共查询到20条相似文献,搜索用时 31 毫秒
1.
Clara Pampillón 《Journal of organometallic chemistry》2007,692(11):2153-2159
From the carbolithiation of N,N-dimethylamino fulvene (3a) and different ortho-lithiated heterocycles (furan, thiophene and N-methylpyrrole), the corresponding lithium cyclopentadienide intermediate (4a-c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in dimethylamino-functionalised titanocenes 5a-c. When these titanocenes were tested against LLC-PK cells, the IC50 values obtained were of 240, and 28 μM for titanocenes 5a and 5b, respectively. The most cytotoxic titanocene 5c with an IC50 value of 5.5 μM is found to be almost as cytotoxic as cis-platin, which showed an IC50 value of 3.3 μM, when tested on the LLC-PK cell line, and titanocene 5c is approximately 400 times better than titanocene dichloride itself. 相似文献
2.
Katja Strohfeldt Helge Müller-Bunz Clara Pampillón Matthias Tacke 《Transition Metal Chemistry》2007,32(7):971-980
Substituted titanocenes like ansa-titanocenes, diarylmethyl-substituted and benzyl-substituted titanocenes, are known for
their cytotoxic potential and they can be synthesised using 6-arylfulvenes. Nevertheless, in the case of using 6-(4-morpholin-4yl-phenyl)
fulvene (5a) or 6-{[bis-(2-methoxyethyl)amino]phenyl} fulvene (5b) the synthetic possibilities seem to be limited, but the morpholino and the bis-(2-methoxyethyl)amino substituent are in terms of an improved water solubility and drug availability in the cell very interesting
groups. The corresponding benzaldehydes, which are the starting material for the synthesis of these fulvenes, were not commercially
available and therefore, a modified synthetic approach had to be introduced. Nevertheless, the reactivity of the obtained
fulvenes was unexpected and only the ansa-titanocene bis-[{[bis-(2-methoxyethyl)amino]phenyl}cyclopentadienyl] titanium(IV) dichloride (6b) and the benzyl-substituted titanocene [1,2-di(cyclopentadienyl)-1,2-di(4-morpholin-4yl-phenyl)-ethanediyl] titanium dichloride
(8a) could be obtained and characterised.
When the benzyl-substituted titanocene (8a) was tested against pig kidney cells (LLC-PK) an anti-proliferative effect, resulting in an IC50 value of 25 μM, was observed. This IC50 value is in the lower range of the cytotoxicities evaluated for titanocenes up to now. The ansa-titanocene (6b) showed surprisingly, when tested on the same cell line, a proliferative effect. 相似文献
3.
James Claffey 《Journal of organometallic chemistry》2008,693(3):526-536
From the reaction of 6(2-methoxy-phenyl)fulvene (1a), 6(3-methoxy-phenyl)fulvene (1b), 6(3,4-dimethoxy-phenyl)fulvene (1c) and 6(3,4,5-trimethoxy-phenyl)fulvene (1d) with LiBEt3H, lithiated cyclopentadienide intermediates 2a-d were synthesised. These intermediates were then transmetallated to titanium with TiCl4 to give benzyl substituted titanocenes bis-[(2-methoxy-benzyl)cyclopentadienyl]titanium(IV) dichloride (3a), bis-[(3-methoxy-benzyl)cyclopentadienyl]titanium(IV) dichloride (3b), bis-[(3,4-dimethoxy-benzyl)cyclopentadienyl]titanium(IV) dichloride (3c) and bis-[(3,4,5-trimethoxy-benzyl)cyclopentadienyl]titanium(IV) dichloride (3d). The three titanocenes 3a-c were characterised by single crystal X-ray diffraction, while the structure of the fourth titanocene 3d was elucidated through a DFT calculation. All four titanocenes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values. Titanocenes 3a-d were found to have IC50 values of 97, 159, 88 and 253 μM, respectively. All four titanocene derivatives show significant cytotoxicity improvement when compared to unsubstituted titanocene dichloride. 相似文献
4.
