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1.
烟酰型辅酶NAD(P)+和NAD(P)H再生的研究进展   总被引:8,自引:0,他引:8  
吕陈秋  姜忠义  王姣 《有机化学》2004,24(11):1366-1379
大部分氧化还原酶的催化反应需要烟酰型辅酶NAD(P) 和NAD(P)H作为氧化剂或还原剂参与,由于氧化还原酶应用广泛而辅酶价格昂贵,使得辅酶再生逐渐成为研究热点.综述了近年来NAD(P) 和NAD(P)H酶法再生、电化学法及光化学法再生的研究进展,并介绍了各再生技术的应用和开发状况.  相似文献   

2.
The crystal structures of six members of the homologous series with general formula [BiQX]2[AgxBi1?xQ2?2xX2x?1]N+1 (Q = S, Se; X = Cl, Br; 1/2 ≤ x ≤ 1) and N = 4, 5, or 7 were determined by single‐crystal X‐ray diffraction. The series are characterized by the parameters N and x and are denoted (N, x)P. Ag3Bi4S6Cl3 (x = 0.60) (I) , Ag3.5Bi3.5S5Br4 (x = 0.70) (II) and Ag3.65Bi3.35Se4.70Br4.30 (x = 0.73) (III) belong to (4, x)P series Ag5xBi7?5xQ12?10xX10x?3 and adopt the AgBi6S9 structure type. The (5, x)P compound Ag3.66Bi4.34S6.68Br3.32 (IV) , which corresponds to x = 0.61 in Ag6xBi8?6xS14?12xBr12x?4, crystallizes isostructurally to AgBi3S5. The compounds Ag4.56Bi5.44Se8.88Br3.12 (x = 0.57) (V) and Ag5.14Bi4.86S7.76Br4.24 (x = 0.64) (VI) , which are members of (7, x)P series Ag8xBi10?8xQ18?16xBr16x?6, adopt the Ag3Bi7S12 structure type. In the monoclinic crystal structures (space group C2/m) two kinds of layered modules alternate along [001]. Modules of type A uniformly consist of paired rods of face‐sharing monocapped trigonal prisms around Bi atoms with octahedra around mixed occupied metal positions (M = Ag/Bi) between them. Modules of type B are composed of [MZ6] octahedra, which are arranged in NaCl‐type fragments of thickness N. All structures exhibit Ag/Bi disorder in octahedrally coordinated metal positions as well as Q/X mixed occupation of some anion positions. Corresponding to their black color, all compounds are narrow‐gap semiconductors (Eg = 0.35 eV for (II) ). General characteristics of the entire class of (N, x)P compounds are gathered in a catalogue.  相似文献   

3.
Olefinic double bonds in α,β-unsaturated carbonyl or nitro compounds are reduced chemoselectively by Hantzsch ester on silica gel in excellent yields.  相似文献   

4.
The Crystal Structure of Tetrakis(di-tert.-butylphosphino)diphosphane [(tBu)2P]2P? P[P(tBu)2]2 [(tBu)2P]2P? P[P(tBu)2]2 1 obtained at ?20°C from a solution of (tBu)2P? P=P(Br)tBu2 forms yellow crystals (regular hexagons). 1 crystallizes monoclinic in the space group C2/c with a = 2145.6pm, b = 1137pm, c = 1696.1pm, β = 110.075° and Z = 4 formula units in the elementary cell. Due to high steric load the bond angles at the tertiary P atoms with δ = 115.7° are significantly larger than those at the primary P atoms with δ = 108.6°.  相似文献   

5.
6.
The crystal structures of two new diphosphates, sodium hexamanganese bis­(diphosphate) triphosphate, NaMn6(P2O7)2(P3O10), and potassium hexacadmium bis­(diphosphate) triphosphate, KCd6(P2O7)2(P3O10), confirm the rigidity of the M6(P2O7)2(P3O10) matrix (M is Mn or Cd) and the relatively fixed dimensions of the tunnels extending in the a direction of the unit cell. The compounds are isomorphous; the P2O74? anion and the alkali metal cations lie on mirror planes. Bond‐valence analysis of the bonding details of the atoms found within the tunnels permits a prediction of the conductivity.  相似文献   

7.
H ? C Bond Cleavage in Ferrocene by Organylruthenium Complexes Cp*(Me3P)2RuCH2CMe3 ( 1 ) reacts at 85°C with ferrocene ( 2 ) by cleavage of one H? C bond in 2 to give CpFe[η5-C5H4Ru(PMe3)2Cp*] ( 3 ) (Cp = η5-C5H5; Cp* = η5-C5Me5) and neopentane. The ruthenium atom in 3 has a distorted tetrahedral geometry, the planar Cp ligands in the ferrocenyl fragment are eclipsed. Solutions of 3 in [D6]benzene or [D8]THF exhibit H? D exchange of the ferrocenyl protons. In the [D8]THF molecule only the α-deuterium atoms are exchanged. Reaction pathways for this exchange are discussed.  相似文献   

