Efficient excitation energy transfer in long meso-meso linked Zn(II) porphyrin arrays bearing a 5,15-bisphenylethynylated Zn(II) porphyrin acceptor

Electronically coupled porphyrin arrays are suitable for artificial light harvesting antenna in light of a large absorption cross-section and fast excitation energy transfer (EET). Along this line, an artificial energy transfer model system has been synthesized, comprising of an energy donating meso-meso linked Zn(II) porphyrin array and an energy accepting 5,15-bisphenylethynylated Zn(II) porphyrin linked via a 1,4-phenylene spacer. This includes an increasing number of porphyrins in the meso-meso linked Zn(II) porphyrin array, 1, 2, 3, 6, 12, and 24 (Z1A, Z2A, Z3A, Z6A, Z12A, and Z24A). The intramolecular singlet-singlet EET processes have been examined by means of the steady-state and time-resolved spectroscopic techniques. The steady-state fluorescence comes only from the acceptor moiety in Z1A-Z12A, indicating nearly the quantitative EET. In Z24A that has a molecular length of ca. 217 A, the fluorescence comes largely from the acceptor moiety but partly from the long donor array, indicating that the intramolecular EET is not quantitative. The transient absorption spectroscopy has provided the EET rates in real time scale: (2.5 ps)(-1) for Z1A, (3.3 ps)(-1) for Z2A, (5.5 ps)(-1) for Z3A, (21 ps)(-1) for Z6A, (63 ps)(-1) for Z12A, and (108 ps)(-1) for Z24A. These results have been well explained by a revised F?rster equation (Sumi formula), which takes into account an exciton extending coherently over several porphyrin pigments in the donor array, whose length is not much shorter than the average donor-acceptor distance. Advantages of such strongly coupled porphyrin arrays in light harvesting and transmission are emphasized in terms of fast EET and a large absorption cross-section for incident light.     

Synthesis of the N-((1E)-alkenyl)-(2Z,4Z)-heptadienamide side chain of salicylihalamide A and apicularens A and B

[reaction: see text] The unstable N-((1E)-alkenyl)-(2Z,4Z)-heptadienamide side chain of salicylihalamide A (1) and apicularens A and B (3 and 4) has been prepared in one pot by the addition of (1Z,3Z)-hexadienylcuprate, prepared in situ from EtLi, CuBr.SMe2, and acetylene, to a (1 E)-alkenyl isocyanate.     

Ab initio studies of

Ab initio calculations of the [1,5]-H shift in (3Z)-penta-1,3-diene and other substituted pentadienes and heteroanalogues using the hybrid density functional Becke3LYP with the 6-31G basis set are presented. Electron-donating substituents, such as methoxy in (3Z)-3-methoxypenta-1,3-diene 1, or heteroatoms such as a nitrogen atom in (Z)-ethylidenevinylamine 2, (1Z)-buta-1,3-dienylamine 3, (2Z)-but-2-enylideneamine 4, (Z)-allylidenemethylamine 5, and methylene-(Z)-propenylamine 6 are introduced. The electron-withdrawing fluoride is substituted for the hydrogen atoms in (3Z)-3-fluoropenta-1,3-diene 7, (3Z)-2,4-difluoropenta-1,3-diene 8, (3Z)-1,1',2,3,4,5,5'-heptafluoropenta- 1,3-diene 10, (1E,3E)-1,3,5-trifluoropenta-1,3-diene 11, and (1Z,3E)-1,3,5- trifluoropenta-1,3-diene 13. A detailed analysis of the geometries, energies, and electronic characteristics of the sigmatropic transposition compared to those of the unsubstituted case provides insights into substituent effects of this prototype of pericyclic reaction. The inductive and mesomeric effects of heteroatoms or heterosubstituents are of a great importance and in a continuous balance in the energetics of the transformation. Sterics can also play an important role due to the geometrical constraints of the reaction. As a general trend, decreasing the electron density of the phi system destabilizes the aromatic transition structure and increases the activation energy, and vice versa.     

