Naphthylimido-substituted hexamolybdate: preparation, crystal structures, solvent effects, and optical properties of three polymorphs

[(n-C4H9)4N]2[Mo6O18(N-1-C10H(6)-2-CH3)] (1) has been prepared by the reaction of 1-amino-2-methylnaphthalene hydrochloride with [(n-C4H9)4N]4[alpha-Mo8O26] in the presence of 1,3-dicyclohexylcarbodiimide. Three solvent-free crystalline phases are isolated from the mixed solvents of acetone and acetic ether. The X-ray single-crystal structures of the three phases have been determined, showing the packing and supramolecular assembly characters (pseudohigher symmetry, helical chains, and pi-pi stacking) by which the effect of solvent polarity and crystallization speed on polymorphism in organic-inorganic hybrids has been demonstrated.     

Synthesis, structure and magnetic behavior of five-coordinate bis(iminopyrrolyl) complexes of cobalt(II) containing PMe3 and THF ligands

The new bis-iminopyrrolyl five-coordinate Co(II) complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2(PMe 3)] (R = H 3a; Me 3b) were synthesized in high yields (ca. 80-90%), using THF and diethyl ether as solvents, respectively, by (a) treatment of CoCl 2(PMe 3) 2 with the corresponding iminopyrrolyl Na salts ( Ie or If) or (b) reaction of anhydrous CoCl 2 and PMe 3 with Ie or If. A third route was tested, involving the addition of excesses of PMe 3 to the complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2] (R = H 1e; Me 1f), which was only successful for the synthesis of 3a, in lower yields (ca. 30%). The synthesis of 3b in THF was unfruitful because of the kinetic competition of the solvent, giving rise to mixtures of 1f and its coordinated THF adduct 4b. The synthesis of the new bis-iminopyrrolyl five-coordinate Co(II) complexes [Co(kappa (2) N, N'-NC 4H 3C(R)N-2,6- (i)Pr 2C 6H 3) 2(THF)] (R = H 4a; Me 4b) were carried out in high yields (ca. 80-90%) by the reaction of CoCl 2(THF) 1.5 with the corresponding iminopyrrolyl Na salt. All the compounds have been characterized by X-ray diffraction, with 3a and 3b showing axially compressed trigonal bipyramidal geometry (with the PMe 3 ligand lying on the equatorial plane), whereas complexes 4a and 4b exhibit distorted square pyramidal geometries with the THF molecule occupying the axial position. Complex 4a shows clearly a compressed geometry, but for complex 4b, two polymorphs were characterized, exhibiting molecules with different Co-O (THF) bond lengths, one of them being compatible with an elongated form. Magnetic measurements either in the solid or in the liquid phases indicate that complexes 3a and 3b have low-spin ground states ( S = 1/2). In toluene solution, the geometry is fully confirmed by EPR data, which further indicates a d x (2) - y (2) /d xy ground state. However, compounds 4a and 4b behave unusually because they show magnetic moments that are compatible with high-spin ground states ( S = 3/2) in the solid state, but conform to low-spin ground states ( S = 1/2) when both complexes are dissolved in toluene solutions. The low-spin ground states in toluene solution are confirmed by EPR spectroscopy, which further supports, for complexes 4a and 4b, an axially elongated square pyramidal geometry and a d z (2) ground state. Thus the change in the ground-state and, consequently, in the geometry of complexes 4a and 4b from solid state to toluene solution might be a consequence of the elongation of the Co-O(THF) bond length. DFT studies performed on complexes 3 and 4 corroborate their different structure and magnetic behaviors and verify, for the latter complexes, the structural differences observed in the solid state and in toluene solution.     