Megan Hogan Juliet Cotter James Claffey Brendan Gleeson Denise Wallis Donal O'Shea Matthias Tacke 《Helvetica chimica acta》2008,91(9):1787-1797
From the carbolithiation of 1‐(cyclopenta‐2,4‐dien‐1‐ylidene)‐N,N‐dimethylmethanamine (=6‐(dimethylamino)fulvene; 3 ) and different lithiated azaindoles 2 (1‐methyl‐7‐azaindol‐2‐yl, 1‐[(diethylamino)methyl]‐7‐azaindol‐2‐yl, and 1‐(methoxymethyl)‐7‐azaindol‐2‐yl), the corresponding lithium cyclopentadienide intermediates 4a – 4c were formed (7‐azaindole=1H‐pyrrolo[2,3‐b]pyridine). The latter underwent a transmetallation reaction with TiCl4 resulting in the (dimethylamino)‐functionalised ‘titanocenes’ 5a – 5c . When the ‘titanocenes’ 5a – 5c were tested against LLC‐PK cells, the IC50 values obtained were of 8.8, 12, and 87 μM , respectively. The most cytotoxic ‘titanocene’, 5a , with an IC50 value of 8.8 μM is nearly as cytotoxic as cis‐platin, which showed an IC50 value of 3.3 μM when tested on the epithelial pig kidney LLC‐PK cell line, and ca. 200 times better than ‘titanocene dichloride’ itself. 相似文献
5.
From the carbolithiation of 6‐morpholino fulvene ( 3a ) and different ortho‐lithiated heterocycles (furan, thiophene and N‐methylpyrrole), the corresponding lithium cyclopentadienide intermediate ( 4a – c ) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in morpholino‐functionalised titanocenes 5a – c . When these titanocenes were tested against LLC‐PK cells, the IC50 values obtained were of 58, 63 and 115 μM for titanocenes 5a – c respectively. The most cytotoxic titanocene 5a with an IC50 value of 58 μM is found to be approximately 20 times less cytotoxic than cis‐platin, which showed an IC50 value of 3.3 μM, when tested on the LLC‐PK cell line, and 10 times less cytotoxic than its dimethylamino‐functionalised analogue (Titanocene C , IC50 = 5.5 μM). 相似文献
6.
Nigel J. Sweeney James Claffey Helge Müller‐Bunz Clara Pampillón Katja Strohfeldt Matthias Tacke 《应用有机金属化学》2007,21(2):57-65
Using 6‐benzo[1,3]dioxolefulvene ( 1a ), a series of benzodioxole substituted titanocenes was synthesized. The benzyl‐substituted titanocene bis[(benzo[1,3]dioxole)‐5‐methylcyclopentadienyl] titanium (IV) dichloride ( 2a ) was synthesized from the reaction of Super Hydride with 1a . An X‐ray determined crystal structure was obtained for 2a . The ansa‐titanocene {1,2‐di(cyclopentadienyl)‐1,2‐di‐(benzo[1,3]dioxole)‐ethanediyl} titanium(IV) dichloride ( 2b ) was synthesized by reductive dimerisation of 1a with titanium dichloride. The diarylmethyl substituted titanocene bis(di‐(benzo[1,3]dioxole)‐5‐methylcyclopentadienyl) titanium(IV) dichloride ( 2c ) was synthesized by reacting 1a with the para‐lithiated benzodioxole followed by transmetallation with titanium tetrachloride. When titanocenes 2a–c were tested against pig kidney (LLC‐PK) cells inhibitory concentrations (IC50) of 2.8 × 10?4, 1.6 × 10?4 and 7.6 × 10?5 M , respectively, were observed. These values represent improved cytotoxicity against LLC‐PK, when compared with unsubstituted titanocene dichloride, but are not as impressive as values obtained for titanocenes previously synthesized using the above methods. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
7.
