Structural and 31P NMR solution studies on some cyclic triphosphenium ions and their 2‐arsa‐analogues

Several new cyclic triphosphenium ions and their 2‐arsa‐analogues have been identified in solution by ³¹P NMR spectroscopy. The crystal and molecular structures of the cations 1a,b , as their hexachlorostannate (IV) salts have shown that the five membered heterocyclic rings are planar, whereas the cation 9b as its diphosphanedioxide‐bis[pentachlorostannate(IV)] salt is nonplanar, like its saturated phosphorus counterpart. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:501–510, 2001     

Syntheses,crystallographic/computational characterizations,and reactions of the first 10-vertex arachno- and nido-phosphamonocarbaboranes

A synthetic sequence involving the initial reaction of a substituted phosphorus dihalide (RPCl(2), R = CH(3), C(6)H(5)) with the arachno-CB(8)H(13)(-) (1-) monoanion followed by an in situ dehydrohalogenation reaction initiated by Proton Sponge, resulted in phosphorus cage insertion to yield the first 10-vertex arachno- and nido-phosphamonocarbaboranes, exo-6-R-arachno-6,7-PCB(8)H(12) (2a, 2b) and PSH(+)6-R-nido-6,9-PCB(8)H(9)(-) (PSH+3a-, PSH+3b-) (R = C(6)H(5) (a), CH(3) (b)). Alternatively, 2a and 2b were synthesized in high yield as the sole product of the reaction of the arachno-4-CB(8)H(12)(2-) (1(2-)) dianion with RPCl(2). Crystallographic determinations of PSH+3a- and PSH+3b- in conjunction with DFT/GIAO computational studies of the anions have confirmed the expected nido cage framework based on an octadecahedron missing the six-coordinate vertex. DFT/GIAO computational studies have also shown that while the gross cage geometries of the exo-6-R-arachno-6,7-PCB(8)H(12) compounds 2a and 2b resemble the known isoelectronic arachno-6,9-SCB(8)H(12), the phosphorus and carbon atoms are in thermodynamically unfavorable adjacent positions on the six-membered puckered face. They also each have an endo-hydrogen at the P6-position arising from proton transfer to the basic phosphorus during the cage-insertion reaction. Possible stepwise reaction pathways that can account for the formation of both the arachno and nido products are discussed. Deprotonation of 2a and 2b resulted in the formation of their corresponding conjugate monoanions, 6-R-arachno-6,7-PCB(8)H(11)(-) (2a-, 2b-), in which the proton that had been attached to the P6 atom was removed. Reactions of 2a- with O(2), S(8), BH(3).THF, or Br(2) further demonstrated the basicity of the P6-phosphorus yielding the new arachno-substituted compounds, endo-6-O-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (4a-), endo-6-S-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (5a-), endo-6-BH(3)-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (6a-), and endo-6-Br-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11) (7a), respectively, in which the O, S, BH(3), and Br substituents are bound to the phosphorus at the endo position.     

Reactions of 2-indolylphosphines with Ru3(CO)12: cluster capping with mu 3,eta 2-indolylphosphine as an anionic six-electron P,N-donor ligand

Stepwise bidentate coordination of the novel indolylphosphine ligands HL (1, HL = P(C(6)H(5))(2)(C(9)H(8)N)(diphenyl-2-(3-methylindolyl)phosphine); 2, HL = P(C(6)H(5))(C(9)H(8)N)(2)(phenyldi-2-(3-methylindolyl)phosphine); and 3, HL = P(C(6)H(5))(C(17)H(12)N(2))(di(1H-3-indolyl)methane-(2,12)-phenylphosphine)) to the ruthenium cluster Ru(3)(CO)(12) is demonstrated. Reactions of 1-3 with Ru(3)(CO)(12) led to the formation of Ru(3)(CO)(11)(HL) (4-6), in which HL is mono-coordinated through the phosphorus atom. The X-ray structures of 4-6 show that the phosphorus atom is equatorially coordinated to the triruthenium core. In all cases, gentle heating of Ru(3)(CO)(11)(HL) resulted in the formation of Ru(3)(CO)(9)(mu-H)(mu(3),eta(2)-L)(7-9) in which the NH proton of the indolyl substituent had migrated to the ruthenium core to form a bridging hydride ligand. The X-ray structure of Ru(3)(CO)(9)(mu-H)[mu(3),eta(2)-P(C(6)H(5))(2)(C(9)H(7)N)] (7) shows the deprotonated nitrogen atom of the indolyl moiety bridging over the face of the triruthenium core, bonding to the two ruthenium metal centers to which the phosphorus atom is not bound. The phosphorus atom is forced to adopt an axial bonding mode due to the geometry of the indolylphosphine ligand. Cluster electron counting and X-ray data suggest that the indolylphosphine behaves as a six-electron ligand in this mode of coordination. Compounds 4-9 have been characterized by IR, (1)H, (13)C and (31)P NMR spectroscopy.     