8.
9.
The crystal structures of two members of the solid solution series Ag3xBi5?3xS8?6xCl6x?1 (x = 0.52 (I) , x = 0.67 (II) ) and three compounds of the Ag4xBi6?4xQ10?8xBr8x?2 series (Q = S: x = 0.70 (III) , x = 0.84 (IV) ; Q = Se: x = 0.72 (V) ) were determined by single‐crystal X‐ray diffraction. The compounds crystallize in the monoclinic space group C2/m (No. 12) with a = 1326.7(3), b = 403.9(1), c = 1176.7(2) pm, β = 107.83(3)° for (I) ; a = 1325.4(3), b = 403.3(1), c = 1170.6(2) pm, β = 108.14(3)° for (II) ; a = 1338.9(4), b = 407.7(1), c = 1426.4(4) pm, β = 113.95(2)° for (III) ; a = 1346.7(4), b = 409.3(1), c = 1440.7(4) pm, β = 114.40(1)° for (IV) ; and a = 1370.9(2), b = 417.64(4), c = 1480.4(2) pm, β = 114.92(2)° for (V) . (I) and (II) adopt the PbBi4S7 structure type, (III) to (V) crystallize in the CuBi5S8 type. All five compounds belong to the homologous series with general formula [BiQX]2[AgxBi1?xQ2?2xX2x?1]N+1 (Q = S, Se; X = Cl, Br; 1/2 ≤ x ≤ 1)), which resemble minerals of the pavonite series. They are characterized by the parameters N and x and are denoted (N, x)P. In the crystal structures, two kinds of layered modules alternate along [001]. Modules of type A uniformly consist of paired rods of face‐sharing monocapped trigonal prisms around Bi atoms with octahedra around mixed occupied metal positions (M = Ag/Bi) between them. Modules of type B are composed of chains of edge‐sharing [MZ6] octahedra (M = Ag/Bi; Z = Q/X). These NaCl‐type fragments are of thickness N = 2 in Ag3xBi5?3xS8?6xCl6x?1 and N = 3 in Ag4xBi6?4xQ10?8xBr8x?2. All structures exhibit Ag/Bi disorder in octahedrally coordinated metal positions and Q/X mixed occupation of some anion positions.  相似文献   

10.
Structural Chemistry -  相似文献   

11.
4-Monodeuterated NAD(P)H model compounds (1,4,6,7-tetrahydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]az epin; 11Me-MMPAH) have been oxidized with a series of p-benzoquinone and its derivatives in the presence of Mg2+. The models have an axial chirality with respect to the orientation of carbonyl dipole, the dihedral angle of which is larger than 55 degrees out of the plane of dihydropyridine ring. Without Mg2+, the anti- (with respect to the carbonyl dipole) hydrogen is 3 to 32 times more reactive than the corresponding syn-hydrogen, whereas, when Mg2+ is present in the system, the selectivity is shifted toward the syn-preferency. Mg2+ plays the role of a Lewis acid catalyst to control the stereochemistry at the same time as it catalyzes the reaction.  相似文献   

12.
The synthesis and characterization of the extremely hindered phosphine ligands, P(CH(2)CH(2)P(t)Bu(2))(3) (P(2)P(3)(tBu), 1), PhP(CH(2)CH(2)P(t)Bu(2))(2) (PhP(2)P(2)(tBu), 2), and P(CH(2)CH(2)CH(2)P(t)Bu(2))(3) (P(3)P(3)(tBu), 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl(2)(P(2)P(3)(tBu)) (4), RuCl(2)(PhP(2)P(2)(tBu)) (5), and RuCl(2)(P(3)P(3)(tBu)) (6). The bulky P(2)P(3)(tBu) (1) and P(3)P(3)(tBu) (3) ligands are the most sterically encumbered PP(3)-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl(2)(PhP(2)P(2)(tBu)) (5) and RuCl(2)(P(3)P(3)(tBu)) (6) were characterized by crystallography. Low temperature solution and solid state (31)P{(1)H} NMR were used to demonstrate that the structure of RuCl(2)(P(2)P(3)(tBu)) (4) is probably analogous to that of RuCl(2)(PhP(2)P(2)(tBu)) (5) which had been structurally characterized.  相似文献   