NMR studies of solvent-assisted proton transfer in a biologically relevant Schiff base: toward a distinction of geometric and equilibrium H-bond isotope effects

The tautomeric equilibrium in a Schiff base, N-(3,5-dibromosalicylidene)-methylamine 1, a model for the hydrogen bonded structure of the cofactor pyridoxal-5'-phosphate PLP which is located in the active site of the enzyme, was measured by means of 1H and 15N NMR and deuterium isotope effects on 15N chemical shifts at variable temperature and in different organic solvents. The position of the equilibrium was estimated using the one-bond 1J(OHN) and vicinal 3J(H(alpha)CNH) scalar coupling constants. Additionally, DFT calculations of a series of Schiff bases, N-(R1-salicylidene)-alkyl(R2)amines, were performed to obtain the hydrogen bond geometries. The latter made it possible to investigate a broad range of equilibrium positions. The increase of the polarity of the aprotic solvent shifts the proton in the intramolecular OHN hydrogen bond closer to the nitrogen. The addition of methanol and of hexafluoro-2-propanol to 1 in aprotic solvents models the PLP-water interaction in the enzymatic active site. The alcohols, which vary in acidity and change the polarity around the hydrogen bond, also stabilize the equilibrium, so that the proton is shifted to the nitrogen.     

Vibrational relaxation of CN stretch of pseudo-halide anions (OCN-, SCN-, and SeCN-) in polar solvents

The vibrational relaxation dynamics of pseudo-halide anions XCN- (X = O, S, Se) in polar solvents were studied to understand the effect of charge on solute-to-solvent intermolecular energy transfer (IET) and solvent assisted intramolecular vibrational relaxation (IVR) pathways. The T1 relaxation times of the CN stretch in these anions were measured by IR pump/IR probe spectroscopy, in which the 0-1 transition was excited, and the 0-1 and 1-2 transitions were monitored to follow the recovery of the ground state and decay of the excited state. For these anions in five solvents, H2O, D2O, CH3OH, CH3CN, and (CH3)2SO, relaxation rates followed the trend of OCN- > SCN- > SeCN-. For these anions and isotopes of SCN-, the relaxation rate was a factor of a few (2.5-10) higher in H2O than in D2O. To further probe the solvent isotope effect, the relaxation rates of S12C14N-, S13C14N-, and S12C15N- in deuterated methanols (CH3OH, CH3OD, CH3OH, CD3OD) were compared. Relaxation rate was found to be affected by the change of solvent vibrational band at the CN- stretching mode (CD3 symmetric stretch) and lower frequency regions, suggesting the presence of both direct IET and solvent assisted IVR relaxation pathways. The possible relaxation pathways and mechanisms for the observed trends in solute and solvent dependence were discussed.     

High-molecular-weight Polyethylene Prepared with Early Transition Metal Catalysts

Early transition metal catalysts [N,N]MCln, in which [N,N] is N-（2,6-diisopropylphenyl） pyridine-2-carboxaldimine （C18H22N2, NN-1）, N-（2,6-diisopropylphenyl）-6-methylpyridine-2- carboxaldimine （C19H24N2, NN-2）, N-（2,4,6-trimethylphenyl）pyridine-2-carboxaldimine （CIsH16N2, NN-3）, M is Ti, Zr and V, and n is 3 or 4, e.g. [NN-1]TiCh 1a, [NN-1]ZrCh 1b, [NN-1]VC13 1c, [NN-2]TiCh 2a, [NN-2]ZrCh 2b, [NN-2]VC13 2e, [NN-3]TiCh 3a have been investigated to catalyze ethylene polymerization in the presence of methylaluminoxane （MAO）. It was noteworthy that polyethylene characteristic of high molecular weight and wide or bimodal molecular weight distribution was formed with moderate to high activities.     

NMR studies of coupled low- and high-barrier hydrogen bonds in pyridoxal-5'-phosphate model systems in polar solution