Monovalent indium in a sulfur-rich coordination environment: synthesis, structure and reactivity of tris(2-mercapto-1-tert-butylimidazolyl)hydroborato indium, [TmBut]In

[Tm(Bu(t))]In, the first structurally-characterized monovalent indium compound that features a sulfur-rich coordination environment, has been synthesized via treatment of InCl with [Tm(Bu(t))]K; in contrast to the thallium counterpart, the lone pair of [Tm(Bu(t))]In is a site of reactivity, thereby allowing formation of [Tm(Bu(t))]In-->B(C(6)F(5))(3) and [Tm(Bu(t))]In(kappa(2)-S(4)) upon treatment with B(C(6)F(5))(3) and S(8), respectively.     

Beiträge zur Chemie des Phosphors. 117. Synthese und Eigenschaften der Hexaorganyl-octaphosphane(6) P8R6, R = Me,Et, Pri

Contributions to the Chemistry of Phosphorus. 117. Synthesis and Properties of the Hexaorganyl-octaphosphanes(6) P₈R₆, R = Me, Et, Prⁱ The Hexaorganyl-octaphosphanes(6) P₈Me₆ ( 1 ), P₈Et₆ ( 2 ), and P₈Pr ( 3 ) have been obtained by reacting mixtures of the corresponding organyldichlorophosphanes and phosphorus(III) chloride with magnesium. In the case of 1 and 2 the organyl-cyclophosphanes (PR)_n can also be used in the reaction with phosphorus(III) chloride and magnesium. Besides, mainly P₇R₅ as well as other polycyclic organylphosphanes are formed. 2 and 3 have been isolated as pure substances, whereas 1 was concentrated to ?50 mol-% in the product mixture. According to their ³¹P-NMR spectra the three compounds possess a pentalane-analogous P₈-skeleton with the substituents within each five-membered ring in trans position and the substituents of different five-membered rings next to the zero bridge in cis position; the organyl groups in the 3, 7 position are trans oriented with respect to the free electron pairs of the bridgehead atoms. Therefore, the structures of 1 – 3 differ from the known tert-butyl compound P₈Bu, whereas the corresponding phosphorus hydride P₈H₆ has the same pentalane-analogous P₈-skeleton, thus being a bicyclo[3.3.0]octaphosphane.     