13.
Das P(SiMe2)3P     
P(SiMe2)3P Li3P (produced from the elements) forms with Me2SiCl2 at 20°C in toluene the bicyclic compound P(SiMe2)3P 4 beside small amounts of ClMe2Si? P(SiMe2)2P? SiMe2Cl and traces of P4(SiMe2)6 7. 4 can be transformed into 7 by thermal treatment. With the formation of 4 the existence of a bicyclic silylphosphane is confirmed which has already been mentioned in connection with P(SiEt2)3P [1], but could not be proven until now.  相似文献   

14.
Formation and Structure of the Cyclophosphanes P4(CMe3)2[P(CMe3)2]2 and P4(SiMe3)2[P(CMe3)2]2 n-Triphosphanes showing a SiMe3 and a Cl substituent at the atoms P1 and P2, like (Me3C)2P? P(SiMe3)? P(CMe3)Cl 3 or (Me3C)2P? P(Cl)? P(SiMe3)2 4 are stable only at temperatures below ?30°C. Above this temperature these compounds lose Me3SiCl, thus forming cyclotetraphosphanes, P4(CMe3)2[P(CMe3)2]2 1 out of 3 , P4(SiMe3)2[P(SiMe3)2]2 2a (cis) and 2b (trans) out of 4 . The formation of 1 proceeds via (Me3C)2P? P?PCMe3 5 as intermediate compound, which after addition to cyclopentadiene to give the Diels-Alder-adduct 6 (exo and endo isomers) was isolated. 6 generates 5 , which then forms the dimer compound 1 . Likewise (Me3C)2P? P?P-SiMe3 8 (as proven by the adduct 7 ) is formed out of 4 , leading to 2a (cis) and 2b (trans). Compound 1 is also formed out of the iso-tetraphosphane P[P(CMe3)2]2[P(CMe3)Cl] 9 , which loses P(CMe3)2Cl when warmed to a temperature of 20°C. 1 crystallizes monoclinically in the space group P21/a (no. 14); a = 1762.0(15) pm; b = 1687.2(18) pm; c = 1170.5(9) pm; β = 109.18(5)° and Z = 4 formula units in the elementary cell. The molecule possesses E conformation. The central four-membered ring is puckered (approx. symmetry 4 2m; dihedral angle 47.4°), thus bringing the substituents into a quasi equatorial position and the nonbonding electron pairs into a quasi axial position. The bond lengths in the four-membered ring of 1 (d (P? P) = 222.9 pm) are only slightly longer than the exocyclic bonds (221.8 pm). The endocyclic bond angles \documentclass{article}\pagestyle{empty}\begin{document}$ \bar \beta $\end{document}(P/P/P) are 85.0°, the torsion angles are ±33° and d (P? C) = 189.7 pm.  相似文献   

15.
《Russian Chemical Bulletin》1992,41(11):1940-1940
B. P. Zhukov (on his 80th birthday)  相似文献   

16.
Thermodynamic characteristics of the dissociation of carbon diselenide are examined. Results of a shock-tube study of CSe2 pyrolysis are combined with previously unreported photoionization spectroscopy data on CSe2 and with a critical examination of the available literature on Se(g), Se2(g), CSe(g), CSe2(g), and CSe2(t). Based on the best currently available information, recommendations are made for the values of enthalpies, entropies, heat capacities, and derived functions. In particular, the most likely value for ΔH0 (CSe2(g) → CSe(g) + Se(g, 3P)) is +83 kcal/mol, and for Kp at 2000°K it is 0.018 atm.  相似文献   

17.
Formation and N.M.R.-Spectroscopic Characterization of Alk-(ar-)oxy Derivatives of Trichlorophosphazene-N-phosphoryldichloride, Cl3P?N? P(O)Cl2, Imido- and N-Methylimidodiphosphoryltetrachloride, Cl2P(O)NHP(O)Cl2 and Cl2P(O)N(CH3)P(O)Cl2 The ester chlorides and esters P2NOCl5?x(OR)x (x = 1?5), P2(NH)O2Cl4?x(OR)x (x = 1–4) and P2(NCH3)O2Cl4–x(OR)x (x = 1–4) derived from the title compounds by substitution of chlorine atoms by alk- or aroxy groups are characterized by their 31P-n.m.r. data. The possibilities for forming these compounds by alcoholysis, chloridolysis, dealkylation and P? N-bond formation are discussed.  相似文献   

18.
19.
20.
Conclusions Based on the dipole moment data, either a cis or near-cis orientation of the phosphoryl and methyl groups, or of the thiophosphoryl and trimethylsilyl groups, is realized in the 2-oxo-2-methylthio- and the 2-thiono-2-trimethylsiloxy-4-methyl- and -4,5-dimethyl-1,3,2-dioxaphospholanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1880–1883, August, 1976.The authors are indebted to A. N. Vereshchagin and V. A. Naumov for their valuable counsel.  相似文献   

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