Coordination polymers and hybrid networks of different dimensionalities formed by metal sulfites

In our effort to explore the use of the sulfite ion to design hybrid and open-framework materials, we have been able to prepare, under hydrothermal conditions, zero-dimensional [Zn(C12H8N2)(SO3)].2H2O, I (a = 7.5737(5) A, b = 10.3969(6) A, c = 10.3986(6) A, alpha = 64.172(1) degrees , beta = 69.395(1) degrees , gamma = 79.333(1) degrees , Z = 2, and space group P), one-dimensional [Zn2(C12H8N2)(SO3)2(H2O)], II (a = 8.0247(3) A, b = 9.4962(3) A, c = 10.2740(2) A, alpha = 81.070(1) degrees , beta = 80.438(1) degrees , gamma = 75.66(5) degrees , Z = 2, and space group P), two-dimensional [Zn2(C10H8N2)(SO3)2].H2O, III (a = 16.6062(1) A, b = 4.7935(1) A, c = 19.2721(5) A, beta = 100.674(2) degrees , Z = 4, and space group C2/c), and three-dimensional [Zn4(C6H12N2)(SO3)4(H2O)4], IV (a = 11.0793(3) A, c = 8.8246(3) A, Z = 2, and space group P42nm), of which the last three are coordination polymers. A hybrid open-framework sulfite-sulfate of the composition [C2H10N2][Nd(SO3)(SO4)(H2O)]2, V (a = 9.0880(3) A, b = 6.9429(2) A, c = 13.0805(5) A, beta = 91.551(2) degrees , Z = 2, and space group P21/c), with a layered structure containing metal-oxygen-metal bonds has also been described.     

Four new cycloartane glycosides from Thalictrum fortunei

Four new cycloartane glycosides were isolated from the aerial parts of Thalictrum fortunei (Ranunculaceae). The chemical structures of these new glycosides were elucidated as 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-quinovopyranosyl-(1-->6)-beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside, and 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-fucopyranosyl (22S,24Z)-cycloart-24-en-3beta,22,26-triol 26-O-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside by extensive NMR methods, HR-ESI-MS, and hydrolysis. This is the first report of (22S,24Z)-3beta,22,26-trihydroxycycloartan-24-ene (thelictogenin A, 5) being glycosylated at C-26.     

Studies on Synthesis and Photochromism of a Novel Class of Fulgimide： （Z）-4-Oxazolylfulgimide

A novel class of fulgimide, (Z)-4-oxazolylfulgimide ((Z)-1-benzyl-4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl)ethylidene]tetrahydropyrrole-2,5-dione), was synthesized by the reaction of (Z)-4-oxazolyl fulgide (4-isopropylidene-3-[1-(2-aryl-5-methyloxazolyl) ethylidene]tetrahydrofuran-2,5-dione) with benzyl amine. Photochromic property of (Z)-4-oxazolylfulgimide was studied. Compared with (Z)-4-oxazolylfulgide, the absorption maximum of the colored form of (Z)-4-oxazolylfulgimide is bathochromic-shifted. Substituents on the aryl ring affect the absorption maximum of the open form and the colored form of (Z)-4-oxazolylfulgimide.     

Rhenium(I) carbonyl complexes of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPT). Rhenium(I)-promoted methoxylation of the triazine ring carbon atom in dinuclear rhenium complexes