Synthesis of 2-(β-D-ribofuranosyl)pyrimidines,A new class of C-nucleosides

A new C-glycosyl precursor for C-nucleoside synthesis, 2,5-anhydroallonamidine hydrochloride ( 4 ) was prepared and utilized in a Traube type synthesis to prepare 2-(β-D-ribofuranosyl)pyrimidines, a new class of C-nucleosides. The anomeric configuration of 4 was confirmed by single-crystal X-ray analysis. Reaction of 4 with ethyl acetoacetate gave 6-methyl-2-(β-D-ribofuranosyl)pyrimidin-4-(1H)-one ( 5 ). Reaction of 4 with diethyl sodio oxaloacetate gave 2-(β-D-ribofuranosyl)pyrimidin-6(1H)-oxo-4-carboxylic acid ( 6 ). Esterification of 6 with ethanolic hydrogen-chloride gave the corresponding ester 7 which when treated with ethanolic ammonia gave 2-(β-D-ribofuranosyl)pyrimidin-6(1H)-oxo-4-carboxamide ( 8 ). Condensation of 2,5-anhydroallonamidine hydrochloride ( 4 ) with ethyl 4-(dimethylamino)-2-oxo-3-butenoate ( 9 ), gave ethyl 2-(β-D-ribofuranosyl)pyrimidine-4-carboxylate ( 10 ). Treatment of 10 with ethanolic ammonia gave 2-(β-D-ribofuranosyl)pyrimidine-4-carboxamide ( 11 ). Single-crystal X-ray analysis confirmed the β-anomeric configuration of 11. Acetylation of 11 followed by treatment with phosphorus pentasulfide and subsequent deprotection with sodium methoxide gave 2-(β-D-ribofuranosyl)pyrimidine-4-thiocarboxamide ( 14 ). Dehydration of the acetylated amide 12 with phosphorous oxychloride provided 2-(β-D-ribofuranosyl)pyrimidine-4-carbonitrile ( 15 ). Treatment of 15 with sodium ethoxide gave ethyl 2-(β-D-ribofuranosyl)pyrimidine-4-carboximidate ( 16 ), which was converted to 2-(β-D-ribofuranosyl)pyrimidine-4-carboxamidine hydrochloride ( 17 ) by treatment with ethanolic ammonia and ammonium chloride. Treatment of 16 with hydroxylamine yielded 2-(β-D-ribofuranosyl)pyrimidine-4-N-hydroxycarboxamidine ( 18 ). Treatment of 2-(β-D-ribofuranosyl)pyrimidine-4-carboxamide ( 11 ) with phosphorus oxychloride gave the corresponding 5′-phosphate, 19 , Coupling of 19 with AMP using the carbonyldiimidazole activation procedure gave the corresponding NAD analog, 2-(β-D-ribofuranosyl)pyrimidine-4-carboxamide-(5′ ? 5′)-adenosine pyrophosphate ( 20 ).     

Struktur und Bindungscharakter von Ba3P2

The structure of the compound Ba₃P₂ was elucidated. It cristallizes with the inverse Th₃P₄ structure, or strictly, with the inverse Ce₂S₃ structure with randomly distributed phosphorus vacancies. The lattice parameter a₀ is 9.775 Å, the x-ray density dx is 4.52 g/cm³. The coordinate parameter x of the barium sites is 0.0665. Barium is surrounded by 6 phosphorus and 5 barium atoms; the distance of 3,81 Å between 3 of the barium atoms is extremely short. Phosphorus is surrounded by 8 barium atoms. The phosphorus atoms are isolated from one another. The structure is best described as a filling of the octahedral spaces in the bee lattice of the barium metal by phosphorus atoms. The partially negative charge of the phosphorus atoms (P^? + 2e ? P^?? + e) causes a strong distortion of the interstitial lattice. The bonding character of Ba₃P₂ has to be interpreted as mixed metallic-ionic.     

Preparation and characterization of the argentates: [Ag[P(CF(3))(2)](2)](-), [Ag[(micro-P(CF(3))(2))M(CO)(5)](2)](-) (M = Cr, W), and [Ag[(micro-P(C(6)F(5))(2))W(CO)(5)](2)](-): X-ray crystal structure of [K(18-crown-6)][Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)

The first example of a mononuclear diphosphanidoargentate, bis[bis(trifluoromethyl)phosphanido]argentate, [Ag[P(CF(3))(2)](2)](-), is obtained via the reaction of HP(CF(3))(2) with [Ag(CN)(2)](-) and isolated as its [K(18-crown-6)] salt. When the cyclic phosphane (PCF(3))(4) is reacted with a slight excess of [K(18-crown-6)][Ag[P(CF(3))(2)](2)], selective insertion of one PCF(3) unit into each silver phosphorus bond is observed, which on the basis of NMR spectroscopic evidence suggests the [Ag[P(CF(3))P(CF(3))(2)](2)](-) ion. On treatment of the phosphane complexes [M(CO)(5)PH(CF(3))(2)] (M = Cr, W) with [K(18-crown-6)][Ag(CN)(2)], the analogous trinuclear argentates, [Ag[(micro-P(CF(3))(2))M(CO)(5)](2)](-), are formed. The chromium compound [K(18-crown-6)][Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)] crystallizes in a noncentrosymmetric space group Fdd2 (No. 43), a = 2970.2(6) pm, b = 1584.5(3) pm, c = 1787.0(4), V = 8.410(3) nm(3), Z = 8. The C(2) symmetric anion, [Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)](-), shows a nearly linear arrangement of the P-Ag-P unit. Although the bis(pentafluorophenyl)phosphanido compound [Ag[P(C(6)F(5))(2)](2)](-) has not been obtained so far, the synthesis of its trinuclear counterpart, [K(18-crown-6)][Ag[(micro-P(C(6)F(5))(2))W(CO)(5)](2)], was successful.     

