Three kinds of crystalline compounds containing the nitrosylpentaamminechromium complexes [Cr(NO)(NH3)5]2+(A) were obtained: chloride ACl2 (red-orange), chloride perchlorate ACl(ClO4) (brown), and perchlorate A(ClO4)2 (green). The cause of the color change of the complex A with the change of outer sphere anions was sought using X-ray structural data of ACl2, ACl(ClO4), and A(ClO4)2. Crystal data: ACl2, orthorhombic, space group Cmcm, a=10.0236 (9) Å, b=9.098 (3) Å, c=10.357(1) Å, V=944.5 (5) Å3, Z=4; ACl(ClO4), tetragonal, space group P4/nmm, a=7.6986 (8) Å, c=9.9566(8) Å, V=590.1 (1) Å3,Z=2; A(ClO4)2, orthorhombic, space group Pnma, a=15.760 (2) Å, b=11.480(2) Å, c=7.920 (2) Å, V=1432.9 (4) Å3, Z=4. The complex cation in ACl2 has a distorted octahedral structure with a linear CrNO moiety. The short CrN (nitrosyl) distance of 1.692 (7) Å indicates the presence of multiple bonding between the chromium atom and the nitrogen atom in the nitrosyl group. The interatomic distances and angles within the complex cations hardly change with the change of the counter anions, while the distances between the complex cations in each crystal increase in the order ACl2<ACl(ClO4)<A(ClO4)2. The bulky perchlorate anions seems to separate the complex cations, while smaller chloride anions are not large enough to separate them. The distance (3.213(5) Å) between O(NO) and N(NH3 in the adjacent complex cation) is rather short in the crystal of ACl2, and there are six hydrogen bonds, where the NO group is surrounded by four NH3 ligands. The distance (4.002(5) Å) between O(NO) and N(NH3) is much longer in the crystal of A(ClO4)2, indicating the presence of no hydrogen bonding. In the crystal of ACl(ClO4) the distance (3.452(4) Å) between O(NO) and N(NH3) is in between those of ACl2 and A(ClO4)2. The presence of hydrogen bonding between O(NO) and N(NH3 in the adjacent complex cation) seems to cause the color change with the change of outer sphere anions. 相似文献
The preparation is reported of [(NH3)3Pt(9- MeA)] X2 (9-MeA = 9-methyladenine) with XCl (1a) and XClO4 (1b) and of trans-[(OH)2Pt(NH3)3- (9-MeA)]X2 with XCl (2a) and XClO4 (2b), and the crystal structure of 1b. [(NH3)3Pt(C6H7N5)](ClO4)2 crystallizes in space group P21/n with a = 20.810(7) Å, b = 7.697(3) Å, c = 10.567(4) Å, β = 91.57(6)°, Z = 4. The structure was refined to R = 0.054, Rw = 0.063. In all four compounds Pt coordination is through N7 of 9-MeA, as is evident from 3J coupling between H8 of the adenine ring and 195Pt. Pt(II) and Pt(IV) complexes can be differentiated on the basis of different 3J values, larger for Pt(II) than for Pt(IV) by a factor of 1.57 (av). In Me2SO-d6, hydrogen bonding occurs between Cl? and C(8)H of 9-MeA as weil as between Cl? and the NH3 groups in the case of the Pt(II) complex 1a. Protonation of the 9-MeA ligands was followed using 1H NMR spectroscopy and pKa values for the N1 protonated 9-MeA ligands were determined in D2O. They are 1.9 for 1a and 1.8 for 2a, which compares with 4.5 for the non-platinated 9-MeA. Possible consequences for hydrogen bonding with the complementary bases thymine or uracil are discussed briefly. Protonation of the OH groups in the Pt(IV) complexes has been shown not to occur above pH 1. 相似文献