2,4,6-Tris(2-pyridyl)-1,3,5-triazine (TPT) bridged dinuclear rhenium(I) tricarbonyl halide complexes with the composition (mu-TPT)[ReX(CO)(3)](2) (3, X = Cl; 4, X = Br) can be made either by one-pot reaction of TPT with 2 equiv of [ReX(CO)(5)] (X = Cl and Br) in chloroform or by reacting mononuclear [ReX(CO)(3)(TPT)] (2) (1, X = Cl; 2, X = Br) with an excess amount of [ReX(CO)(5)]. Crystal data are as follows. 1: monoclinic, P2(1)/c, a = 11.751(1) A, b = 11.376(1) A, c = 15.562(2) A, beta = 103.584(2) degrees, V = 2022.0(4) A(3), Z = 4. 2: monoclinic, P2(1)/c, a = 11.896(1) A, b = 11.396(1) A, c = 15.655(1) A, beta = 104.474(2) degrees, V = 2054.9(3) A(3), Z = 4. 3: triclinic, P1, a = 11.541(2) A, b = 12.119(2) A, c = 13.199(2) A, alpha = 80.377(2) degrees, beta = 76.204(3) degrees, gamma = 66.826(2) degrees, V = 1642.5(4) A(3), Z = 2. Crystals of 4 crystallized from acetone: triclinic, P1, a = 11.586(5) A, b = 12.144(5) A, c = 13.364(6) A, alpha = 80.599(7) degrees, beta = 76.271(8) degrees, gamma = 67.158(8) degrees, V = 1678.0(12) A(3), Z = 2. Crystals of 4' are obtained from CH(2)Cl(2)-pentane solution: monoclinic, C2/c, a = 17.555(4) A, b = 15.277(3) A, c = 13.093(3) A, beta = 111.179(3) degrees, V = 3274.0(12) A(3), Z = 4. By contrast, similar reactions in the presence of methanol yielded complexes with the composition [mu-C(3)N(3)(OMe)(py)(2)(pyH)][ReX(CO)(3)](2) (5, X = Cl; 6, X = Br). Crystal data for 5: monoclinic, C2/c, a = 26.952(2) A, b = 16.602(1) A, c = 14.641(1) A, beta = 116.147(1) degrees, V = 5880.5(8) A(3), Z = 8. 6: monoclinic, C2/c, a = 27.513(3) A, b = 16.740(2) A, c = 14.837(2) A, beta = 116.925(2) degrees, V = 6092.8(10) A(3), Z = 8. An unusual metal-induced methoxylation at the carbon atom of the triazine ring of the bridging TPT ligand was observed. The nucleophilic attack of MeO(-) on C(3) results in a tetrahedral geometry around the carbon atom. Concomitantly, the uncoordinated pyridyl ring is protonated and rotated into a perpendicular orientation relative to the central C(3)N(3) ring. Reaction of TPT with [NEt(4)](2)[ReBr(3)(CO)(3)] in benzene-methanol resulted in an unexpected dinuclear complex 7, with formulation [mu-C(3)N(3)(OMe)(py)(3)][Re(CO)(3)][ReBr(CO)(3)]. The methoxylated TPT ligand functions simultaneously as a tridentate and bidentate ligand with two fac-Re(CO)(3)(+) cores. Crystal data for 7: monoclinic, P2(1)/n, a = 12.114(1) A, b = 14.878(1) A, c = 15.807(1) A, beta = 104.601(1) degrees, V = 2756.9(3) A(3), Z = 4.     

Adduct formation between alkali metal ions and divalent metal salicylaldimine complexes having methoxy substituents. A structural investigation

Sodium, potassium, and cesium salts (iodides, nitrates, acetates, and tetraphenylborates) form 1/1, 1/2 and 2/3 adducts with MLn [M = Co, Ni, Cu, and Zn; n = 1-4; H2L1 = N,N'-(3-methoxysalicyliden)ethane-1,2-diamine; H2L2, H2L3, and H2L4 are the -propane-1,2-diamine, -o-phenylenediamine, and -propane-1,3-diamine analogues of H2L1). Metal salicyladimine, alkali metal, and anion all exert influence on stoichiometry and reactivity. Sodium ions tend to reside within the planes of the salicylaldimine oxygens, as in Na(NO3)(MeOH).NiL4 (1), Na(NO3)(MeOH).CuL1 (2; both with unusual seven-coordinated sodium), and Na.(NiL4)2I.EtOH.H2O (3; with dodecahedral sodium coordination geometry). Potassium and cesium tend to locate between salicylaldimine ligands as in KI.NiL4 (4) and [Cs(NO3).NiL4]3.MeOH (5; structures with infinite sandwich assemblies), CsI.(NiL2)2.H2O (6), CsI3.(NiL4)2 (7; simple sandwich structures), and [K(MeCN)]2.(NiL4)3 (8; a triple-decker sandwich structure). Crystal data for 1 are the following: triclinic, P1, a = 7.3554(6) A, b = 11.2778(10) A, c = 13.562(2) A, alpha = 96.364(10) degrees, beta = 101.924(9) degrees, gamma = 96.809(10) degrees, Z = 2. For 2, triclinic, P1, a = 7.2247(7) A, b = 11.0427(6) A, c = 13.5610(12) A, alpha = 94.804(5) degrees, beta = 98.669(7) degrees, gamma = 99.26(6) Z = 2. For 3, orthorhombic, Pbca, a = 14.4648(19) A, b = 20.968(3) A, c = 28.404(3) A, Z = 8. For 4, triclinic, P1, a = 12.4904(17) A, b = 13.9363(13) A, c = 14.1060(12) A, alpha = 61.033(7) degrees, beta = 89.567(9) degrees, gamma = 71.579(10) degrees, Z = 2. For 5, monoclinic. P2(1)/n, a = 12.5910(2) A, b = 23.4880(2) A, c = 22.6660(2) A, beta = 99.3500(1) degree, Z = 4. For 6, orthorhombic, Pbca, a = 15.752(3) A, b = 23.276(8) A, c = 25.206(6) A, Z = 8. For 7, triclinic, P1, a = 9.6809(11) A, b = 10.0015(13) A, c = 11.2686(13) A, alpha = 101.03 degrees, beta = 90.97 degrees, gamma = 100.55 degrees, Z = 2. For 8, monoclinic, C2/c, a = 29.573(5) A, b = 18.047(3) A, c = 23.184(3) A, beta = 122.860(10) degrees, Z = 8.     