Hexamincyclotriphosphazenhemiammoniakat,P3N3(NH2)6 · 0,5 NH3, ein Produkt der Hochdruckammonolyse von weißem Phosphor

Hexaminecyclotriphosphazenehemiammoniate, P₃N₃(NH₂)₆ · 0.5 NH₃, a Product of High Pressure Ammonolysis of White Phosphorus White phosphorus gives at NH₃-pressures ≥5 kbar and temperatures above 250°C in a disproportionation reaction P₃N₃(NH₂)₆ · 0.5 NH₃; besides these products red phosphorus is formed. The yield on P₃N₃(NH₂)₆ · 0.5 NH₃ increases with T and is about 70–80% at 400°C as to the disproportionation reaction of the amount of white phosphorus. X-ray structure determination was successful on single crystals of P₃N₃(NH₂)₆ · 0.5 NH₃. Pbca, N = 8 a = 11.395(3) Å, b = 12.935(4) Å, c = 12.834(4) Å R = 0.035, R_w = 0.041 with w = 1, N (F_o²) ≥ 3σ(F_o²) = 1371, N(Var.) = 166. The molecules are connected by N? H? N-bridgebonds with 3.04 Å ≤ d(N …? N) ≤ 3,19 Å and d (N? H) = 0.87 Å. The compound is furthermore characterized by IR-data and its thermical behaviour.     

Unusual behavior of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one towards some phosphorus reagents: Synthesis of novel diethyl 2-phosphonochromone,diethyl 3-phosphonopyrone and 1,3,2-oxathiaphosphinines

The chemical reactivity of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) towards some phosphorus reagents was studied. The enaminone 1 was cyclized into diethyl 2-phosphonochromone 2 via its treatment with diethyl phosphite in basic medium. However, its reaction with triethoxy phosphonoacetate gave the substituted pyrone phosphonate 3. In addition, two novel examples of 4-(dimethylamino)-6-(2-hydroxyphenyl)-2-sulfido-4H-1,3,2-oxathia-phosphinines 6 and 7 were obtained from treatment of enaminone 1 with O,O-diethyl dithiophosphoric acid and Lawesson’s reagent. When enaminone 1 was also treated with phosphorus decasulfide, it was turned into 4H-thiochromene-4-thione while its treatment with phosphorus tribromide, phosphorus oxychloride, or phenylphosphonic dichloride, 4H-4-oxo-chromene was isolated in all cases. The possible reaction mechanisms of the formation of these products were discussed. The structures of newly isolated products were established by elemental analysis and spectral tools.     

Syntheses, characterizations, and coordination chemistry of the 10-vertex phosphadicarbaboranes 6-R-arachno-6,8,9-PC2B7H11 and 6-R-arachno-6,5,7-PC2B7H11