James Claffey 《Journal of organometallic chemistry》2010,695(18):2105-11110
Through the reaction of Super Hydride (LiBEt3H) with 6-phenyl-substituted fulvenes followed by transmetallation to TiCl4 ten novel benzyl-substituted titanocene dichloride derivatives were synthesised. 6(4-morpholinomethyl-phenyl) fulvene (6g) and (bis-[(4-methoxymethyl-benzyl)cyclopentadienyl]titanium(IV) dichloride) (8a) were characterised by single crystal X-ray diffraction. All of the titanocenes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line and CAKI-1 human kidney cell human carcinoma cell line in an MTT based assay in order to determine their IC50 values. The titanocenes synthesised were found to have IC50 values ranging from 2.3 (±0.3) μM (comparable to cisplatin) to others which show no anti-proliferative activity on this cell line in standard DMSO formulations on LLC-PK cell line. Eight of the titanocenes were found to be completely water-soluble and had IC50 values of 6.5 (±0.7) μM to no activity when using medium only for formulation. On the CAKI-1 cell line, IC50 values of 7.8 (±1.4) μM to no activity were found using DMSO formulation, while IC50 values of 0.55 (±0.32) μM to no activity were measured using just medium as the formulation reagent. Some of the titanocenes show significant cytotoxicity improvement when compared directly to the lead compound Titanocene Y (bis-[(p-methoxybenzyl)cyclopentadienyl] titanium(IV) dichloride) and are more cytotoxic than cisplatin. Bis-[(4-diethylaminomethyl-benzyl)cyclopentadienyl]titanium(IV) dichloride (8d) at this preliminary stage seems to be the most promising of the ten compounds prepared and exhibits nanomolar activity against CAKI-1. 相似文献
8.
Rajiv Dahiya Monika Maheshwari Anil Kumar 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):121-127
Abstract The present investigation deals with the synthesis of a N-methylated cyclotetrapeptide, hirsutide (2), by coupling of the dipeptide units Boc-l-phenylalanyl-l-N-methylphenylalanine-OH and l-valyl-l-N-methylphenylalanine-OMe followed by cyclization of the linear tetrapeptide fragment. The chemical structure was established
on the basis of analytical as well as spectroscopic data. The newly synthesized cyclic peptide was subjected to pharmacological
screening and found to be highly potent against the gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae at 6 μg cm−3. In addition, potent antihelmintic activity against the earthworms Megascoplex konkanensis and Pontoscotex corethruses at 1 and 2 mg cm−3, and potent cytotoxic activity against Dalton’s lymphoma ascites and Ehrlich’s ascites carcinoma cell lines with IC50 values of 14 and 22 μM were also observed. Studies revealed that the pentafluorophenyl ester method employing a catalytic
amount of N-methylmorpholine proved to be better for cyclization of the linear tetrapeptide unit.
Graphical abstract
相似文献
9.
Matthias Tacke Lorcan T. Allen William M. Gallagher Oscar Mendoza Franz-Josef K. Rehmann 《Journal of organometallic chemistry》2004,689(13):2242-2249
Starting from 6-(p−N,N-dimethylanilinyl)fulvene (1a) or 6-(pentamethylphenyl)fulvene (1b) [1,2-di(cyclopentadienyl)-1,2-di(p−N,N-dimethylaminophenyl)ethanediyl] titanium dichloride (2a) and [1,2-di(cyclopentadienyl)-1,2-bis(pentamethylphenyl)ethanediyl] titanium dichloride (2b) and their corresponding dithiocyanato complexes (3a, 3b) were synthesized. Titanocene 2b did not show a cytotoxic effect, but when 2a was tested against pig kidney carcinoma cells (LLC-PK) or human ovarian carcinoma cells (A2780/cp70) inhibitory concentrations (IC50) of 2.7 × 10−4 and 1.9 × 10−4 M, respectively, were observed. 相似文献
10.
Denise Wallis 《Journal of organometallic chemistry》2009,694(6):828-6143
From the reaction of Super Hydride (LiBEt3H) with 6-(4-methoxyphenyl) fulvene (1a), 6-(2-fluoro-4-methoxyphenyl) fulvene (1b), and 6-(4-N,N-dimethylaminophenyl) fulvene (1c) lithiated cyclopentadienide intermediates (2a-c) were synthesised. These intermediates were then transmetallated to zirconium with ZrCl4 to give benzyl-substituted zirconocenes bis-[(4-methoxybenzyl)cyclopentadienyl] zirconium(IV) dichloride (3a), bis-[(2-fluoro-4-methoxybenzyl)cyclopentadienyl] zirconium(IV) dichloride (3b) and bis-[(4-N,N-dimethylaminobenzyl)cyclopentadienyl] zirconium(IV) dichloride (3c). All three zirconocenes were characterised by single crystal X-ray diffraction and preliminary in vitro cell tests were performed with the zirconocene derivatives on the LLC-PK cell line in order to determine their cytotoxicity. Zirconocenes 3b and 3c did not show cytotoxicity up to a concentration of 170 μM, while 3a exhibited an IC50 value of 57 μM against LLC-PK. 相似文献
11.
