with benzylamine in the presence of CuI and K₃PO₄ results in the displacement of a TfO moiety with a benzylamino group, which provides an easy access to monoaminothiacalix[4]arene 4a and its methylene-bridged counterpart 4b. On the other hand, the reaction of 6a in the absence of benzylamine leads to intramolecular dietherification, giving 4,4′:6,6′-diepithiobis(phenoxathiine) 7a.     

Reactions of Mo(II)-tetraphosphine complex [MoCl2{meso-o-C6H4(PPhCH2CH2PPh2)2}] with a series of small molecules

Reactions of Mo(II)-tetraphosphine complex [MoCl₂(κ⁴-P4)] (2; P4 = meso-o-C₆H₄(PPhCH₂CH₂PPh₂)₂) with a series of small molecules have been investigated. Thus, treatment of 2 with alkynes RCCR′ (R = Ph, R′ = H; R = p-tolyl, R′ = H; R = Me, R′ = Ph) in benzene or toluene gave neutral mono(alkyne) complexes [MoCl₂(RCCR′)(κ³-P4)] containing tridentate P4 ligand, which were converted to cationic complexes [MoCl(RCCR′)(κ⁴-P4)]Cl having tetradentate P4 ligand upon dissolution into CDCl₃ or CD₂Cl₂. The latter complexes were available directly from the reactions of 2 with the alkynes in CH₂Cl₂. On the other hand, treatment of 2 with 1 equiv. of XyNC (Xy = 2,6-Me₂C₆H₃) afforded a seven-coordinate mono(isocyanide) complex [MoCl₂(XyNC)(κ⁴-P4)] (7), which reacted further with XyNC to give a cationic bis(isocyanide) complex [MoCl(XyNC)₂(κ⁴-P4)]Cl (8). From the reaction of 2 with CO, a mono(carbonyl) complex [MoCl₂(CO)(κ⁴-P4)] (9) was obtained as a sole isolable product. Reaction of 9 with XyNC afforded [MoCl(CO)(XyNC)(κ⁴-P4)]Cl (10a) having a pentagonal-bipyramidal geometry with axial CO and XyNC ligands, whereas that of 7 with CO resulted in the formation of a mixture of 10a and its isomer 10b containing axial CO and Cl ligands. Structures of 7 and 9 as well as [MoCl(XyNC)₂(κ⁴-P4)][PF₆](8′) and [MoCl(CO)(XyNC)(κ⁴-P4)][PF₆] (10a′) derived by the anion metathesis from 8 and 10a, respectively, were determined in detail by the X-ray crystallography.     

Diester intrabridging of p-tert-butylcalix[8]arene and unexpected formation of the monospirodienone derivative

Reaction of p-tert-butylcalix[8]arene 1 with adipoyl chloride in the presence of NaH as the base yielded singly and doubly intrabridged esters 2-4 and 6. Surprisingly, calix[8]arene monospirodienone derivative 7 was also isolated, which was originated by O₂ oxidation. The conditions of this oxidation were optimized leading to a novel synthetic approach to calixarene monospirodienones based on the O₂/NaH/acyl-chloride oxidizing system. Xantheno calix[8]arenes 8-8a were obtained by rearrangement of 7.     

Synthesis and characterization of hetero-binuclear Co-Rh complexes [CpCoS2C2(B9H10)][Rh(COD)] and [CpCoSe2C2(B10H10)][Rh(COD)]

Two hetero-binuclear complexes [Cp^∗CoS₂C₂(B₉H₁₀)][Rh(COD)] (2a) and [Cp^∗CoSe₂C₂(B₁₀H₁₀)][Rh(COD)] (2b) [Cp^∗ = η⁵-pentamethylcyclopentadienyl, COD = cyclo-octa-1,5-diene (C₈H₁₂)] were synthesized by the reactions of half-sandwich complexes [Cp^∗CoE₂C₂(B₁₀H₁₀)] [E = S (1a), Se (1b)] with low valent transition metal complexes [Rh(COD)(OEt)]₂ and [Rh(COD)(OMe)]₂. Although the reaction conditions are the same, the structures of two products for dithiolato carborane and diselenolato carborane are different. The cage of the carborane in 2a was opened; However, the carborane cage in 2b was intact. Complexes 2a and 2b have been fully characterized by ¹H, ¹¹B NMR and IR spectroscopy, as well as by elemental analyses. The molecular structures of 2a and 2b have been determined by single-crystal X-ray diffraction analyses and strong metal-metal interactions between cobalt and rhodium atoms (2.6260 Å (2a) and 2.7057 Å (2b)) are existent.     