The 10-vertex phosphadicarbaboranes, 6-R-arachno-6,8,9-PC(2)B(7)H(11) (1) (R = Ph 1a or Me 1b) and 6-R-arachno-6,5,7-PC(2)B(7)H(11) (2) (R = Ph 2a or Me 2b) have been synthesized using in situ dehydrohalogenation reactions of RPCl(2) (R = Ph or Me) with the arachno-4,5-C(2)B(7)H(13) and arachno-4,6-C(2)B(7)H(13) carboranes, respectively. X-ray crystallographic determinations in conjunction with DFT/GIAO/NMR calculations and NMR spectroscopic studies have established that both 1 and 2 have open cage structures based on an icosahedron missing two vertexes. The two isomeric compounds differ in the positions of the carbons and bridging hydrogens on the open face. Studies of the reactions of 2a with BH(3).THF, S(8), and hydrogen peroxide demonstrated that 2a shows strong donor properties yielding the compounds endo-6-H(3)B-exo-6-Ph-arachno-6,5,7-PC(2)B(7)H(11) (3), endo-6-S-exo-6-Ph-arachno-6,5,7-PC(2)B(7)H(11) (4), and endo-6-O-exo-6-Ph-arachno-6,5,7-PC(2)B(7)H(11) (5) in which the BH(3), S, and O substitutents are bonded to an electron lone pair localized at the phosphorus endo-position. The reaction of 2a with an excess of S(8) results in the loss of a framework boron to produce the unique open-cage compound micro(7,8)-[HS(Ph)P]-hypho-7,8-C(2)B(6)H(11) (6). 2a also formed the donor complexes cis-(eta(1)-[6-Ph-arachno-6,5,7-PC(2)B(7)H(11)])(2)PtBr(2) (7) and trans-(eta(1)-[6-Ph-arachno-6,5,7-PC(2)B(7)H(11)])(2)PdBr(2) (8) in which the metal fragment is bonded in an eta(1)-fashion at the phosphorus endo-position. In these complexes, 2a is functioning as a two-electron sigma donor to the metals and can thus be considered as an analogue of the PR(3) ligands in the classical cis-(PPh(3))(2)PtBr(2) and trans-(PPh(3))(2)PdBr(2) coordination complexes. Although 1a did not show the donor properties exhibited by 2a, its dianion 6-Ph-6,8,9-PC(2)B(7)H(9)(2)(-) (1a(2)()(-)()) readily formed eta(4)-coordinated complexes with late transition metals including 8-Ph-7-(Ph(3)P)(2)-nido-7,8,10,11-PtPC(2)B(7)H(9) (9), 7-Ph-11-(eta(5)-C(5)H(5))-nido-11,7,9,10-CoPC(2)B(7)H(9) (10), and commo-Ni-(7-Ni-8'-Ph-nido-8',10',11'-PC(2)B(7)H(9))(7-Ni-8-Ph-nido-8,10,11-PC(2)B(7)H(9)) (11).     

Synthesis of Alkyl 6-(2-Alkoxy-2-oxoethyl)dibenzo[d,f][1,3]dioxepine-6-carboxylates from Stabilized Phosphorus Ylides

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by biphenyl-2,2′ -diol leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with a conjugate base to produce the corresponding stabilized phosphorus ylides. Magnesium oxide powder was found to catalyze the conversion of the stabilized phosphorus ylides to alkyl 6-(2-alkoxy-2-oxoethyl)dibenzo[d,f][1,3]dioxepine-6-carboxylates in solvent-free conditions under microwave (0.5 KW, 3 min) and thermal (90 °C, 60 min) conditions.     

Luminescent phosphine gold(I) thiolates: correlation between crystal structure and photoluminescent properties in [R3PAu{SC(OMe)=NC6H4NO2-4}] (R = Et, Cy, Ph) and [(Ph2P-R-PPh2){AuSC(OMe)=NC6H4NO2-4}2] (R = CH2, (CH2)2, (CH2)3, (CH2)4, Fc)

X-ray crystallography shows the gold atoms in [R3PAu{SC(OMe)=NC6H4NO2-4}] (R = Et, Cy, Ph; 1-3, respectively) and [(Ph2P-R-PPh2){AuSC(OMe)=NC6H4NO2-4}(2)] (R = CH2, (CH2)2, (CH2)3, (CH2)4, Fc; 4-8, respectively) are linearly coordinated by phosphorus and thiolate-sulfur; weak intramolecular Au...O interactions are featured in all structures. The smaller ethyl substituents in 1 allow for supramolecular association via Au...S and Au...Au interactions that are not found in 2 and 3, which contain larger phosphorus-bound Cy and Ph groups, respectively. Intramolecular Au...Au interactions are found in the dppm, dppe, dppp, and Fc structures but not in the dppp analogue, for which an anti conformation was found. The structures have been correlated with the results from photophysical study conducted in the solid state. Thus, photoexcitation of 1-7 with lambda > 350 in the solid state and in solution produces green and blue luminescence, respectively. The spectra in each medium are remarkably similar to each other, and so the emission energy and excitation maxima observed for 1-7 appear to be independent of the nature of the ancillary phosphines, as well as the presence or absence of Au...Au interactions, either intermolecularly or intramolecularly.     

