Several new Ru(III) compounds containing both DMSO and a heterocyclic dinitrogen ligand were synthesized. The crystal structures of the
trans-Ru(DMSO)(pz)Cl
4
− (pz
=
pyrazine) monoanion, an analogue ...to the anticancer complex NAMI, with two different cations, tetraphenylphosphonium and Na show very different architectures. The Na complex has an interesting extended structure, while the PPh
4 complex shows discrete ions.
Several new Ru(III) DMSO compounds including PPh
4
trans-Ru(DMSO)
2Cl
4, PPh
4
trans-Ru(DMSO)(pyrazine)Cl
4 (
2), PPh
4
trans-Ru(DMSO)(4,4′-bipyridine)Cl
4 and PPh
4
trans-Ru(DMSO)(pyrimidine)Cl
4 were reported and characterized. The crystal structure of
2 and its Na
+ analogue were determined by X-ray diffraction methods. The
PPh
4
+
complex
2 is a discrete ionic compound, while the compound Na
trans-Ru(DMSO)(pyrazine)Cl
4
·
DMSO (
3) crystallized with a molecule of DMSO. The environment around the Na atom is a distorted octahedron with short contacts with three chloro ligands, two O atoms from the bonded and unbonded DMSO molecules, and the unbonded N atom of the pyrazine ligand. The Na atoms form bridges between the complexed anions in
3 resulting in the formation of infinite chains or ribbons parallel to the
b axis. The chains are held together by van der Waals interactions.
17α-substituted ethynylestradiols, derived from estrone, were converted to their corresponding 17α-(bromo- or iodo-propargyl)estrone intermediates. Nucleophilic substitution onto these moieties with ...malonate diester followed by hydrolysis and complexation with
cis-Pt(Me
2en)I
2 (Me
2en
=
N,
N-dimethylethylenediamine) gave
cis-Pt(Me
2en)(2-(3-(17β-estradiol-17α-yl)-prop-2-ynyl)malonato)
7, thus demonstrating that these estrogen-derived compounds can be used to synthesize stable Pt(II) complexes. The 3-(17β-estradiol-17α
-yl)-prop-2-ynyl-1-sulfanylethylthiol
23 was also prepared.
Two new types of pyrimidine-bridged Pt(II) complexes, (NR4)2(PtCl3)2(μ-pm) and cis- and trans-{Pt(R2SO)Cl2}2(μ-pm) where pm = pyrimidine, were synthesized and characterized by IR and multinuclear ...magnetic resonance spectroscopies and by crystallographic methods. Compounds with dimethylsulfoxide, tetramethylenesulfoxide, di-n-propylsulfoxide (DPrSO), di-n-butylsulfoxide (DBuSO), dibenzylsulfoxide (DBzSO), and diphenylsulfoxide were studied. The aqueous reaction of K2PtCl4 with pyrimidine produced the (PtCl3)2(μ-pm)2- ions, which can be precipitated with a NR4 + salt. The aqueous reaction of KPt(R2SO)Cl3 with pyrimidine in a 2:1 ratio produced the dinuclear species trans-{Pt(R2SO)Cl2}2(μ-pm). With DBuSO and DBzSO, the analogous cis isomers were also obtained. The 195Pt NMR resonances of the trans dimeric complexes were observed at higher field (av −3088 ppm) than the cis compounds (av −2948 ppm). The 195Pt coupling constants with the atoms of pyrimidine 3 J(195Pt−1H) and 3 J(195Pt−13C) are larger in the cis configuration than in the trans analogues. The crystal structures of two ionic complexes, (NR4)2(PtCl3)2(μ-pm) (R = Me and n-Bu), and of three mixed-ligands dimers, trans-{Pt(R2SO)Cl2}2(μ-pm) (R2SO = DMSO, DPrSO) and cis-{Pt(DBuSO)Cl2}2(μ-pm), were determined.
The ReOX2(met) compounds (X = Cl, Br) adopt a distorted octahedral structure in which a carboxylato oxygen lies trans to the ReO bond, whereas the equatorial plane is occupied by two cis halides, an ...NH2, and an SCH3 group. Coordination of the SCH3 unit creates an asymmetric center, leading to two diastereoisomers. X-ray diffraction studies reveal that the crystals of ReOBr2(d,l-met)·1/2H2O and ReOBr2(d,l-met)·1/2CH3OH contain only the syn isomer (S−CH3 bond on the side of the ReO bond), whereas ReOCl2(d-met) and ReOCl2(d,l-met) consist of the pure anti isomer. 1H NMR spectroscopy shows that both isomers coexist in equilibrium in acetone (anti/syn ratio = 1:1 for X = Br, 3:1 for X = Cl). Exchange between these two isomers is fast above room temperature, but it slows down below 0 °C, and the sharp second-order spectra of both isomers at −20 °C were fully assigned. The coupling constants are consistent with the solid-state conformations being retained in solution. Complexes of the type ReOX2(His-aa)X (X = Cl, Br) are isolated with the dipeptides His-aa (aa = Gly, Ala, Leu, and Phe). X-ray diffraction work on ReOBr2(His-Ala)Br reveals the presence of distorted octahedral cations containing the ReO3+ core and a dipeptide coordinated through the histidine residue via the imidazole nitrogen, the terminal amino group, and the amide oxygen, the site trans to the ReO bond being occupied by the oxygen. The alanine residue is ended by a protonated carboxylic group that does not participate in the coordination. The constant pattern of the1H NMR signals for the protons in the histidine residue confirms that the various dipeptides adopt a similar binding mode, consistent with the solid-state structure being retained in CD3OD solution.