Brendan Gleeson James Claffey Daniel Ertler Megan Hogan Helge Müller-Bunz Francesca Paradisi Denise Wallis Matthias Tacke 《Polyhedron》2008,27(18):3619-3624
From the reaction of 6-(p-methoxyphenyl) fulvene (1a), 6-(p-N,N-dimethylaminophenyl) fulvene (1b) and 6-(3,4-dimethoxyphenyl) fulvene (1c) with LiBEt3H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to tin with SnCl4 to yield tetra-substituted bis(cyclopentadienyl)tin dichloride complexes (3a–c). Further reaction with tin tetrachloride yielded the benzyl-substituted derivatives bis-[(p-methoxybenzyl)cyclopentadienyl] tin(IV) dichloride (4a), bis-[(p-N,N-dimethylaminobenzyl)cyclopentadienyl] tin(IV) dichloride (4b), and bis-[(3,4-dimethoxyphenyl)cyclopentadienyl] tin(IV) dichloride (4c). Preliminary antibacterial tests were carried out using the Kirby–Bauer disk-diffusion method, in which 4a–c showed little to no activity against the Gram-negative bacterium Escherichia coli, but medium activity against Gram-positive bacteria (MRSA, MSSA). In addition, the organotin complexes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values. Compound 4c showed no cytotoxic activity, while 4a and 4b were found to have IC50 values of 15 and 205 μM, respectively. 相似文献
12.
New complexes of Cu(II), Zn(II) and Ni(II) with naringenin have been synthesized and characterized on the basis of elemental analyses, molar conductivities, 1H-n.m.r., i.r. spectra, u.v. spectra, thermal analyses, and fluorescence spectra. In addition, the suppression ratio for O2−· (a) and OH· (b) of the complexes were studied by spectrophotometric methods. The results show that the effect of the Cu(II)-complex IC50 (a) = 0.003 μm, IC50 (b) = 0.06 μm is the most remarkable, and the average scavenger ability of the complexes (IC50=0.06–2.67μm) against OH· is higher than that of the ligand (IC50 = 28.5 μm). Taken together, these results indicate that the scavenger effect can be enhanced by the formation of metal-ligand coordination
complexes, and the transition-metal ions may have differential and selective roles. 相似文献
13.
Isabel Castro Juan Faus Miguel Julve Michèle Philoche-Levisalles 《Transition Metal Chemistry》1992,17(3):263-269
Two complexes of formula [Cu(terpy)(H2O)](CF3SO3)2 (1) and [Cu(terpy)(OH)]BPh4 (2) (terpy=2,2′∶6′,2″-terpyridine and BPh4=tetraphenylborate anion) have been synthesized and characterized by spectroscopic techniques. The x-ray crystal structure
of (1) has been determined by x-ray diffraction. The structure is made up of [Cu(terpy)(H2O)]2+ mononuclear cations plus semi-coordinated CF3SO3
− anions. The coordination geometry around the copper atom is approximately elongated tetragonal octahedral. The oxygen atom
of water and the three nitrogen atoms of terpy occupy the equatorial sites whereas the apical ones are filled by trifluoromethanesulphonate
oxygen atoms. The formation of hydroxo complexes of [Cu(terpy)(H2O)]2+ has been investigated by potentiometry in aqueous solutions and the constants of the Equilibria (1) and (2)
相似文献
14.