The 1H and 15N NMR spectra of several 15N-labeled pyridoxal-5'-phosphate model systems have been measured at low temperature in various aprotic and protic solvents of different polarity, i.e., dichloromethane-d2, acetonitrile-d3, tetrahydrofuran-d8, freon mixture CDF3/CDClF2, and methanol. In particular, the 15N-labeled 5'-triisopropyl-silyl ether of N-(pyridoxylidene)-tolylamine (1a), N-(pyridoxylidene)-methylamine (2a), and the Schiff base with 15N-2-methylaspartic acid (3a) and their complexes with proton donors such as triphenylmethanol, phenol, and carboxylic acids of increasing strength were studied. With the use of hydrogen bond correlation techniques, the 1H/15N chemical shift and scalar coupling data could be associated with the geometries of the intermolecular O1H1N1 (pyridine nitrogen) and the intramolecular O2H2N2 (Schiff base) hydrogen bonds. Whereas O1H1N1 is characterized by a series of asymmetric low-barrier hydrogen bonds, the proton in O2H2N2 faces a barrier for proton transfer of medium height. When the substituent on the Schiff base nitrogen is an aromatic ring, the shift of the proton in O1H1N1 from oxygen to nitrogen has little effect on the position of the proton in the O2H2N2 hydrogen bond. By contrast, when the substituent on the Schiff base nitrogen is a methyl group, a proton shift from O to N in O1H1N1 drives the tautomeric equilibrium in O2H2N2 from the neutral O2-H2...N2 to the zwitterionic O2-...H2-N(2+) form. This coupling is lost in aqueous solution where the intramolecular O2H2N2 hydrogen bond is broken by solute-solvent interactions. However, in methanol, which mimics hydrogen bonds to the Schiff base in the enzyme active site, the coupling is preserved. Therefore, the reactivity of Schiff base intermediates in pyridoxal-5'-phosphate enzymes can likely be tuned to the requirements of the reaction being catalyzed by differential protonation of the pyridine nitrogen.     

芳香氮化物-CHCl3系列复合物密度泛函法研究

报道对芳香氮化物吡咯(C4H5N)、苯胺(C6H5NH2)、对位氯代吡啶(C5H4NCl)、吡啶(C5H5N)及吡咯负离子(C4H4N-)与三氯甲烷(CHCl3)形成的系列弱作用复合物的理论计算结果.把复合物看作是一个超分子,在密度泛函B3LYP/6-311G(d,p)的水平上进行计算,探讨该系列复合物的稳定性规律、电荷转移及主要几何参数变化等规律.计算结果表明:此类芳香氮化物与三氯甲烷(CHCl3)可形成一系列弱化学作用复合物,特别是带负电荷的芳香氮化物可与CHCl3形成较稳定的复合物.形成复合物的过程包含着电荷转移,该系列复合物的稳定性与广义H键距离的变化规律相一致,与电荷转移量的变化规律大体一致.     

新型N,N'-二(邻氧乙酸)苄叉丙二胺合铜(II)和镍(Ⅱ)及N-(邻氧乙酸)苄叉丙二胺合铜(Ⅱ)的合成、晶体结构及抑菌活性

在乙醇和水的混合溶液中, 将N,N'-二(邻氧乙酸)苄叉丙二胺(1)与氯化铜反应, 获得配合物Cu(Ⅱ)L1·H2O·0.25CH3CH2OH(2)[L1=N,N'-二(邻氧乙酸)苄叉丙二胺]; 当将反应混合溶液的pH值调至8~9, 获得Cu(Ⅱ)ClL2·3H2O(3)[L2=N-(邻氧乙酸)苄叉丙二胺]; 将N,N'-二(邻氧乙酸)苄叉丙二胺(1)与氯化镍反应, 获得配合物Ni(Ⅱ)L1·2.75H2O(4). 用元素分析、1H NMR和IR谱等方法对所合成的化合物1和配合物2~4进行了表征, 并测定了配合物2~4的晶体结构. 在配合物2中, 铜原子为六配位[CuN2O4], 在配合物3中, 铜原子为六配位[CuN2O3Cl], 在配合物4中, 镍原子为六配位[NiN2O4], 三个配合物均为畸变八面体结构. 抑菌活性大小的顺序: 配合物3>配合物2>化合物1.     

Complete 1H, 13C and 15N NMR assignment of tirapazamine and related 1,2,4-benzotriazine N-oxides

1H, 13C and 15N NMR measurements (1D and 2D including 1H--15N gs-HMBC) have been carried out on 3-amino-1, 2,4-benzotriazine and a series of N-oxides and complete assignments established. N-Oxidation at any position resulted in large upfield shifts of the corresponding N-1 and N-2 resonances and downfield shifts for N-4 with the exception of the 3-amino-1,2,4-benzotriazine 1-oxide in which a small upfield shift of N-4 was observed. Density functional GIAO calculations of the 15N and 13C chemical shifts [B3LYP/6-31G(d)//B3LYP/6-311+G(2d,p)] gave good agreement with experimental values confirming the assignments. The combination of 13C and 15N NMR provides an unambiguous method for assigning the 1H and 13C resonances of N-oxides of 1,2,4-benzotriazines.     