Analysis of melt copolymers

Melt copolymer chains are the main (most abundant) reaction product obtained when heating a blend of two (or more) condensation polymers (such as polyester + polycarbonate or polyester + polyamide or polyester + polyester) in which exchange reactions occur. In fact, during the melt-mixing reaction, an AB copolymer is formed and, as a consequence, the sample is a complex mixture made of three components or simply "parts", referred to as Z1, Z2 and Z3, where Z1 and Z2 are the parts for unreacted homopolymers (A and B), whereas Z3 is the part for the copolymer. In this paper, it is shown that matrix-assisted laser desorption/ionization mass spectrometry (and mass spectrometry in general) can be used to monitor the yield of the reactive blending reaction, YR, by measuring the amount of unreacted homopolymer (Z1 and Z2). In order to allow for comparisons, the paper also discusses conventional methods for measuring Z1 and Z2, such as liquid chromatography and nuclear magnetic resonance.     

Metal-metal interactions in weakly coupled mixed-valence E- and Z-diferrocenylethylene complexes

To study metal-to-metal interactions in mixed-valence states of two weakly coupling ferrocenyl groups assembled in E or Z conformation on an ethylenic double bond, E-1,2-dimethyldiferrocenylethylene (1), Z-1,2-dimethyldi-ferrocenylethylene (2), and 1,2-diferrocenylcyclohexene (3) were synthesized and structurally characterized. Crystals of 1 are triclinic, P1, with a = 7.494(9) A, b = 10.801(3) A, c = 11.971(2) A, alpha = 102.17(2) degrees, beta = 106.12(9) degrees, gamma = 90.42(2) degrees, V = 907.8 A3, and Z = 2. Crystals of 2 are monoclinic, P2(1)/c, with a = 13.601(8) A, b = 11.104(4) A, c = 13.732(1) A, beta = 114.26(7) degrees, V = 1890.8(3) A3, and Z = 4. Crystals of 3 are orthorhombic, P2(1)2(1)2(1), with a = 5.766(2) A, b = 13.090(1) A, c = 26.695(2) A, V = 2014.9(3) A3, and Z = 4. Intervalence transition spectra (IT) and electrochemical data have been determined and compared with those of diferrocenyl-benzene (para, ortho, and meta). The comproportionation constants in nitrobenzene at 25 degrees C were found to be 490 and 813 for 1 and 3, respectively. That of 2 was not measured because of the fact that 2+ isomerizes rapidly in all solvents tested, yielding nearly a racemic mixture of E and Z conformers. This finding helps to clear the paradoxical phenomenon between experimental results of mixed-valence complexes of E- and Z-1,2-bis(1'-ethyl-1-ferrocenyl)-1,2-dimethylethylene and theories. The stability of the mixed-valence species was discussed in terms of resonance delocalization, Coulomb repulsion energy, inductive effect, magnetic interaction, structural factors, and statistical factor. According to our analysis based on the Hush formalism, the contribution due to Coulomb repulsion energy dominates the overall stability of the mixed-valence state in 1+, 2+, and 3+. Stabilization that arises from resonance delocalization is only minor and contributes less than 4% to the overall stability, even in 3+ where linked Cp rings and the ethylenic plane are coplanar. In calculating the resonance contribution, crystallographic Fe-Fe distances of 7.44 A (1) and 6.68 A (3) were used for 1+, and 3+, respectively.     

Coordination of lanthanide triflates and perchlorates with N,N,N',N'-tetramethylsuccinamide