Assembly of diverse structural types of organotellurium compounds in the reactions of (4-MeO-C6H4)2TeO with pyridine carboxylic acids

The reactions of Ar₂TeO (Ar = 4-MeO-C₆H₄) with 2-, 3- and 4-pyridine carboxylic acids (LH) afforded different organotelluroxane structural types depending on the stoichiometry of the reactants and the conditions of the reaction. Ar₂Te(L)OH (1a-1c) are formed in a 1:1 reaction of Ar₂TeO with LH in the presence of water. On the other hand a 1:2 reaction under anhydrous conditions leads to the formation of Ar₂TeL₂ (2a-2c). A 2:2 reaction under anhydrous conditions affords the ditelluroxanes Ar₂Te(L)OTe(L)Ar₂ (3a-3c) while tritelluroxanes Ar₂Te(L)OTeAr₂OTe(L)Ar₂ (4a-4c) are formed in 3:2 reactions. Interestingly, 3a-3c are formed in the reaction of 2a-2c with Ar₂TeO. The former can be hydrolyzed to 1a-1c while the latter upon reaction with Ar₂TeO lead to the formation of the tritelluroxanes 4a-4c. Attempts to metalate 2a with PdCl₂(MeCN)₂ leads to a transfer of the carboxylate ligand to palladium affording Ar₂TeCl₂ and PdL₂. X-ray crystal structures of representative examples of the family of 1, 2 and 3 reveal interesting supramolecular structures and the formation of a novel [TeO]₂ structural unit. The latter results from intermolecular secondary Te?O interactions.     

The reaction of manganese carbonyl with tert-butylisocyanide: Synthesis and characterization of cis- and trans-[Mn(BuNC)4(CN)(CO)]

The reaction of Mn₂(CO)₁₀ with tert-butyl isocyanide in the presence of 10 bar of carbon monoxide leads to the formation of cis- and trans-[Mn(^tBuNC)₄(CN)(CO)], 1a and 1b, in good yields together with [Mn(^tBuNC)₆]CN (2), as a minor product. Nevertheless, the reaction pathway highly depends on the reaction conditions. An interesting side-product is obtained, if chloroform is used during the workup procedure. Compound 3 is composed of cationic [Mn(^tBuNC)₅(CO)] units as well as dinuclear anionic [Mn(^tBuNC)₄(CO)(μ-CN)MnCl₃] moieties. If no additional CO pressure is applied to the system, the organic product N,N′-di-tert-butyl-3,5-bis-tert-butylimino-4-phenyl-cyclopent-1-ene-1,2-diamine (4), is formed in considerable amount. Compound 4 most probably is produced via a double benzylic C-H activation of the solvent toluene and the oligomerization of four isocyanide moieties. The reaction of 1b with Co(NO₃)₂ leads to the isolation of the trinuclear cyanide bridged coordination compound {[Mn(^tBuNC)₄) (CO) (μ-CN)]₂Co(NO₃)₂}, 5, in which the cobalt atoms are tetrahedrally surrounded by the two cyanide ligands and the η¹-coordinated nitro groups. In contrast to the reaction of 1b, treatment of the dicyano complexes cis- or trans-[Ru(^tBuNC)₄(CN)₂] with Co(NO₃)₂ results in the formation of the coordination polymers {[Ru(^tBuNC)₄(CN)₂]Co(NO₃)₂}_n, 7 (trans) and 9 (cis). All new compounds are characterized by X-ray diffraction experiments.     

Regioselective synthesis of 2,5-dihydro-4H-pyrazolo[4,3-c]quinolin-4-ones by the cyclization of 3-acyl-4-methoxy-1-methylquinolinones with hydrazines

Reaction of 3-acyl-4-methoxy-1-methylquinolinones 2 and 5 with hydrazines has been investigated under different experimental conditions. Compound 2 always gave rise selectively and exclusively to the regioisomeric 1,3-disubstituted- or 2,3-disubstituted-pyrazolo[4,3-c]quinolin-4(5H)one (compounds 3a,b or 4a,b, respectively), while reaction of 5 with N-methylhydrazine led to a mixture of pyrazoles 7a and 8a. With N-phenylhydrazine, compounds 7b or 8b were regioselectively obtained. Compound 8a could be selectively synthesized working in solventless conditions. Structural elucidation of all products was independently achieved by NMR spectroscopy.     

Synthesis and properties of pyrazine-pillared Ag3Mo2O4F7 and AgReO4 layered phases

The new pyrazine-pillared solids, AgReO₄(C₄H₄N₂) (I) and Ag₃Mo₂O₄F₇(C₄H₄N₂)₃ (C₄H₄N₂=pyrazine, pyz) (II), were synthesized by hydrothermal methods at 150 °C and characterized using single crystal X-ray diffraction (I—P2₁/c, No. 14, Z=4, a=7.2238(6) Å, b=7.4940(7) Å, c=15.451(1) Å, β=92.296(4)°; II—P2/n, No. 13, Z=2, a=7.6465(9) Å, b=7.1888(5) Å, c=19.142(2) Å, β=100.284(8)°), thermogravimetric analysis, UV-Vis diffuse reflectance, and photoluminescence measurements. Individual Ag(pyz) chains in I are bonded to three perrhenate ReO₄^- tetrahedra per layer, while each layer in II contains sets of three edge-shared Ag(pyz) chains (π-π stacked) that are edge-shared to four Mo₂O₄F₇^3- dimers. A relatively small interlayer spacing results from the short length of the pyrazine pillars, and which can be removed at just slightly above their preparation temperature, at >150-175 °C, to produce crystalline AgReO₄ for I, and Ag₂MoO₄ and an unidentified product for II. Both pillared solids exhibit strong orange-yellow photoemission, at 575 nm for I and 560 nm for II, arising from electronic excitations across (charge transfer) band gaps of 2.91 and 2.76 eV in each, respectively. Their structures and properties are analyzed with respect to parent ‘organic free’ silver perrhenate and molybdate solids which manifest similar photoemissions, as well as to the calculated electronic band structures.