Four cobalt(III) complexes containing the polypyridine pentadentate ligands N,N-bis(2-pyridylmethyl)amine-N′-ethyl-2-pyridine-2-carboxamide (PaPy3H), N,N-bis(2-pyridylmethyl)amine-N′-[1-(2-pyridylethyl)acetamide (MePcPy3H), and N,N-bis(2-pyridylmethyl)amine-N′-(2-pyridylmethyl)acetamide (PcPy3H), have been synthesized. All three ligands bind the Co(III) center in the same fashion with the exception of loss of conjugation between the carboxamide moiety and the pyridine ring in the latter two. The structures of [(PaPy3)Co(OH)][(PaPy3)Co(H2O)](ClO4)3 · 3H2O (1), [(PaPy3)Co(NO2)](ClO4) · 2MeCN (2), [(MePcPy3)Co(MeCN)](ClO4)2 · 0.5MeCN (3), and [(PcPy3)Co(Cl)](ClO4) · 2MeCN (4) have been determined. These ligands with strong-field carboxamido N donor stabilize the +3 oxidation state of the Co center as demonstrated by the facile oxidation of the corresponding Co(II) complexes (prepared in situ) by H2O2, [Fe(Cp)2](BF4), or nitric oxide (NO). The Co-Namido bond distances of 1-4 lie in the narrow range of 1.853-1.898 Å. 1H NMR spectra of these complexes confirm the low-spin d6 ground states of the metal centers. 相似文献
The light green coloured complexes of general formula [ReVO(L)Cl(OH2)]Cl have been synthesised in good yields by reacting [ReVOCl3(AsPh3)2] with HL in dichloromethane in dinitrogen atmosphere. Here, L− is the deprotonated form of N,N-bis(2-pyridylmethyl)amine (HL1); N-(2-pyridylmethyl)-N′,N′-dimethylethylenediamine (HL2) and N-(2-pyridylmethyl)-N′,N′-diethylethylenediamine (HL3). Single crystal X-ray structure determination of [ReVO(L1)Cl(OH2)]Cl confirms the amido binding of ReO3+ species. In the solid state of [ReVO(L1)Cl(OH2)]Cl, the coordinated and counter chloride ions are engaged in Re-Cl…H-C(ring), Cl…H-C(ring) and Re-(OH2)…Cl hydrogen bonding and forming of a supramolecular network in the solid state. The subunit of the supramolecular network consists of one eight-membered and two nine-membered hydrogen bonded rings. The average diameters of eight-membered and nine-membered rings are ∼3.70 and ∼5.26 Å, respectively. 相似文献
The reaction of 2,3-tri with CrCl3·6H2O1, dehydrated in boiling DMF, results in the formation of mer-CrCl3(2,3-tri) and anation of hydrolysed solutions of mer-MCl3(2,3,-tri) (M=Co, Cr) with 6 M HCl containing HClO4, forms trans-dichloro- mer-[MCl2(2,3-tri)(OH2)]ClO4·H2O (M=Cr, Co; I, II). trans-Dinitro-mer-[Co(NO2)2(NH3)(2,3-tri)] ClO4 crystallises from the reaction between mer-Co(NO2)3(2,3-tri) and aqueous 7 M ammonia, on addition of NaClO4·H2O, and trans-dichloro-mer-[CoCl2(NH3)(2,3-tri)]ClO4 (III) can be isolated by treatment of the dinitro with 12 M HCl. Reaction of mer-CoCl3(2,3-tri) with C2O42−, followed by addition of aqueous NH3 and NaClO4·H2O results in the isolation of racemic mer-[Co(ox)(NH3)(2,3-tri)]ClO4· H2O. This complex was resolved into its enantiomeric forms and treatment of these with SOCl2/MeOH/ HClO4 gave the chiral forms of trans-dichloro-mer- [CoCl2(NH3)(2,3-tri)]ClO4 (R or S at the see-NH center). The rates of loss of the first chloro ligand from these dichloro complexes have been measured spectrophotometrically in 0.1 M HNO3 over a 15 K temperature range to give the following kinetic parameters; (I) kH(298)=7.25 × 10−5 s−1, Ea=78.5 kJ mol−1, δS298#=−69 J K−1 mol−1; (II) kH(298)=4.00 × 10−3 s−1, Ea=89.9, δS298#= +87.5; (III) kH(298)=3.09 × 10−4 s−1, Ea=103, δS298#=+27. Treatment of the dichloro cations with Hg2+/HNO3 results in the generation of mer- M(2,3-tri)(OH2)33+ (M=Cr, Co; IV, V) and trans- diaqua-mer-Co(NH3)(2,3-tri)(OH2)23+ (VI). The Co(III) cations isomerise to the fac configuration with (V) Kisom(298) μ=1.0 M)=2.97 × 10−5 s−1, Ea=115, δS298#=+46. (VI) Kisom(298) (μ=1.0 M)=4.13 × 10−5 s−1, Ea=113, δS298#=+52. 相似文献