Compounds formed from the reaction of N,N,N',N'-tetramethylsuccinamide (TMSA) with trivalent lanthanide salts possessing the poorly coordinating counteranions triflate (CF3SO3-) and perchlorate (ClO4-) have been prepared and examined. Structural features of these Ln-TMSA compounds have been studied in the solid phase by thermogravimetric analysis, infrared spectroscopy, and, in selected cases, by single-crystal X-ray diffraction and in solution by infrared spectroscopy. Eight-coordinate compounds, [Ln(TMSA)4]3+, derived from coordination of four succinamide ligands to the metal ion could be formed with all lanthanides examined (Ln = La, Pr, Nd, Eu, Yb, Lu). Structural analyses by single-crystal X-ray diffraction were performed for the lanthanide triflate salts Ln(C8H16N2O2)4(CF3SO3)3: Ln = La, compound 1, monoclinic, P2(1)/n, a = 11.0952(2) A, b = 19.2672(2) A, c = 24.9759(3) A, beta = 90.637(1) degrees, Z = 4, Dcalcd = 1.586 g cm-3; Ln = Nd, compound 2, monoclinic, C2/c, a = 24.6586(10) A, b = 19.3078(7) A, c = 11.1429(4) A, beta = 90.450(1) degrees, Z = 4, Dcalcd = 1.603 g cm-3; Ln = Eu, compound 3, monoclinic, C2/c, a = 24.4934(2) A, b = 19.3702(1) A, c = 11.1542(1) A, beta = 90.229(1) degrees, Z = 4, Dcalcd = 1.617 g cm-3; Ln = Lu, compound 5, monoclinic, C2/c, a = 24.2435(4) A, b = 19.6141(2) A, c = 11.2635(1) A, beta = 90.049(1) degrees, Z = 4, Dcalcd = 1.626 g cm-3. X-ray analysis was also carried out for the perchlorate salt: Ln = Eu, compound 4, triclinic, P1, a = 10.9611(2) A, b = 14.6144(3) A, c = 15.7992(2) A, alpha = 106.594(1) degrees, beta = 91.538(1) degrees, gamma = 90.311(1) degrees, Z = 2, Dcalcd = 1.561 g cm-3. In the presence of significant amounts of water, 7-coordinate compounds with mixed aquo-TMSA cation structures [Ln(TMSA)3(H2O)]3+ (Ln = Yb) and [Ln(TMSA)2(H2O)3]3+ (Ln = La, Pr, Nd, Eu, Yb) have been isolated with structural determinations by single-crystal X-ray diffraction obtained for the following species: Yb(C8H16N2O2)3(H2O)(CF3SO3)3, compound 6, monoclinic, P2(1)/n, a = 8.9443(3) A, b = 11.1924(4) A, c = 44.2517(13) A, beta = 93.264(1) degrees, Z = 4, Dcalcd = 1.735 g cm-3; Yb(C8H16N2O2)3(H2O)(ClO4)3, compound 7, monoclinic, Cc, a = 19.2312(6) A, b = 11.1552(3) A, c = 19.8016(4) A, beta = 111.4260(1) degrees, Z = 4, Dcalcd = 1.690 g cm-3; Yb(C8H16N2O2)2(H2O)3(CF3SO3)3, compound 8, triclinic, P1, a = 8.6719(1) A, b = 12.2683(2) A, c = 19.8094(3) A, alpha = 75.815(1) degrees, beta = 86.805(1) degrees, gamma = 72.607(1) degrees, Z = 2, Dcalcd = 1.736 g cm-3. Unlike in the analogous nitrate salts, only bidentate binding of the succinamide ligand to the lanthanide metal is observed. IR spectroscopy studies in anhydrous acetonitrile suggest that the solid-state structures of these Ln-TMSA compounds are maintained in solution.     

Synthesis and characterization of six new quaternary actinide thiophosphate compounds: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6)(,) K(10)Th(3)(P(2)S(7))(4)(PS(4))(2), and A(5)An(PS(4))(3), (A = K, Rb, Cs; An = U, Th)

