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1.  Efficient Synthesis of a Maghemite/Gold Hybrid Nanoparticle System as a Magnetic Carrier for the Transport of Platinum-Based Metallotherapeutics 
The preparation and thorough characterization of a hybrid magnetic carrier system for the possible transport of activated platinum-based anticancer drugs, as demonstrated for cisplatin (cis-[Pt(NH3)2Cl2], CDDP), are described. The final functionalized mag/Au–LA–CDDP* system consists of maghemite/gold nanoparticles (mag/Au) coated by lipoic acid (HLA; LA stands for deprotonated form of lipoic acid) and functionalized by activated cisplatin in the form of cis-[Pt(NH3)2(H2O)2]2+ (CDDP*). The relevant techniques (XPS, EDS, ICP-MS) proved the incorporation of the platinum-containing species on the surface of the studied hybrid system. HRTEM, TEM and SEM images showed the nanoparticles as spherical with an average size of 12 nm, while their superparamagnetic feature was proven by 57Fe Mössbauer spectroscopy. In the case of mag/Au, mag/Au–HLA and mag/Au–LA–CDDP*, weaker magnetic interactions among the Fe3+ centers of maghemite, as compared to maghemite nanoparticles (mag), were detected, which can be associated with the non-covalent coating of the maghemite surface by gold. The pH and time-dependent stability of the mag/Au–LA–CDDP* system in different media, represented by acetate (pH 5.0), phosphate (pH 7.0) and carbonate (pH 9.0) buffers and connected with the release of the platinum-containing species, showed the ability of CDDP* to be released from the functionalized nanosystem.
doi:10.3390/ijms16012034
PMCID: PMC4307347  PMID: 25603182
nanoparticles; maghemite; magnetic; cisplatin; drug delivery
2.  Gold(I) Complexes of 9-Deazahypoxanthine as Selective Antitumor and Anti-Inflammatory Agents 
PLoS ONE  2014;9(10):e109901.
The gold(I) mixed-ligand complexes involving O-substituted derivatives of 9-deazahypoxanthine (HLn) and triphenylphosphine (PPh3) with the general formula [Au(Ln)(PPh3)] (1–5) were prepared and thoroughly characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopy, ESI+ mass spectrometry, single crystal X-ray (HL5 and complex 2) and TG/DTA analyses. Complexes 1–5 were evaluated for their in vitro antitumor activity against nine human cancer lines, i.e. MCF7 (breast carcinoma), HOS (osteosarcoma), A549 (adenocarcinoma), G361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) and THP-1 (monocytic leukaemia), for their in vitro anti-inflammatory activity using a model of LPS-activated macrophages, and for their in vivo antiedematous activity by λ-carrageenan-induced hind paw edema model on rats. The results showed that the complexes 1–5 exhibit selective in vitro cytotoxicity against MCF7, HOS, 22Rv1, A2780 and A2780R, with submicromolar IC50 values for 2 against the MCF7 (0.6 µM) and HOS (0.9 µM). The results of in vitro cytotoxicity screening on primary culture of human hepatocytes (HEP220) revealed up to 30-times lower toxicity of compounds against healthy cells as compared with cancer cells. Additionally, the complexes 1–5 significantly influence the secretion and expression of pro-inflammatory cytokines TNF-α and IL-1β by a similar manner as a commercially used anti-arthritic drug Auranofin. The tested complexes also significantly influence the rate and overall volume of the edema, caused by the intraplantar application of λ-carrageenan polysaccharide to rats. Based on these promising results, the presented compounds could qualify to become feasible candidates for advanced testing as potential antitumor and anti-inflammatory drug-like compounds.
doi:10.1371/journal.pone.0109901
PMCID: PMC4198181  PMID: 25333949
3.  Gold(I)-Triphenylphosphine Complexes with Hypoxanthine-Derived Ligands: In Vitro Evaluations of Anticancer and Anti-Inflammatory Activities 
PLoS ONE  2014;9(9):e107373.