Irradiation of benzene solutions 10?3M in both titanocene-d10 dichloride and titanocene dichloride with light of wavelengths 313, 360, 400, and 520 nm leads to the formation of titanocene-d5 dichloride with quantum yields of 0.02, 0.005, 0.01 and 0.007 mol Ei?1, respectively. Photodecomposition of titanocene dichloride is negligible even at much longer photolysis times than those required for isotopic equilibration. Photolysis of benzene solutions 10?2M in titanocene dichloride and 1.0 M in methanol leads to the formation of cyclopentadienyl(methoxo)titanium dichloride with a quantum yield of about 0.08 mol Ei?1 when the irradiating wavelength is 313 nm. 相似文献
15.
Reena Singh Atanu Banerjee Yee Gordon Kajal Krishna Rajak 《Transition Metal Chemistry》2009,34(6):689-694
Abstract The title complexes and have been synthesized in excellent yields by reacting Co(OAc)2·4H2O with H2L1 and H2L2, respectively, in acetonitrile solution. Here, [L1]2− and [L2]2− are the deprotonated forms of N,N-bis(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine and N,N-bis(2-hydroxybenzyl)-2-picolylamine, respectively. The crystal structures of and were determined by x-ray crystallography. In , each cobalt atom has distorted trigonal bipyramid geometry, while in , each cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic
interaction in . The magnetic characterization for is in agreement with the presence of Co(II) and Co(III) centers.
Graphical Abstract The title complexes and have been synthesized in excellent yields by reacting Co(OAc)2·4H2O with dianionic N2O2 coordinating ligands. In complex 1, each cobalt atom has distorted trigonal bipyramid geometry, while in complex 2, each
cobalt atom has distorted octahedral geometry. Variable temperature magnetic moment measurements show weak antiferromagnetic
interaction in complex 1. The magnetic characterization for complex 2 is in agreement with the presence of Co(II) and Co(III)
centers.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Brendan Gleeson James Claffey Megan Hogan Helge Müller-Bunz Denise Wallis Matthias Tacke 《Journal of organometallic chemistry》2009,694(9-10):1369-1374
From the reaction of 6-(p-methoxyphenyl) fulvene (1a), 6-(3,4-dimethoxyphenyl) fulvene (1b) and 6-(3,4,5-trimethoxyphenyl) fulvene (1c) with LiBEt3H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to vanadium with VCl4 to yield the benzyl-substituted vanadocenes bis-[(p-methoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3a), bis-[(3,4-dimethoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3b), and bis-[(3,4,5-trimethoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3c). The two vanadocenes 3a and 3c were characterised by single crystal X-ray diffraction. All three vanadocenes had their cytotoxicity investigated through MTT based preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values and compare them with the corresponding titanocene dichloride derivatives. Vanadocenes 3b–c were found to have IC50 values of 9.1 and 8.3 μM, while 3a showed a superior value of 3.0 μM, respectively. 相似文献
17.
Thato N. Mtshali Walter Purcell Hendrik G. Visser Steven S. Basson 《Transition Metal Chemistry》2008,33(4):481-491
The kinetics of the reaction between [ReN(H2O)-(CN)4]2− with different κ2
N,O-donor ligands (quin− and 2,3-dipic−, respectively) have been studied in the pH 4–12 range in aqueous solution. Two consecutive reaction steps with the formation
of the [ReN(η1-quin)(CN)4]3− and [ReN(μ2-quin) (CN)3]2− complexes, respectively, were spectrophotometrically observed and kinetically investigated. The same reaction mechanism is
proposed for these two ligands. The first fast reaction (for quin−) is attributed to the aqua substitution of [ReN(H2O)(CN)4]2− with forward and reverse rate constants of 1.96(5) × 10−1 M−1 s−1 and 5.6(3) × 10−2 s−1, while a rate of 2.64(3) M−1 s−1 was observed for the reaction between the conjugate base [ReN(OH)(CN)4]3− and quin− at 40.2 °C. Due to small absorbance changes, it was difficult to obtain any good quality data for the fast reactions for
2,3-dipic−. The second, slower reaction is attributed to cyano substitution with rate constants (k