A 1:1 complex of mercuric chloride with D-peniccillamine has been isolated and characterised as 2[(μ3-Cl){HgSC(CH3)2CH(NH3)COO}3]·3(μ2-Cl)·2(H3O)·(H2O·Cl)3. The compound crystallises in cubic space group P4132, with a = 18.679(5) Å and Z = 4. The structure, refined to RF = 0.086 for 443 observed Mo-Kα diffractometer data, features a triply bridging chloride ion linking three equivalent [HgSC(CH3)2CH(NH3)COO]+ units [Hg-Cl = 2.37(1) Å, Hg-Cl-Hg′ = 98.5(9)°]. The carboxylate groups of a pair of adjacent penicillamine ligands are strongly linked via a symmetrical O?H?O hydrogen bond of length 2.24(8) Å, and neighboring pyramidal trinuclear [μ3-Cl){HgSC(CH3)2CH(NH3)-COO}3]2+ moieties are further connected by symmetrical chloride bridges [Hg-Cl = 3.06(2) Å; HgClHg′' = 79.6(7)°] to form a three-dimensional network. The voids in the lattice are filled by hydronium ions and novel planar cyclic hydrogen-bonded (H2O·Cl?)3 rings of edge O-H?Cl = 2.46(4) Å. 相似文献
The complexes CodptX3 and [Codpt(H2O)X2]ClO4 (X = Cl, Br; dpt = dipropylenetriamine = NH(CH2CH2CH2NH2)2) have been prepared and characterized. Rate constants (s−1) for aqueous solution at 25 °C and μ = 0.5 M (NaClO4), for the acid-independent sequential ractions. have been measured spectrophotometrically. For X = Cl: k1 ⋍ 2 × 10−2, k2 = 1.7 × 10−4 and k3 = 4.8 × 10−6, and for X = Br: k1 ⋍ 2 × 10−2, k2 = 5.25 × 10−4 and k3 = 2.5 × 10−5 The primary equation was found to be acid independent, while the secondary and tertiary aquations were acid-inhibited reactions. For the second step, the rate of the reaction was given by the rate equation where Ct is the complex concentration in the aqua-and hydroxodihalo species, k′2 is the rate constant for the acid-dependent pathway and Ka is the equilibrium constant between the hydroxo and aqua complex ions. The activation parameters were evaluated, for X = Cl: ΔH≠2 = 106.3 ± 0.4 kJ mol−1 and ΔS≠2 = 40.2 ± 1.7 J K−1 mol−, and for X = Br: ΔH≠2 = 91.6 ± 0.4 kJ mol−1 and ΔS≠2 = 0.4 ± 1.7 J K−1 mol−1. The results are discussed and detailed comparisons of the reactivities of these complexes with other haloaminecobalt(III) species are presented. 相似文献
Six-coordinate cobalt(III) complex trans-[Co{o-C6H4(PPh2)2}2X2]ClO4, fac-[Co{PhP(CH2CH2PPh2)2}X3],cis-[Co{P(CH2CH2PPh2)3}X2]ClO4 and cis-β-[Co{-CH2P(Ph)CH2CH2PPh2}2X2]PF6 (X = Cl, Br) have been prepared by halogen oxidation of the Co(II) analogues, and characterised by IR, electronic and 31P NMR spectroscopy. The failure to obtain complexes with X = I, and with some related ligands is discussed, and the rather low stability of the above complexes is rationalised in terms of steric crowding at the metal centre. 相似文献
The reaction products of adenosine with [Pt(NH3)3Cl]Cl or cis-Pt(NH3)2Cl2 have been studied using high performance liquid chromatography and uv spectroscopy. The reaction of [Pt(NH3)3Cl]Cl with adenosine (pH = 7.0, Pt/base = 0.5) gives four products. Two of them, mononuclear complexes in which platinum is bound to adenosine through N(7) or N(1), comprise more than 90% of all the products. The N(1) and N(7) sites on adenosine indicate almost equal binding affinity for [Pt(NH3)3Cl]Cl. The reaction of cis-Pt(NH3)2Cl2 with adenosine has been studied in the presence of a large excess of adenosine (Pt/base ? 0.05). The reaction gives four products. One is the monomeric 2:1 complex with cis-Pt(NH3)22+ bound to two adenosine molecules through the N(7) site and the N(1) site, and another is the monomeric 2:1 complex with cis-Pt(NH3)22+ bound to two adenosine molecules through the N(7) sites. cis-Pt(NH3)2Cl2 is stronger affinity to the N(7) site than of adenosine to the N(1) site. 相似文献