A series of gold(I) complexes involving triphenylphosphine (PPh3) and one N-donor ligand derived from deprotonated mono- or disubstituted hypoxanthine (HLn) of the general composition [Au(Ln)(PPh3)] (1–9) is reported. The complexes were thoroughly characterized, including multinuclear high resolution NMR spectroscopy as well as single crystal X-ray analysis (for complexes 1 and 3). The complexes were screened for their in vitro cytotoxicity against human cancer cell lines MCF7 (breast carcinoma), HOS (osteosarcoma) and THP-1 (monocytic leukaemia), which identified the complexes 4–6 as the most promising representatives, who antiproliferative activity was further tested against A549 (lung adenocarcinoma), G-361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) cell lines. Complexes 4–6 showed a significantly higher in vitro anticancer effect against the employed cancer cells, except for G-361, as compared with the commercially used anticancer drug cisplatin, with IC50 ≈ 1–30 µM. Anti-inflammatory activity was evaluated in vitro by the assessment of the ability of the complexes to modulate secretion of the pro-inflammatory cytokines, i.e. tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in the lipopolysaccharide-activated macrophage-like THP-1 cell model. The results of this study identified the complexes as auspicious anti-inflammatory agents with similar or better activity as compared with the clinically applied gold-based antiarthritic drug Auranofin. In an effort to explore the possible mechanisms responsible for the biological effect, the products of interactions of selected complexes with sulfur-containing biomolecules (L-cysteine and reduced glutathione) were studied by means of the mass-spectrometry study.
doi:10.1371/journal.pone.0107373
PMCID: PMC4167326  PMID: 25226034
4.  Pharmacological and Molecular Effects of Platinum(II) Complexes Involving 7-Azaindole Derivatives 
PLoS ONE  2014;9(3):e90341.
The in vitro antitumour activity studies on a panel of human cancer cell lines (A549, HeLa, G-361, A2780, and A2780R) and the combined in vivo and ex vivo antitumour testing on the L1210 lymphocytic leukaemia model were performed on the cis-[PtCl2(naza)2] complexes (1–3) involving the 7-azaindole derivatives (naza). The platinum(II) complexes showed significantly higher in vitro cytotoxic effects on cell-based models, as compared with cisplatin, and showed the ability to avoid the acquired resistance of the A2780R cell line to cisplatin. The in vivo testing of the complexes (applied at the same dose as cisplatin) revealed their positive effect on the reduction of cancerous tissues volume, even if it is lower than that of cisplatin, however, they also showed less serious adverse effects on the healthy tissues and the health status of the treated mice. The results of ex vivo assays revealed that the complexes 1–3 were able to modulate the levels of active forms of caspases 3 and 8, and the transcription factor p53, and thus activate the intrinsic (mitochondrial) pathway of apoptosis. The pharmacological observations were supported by both the histological and immunohistochemical evaluation of isolated cancerous tissues. The applicability of the prepared complexes and their fate in biological systems, characterized by the hydrolytic stability and the thermodynamic aspects of the interactions with cysteine, reduced glutathione, and human serum albumin were studied by the mass spectrometry and isothermal titration calorimetric experiments.
doi:10.1371/journal.pone.0090341
PMCID: PMC3948342  PMID: 24603594
5.  Effect of 2-Chloro-Substitution of Adenine Moiety in Mixed-Ligand Gold(I) Triphenylphosphine Complexes on Anti-Inflammatory Activity: The Discrepancy between the In Vivo and In Vitro Models 
PLoS ONE  2013;8(11):e82441.
A series of gold(I) triphenylphosphine (PPh3) complexes (1–9) involving 2-chloro-N6-(substituted-benzyl)adenine derivatives as N-donor ligands was synthesized and thoroughly characterized by relevant methods, including electrospray-ionization (ESI) mass spectrometry and multinuclear NMR spectroscopy. The anti-inflammatory and antiedematous effects of three representatives 1, 5 and 9 were evaluated by means of in vitro model based on the expression of pro- and anti-inflammatory cytokines and influence of the complexes on selected forms of matrix metalloproteinases secreted by LPS-activated THP-1 monocytes and in vivo model evaluating the antiedematous effect of the complexes in the carrageenan-induced rat hind-paw edema model. In addition to the pharmacological observations, the affected hind paws were post mortem subjected to histological and immunohistochemical evaluations. The results of both in vivo and ex vivo methods revealed low antiedematous and anti-inflammatory effects of the complexes, even though the in vitro model identified them as promising anti-inflammatory acting compounds. The reason for this discrepancy lies probably in low stability of the studied complexes in biological environment, as demonstrated by the solution interaction studies with sulfur-containing biomolecules (cysteine and reduced glutathione) using the ESI mass spectrometry.