Furopyridines. XXVII. Reactions of 2-methyl and 2-cyano derivatives of furo[2,3-b]-, -[3,2-b]-, - [2,3-c]- and -[3,2-c]pyridine

Bromination of 2-methylfuropyridines 1a-d-Me gave the 3-bromo derivatives 2a-d , while the 2-cyano compounds 1a-d-CN resulted in the recovery of the starting compounds. Nitration of 1a-d-Me and 1a-d-CN did not yield the corresponding nitro derivative, except for 1-c-CN giving 3-nitro derivative 3c in 7% yield. N-Oxidation of 1a-d-Me and 1b-d-CN with m-chloroperbenzoic acid yielded the N-oxides 4a-d-Me and 4b-d-CN , whereas 1a-CN did not afford the N-oxide. Cyanation of N-oxides 4a-d-Me and 4b-d-CN with trimethylsilyl cyanide gave the corresponding α-cyanopyridine compounds 5a-d-Me and 5b-d-CN . Chlorination of 4a-d-Me and 4b-d-CN with phosphorus oxychloride also gave the α-chloropyridine compounds 6b-d-Me and 6b-d-CN , accompanying formation of γ-chloropyridine 6a-Me, 6′b-Me and 6′b-CN , β-chloropyridine 6′b-CN , and α'-chloropyridine derivatives 6′c-Me and 6′c-CN . Acetoxylation of 4a-d-Me and 4b-d-CN with acetic anhydride yielded α-acetoxypyridine compounds 7a-Me and 7b-CN , pyridone compounds 11d-Me, 11c-CN and 11d-CN , 3-acetoxy compounds 8, 9b, 9c , and 2-acetoxymethyl derivatives 10b and 10c.     

KCo(H2O)2BP2O8·0.48H2O and K0.17Ca0.42Co(H2O)2BP2O8·H2O: two cobalt borophosphates with helical ribbons and disordered (K,Ca)/H2O schemes

The two title compounds, potassium diaquacobalt(II) borodiphosphate 0.48‐hydrate and potassium–calcium(0.172/0.418) diaquacobalt(II) borodiphosphate monohydrate, were synthesized hydrothermally. They are new members of the borophosphate family characterized by _∞[BP₂O₈]³⁻ helices running along [001] and constructed of boron (Wyckoff position 6b, twofold axis) and phosphorus tetrahedra. The [CoBP₂O₈]⁻ anionic frameworks in the two materials are structurally similar and result from a connection in the ab plane between the CoO₄(H₂O)₂ coordination octahedra (6b position) and the helical ribbons. Nevertheless, the two structures differ in the disorder schemes of the K,Ca and H₂O species. The alkali cations in the structure of the pure potassium compound are disordered over three independent positions, one of them located on a 6b site. Its framework is characterized by double occupation of the tunnels by water molecules located on twofold rotation axes (6b) and a fraction of alkali cations; its cell parameters, compared with those for the mixed K,Ca compound, show abnormal changes, presumably due to the disorder. For the K,Ca compound, the K and Ca cations are on twofold axes (6b) and the channels are occupied only by disordered solvent water molecules. This shows that it is possible, due to the flexibility of the helices, to replace the alkali and alkaline earth cations while retaining the crystal framework.     

Systematic synthesis, isolation, and photophysical properties of linear-shaped Re(I) oligomers and polymers with 2-20 units

Systematic synthesis routes have been developed for the linear-shaped rhenium(I) oligomers and polymers bridged with bidentate phosphorus ligands, [Re(N--N)(CO)3-PP-{Re(N--N)(CO)2-PP-}(n)Re(N--N)(CO)3](PF6)(n+2) (N--N = diimine, PP = bidentate phosphine, n = 0-18). These were isolated by size exclusion chromatography (SEC) and identified by (1)H NMR, IR, electrospray ionization Fourier transform mass spectrometry, analytical SEC, and elemental analysis. Crystal structures of [Re(bpy)(CO)3-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)3](PF6)2, [Re(bpy)(CO)3-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)2-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)3](PF6)3 and [Re(bpy)(CO)3-Ph2PC2H4PPh2-{Re(bpy)(CO)2Ph2PC2H4PPh2-}(n)Re(bpy)(CO)3](PF6)(n+2) (bpy = 2,2'-bipyridine, n = 1, 2) were obtained, showing that they have interligand pi-pi interaction between the bpy ligand and the phenyl groups on the phosphorus ligand. All of the oligomers and polymers synthesized were emissive at room temperature in solution. For the dimers, broad emission was observed with a maximum at 523-545 nm, from the (3)MLCT excited-state of the tricarbonyl complex unit, [Re(N--N)(CO)3-PP-]. Emission from the longer oligomers and polymers with > or = 3 Re(I) units was observed at wavelengths 50-60 nm longer than those of the corresponding dimers. This fact and the emission decay results clearly show that energy transfer from the edge unit to the interior unit occurs with a rate constant of (0.9 x 10(8))-(2.5 x 10(8)) s(-1). The efficient energy transfer and the smaller exclusive volume of the longer Re(I) polymers indicated intermolecular aggregation for these polymers in an MeCN solution.     