2′-Deoxy-5′-guanosinemonosphoric acid (B) reacts with cis-[Pt(NH3)2(OH2)2]2+ in two steps to form the cis-[Pt(NH3)2B2]y+ ion. In the first step 2′-d-5′- GMPH2 reacts some ten times faster than 5′-GMPH2 does. Rate constants, ΔH#, ΔS# and ΔV# are very similar for the two bases in the second reaction. It is proposed that the product in the first step contains no water and is cis-[Pt(NH3)2B]x+ in which the nucleobase is bidentate bonding through both N(7) of guanine and an oxygen atom of the phosphate group. 相似文献
The crystal and molecular structure of Δ- cis-α- ethylenebis-S-prolinato(1,2-diaminoethane)cobalt(III) perchlorate dihydrate, Δ-cis-α-[Co(SS-EBP)(en)] ClO4· 2H2O, was determined from three-dimensional X-ray diffractometer data. The complex crystallizes in the orthorhombic system, space group P212121 with a = 7.879(4) Å, b = 13.738(9) Å, c = 19.445(2) Å, V = 2104(2) Å3. With Z = 4, the observed and calculated densities are 1.60(2) and 1.605 g cm?3, respectively. The structure was refined by the block- diagonal least-squares technique to a final R = 0.0560 for 1604 observed reflections. The geometry about the cobalt atom is roughly octahedral with the tetradentate SS-EBP (= ethylenebis-S-prolinate ion), assuming cis-α configuration in which the complex possesses two out-of-plane amino acidate (R) rings and the backbone ethylenediamine (E) ring. The E ring conformation is δ. On the other hand, the R rings have λ conformation as well as the en ring. Δ-RNRN?(δE λR1 λR2)(λen)-cis-α-[Co(SS-EBP)(en)]+ is one of two possible isomers of this compound which have been isolated and whose absolute configurations have been tentatively assigned by spectroscopy. The crystal and molecular structure determination confirms these assignments. 相似文献
The aquation equilibria for cis-dibromodiammineplatinum(II) have been measured. For the first and second aquations at 25°C: K1 = 1.13 mM. ΔH° = 3.9 ± .7 kcal/mol, K2 = 0.042 mM, ΔH° = 10 ± 3 kcal/mol. Some isotopic exchange of 82Br between c-Pt(NH3)2Br2 and PtBr42− occurs without the formation of a free bromide ion and with a rate expression: Rate Exchange = (kac′ + kac″/[Br−])[Pt(NH3)2Br2] [PtBr42−]. It has been shown that the presence of c-Pt(NH3)2Br(H2O)+ serves to catalyze the aquation of PtBr42−, but that the catalysis step does not account for all the bromide dependent exchange. 相似文献
Delayed fluorescence (luminescence) from spinach chloroplasts, induced by short saturating flashes, was studied in the temperature region between 0 and ?40 °C. At these temperatures, in contrast to what is observed at room temperature, luminescence at 40 ms after a flash was strongly dependent, with period four, on the number of preilluminating flashes (given at room temperature, before cooling). At ?35 °C luminescence of chloroplasts preilluminated with two flashes (the optimal preillumination) was about 15 times larger than that of dark-adapted chloroplasts. The intensity of luminescence obtained with preilluminated chloroplasts increased steeply below ?10 °C, presumably partly due to accumulation of reduced acceptor (Q?), and reached a maximum at ?35 °C.In the presence of 50 mM NH4Cl the temperature optimum was at ?15 °C; at this temperature luminescence was increased by NH4Cl; at temperatures below ?20 °C luminescence at 40 ms was decreased by NH4Cl. At room temperature a strongly enhanced 40-ms luminescence was observed after the third and following flashes. The results indicate that both the S2 to S3 and the S3 to S4 conversion are affected by NlH4Cl.Inhibitors of Q? reoxidation, like 3-(3, 4-dichlorophenyl)-1, 1- dimethylurea, did only slightly affect the preillumination dependence of luminescence at sub-zero temperatures if they were added after the preillumination. This indicates that these substances by themselves do not accelerate the deactivation of S2 and S3. 相似文献