Structural characterization and self-association of (Arylimido)vanadium(V) triisopropoxides

(Arylimido)vanadium(V) triisopropoxides, [( p-RC 6H 4N)V(O (i) Pr) 3] (R = NMe 2, OMe, H, CN, NO 2, Br), were prepared by the reaction of VO(O (i) Pr) 3 with the aryl isocyanates without solvent. The structures of the (arylimido)vanadium(V) triisopropoxides were characterized by single-crystal X-ray structure determination to elucidate the substituent effect on the self-association properties. Controlled association of the (arylimido)vanadium(V) triisopropoxides to the mu-oxo-bridged dimer complexes or the mu-imido-bridged dinuclear complex was achieved by changing the p-substituent on the benzene rings, which regulates the nature of the imido bonds. Furthermore, the one-dimensional linear polymer complex or the one-dimensional zigzag one through mu-oxo-bridging was formed in a solid state with the bimetallic (arylimido)vanadium(V) complex, [( (i) PrO) 3V(N- p-C 6H 4N)V(O (i) Pr) 3] or [( (i) PrO) 3V(N- m-C 6H 4N)V(O (i) Pr) 3], respectively.     

Mononuclear, helical binuclear palladium and lithium complexes bearing a new pyrrole-based NNN-pincer ligand: fluxional property

A new pyrrole based NNN-pincer ligand, 2,5-bis(3,5-dimethylpyrazolylmethyl)pyrrole 2, was readily synthesized in two steps from pyrrole in 56% yield. The lithiation of the pincer ligand 2 using n-BuLi led to isolation of the dimeric lithium complex, [Li{μ-C(4)H(2)N-2,5-(CH(2)Me(2)pz)(2)-N,N,N}](2) 4, in 23% crystalline yield. The transmetalation reaction of 4 with [Pd(PhCN)(2)Cl(2)] afforded the mononuclear Pd(II) complex, [PdCl{C(4)H(2)N-2,5-(CH(2)Me(2)pz)(2)-N,N,N}] 5, containing one chloride ion in 45% yield. Alternatively 5 was obtained in an excellent yield of 87% by the reaction 2 of with [Pd(COD)Cl(2)] in the presence of triethylamine. On the contrary, a 20-membered macrometalacyclic molecule, [Pd(2)Cl(4){μ-C(4)H(3)N-2,5-(CH(2)Me(2)pz)(2)-N,N}(2)] 6, in which two PdCl(2) units are bridged by two molecules of 2 to give a helical structure, was synthesized by the reaction of 2 with [Pd(COD)Cl(2)] in the absence of base. The acetate analogue of complex 5, [Pd(OAc){C(4)H(2)N-2,5-(CH(2)Me(2)pz)(2)-N,N,N}] 3, was obtained by the treatment of 2 with [Pd(OAc)(2)]. The pyrrole twist angle of 5 is higher than that of 3. Complexes 3 and 5 show an AB pattern for their methylene protons at room temperature in CDCl(3) as well as in DMSO-d(6). The variable temperature NMR studies showed that the acetate and chloride complexes exhibit slightly different coalescence temperatures, which is a solvent dependent phenomenon, and twist angles.     

Nickel Complexes Bearing Bidentate Schiff Base as Ethylene Oligomerization Catalysts

Several nickel complexes [N,N]NiBr2, in which IN,N] indicates bidentate nitrogen-containing ligands (1: [N,N]=N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine (Cl8H22N2); 2: N-(2,6-diisopropylphenyl)-6-methylpyridine-2-carboxaldimine (C19H24N2); 3: N-(2,4,6-trimethylphenyl)pyridine-2-carboxaldimine(Cl5Hl6N2); 4: N-(2,4,6-trimethylphenyl)-6-methylpyridine-2-carboxaldlmlne (Cl6Hl8N2) were synthesized. Some of the nickel complexes exhibit high activity for ethylene oligomerization in the presence of an organoaluminum activator. The main factor affecting the activity and the structure of oligomers is the steric effect of substituents on [N,N] ligands. Methylaluminoxane (MAO) -activated catalysts showed higher activities and produced oligomers with higher molecular weight than Et2AlCl-activated ones. The oligomerization in toluene rather than hexane results in much higher activity, and the oligomers produced in toluene have relatively high molecular weight. With activation of MAO or Et2AlCl,the [N,N]NiBr2 system tended to produce highly branched oligomers with low α-olefin content, but the α-olefin content could be increased by changing the reaction conditions.     