Pendant cyclodicarbaphosphazatriene-containing monomers and polymers: synthesis,crystal structures and polymerization behavior of [NC(NMe2)]2[NP(O-C6H4-p-C6H4-p-CH=CH2)(X)], X = Cl,OCH2CF3, OC6H5, OC6H4-m-CH3, OC6H4-p-Br

The reaction of the dicarbaphosphazene, [NC(NMe(2))](2)[NPCl(2)] (2), with the sodium salt of 4-hydroxy-4'-vinylbiphenyl afforded the vinyl group containing monomer [NC(NMe(2))](2)[NP(Cl)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2))] (3). Replacement of the lone chlorine atom of 3 by oxygen nucleophiles gave [NC(NMe(2))](2)[NP(OR)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2))] [R = CH(2)CF(3) (4); C(6)H(5) (5); C(6)H(4)-m-CH(3) (6); C(6)H(4)-p-Br(7)]. The X-ray crystal structures of 3-7 reveal that all the cyclodicarbaphosphazenes have a planar N(3)PC(2) ring; the ring carbons are completely planar, while the geometry around phosphorus is pseudotetrahedral. The presence of weak intermolecular hydrogen bonding [C-H---X(Cl or Br), C-H---N, or C-H---pi] interactions in 3-7 leads to the formation of polymeric architectures in the solid-state. The monomers 4-7 can be polymerized by a free-radical initiator to afford the corresponding air-stable homopolymers 8-11. These have moderate molecular weights with polydispersity indices ranging from 1.33 to 1.58. All of these polymers have high glass transition temperatures and have excellent thermal stability.     

Synthesis of 4H-1,3,4-oxadiazino[5,6-b]quinoxalines from 2-substituted quinoxaline 4-oxides

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 8 with acetic anhydride resulted in the intramolecular cyclization to give 8-chloro-2,4-dimethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7a , while the reaction of compound 8 with acetic anhydride/pyridine or acetic anhydride/acetic acid afforded 3-(2,2-diacetyl-1-memymydrazmo)-7-chloro-2-oxo-1,2-dihydroquinoxaline 9 , effecting no intramolecular cyclization. The reaction of 2-(2-acetyl-1-methylhydrazino)-6-chloroquinoxaline 4-oxide 10a or 6-chloro-2-(1-methyl-2-trifluoroacetylhydrazino)quinoxaline 4-oxide 10b with phosphoryl chloride provided compound 7a or 8-chloro-4-memyl-2-trifluoromethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7b , respectively. The reaction of compound 7b with phosphorus pentasulfide gave 7-chloro-3-(1-methyl-2-trifluoroacetylhydrazino)-2-thioxo-1,2-dihydroquinoxaline 11 , whose dehydration with sulfuric acid in acetic acid afforded 8-chloro-4-methyl-2-trifluoromemyl-4H-1,3,4-thiadiazino[5,6-b]quinoxaline 12 .     

2-芳基-5-(5-苯基-2H-四唑-2-亚甲基)-1,3,4-噁二唑类化合物的研究

作者曾研究2-芳基-5-(2-苯基-4-喹啉基)-1,3,4-噁二唑类衍生物,并发现它们具有促进小麦发芽生长的功效。Juby和Shan等报道某些四唑类化合物具有消炎性     

STUDIES ON 1,2,3-DIAZAPHOSPHOLE Ⅳ REACTION OF 1,2,3-DIAZAPHOSPHOLE WITH ALCOHOLS

Rapid addition of alcohols to 1,2,3-diazaphosphole 1 easily gave tricoordinatedphosphorus compounds,which were sulfurized to tetracoordinated phosphorus compounds.When ethylene glycol and aminoethanol were used separately to react with 1,the tricoordinatedphosphorus compounds which formed,rearranged to pentacoordinated phosphorus compoundsand the substituents at N_2 affected the rearrangement significantly.