3
K
1) of 4.17(4) × 10−3 for quin− and 4.68(7) × 10−3 M−1 s−1 for 2,3-dipic−, at 80.02 °C, respectively. The acid dissociation constant for the aqua complex was spectrophotometrically determined as
11.58(3) and 11.54(2) and kinetically as 11.51(8) and 11.41(1), at 80.4 °C, respectively. Negative values of −83.5(2) and −144.1(2) J K−1 mol−1 as well as the of 71.4(3) and 47.3(3) kJ mol−1, for the slow quin− and 2,3-dipic− reactions, respectively, point to an ordered transition state where bond formation is responsible for the major driving force
of the reaction. The and for the fast forward reaction of quin− is indicative of expected associative activation in the transition state.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
A u.v.–vis spectrophotometric study of the adduct formation of the nickel(II) Schiff base complexes,([NiL]) where L = [3-methoxysalophen,
N,N′-bis(3-methoxysalicylidene)-1,2-phenylenediimine] (1), [4-methoxysalophen, N,N′-bis(4-methoxysalicylidene)-1,2-phenylenediimine] (2), [5-methoxysalophen, N,N′-bis(5-methoxysalicylidene)-1,2-phenylenediimine] (3) and [Salophen, [N,N′-bis(salicylaldehydo)-1,2-phenylenediimine] (4) as donors with R2SnCl2 (R = methyl, phenyl and n-butyl) as acceptors have been investigated in chloroform, as solvent. Adducts have been characterized by 1H, 13C and 119Sn NMR, IR and electronic spectroscopy and CHN elemental microanalysis. The formation constants and the thermodynamic free
energies were measured using u.v.–vis spectrophotometry titration for 1:1 adduct formation at various temperatures (T = 278
to 308 K). The trend of the adduct formation of the nickel Schiff base complexes with a given tin acceptor decreases as follows:
and
The trend of the reaction of R2SnCl2 acceptors toward a given nickel Schiff base complex is as follows:
相似文献
19.
Rajiv Dahiya Monika Maheshwari Anil Kumar 《Monatshefte für Chemie / Chemical Monthly》2009,62(5):121-127
Abstract
The present investigation deals with the synthesis of a N-methylated cyclotetrapeptide, hirsutide (2), by coupling of the dipeptide units Boc-l-phenylalanyl-l-N-methylphenylalanine-OH and l-valyl-l-N-methylphenylalanine-OMe followed by cyclization of the linear tetrapeptide fragment. The chemical structure was established on the basis of analytical as well as spectroscopic data. The newly synthesized cyclic peptide was subjected to pharmacological screening and found to be highly potent against the gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae at 6 μg cm−3. In addition, potent antihelmintic activity against the earthworms Megascoplex konkanensis and Pontoscotex corethruses at 1 and 2 mg cm−3, and potent cytotoxic activity against Dalton’s lymphoma ascites and Ehrlich’s ascites carcinoma cell lines with IC50 values of 14 and 22 μM were also observed. Studies revealed that the pentafluorophenyl ester method employing a catalytic amount of N-methylmorpholine proved to be better for cyclization of the linear tetrapeptide unit. 相似文献20.
Zafar Ahmad Siddiqi M. Mansoob Khan Mohd Khalid Sarvendra Kumar 《Transition Metal Chemistry》2007,32(7):927-935
Reactions of a 32-membered [N12] macrocyclic ligand, L.2HClO4 with metal salts MCl3 (M=Cr or Fe) and MCl2 (M=Co, Ni or Cu) have produced complexes of stoichiometries M2LCl4(ClO4)2 and M2LCl2(ClO4)2, respectively. However, reactions with [M(Ph3P)2Cl2] (M=Co or Ni) and [(η5-C5H5)Ni(Ph3P)I] follow a ligand substitution path resulting in products with stoichiometries M2LCl2(ClO4)2 and [(η5-C5H5)2Ni2L(ClO4)2], respectively. The mode of bonding and geometry of the complexes have been derived on the basis of i.r., ligand field spectral
and magnetic susceptibility measurements. EPR of CuII complex shows anisotropy with
, G < 4.0 and orbital reduction factor
. Thermodynamic first ionic association constants (K1) and the corresponding free energy change (ΔG) of complexes in DMSO have been determined and discussed. Cyclic voltammetric studies indicate the presence of a quasi-reversible
redox couples CrIII/II, CoII/I, NiII/I, NiII/III and CuII/I in solutions suggesting flexible nature of the macrocyclic cavity. 相似文献