Electron attachment and detachment, and the electron affinities of C5F5N and C5HF4N

Rate constants have been measured for electron attachment to C5F5N (297-433 K) and to 2, 3, 5, 6-C5HF4N (303 K) using a flowing-afterglow Langmuir-probe apparatus (at a He gas pressure of 133 Pa). In both cases only the parent anion was formed in the attachment process. The attachment rate constants measured at room temperature are 1.8 +/- 0.5 X 10(-7) and 7 +/- 3 X 10(-10) cm(-3) s(-1), respectively. Rate constants were also measured for thermal electron detachment from the parent anions of these molecules. For C5F5N- detachment is negligible at room temperature, but increases to 2530 +/- 890 s(-1) at 433 K. For 2, 3, 5, 6-C5HF4N-, the detachment rate at 303 K was 520 +/- 180 s(-1). The attachment/detachment equilibrium yielded experimental electron affinities EA(C5F5N)=0.70 +/- 0.05 eV and EA(2, 3, 5, 6-C5HF4N)=0.40 +/- 0.08 eV. Electronic structure calculations were carried out for these molecules and related C5HxF5-xN using density-functional theory and the G3(MP2)//B3LYP compound method. The EAs are found to decrease by 0.25 eV, on average, with each F substitution by H. The calculated EAs are in good agreement with the present experimental results.     

Tri- and tetracoordinate copper(I) complexes bearing bidentate soft/hard SN and SeN ligands based on 2-aminopyridine

The coordination properties of the EN ligands N-(2-pyridinyl)amino-diphenylphosphine sulfide, N-(2-pyridinyl)amino-diisopropylphosphine sulfide, N-(2-pyridinyl)amino-diphenylphosphine selenide, N-(2-pyridinyl)amino-diisopropylphosphine selenide towards copper(I) precursors CuX (X = Br, I), [Cu(IPr)Cl] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), and [Cu(CH(3)CN)(4)]PF(6) were studied. Treatment of CuX with EN ligands resulted in the formation of tricoordinate complexes of the type [Cu(κ(2)(E,N)-EN)X]. The reaction of [Cu(IPr)Cl] with EN ligands, followed by halide abstraction with AgSbF(6), afforded cationic tricoordinate complexes [Cu(κ(2)(S,N)-EN)(IPr)](+), while the reaction of [Cu(CH(3)CN)(4)](+) with two equivalents of EN ligands yielded tetrahedral complexes [Cu(κ(2)(E,N)-EN)(2)](+). Halide removal from [Cu(κ(2)(S,N)-SN)I] with silver salts in the presence of L = CH(3)CN and CNtBu afforded dinuclear complexes of the type [Cu(κ(2)(S,N),μ(S)-SN)(L)](2)(2+) containing bridging SN ligands. With the terminal alkynes HC≡CC(6)H(4)Me and HC≡CC(6)H(4)OMe, complexes of the formula [Cu(κ(2)(S,N)-SN-iPr)(η(2)-HC≡CC(6)H(4)Me)](+) and [Cu(κ(2)(S,N)-SN-iPr)(η(2)-HC≡CC(6)H(4)OMe)](+) were obtained. The mononuclear nature of these compounds was supported by DFT calculations. Most complexes were also characterized by X-ray crystallography.     