doi:10.1371/journal.pone.0082441
PMCID: PMC3842384  PMID: 24312423
6.  Zn(II)-Chlorido Complexes of Phytohormone Kinetin and Its Derivatives Modulate Expression of Inflammatory Mediators in THP-1 Cells 
PLoS ONE  2013;8(6):e65214.
Kinetin (N6-furfuryladenine) belongs to a group of plant growth hormones involved in cell division, differentiation and other physiological processes. One of the possible ways to obtain biologically active compounds is to complex biologically relevant natural compounds to suitable metal atoms. In this work, two structural groups of Zn(II) complexes [Zn(Ln)2Cl2]·Solv (1–5) and [Zn(HLn)Cl3]·xLn (6–7); n = 1–5, Solv = CH3OH for 1 and 2H2O for 2; x = 1 for 6 and 2 for 7; involving a phytohormone kinetin and its derivatives (Ln) were evaluated for their ability to modulate secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and matrix metalloproteinase (MMP)-2 in a lipopolysaccharide (LPS)-activated macrophage-like THP-1 cell model. The penetration of the complexes to cells was also detected. The mechanism of interactions of the zinc(II) complexes with a fluorescent sensor N-(6-methoxy-8-quinolyl)-p-toluene sulphonamide (TSQ) and sulfur-containing biomolecules (l-cysteine and reduced glutathione) was studied by electrospray-ionization mass spectrometry and flow-injection analysis with fluorescence detection. The present study showed that the tested complexes exhibited a low cytotoxic effect on the THP-1 cell line (IC50>40 µM), apart from complex 4, with an IC50 = 10.9±1.1 µM. Regarding the inflammation-related processes, the Zn(II) complexes significantly decreased IL-1β production by a factor of 1.47–2.22 compared with the control (DMSO), but did not affect TNF-α and MMP-2 secretions. However, application of the Zn(II) complexes noticeably changed the pro-MMP-2/MMP-2 ratio towards a higher amount of maturated MMP-2, when they induced a 4-times higher production of maturated MMP-2 in comparison with the vehicle-treated cells under LPS stimulation. These results indicated that the complexes are able to modulate an inflammatory response by influencing secretion and activity of several inflammation-related cytokines and enzymes.
doi:10.1371/journal.pone.0065214
PMCID: PMC3670929  PMID: 23755195
7.  trans-Dichloridobis{2-chloro-6-[(3-fluoro­benz­yl)amino]-9-isopropyl-9H-purine-κN 7}platinum(II) 
In the title compound, trans-[PtCl2(C15H15ClFN5)2], the PtII atom, located on an inversion centre, is coordinated by the purine N atoms of the 2-chloro-6-[(3-fluoro­benz­yl)amino]-9-isopropyl-9H-purine ligands and two Cl atoms in a slightly distorted trans-square-planar coordination geometry [N—Pt—Cl angles = 89.91 (5) and 90.09 (5)°]. Weak intra­molecular N—H⋯Cl contacts occur. In the crystal, C—H⋯Cl and C—H⋯F contacts, as well as weak π–π stacking inter­actions [centroid–centroid distances = 3.5000 (11) and 3.6495 (12) Å] connect the mol­ecules into a three-dimensional architecture.
doi:10.1107/S1600536813013202
PMCID: PMC3684891  PMID: 23794993
8.  (Cyclo­butane-1,1-di­carboxyl­ato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)platinum(II) dihydrate 
The title compound, [Pt(C6H6O4)(C12H8N2)]·2H2O, which crystallizes as two independent formula units, has the metal atom in a square-planar geometry defined by two O atoms of the chelating cyclo­butane-1,1-di­carboxyl­ate dianion and two N atoms of the chelating 1,10-phenanthroline mol­ecule (r.m.s. deviations of the PtO2N2 units = 0.026 and 0.026 Å). Adjacent complex and water mol­ecules are connected through inter­molecular O—H⋯O hydrogen bonds and C—H⋯O, C⋯O [shortest C⋯O distance = 3.140 (5) Å], π–π [shortest C⋯C distances = 3.234 (6) and 3.347 (6) Å] and Pt⋯π [shortest Pt⋯C distance = 3.358 (4) Å] inter­actions into a three-dimensional network.