In isolated intact chloroplasts, maximal rates of photosynthetic O2 evolution (in saturating HCO?3) are associated with a critical transthylakoid proton gradient as a result of the stoichiometric consumption of 2 mol NADPH and 3 mol ATP/mol CO2 fixed. Studies with the fluorescent probe 9-aminoacridine reveal that in the illuminated steady state the critical ΔpH is 3.9.CO2-dependent O2 evolution is inhibited by increases of 0.1–0.2 in ΔpH that occur when catalase is omitted from the medium, NO?2 is included as an electron acceptor, or when chloroplasts are illuminated under low partial pressures of O2. Low concentrations of antimycin (0.33 μM) or NH4Cl (0.33 mM) decrease ΔpH and relieve this inhibition of electron flow. The energy transfer inhibitor quercetin lowers the high ATP/ADP ratio associated with these conditions, but does not lower ΔpH or relieve the inhibition.A decrease of ΔpH below 3.9 by weaker illumination, millimolar levels of NH4Cl or micromolar levels of antimycin, results in lower rates of photosynthesis owing to limitation by the phosphorylation rate.These findings show that in absence of rate limitation by the carbon cycle, the extent of thylakoid energization is related to the ratio of ATP to NADPH production and in turn, the rate of CO2 assimilation. 相似文献
Perovskite solar cells based on CH3NH3PbBr3 with a band gap of 2.3 eV are attracting intense research interests due to their high open‐circuit voltage (Voc) potential, which is specifically relevant for the use in tandem configuration or spectral splitting. Many efforts have been performed to optimize the Voc of CH3NH3PbBr3 solar cells; however, the limiting Voc (namely, radiative Voc:Voc,rad) and the corresponding ΔVoc (the difference between Voc,rad and Voc) mechanism are still unknown. Here, the average Voc of 1.50 V with the maximum value of 1.53 V at room temperature is achieved for a CH3NH3PbBr3 solar cell. External quantum efficiency measurements with electroluminescence spectroscopy determine the Voc,rad of CH3NH3PbBr3 cells with 1.95 V and a ΔVoc of 0.45 V at 295 K. When the temperature declines from 295 to 200 K, the obtained Voc remains comparably stable in the vicinity of 1.5 V while the corresponding ΔVoc values show a more significant increase. Our findings suggest that the Voc of CH3NH3PbBr3 cells is primarily limited by the interface losses induced by the charge extraction layer rather than by bulk dominated recombination losses. These findings are important for developing strategies how to further enhance the Voc of CH3NH3PbBr3‐based solar cells. 相似文献
Two oxime-functionalized diazamesocyclic derivates, namely, N,N′-bis(acetophenoneoxime)-1,4-diazacycloheptane (H2L1) and N,N′-bis(acetophenonoxime)-1,5-diazacyclooctane (H2L2), have been prepared and characterized. Both ligands (obtained in the hydrochloride form) can form stable metal complexes with CuII and NiII salts, the crystal structures of which were determined by X-ray diffraction technique. The reactions of H2L1 with Cu(ClO4)2 and Ni(ClO4)2 afford a penta-coordinated mononuclear complex [Cu(H2L1)Cl] · ClO4 (1) and a four-coordinated monomeric [Ni(HL1)] · ClO4 (2), in which the ligand is monodeprotonated. The ligand H2L2 also forms a quite similar mononuclear [Ni(HL2)] · ClO4 complex with Ni(ClO4)2, according to our previous work. However, reactions of different CuII salts [Cu(ClO4)2, CuCl2 and Cu(NO3)2 for 3, and CuSO4 for 4] with H2L2 in the presence of NaClO4 yield two unusual mono-μ-Cl dinuclear CuII complexes [Cu2(HL2)2Cl] · (ClO4) (3), and [Cu2(H2L2)(HL2)Cl] · (ClO4)2 · (H2O)(4). These results indicate that the resultant CuII complexes (1, 3 and 4) are sensitive to the backbones of diazamesocycles and even auxiliary anions. 相似文献