The reactions of barium 1,2,4,5-benzenetetracarboxylate with CoSO
4 produced the dinuclear species Co(H
2O)
5(μ-C
6H
2(COO)
4)Co(H
2O)
5 which was characterized by crystallographic methods. The ...results have shown that the compound belongs to the monoclinic
C2/
c space group and it crystallized with six molecules of water in the lattice. The crystal is stabilized by a very elaborate H-bonded 3D network. The molecule contains an inversion center. The average Co–OH
2 distance is 2.0710(8) Å and the sixth Co–O bond is 2.0356(7) Å. The reaction of MnCl
2 with benzenetetracarboxylate ions produced a similar dinuclear species, Mn(H
2O)
5(μ-C
6H
2(COO)
4)Mn(H
2O)
5·H
2O (
2). The crystallographic results have shown that there are two independent molecules, which each contains an inversion center. This compound crystallized with only one molecule of water, and again the H-bonding system is very elaborate. The aqueous reaction of K
2Mn(C
6H
2(COO)
4)·3H
2O with CoSO
4 produced a compound containing two dinuclear species {Mn(H
2O)
5(μ-C
6H
2(COO)
4)Mn(H
2O)
5}{Co(H
2O)
5(μ-C
6H
2(COO)
4)Co(H
2O)
5}·2H
2O, which was characterized by X-ray diffraction methods. The results have shown that the latter compound is isomorphous with the Mn(II) compound. One of the Mn(II) dimer in
2 has been replaced by a Co(II) dimer.
Equivalent amounts of ReOX3(OPPh3)(Me2S) (where X = Cl, Br) and l-histidine (l-hisH) in acetonitrile yield ReOX2(l-his), in which the amino acid monoanion is N,N,O-tridentate. X-ray diffraction work ...on both compounds shows that the three donors occupy a face in a distorted octahedron and the carboxylate oxygen is coordinated trans to the ReO bond. The 2:1 complex ReO(l-his)2I is obtained by reacting 2 equiv of l-histidine with ReO2I(PPh3)2 in methanol in the presence of NaOCH3. 1H NMR spectroscopy indicates that these complexes contain one N,N,O-tridentate histidine anion coordinated as above and one N,N-bidentate histidine anion, whose carboxylate group is free. By refluxing ReOX2(l-his) in methanol, the carboxylic groups esterify and two octahedral units condense into an oxo-bridged dinuclear complex {ReOX2(l-hisMe)}2O containing N,N-bidentate histidine methyl ester. The ORe−O−ReO backbone is approximately linear, and the two ReOX2(l-hisMe) units are related by a 2-fold axis through the central oxygen. Crystals of {ReOBr2(l-hisMe)}2O consist of an ordered phase containing two of the possible diastereoisomers in a 1:1 ratio. 1H NMR spectra of these crystals include two sets of signals, consistent with the presence of two isomers with C 2 symmetry, and the spectra of the nonrecrystallized material confirm that these are the only two isomers formed.
Three new types of mixed ligands Pt(II) complexes were synthesized and characterized by IR and multinuclear magnetic resonance spectroscopies and by crystallographic methods. These compounds are the ...monomers
cis- and
trans-Pt(Ypy)(pyrimidine)Cl
2 and the dinuclear species
trans,
trans-Cl
2(Ypy)Pt(μ-pyrimidine)Pt(Ypy)Cl
2, where Ypy
=
pyridine derivative.
Mixed-ligand complexes of the type
cis- and
trans-Pt(Ypy)(pm)Cl
2 where Ypy
=
pyridine derivative and pm
=
pyrimidine were synthesized and characterized by IR spectroscopy and by multinuclear (
195Pt,
1H and
13C) magnetic resonance spectroscopy. The
cis compounds were prepared from the reaction of KPt(Ypy)Cl
3 with pyrimidine (1:1 proportion) in water, while most of the
trans isomers were synthesized from the isomerization of the
cis compounds. The
cis isomers could not be isolated with the Ypy ligands containing two –CH
3 groups in
ortho positions. When the aqueous reaction of KPt(Ypy)Cl
3 with pyrimidine was performed in a Pt:pm ratio
=
2:1, the pyrimidine-bridged dinuclear species were formed. Only the most stable
trans–
trans isomers could be isolated pure. In IR spectroscopy, the
cis monomers showed two
ν(Pt–Cl) bands, while the
trans monomers and dimers showed only one
ν(Pt–Cl) band. The
195Pt NMR signals of the
cis monomers were found at slightly higher fields than those of the corresponding
trans isomers. The
δ(
195Pt) of the dimers were found close to those of the
trans monomers. The NMR results were interpreted in relation to the solvent effect, which seems important in these complexes. The coupling constants
J(
195Pt–
1H) and
J(
195Pt–
13C) are larger in the
cis geometry. The crystal structures of the compounds
cis-Pt(2,4-lut)(pm)Cl
2,
trans-Pt(2,6-lut)(pm)Cl
2 and
trans,
trans-Cl
2(2,6-lut)Pt(μ-pm)Pt(Ypy)Cl
2 were studied by X-ray diffraction methods and the results have confirmed the configurations suggested by IR and NMR spectroscopies.