doi:10.1107/S1600536813013378
PMCID: PMC3684894  PMID: 23794996
9.  N-Benzyl­thieno[3,2-d]pyrimidin-4-amine 
The title compound, C13H11N3S, crystallizes with two independent mol­ecules in the asymmetric unit. The two mol­ecules are geometrically very similar and differ mainly in a spatial orientation of the benzene and thieno[3,2-d]pyrimidine ring systems [dihedral angles = 69.49 (4) and 79.05 (3)°]. The nine-membered thieno[3,2-d]pyrimidine moieties have a planar conformation (r.m.s. deviations = 0.020 and 0.012 Å). In the crystal, mol­ecules are linked through N—H⋯N, N—H⋯C and C—H⋯π non-covalent contacts into chains along the c axis, while neighbouring chains are connected via C—H⋯N inter­actions.
doi:10.1107/S1600536813009537
PMCID: PMC3648234  PMID: 23723854
10.  N-(2-Meth­oxy­benz­yl)-9-(oxolan-2-yl)-9H-purin-6-amine 
The title compound, C17H19N5O2, features an almost planar purine skeleton (r.m.s. deviation = 0.009 Å) substituted by a tetra­hydro­furan ring, which adopts an envelope conformation. The purine and benzene rings subtend a dihedral angle of 66.70 (3)°. In the crystal, pairs of N—H⋯N hydrogen bonds connect adjacent mol­ecules into inversion dimers. C—H⋯N, C—H⋯O, C—H⋯π and π–π inter­actions [pyrimidine ring centroid–centroid distance = 3.3909 (1) Å] connect the dimers into a three-dimensional architecture.
doi:10.1107/S1600536813007721
PMCID: PMC3629632  PMID: 23634119
11.  6-(3,5-Dimeth­oxy­benzyl­amino)-9-(oxan-2-yl)-9H-purine 
The mol­ecule of the title compound, C19H23N5O3, contains six-membered pyrimidine and five-membered imidazole rings merged into the essentially planar purine skeleton (r.m.s. deviation = 0.01 Å). In the crystal, pairs of N—H⋯N hydrogen bonds link mol­ecules into inversion dimers. The dimers are linked via C—H⋯O hydrogen bonds, forming double-stranded chains propagating along [001]. These chains are linked via C—H⋯π and parallel slipped π–π inter­actions [centroid–centroid distance = 3.467 (1) Å; slippage 0.519 Å], forming a three-dimensional network.
doi:10.1107/S1600536813006697
PMCID: PMC3629587  PMID: 23634074
12.  2-Chloro-6-[(2,4-dimeth­oxy­benz­yl)amino]-9-isopropyl-9H-purine 
In the title compound, C17H20ClN5O2, the benzene ring and the purine ring system make a dihedral angle of 78.56 (4)°. In the crystal, mol­ecules are linked by pairs of N—H⋯N hydrogen bonds, forming inversion dimers. C—H⋯O and C—H⋯Cl contacts further link the mol­ecules, forming a three-dimensional network.
doi:10.1107/S1600536813004121
PMCID: PMC3588409  PMID: 23476575
13.  5-Bromo-1H-pyrrolo­[2,3-b]pyridine 
In the title compound, C7H5BrN2, fused six-membered pyridine and five-membered pyrrole rings form the essentially planar aza­indole skeleton (r.m.s. deviation = 0.017 Å). In the crystal, pairs of N—H⋯N hydrogen bonds connect the mol­ecules into inversion dimers.
doi:10.1107/S1600536813004157
PMCID: PMC3588463  PMID: 23476567
14.  Thermal decomposition of [Co(en)3][Fe(CN)6]∙ 2H2O: Topotactic dehydration process, valence and spin exchange mechanism elucidation 
Background
The Prussian blue analogues represent well-known and extensively studied group of coordination species which has many remarkable applications due to their ion-exchange, electron transfer or magnetic properties. Among them, Co-Fe Prussian blue analogues have been extensively studied due to the photoinduced magnetization. Surprisingly, their suitability as precursors for solid-state synthesis of magnetic nanoparticles is almost unexplored.