Six new actinide metal thiophosphates have been synthesized by the reactive flux method and characterized by single-crystal X-ray diffraction: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6) (I), K(10)Th(3)(P(2)S(7))(4)(PS(4))(2) (II), K(5)U(PS(4))(3) (III), K(5)Th(PS(4))(3) (IV), Rb(5)Th(PS(4))(3) (V), and Cs(5)Th(PS(4))(3) (VI). Compound I crystallizes in the monoclinic space group P2(1)/c with a = 33.2897(1) A, b = 14.9295(1) A, c = 17.3528(2) A, beta = 115.478(1) degrees, Z = 8. Compound II crystallizes in the monoclinic space group C2/c with a = 32.8085(6) A, b = 9.0482(2) A, c = 27.2972(3) A, beta = 125.720(1) degrees, Z = 8. Compound III crystallizes in the monoclinic space group P2(1)/c with a = 14.6132(1) A, b = 17.0884(2) A, c = 9.7082(2) A, beta = 108.63(1) degrees, Z = 4. Compound IV crystallizes in the monoclinic space group P2(1)/n with a = 9.7436(1) A, b = 11.3894(2) A, c = 20.0163(3) A, beta = 90.041(1) degrees, Z = 4, as a pseudo-merohedrally twinned cell. Compound V crystallizes in the monoclinic space group P2(1)/c with a = 13.197(4) A, b = 9.997(4) A, c = 18.189(7) A, beta = 100.77(1) degrees, Z = 4. Compound VI crystallizes in the monoclinic space group P2(1)/c with a = 13.5624(1) A, b = 10.3007(1) A, c = 18.6738(1) A, beta = 100.670(1) degrees, Z = 4. Optical band-gap measurements by diffuse reflectance show that compounds I and III contain tetravalent uranium as part of an extended electronic system. Thorium-containing compounds are large-gap materials. Raman spectroscopy on single crystals displays the vibrational characteristics expected for [PS(4)](3)(-), [P(2)S(7)](4-), and the new [P(3)S(10)](5)(-) building blocks. This new thiophosphate building block has not been observed except in the structure of the uranium-containing compound Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6).     

Parametric analysis of kinetic models. I. The simplest autocatalytic oscillator

A series of mechanisms allowing oscillations and differring in the form of their buffer steps (step 3)

Solid-state synthesis and characterization of novel aluminophosphates,A3Al2P3O12 (A = Na,K, Rb,Tl): influence of A+ ions on the coordination of aluminum

Four aluminophosphates, A3Al2P3O12 (A = Na, K (1), Rb (2), Tl (3)), have been synthesized by solid-state reactions and characterized by X-ray diffraction and NMR and IR spectroscopic techniques. Aluminum has trigonal bipyramidal coordination in the thallium compound and tetrahedral coordination in the others. Potassium, rubidium and thallium analogues have been structurally characterized by single-crystal X-ray diffraction and found to possess three-dimensional (Al2P3O12)3- anionic frameworks with channels occupied by A+ countercations. These frameworks are built from corner connections of PO4 tetrahedra with AlO4 tetrahedra in 1 and 2 and with AlO5 trigonal bipyramids in 3. Pertinent crystal data are as follows: for 1, orthorhombic space group Pna2(1), a = 8.685(2) A, b = 16.947(2) A, c = 8.458(3) A, Z = 4; for 2, orthorhombic space group Cmc2(1), a = 17.164(2) A, b = 8.6270(6) A, c = 8.8140(14) A, Z = 4; for 3, orthorhombic space group Pna2(1), a = 6.1478(15) A, b = 10.396(3) A, c = 17.787(5) A, Z = 4. Compound 3 is a rare example of an oxide possessing aluminum exclusively in trigonal bipyramidal coordination.     

Syntheses and structural characterization of the (OCnOPor) capped porphyrins: Co(OC2OPor).CH2Cl2, Co(OC2OPor)(NO)out.0.46CHCl3, Co(OC3OPor).CHCl3, and Co(OC3OPor)(MeIm).3C7H8

The compounds Co(OC2OPor).CH2Cl2 (1), Co(OC2OPor)(NO)out.0.46CHCl3 (2), Co(OC3OPor).CHCl3 (3), and Co(OC3OPor)(MeIm).3C7H8 (4) (OC2OPor = 5,10,15,20-(benzene-1,2,4,5- tetrakis(2-phenyloxy)ethoxy)-2',2",2"',2"-tetraylporphyrinato dianion; OC3OPor = 5,10,15,20-(benzene-1,2,4,5-tetrakis(2- phenyloxy)propoxy)-2',2",2"',2"-tetraylporphyrinato dianion; MeIm = 1-methylimidazole), have been synthesized, and their structures have been determined by single-crystal X-ray diffraction methods at T = -120 degrees C: 1, a = 8.824(1) A, b = 16.674(1) A, c = 16.836(1) A, alpha = 104.453(1) degrees, beta = 92.752(1) degrees, gamma = 90.983(1) degrees, P1, Z = 2; 2, a = 9.019(1) A, b = 16.588(2) A, c = 16.909(2) A, alpha = 103.923(2) degrees, beta = 92.082(2) degrees, gamma = 93.583(2) degrees, P1, Z = 2; 3, a = 13.484(3) A, b = 14.404(3) A, c = 14.570(3) A, alpha = 105.508(3) degrees, beta = 100.678(3) degrees, gamma = 93.509(4) degrees, P1, Z = 2; 4, a = 16.490(1) A, b = 22.324(2) A, c = 17.257(1) A, b = 92.437(1) degrees, P2(1)/n, Z = 4. These compounds are the first structurally characterized Co-bound members of the OCnOPor ligand system. The NO ligand in 2 and the MeIm ligand in 4 bind asymmetrically and lead to several metrical changes in these porphyrins, e.g., variations in average porphyrin deviations and Co atom displacements relative to the porphyrinato N atoms and the mean porphyrin planes.     