含O-, S-, N-和C-2,3-不饱和糖苷的合成

以3,4,6-三-O-乙酰基-D-葡萄烯糖为原料,(NH₄)₂S₂O₈为催化剂,利用Ferrier重排反应制得一系列含O-, S-,N-和C-2,3-不饱和糖苷,其结构经¹H NMR, IR和MS（ESI）确证。考察了催化剂及其用量,溶剂和温度对产率的影响。结果表明：在最优条件［反应温度80 ℃,乙腈为溶剂,(NH₄)₂S₂O₈为催化剂(1 eq.)］下,3a产率高达83%。     

A family of oxorhenium(v) complexes incorporating chelated monoanionic ONN reduced Schiff base and dianionic ONNO tetradentate ligands: synthesis, spectroscopic and electrochemical studies

The green colored complexes of the type Re(V)O(L(SB))Cl(2), 1, have been synthesised by reacting NBu(4)[ReOCl(4)] with HL(SB) in dry ethanol. Here, L(SB)(-) are the deprotonated forms of N-(2-hydroxybenzyl)-2-picolylamine (HL(SB)(1)); N-(2-hydroxybenzyl)-N',N'-dimethylethylenediamine (HL(SB)(2)) and N-(2-hydroxybenzyl)-N',N'-diethylethylenediamine (HL(SB)(3)). Similarly, NBu(4)[ReOCl(4)] reacted with N,N-bis(2-hydroxybenzyl)-2-picolylamine (H(2)L(1)); N,N-bis(2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H(2)L(2)); N,N-bis(2-hydroxybenzyl)-N',N'-diethylethylenediamine (H(2)L(3)); [N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)]-2-aminoethanol (H(2)L(4)); [N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)]-2-methyl-2-amino-1-propanol (H(2)L(5)); N,N-bis(1-hydroxyethyl)-2-picolylamine (H(2)L(6)), to give the monochloro complexes Re(V)O(L)Cl, 2. The X-ray structures of the complexes are reported. The molecular structures observed in the solid state are preserved in solution ((1)H NMR). In acetonitrile solution the Re(V)O(L)Cl, 2, display a one-electron couple, Re(VI)O(L)Cl(+)-Re(V)O(L)Cl, near 1.0 V vs SCE. The electrogenerated hexavalent complexes [Re(VI)O(L)Cl]ClO(4), 3, are paramagnetic and display sextet EPR spectra in solution at room temperature (A(av) approximately 417 (G), g approximately 1.914).     

Crystal Structure and Herbicidal Activity of N-（5,7-Dimethoxy-2H-[ 1,2,4]thiadiazolo[2,3-a]pyrimidin-2-ylidene）-2-（2,4- dichlorophenoxy）propanamide

The title compound N-（5,7-dimethoxy-2H-[1,2,4]thiadiazolo[2,3-a]pyrimidin-2- ylidene）-2-（2,4-dichlorophenoxy）propanamide 3 has been synthesized through using bromine as cyclic reagent in 66% isolated yield. Suitable single crystals for X-ray diffraction were obtained by recrystallization from the mixture solvents at room temperature. Crystallographic data of 3： C32H28Ci4N8O9S2, Mr = 874.56, monoclinic, space group P21/c, a = 18.612（8）, b = 14.084（6）, c = 14.757（6） A, α = 90.00, β = 95.505（7）, ）, = 90.00°, Z = 4, V= 3850（3） A^3, Dc = 1.509 g/cm^3, F（000） = 1792, R = 0.0704, wR = 0.1454 and ° = 0.479 mm^-1. The title compound 3 was found to be effective in herbicidal activity.     

两个双冠醚方酸盐的研究

Cohen等于1959年首次合成出方酸(Squaric Acid)。近年来对通式为C_nO_n~(-2)的氧碳化合物(Oxocarbans)化学的研究工作十分活跃。八十年代美国Kodak、IBM、Xerox,日本佳能、富士和三菱等一些著名的大公司,纷纷开展了以方酸衍生物作为信息记录和光电转换材料的研究。在廉价的GaAlAs激光输出范围内有高吸收的一些方酸染料,被用作光信息记录和存储材料如激光光盘。一些方酸衍生物被用作电照相的光受体(Photoreceptor),性能     

Hexacoordinate Phosphorus. 7. Synthesis and Characterization of Neutral Phosphorus(V) Compounds Containing Divalent Tridentate Diphenol Imine, Azo, and Thio Ligands