In this paper, the mechanism of thermal decomposition of [Co(en)3][Fe(CN)6] ∙∙ 2H2O (1a) is elucidated, including the topotactic dehydration, valence and spins exchange mechanisms suggestion and the formation of a mixture of CoFe2O4-Co3O4 (3:1) as final products of thermal degradation.
Results
The course of thermal decomposition of 1a in air atmosphere up to 600°C was monitored by TG/DSC techniques, 57Fe Mössbauer and IR spectroscopy. As first, the topotactic dehydration of 1a to the hemihydrate [Co(en)3][Fe(CN)6] ∙∙ 1/2H2O (1b) occurred with preserving the single-crystal character as was confirmed by the X-ray diffraction analysis. The consequent thermal decomposition proceeded in further four stages including intermediates varying in valence and spin states of both transition metal ions in their structures, i.e. [FeII(en)2(μ-NC)CoIII(CN)4], FeIII(NH2CH2CH3)2(μ-NC)2CoII(CN)3] and FeIII[CoII(CN)5], which were suggested mainly from 57Fe Mössbauer, IR spectral and elemental analyses data. Thermal decomposition was completed at 400°C when superparamagnetic phases of CoFe2O4 and Co3O4 in the molar ratio of 3:1 were formed. During further temperature increase (450 and 600°C), the ongoing crystallization process gave a new ferromagnetic phase attributed to the CoFe2O4-Co3O4 nanocomposite particles. Their formation was confirmed by XRD and TEM analyses. In-field (5 K / 5 T) Mössbauer spectrum revealed canting of Fe(III) spin in almost fully inverse spinel structure of CoFe2O4.
Conclusions
It has been found that the thermal decomposition of [Co(en)3][Fe(CN)6] ∙∙ 2H2O in air atmosphere is a gradual multiple process accompanied by the formation of intermediates with different composition, stereochemistry, oxidation as well as spin states of both the central transition metals. The decomposition is finished above 400°C and the ongoing heating to 600°C results in the formation of CoFe2O4-Co3O4 nanocomposite particles as the final decomposition product.
doi:10.1186/1752-153X-7-28
PMCID: PMC3637566  PMID: 23391378
Hexacyanidoferrate; Crystal structure; Thermal behavior; Mössbauer spectroscopy; Topotactic dehydration; Nanocomposite particles; CoFe2O4
15.  Cellular responses induced by Cu(II) quinolinonato complexes in human tumor and hepatic cells 
Background
Inspired by the unprecedented historical success of cisplatin, one of the most important research directions in bioinorganic and medicinal chemistry is dedicated to the development of new anticancer compounds with the potential to surpass it in antitumor activity, while having lower unwanted side-effects. Therefore, a series of copper(II) mixed-ligand complexes of the type [Cu(qui)(L)]Y · xH2O (1–6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, Y = NO3 (1, 3, 5) or BF4 (2, 4, 6), and L = 1,10-phenanthroline (phen) (1, 2), 5-methyl-1,10-phenanthroline (mphen) (3, 4) and bathophenanthroline (bphen) (5, 6), was studied for their in vitro cytotoxicity against several human cancer cell lines (A549 lung carcinoma, HeLa cervix epitheloid carcinoma, G361 melanoma cells, A2780 ovarian carcinoma, A2780cis cisplatin-resistant ovarian carcinoma, LNCaP androgen-sensitive prostate adenocarcinoma and THP-1 monocytic leukemia).