Unsaturated selenacrown ethers: synthesis, structure, and formation of silver complexes

The unsaturated selenacrown ethers, (Z,Z,Z,Z,Z)-1,4,7,10,13-pentaselenacyclopentadeca-2,5,8,11,14-pentaene (15-US-5) (2), (Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16-hexaselenacyclooctadeca-2,5,8,11,14,17-hexaene (18-US-6) (3), (Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19-heptaselenacycloheneicosa-2,5,8,11,14,17,20-heptaene (21-US-7) (4), (Z,Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19,22-octaselenacyclotetracosa-2,5,8,11,14,17,20,23-octaene (24-US-8) (5), and (Z,Z,Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19,22,25-nonaselenacycloheptacosa-2,5,8,11,14,17,20,23,26-nonaene (27-US-9) (6), were obtained together with 1,4-diselenin (1) by reacting sodium selenide with cis-dichloroethene in the presence of a phase-transfer catalyst. The crystal structures of 2-5 were determined by X-ray crystallographic analysis. The UV spectra of the selenacrown ethers showed absorption maximums in the range of 251-262 nm, which were assigned to n-->pi transitions. The cyclic voltammograms indicated that the large unsaturated selenacrown ethers were oxidized more easily than the small ones. The thermal reactions of the unsaturated selenacrown ethers afforded 1,4-diselenin (1) along with polymeric materials, whereas 1 was thermally stable even at 100 degrees C. The reactions of 1 or unsaturated selenacrown ethers 2-5 with silver ion yielded various novel silver complexes, Ag(C(4)H(4)Se(2))(CF(3)COO) (7), Ag(C(4)H(4)Se(2))(2)(CF(3)COO) (8), Ag(15-US-5)(CF(3)COO) (9), Ag(5)(18-US-6)(3)(CF(3)COO)(5) (10), Ag(7)(21-US-7)(CF(3)COO)(5) (11), Ag(24-US-8)(2)(CF(3)COO) (12), Ag(2)(24-US-8)(CF(3)COO)(2) (13), Ag(3)(24-US-8)(2)(CF(3)COO)(3) (14), Ag(15-US-5)NO(3) (15), and Ag(21-US-7)BF(4) (16). The stoichiometry for the complexation with silver trifluoroacetate in solution was examined by (1)H NMR measurement. The titration plots of 2 and 5 under the dilution conditions showed a distinct inflection point at the 1/1 metal/macrocycle ratio, whereas the plots of 1 and 3 showed gradual change.     

Synthesis and characterization of novel homoleptic N,N-dialkylcarbamato complexes of antimony: precursors for the deposition of antimony oxides

A series of tris(N,N-dialkylcarbamato)antimony(III) complexes, Sb(O(2)CNR(2))(3) (R = Me, Et, Pr(i)()), have been synthesized and are the first members of this class of compound to have been crystallographically characterized. Sb(O(2)CNMe(2))(3) (1) exists as a weakly bound dimer, whereas its diethyl and diisopropyl analogues (2, 3) are monomeric. In addition, tetrakis(N,N-diethylcarbamato)tin(IV) (4) has been prepared for comparison and shown by single-crystal X-ray analysis to exhibit the relatively rare SnO(8) coordination. Crystallographic data: for 1, a = 8.7520(5) A, b = 14.2970(8) A, c = 11.8150(7) A, beta = 108.029(2) degrees, monoclinic, P2(1)/c, Z = 4; for 2, a = b = 14.4690(2) A, c = 16.6740(2) A, trigonal, Rthremacr;, Z = 6; for 3, a = 11.9881(2) A, b = 11.6521(3) A, c = 19.8780(6) A, beta = 90.401(1) degrees, monoclinic, P2(1)/n, Z = 4; for 4, a = 13.9654(2) A, b = 12.0817(2) A, c = 16.6752(2) A, beta = 108.1960(7) degrees, monoclinic, C2/c, Z = 4. Sb(O(2)CNMe(2))(3) has been used as a single-source precursor in the low-pressure chemical vapor deposition of the senarmonite form of Sb(2)O(3).     