The reactions of bis(trimethylsilyl)ated forms of the Schiff base ligands N-(2-hydroxyphenyl)salicylideneamine {(HO)C(6)H(4)N(CH)C(6)H(4)(OH)}, N-(4-tert-butyl-2-hydroxyphenyl)salicylideneamine {(HO)((t)Bu)C(6)H(3)N(CH)C(6)H(4)(OH)}, N-(2-hydroxy-4-nitrophenyl)salicylideneamine {(HO)(O(2)N)C(6)H(3)N(CH)C(6)H(4)(OH)}, and the structurally related ligand 2,2'-azophenol with halogeno- and (trifluoromethyl)halogenophosphoranes yield a series of neutral hexacoordinate phosphorus(V) compounds by means of trimethylsilyl halide elimination. In all of these cases the ligands chelate in a meridional conformation in which bicyclic five- and six-membered chelate rings are formed through structures containing two phenolic P-O bonds and one N-P bond. The hexacoordinate nature of these compounds is evidenced by their high-field (31)P NMR chemical shifts and their characteristic J(PF) coupling patterns and is further substantiated by the crystal structures of {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3) and {OC(6)H(4)N=NC(6)H(4)O}PF(3). Crystal data for {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3): triclinic, space group P&onemacr; (No. 2), a = 11.167(1) ?, b = 15.684(1) ?, c = 17.047(2) ?, V = 2840(1) ?(3), Z = 2. Final R and R(w) values were 0.051 and 0.079, respectively. Crystal data for {OC(6)H(4)N=NC(6)H(4)O}PF(3): monoclinic, space group P2(1)/c (No. 14), a = 6.9393(8) ?, b = 12.450(2) ?, c = 13.907(2) ?, V = 1190.7(6) ?(3), Z = 4. Final R and R(w) values were 0.045 and 0.056, respectively. The molecular structures of {O((t)Bu)C(6)H(3)N(CH)C(6)H(4)O}PCl(3) and {OC(6)H(4)N=NC(6)H(4)O}PF(3) show that in both cases the Schiff base ligand chelates occupy the meridional plane about the six-coordinate phosphorus atom. In the case of {OC(6)H(4)N=NC(6)H(4)O}PF(3) the equivalent nitrogen atoms in the chelate rings are disordered to form half-occupancy pairs. The silylated form of the related thiobis(phenol), 2,2'-thiobis(4,6-tert-butylphenol), reacted similarly with pentavalent halides to form the six-coordinate complex [{2-O-3,5-((t)Bu)(2)C(6)H(2)}(2)S]PCl(3) which was also verified by a crystal structure. Crystal data for [{2-O-3,5-((t)Bu)(2)C(6)H(2)}(2)S]PCl(3): monoclinic P2(1)/n, a = 13.989(2), b = 13.594(2), c = 16.483(2) ?, beta = 97.98(2) degrees, V = 3104(2) ?(3), Z = 4; final R and R(w)() values were 0.039 and 0.052, respectively. In contrast to the above six coordinate complexes, this compound possesses a facial structure in which two phenoxy substituents form planar chelates centered on the bridging sulfur and intersecting at the P-S axis. The P-S bond length, 2.331(1) ?, is slightly shorter than has been previously observed in the example wherein the ligand possesses two tert-butyl groups and the phosphorus carries three OCH(2)CF(3 )substituents indicating stronger interaction between P and S in the present case.     

含萘酰亚胺光功能基元的吡唑啉酮席夫碱的合成及其光谱性质

以4-溴-1,8-萘酐为原料,经亚胺化、取代和还原反应合成了中间体N-对氨基苯基-4-哌啶-1,8-萘酰亚胺(4),4与1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5缩合得到一种含萘酰亚胺光功能基元的的新型吡唑啉酮席夫碱——1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5缩N-对氨基苯基-4-哌啶-1,8-萘酰亚胺(6)。4和6的结构经1H NMR和IR确证。研究了6在不同溶剂中的光谱性质,发现其吸收光谱和荧光光谱随溶剂的极性不同而表现出不同的光谱特性。进一步研究表明6在不同溶剂中可能以不同的互变异构体存在。