Results
The tested complexes displayed a stronger cytotoxic effect against all the cancer cells as compared to cisplatin. The highest cytotoxicity was found for the complexes 4 (IC50 = 0.36 ± 0.05 μM and 0.56 ± 0.15 μM), 5 (IC50 = 0.66 ± 0.07 μM and 0.73 ± 0.08 μM) and 6 (IC50 = 0.57 ± 0.11 μM and 0.70 ± 0.20 μM) against A2780, and A2780cis respectively, as compared with the values of 12.0 ± 0.8 μM and 27.0 ± 4.6 μM determined for cisplatin. Moreover, the tested complexes were much less cytotoxic to primary human hepatocytes than to the cancer cells. The complexes 5 and 6 exhibited significantly high ability to modulate secretion of the pro-inflammatory cytokines TNF-α (2873 ± 238 pg/mL and 3284 ± 139 pg/mL for 5, and 6 respectively) and IL-1β (1177 ± 128 pg/mL and 1087 ± 101 pg/mL for 5, and 6 respectively) tested on the lipopolysaccharide (LPS)-stimulated THP-1 cells as compared with the values of 1173 ± 85 pg/mL and 118.5 ± 4.8 pg/mL found for the commercially used anti-inflammatory drug prednisone. The ability of the tested complexes to interact with sulfur-containing biomolecules (cysteine and reduced glutathione) at physiological levels was proved by electrospray-ionization mass spectrometry.
Conclusions
Overall positive results of the biological activity studies revealed that the presented complexes may represent good candidates for non-platinum anticancer drugs, however, we are aware of the fact that further and deeper studies mainly in relation to the elucidation of their mechanisms of antiproliferative action will be necessary.
doi:10.1186/1752-153X-6-160
PMCID: PMC3556092  PMID: 23256754
Copper(II) complexes; In vitro cytotoxicity; Hepatotoxicity; Gene reporter assay; Inflammatory response; Quinolinone derivatives
16.  SOD-Mimic Cu(II) Dimeric Complexes Involving Kinetin and Its Derivative: Preparation and Characterization 
Two SOD-mimic active dimeric Cu(II) chlorido complexes of the compositions [Cu2(μ-HL1)4Cl2]Cl2 (1) and [Cu2(μ-HL2)2(μ-Cl)2(HL2)2Cl2] · 4H2O (2) involving the cosmetologically relevant cytokinin kinetin (N6-furfuryladenine, HL1) and its derivative N6-(5-methylfurfuryl)adenine (HL2) have been synthesized and characterized by elemental analysis, infrared, and electronic spectroscopy, ESI+ mass spectrometry, conductivity and temperature dependence of magnetic susceptibility measurements, and thermogravimetric (TG) and differential thermal (DTA) analyses. The results of these methods, particularly the temperature dependence of magnetic susceptibility, showed the complexes to be dimeric with a strong antiferromagnetic exchange (J = −290 cm−1 for complex 1 and J = −160 cm−1 for 2). The complexes have been identified as auspicious SOD-mimics, as their antiradical activity evaluated by the in vitro SOD-mimic assay resulted in the IC50 values equal to 8.13 μM (1) and 0.71 μM (2).
doi:10.1155/2012/704329
PMCID: PMC3433123  PMID: 22966218
17.  Di-μ-hydroxido-bis­[hemiaqua­(N,N,N′,N′-tetra­methyl­ethane-1,2-diamine)­copper(II)] bis­(tetra­fluoridoborate) 
The title compound, [Cu2(OH)2(C6H16N2)2(H2O)](BF4)2, consists of dinuclear centrosymmetric [Cu2(OH)2(tmen)2(H2O)]2+ complex cations (tmen = N,N,N′,N′-tetra­methyl­ethane-1,2-diamine) and tetra­fluoridoborate anions. In the cation, the CuII atom shows a slightly distorted square-pyramidal coordination geometry provided by a pair of μ-OH− anions and by the N atoms of a chelate tmen ligand in the basal plane. The apical position is statistically occupied by the O atom of a half-occupancy water mol­ecule. The F atoms of the anion are disordered over three sets of sites with occupancies of 0.598 (9):0.269 (6):0.134 (8). The crystal packing is governed by ionic forces as well as by O—H⋯F hydrogen bonds.