Synthesis and characterization of heavier dioxouranium(VI) dihalides

The synthesis and characterization of the dioxouranium(VI) dibromide and iodide hydrates, UO(2)Br(2)x3H(2)O (1), [UO(2)Br(2)(OH(2))(2)](2) (2), and UO(2)I(2)x2H(2)Ox4Et(2)O (3), are reported. Moreover, adducts of UO(2)I(2) and UO(2)Br(2) with large, bulky OP(NMe(2))(3) and OPPh(3) ligands such as UO(2)I(2)(OP(NMe(2))(3))(2) (4), UO(2)Br(2)(OP(NMe(2))(3))(2) (5), and UO(2)I(2)(OPPh(3))(2)(6) are discussed. The structures of the following compounds were determined using single-crystal X-ray diffraction techniques: (1) monoclinic, P2(1)/c, a = 9.7376(8) A, b = 6.5471(5) A, c = 12.817(1) A, beta = 94.104(1) degrees , V = 815.0(1) A(3), Z = 4; (2) monoclinic, P2(1)/c, a = 6.0568(7) A, b = 10.5117(9) A, c = 10.362(1) A, beta = 99.62(1) degrees , V = 650.5(1) A(3), Z = 2; (4) tetragonal, P4(1)2(1)2, a = 10.6519(3) A, b = 10.6519(3) A, c = 24.0758(6) A, V = 2731.7(1) A(3), Z = 4; (5) tetragonal, P4(1)2(1)2, a = 10.4645(1) A, b = 10.4645(1) A, c = 23.7805(3) A, V = 2604.10(5) A(3), Z = 4, and (6) monoclinic, P2(1)/c, a = 9.6543(1) A, b = 18.8968(3) A, c = 10.9042(2) A, beta =115.2134(5) degrees , V = 1783.01(5) A(3), Z = 2. Whereas 1 and 2 are the first UO(2)Br(2) hydrates and the last missing members of the UO(2)X(2) hydrate (X = Cl --> I) series to be structurally characterized, 4 and 6 contain room-temperature stable U(VI)-I bonds with 4 being the first structurally characterized room temperature stable U(VI)-I compound which can be conveniently prepared on a gram scale in quantitative yield. The synthesis and characterization of 5 using an analogous halogen exchange reaction to that used for the preparation of 4 is also reported.     

Organometallic silver(I) supramolecular complexes generated from multidentate furan-containing symmetric and unsymmetric fulvene ligands and silver(I) salts

One new conjugated symmetric fulvene ligand L1 and two new unsymmetric fulvene ligands L2 and L3 were synthesized. Five new supramolecular complexes, namely Ag2(L1)3(SO3CF3)3 (1) (1, monoclinic, P2(1)/c; a = 12.702(3) A, b = 26.118(7) A, c = 13.998(4) A, beta = 96.063(4) degrees, Z = 4), [Ag(L1)]ClO4 (2) (monoclinic, C2/c; a = 17.363(2) A, b = 13.2794(18) A, c = 13.4884(18) A, beta = 100.292(2) degrees, Z = 8), [Ag(L1)(C6H6)SbF6] x 0.5C6H6 x H2O (3) (monoclinic, P2(1)/c; a = 6.8839(11) A, b = 20.242(3) A, c = 18.934(3) A, beta = 91.994(3) degrees, Z = 4), Ag(L2)(SO3CF3) (4) (triclinic, P1; a = 8.629(3) A, b = 10.915(3) A, c = 11.178(3) A, alpha = 100.978(4) degrees, beta = 91.994(3) degrees, gamma = 105.652(4) degrees, Z = 2), and Ag(L3)(H2O)(SO3CF3) (5) (triclinic, P1; a = 8.914(5) A, b = 10.809(6) A, c = 11.283(6) A, alpha = 69.255(8) degrees, beta = 87.163(9) degrees, gamma = 84.993(8) degrees, Z = 2) were obtained through self-assembly based on these three new fulvene ligands in a benzene/toluene mixed-solvent system. Compounds 1-5 have been fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The results indicate that the coordination chemistry of new fulvene ligands is versatile. They can adopt either cis- or trans-conformation to bind soft acid Ag(I) ion through not only the terminal -CN and furan functional groups but also the fulvene carbon atoms into organometallic coordination polymers or discrete complexes. In addition, the luminescent properties of L1-L3 and their Ag(I) complexes were investigated preliminarily in EtOH and solid state.