The crystal structures of [Cr(NO)(NH3)5](PF6)2 (red) and [Cr(NO)(NH3)5]Cl(PF6) (brown) have been determined. The [Cr(NO)(NH3)5]2+(A) complex cations in these compounds have a slightly distorted octahedral geometry with a strictly linear Cr-N-O arrangement (from symmetry). The short interatomic distances (2.399 Å × 4) between the O (nitrosyl) and H (ammonia in adjacent complex cations) atoms in A(PF6)2 indicate the existence of hydrogen bonds, while the interatomic distances (3.258 Å × 8) between those in ACl(PF6) are much longer, and the hydrogen bonds should be weak in spite of the presence of the smaller counter anion of chloride ion in ACl(PF6). Comparisons of the five crystal structures of A(PF6)2, ACl2, ACl(ClO4), ACl(PF6), and A(ClO4)2 have led to the conclusion that the existence of the strong hydrogen bonds gives red crystals of A(PF6)2, while the absence of hydrogen bonds results in the formation of green crystals of A(ClO4)2 (O ? H, 3.595 Å × 2). The color change of the crystals (from red to green) with the change of outer sphere anions is attributed to the change of the strength of the hydrogen bonding between the complex cations. 相似文献
Synthesis of complexes cis,cis-WVOXL (X=Cl, NCS), cis,trans-WVOXL (X=Cl, OPh, SPh) and cis,trans-WVIE2L (E2=O2, OS, S2) of the title ligand LH2 are reported. cis,cis-WVOCIL crystallises in space group P21/c with a=13.6541(9) Å, b=7.1555(11) Å, c=18.198(2) Å, β=95.294(6)°, V=1770.4(3) Å3 and Z=4 while the cis,trans isomer crystallises in space group P21/n with a=10.361(3) Å, b=14.141(4) Å, c=12.213(5) Å, β=102.56(3)°, V=1747(2) Å3 and Z=4. cis,trans-WVIS2L crystallises in space group P21/n with a=10.645(2) Å, b=13.929(2) Å, c=12.189(2) Å, β=103.14(2)°, V=1760(1) Å3 and Z=4. A short CH3···Cl distance of 3.067(7) Å and an acute OWCl angle of 94.1(2)° are seen in cis,cis-WVOClL, which converts to the cis,trans form on heating in MeCN. The latter isomer features a CH3···Cl distance of 3.38(2) Å and an OWCl angle of 105.1(8)°. Electrochemical and EPR data are reported. In particular, cis,trans-WVIE2L may be reduced to [WVE2L]–. EPR properties of these anions and those of complexes WVOXL are discussed in the context of WV centres in tungsten enzymes. 相似文献
The rate of phosphate hydrolysis of ATP in the substitution-inert complex Co(NH3)4ATP-has been examined in the presence and absence of [Co(cyclen)(H2O)2]3+. The rate of hydrolysis of Co(NH3)4ATP- in the absence of [Co(cyclen)(H2O)2]3+ is essentially independent of pH in the range 6.0 to 9.0, and the rate constant is 2.6 × 10?5 sec ?1 at pH 9.0, 40°C, and 1.0 M ionic strength Rate constants for the hydrolysis of Co(NH3)4ATP- in the presence of [Co(cyclen)(H2O)2]3+ are sharply dependent upon pH in the same range. The rate constants at pH 8.0, 8.6, and 9.0 are 8, 63, and 95 times larger than the rate constant at pH 7.0. At pH 9 the rate constant is 1.2 × 10?3 sec?1 for 16 mM Co(NH3)4ATP- in the presence of 10 mM [Co(cyclen)(H2O)2]3+. The proposed mechanism for hydrolysis involves the coordination of a phosphate group of Co(NH3)4ATP- by [Co(cyclen)(H2O)2]3+ to form a dinuclear species, followed by internal attack of coordinated hydroxide on the phosphate chain. 相似文献