doi:10.1107/S1600536812021836
PMCID: PMC3379114  PMID: 22719335
18.  Bis(4,7-dichloro-1,10-phenanthroline-κ2 N,N′)bis­(dicyanamido-κN)copper(II) 
In the title compound, [Cu(C2N3)2(C12H6Cl2N2)2], the CuII atom is coordinated by two chelating 4,7-dichloro-1,10-phenanthroline (4,7-Cl-phen) ligands and two dicyanamide (dca) ligands in a cis arrangement, forming a distorted octa­hedral geometry. The equatorial plane is occupied by three N atoms from two 4,7-Cl-phen ligands and one N atom from a dca ligand at shorter Cu—N distances. Due to the Jahn–Teller effect, the axial positions are occupied by a 4,7-Cl-phen N atom and a dca N atom at longer Cu—N distances. The dca ligands are nearly planar, with a maximum deviations of 0.006 (1) Å. The crystal structure is stabilized by weak C—H⋯N hydrogen bonds, with cyanide N atoms as acceptors, and π–π inter­actions between adjacent phenyl rings [centroid–centroid distance = 3.725 (3) Å].
doi:10.1107/S1600536810019847
PMCID: PMC2979476  PMID: 21579350
19.  Poly[di-μ2-chlorido-dichlorido(μ3-di­methyl sulfoxide-κ3 O:O:S)(μ2-di­methyl sulfoxide-κ2 O:S)ruthenium(III)sodium] 
The structure of the title compound, [NaRuCl4(C2H6OS)2]n, comprises centrosymmetric [RuCl2(DMSO)Na(DMSO)Cl2Ru] units (DMSO is dimethyl sulfoxide, C2H6OS), with two Ru atoms, each lying on a crystallographic centre of inversion, connected via Na atoms, DMSO and chloride ligands into a two-dimensional (110) array. Both RuIII atoms are octa­hedrally coordinated by four chloride ligands in the equatorial plane and by two DMSO mol­ecules in apical positions within a RuCl4S2 donor set. The Na atom is surrounded by three chloride anions and three O atoms derived from three DMSO mol­ecules, with the resulting Cl3O3 donor set defining an octa­hedron. The crystal structure is further stabilized by inter­atomic inter­actions of the types C⋯Cl [C—Cl = 3.284 (2) Å], C—H⋯Cl [C⋯Cl = 3.903 (3) Å] and C—H⋯O [C⋯O = 3.376 (3) Å].
doi:10.1107/S1600536810007063
PMCID: PMC2984058  PMID: 21580464
20.  6-(2-Methoxy­benzyl­amino)purine 
The title compound, C13H13N5O, consists of discrete mol­ecules connected by N—H⋯N hydrogen bonds to form infinite chains, with N⋯N separations of 3.0379 (15) and 2.8853 (15) Å. The benzene and purine ring systems make a dihedral angle of 77.58 (3)°. The crystal structure is further stabilized by intra­molecular N⋯O inter­actions [2.9541 (12) Å] and inter­molecular C—H⋯C and C⋯C contacts [3.304 (2), 3.368 (2), 3.667 (2), 3.618 (2) and 3.512 (2) Å] which arrange the mol­ecules into graphite-like layers. The inter­layer separations are 3.248 and 3.256 Å.
doi:10.1107/S1600536808009203
PMCID: PMC2961176  PMID: 21202313
21.  6-(2-Chloro­benzyl­amino)purinium tetra­chlorido(dimethyl sulfoxide-κO)(nitrosyl-κN)ruthenate(III) monohydrate 
The asymmetric unit of the title complex salt, (C12H11ClN5)[RuCl4(NO)(C2H6OS)]·H2O, contains a 6-(2-chloro­benzyl­amino)purinium cation, a tetra­chlorido(dimethyl sulfoxide)nitro­sylruthenate(III) anion and one solvent water mol­ecule. The RuIII atom is octa­hedrally coordinated by four Cl atoms in the equatorial plane, and by a dimethyl sulfoxide O atom and a nitrosyl N atom in axial positions. The cation is an N3-protonated N7 tautomer. Inter­molecular N–H⋯N hydrogen bonds connect two cations into centrosymmetric dimers, with an N⋯N distance of 2.821 (4) Å. The crystal structure also involves N—H⋯O, N—H⋯Cl and O—H⋯Cl hydrogen bonds.
doi:10.1107/S1600536808006673
PMCID: PMC2961006  PMID: 21202003
22.  (μ-5-Carboxy­benzene-1,3-dicarboxyl­ato-κ2 O 1:O 3)bis­[bis­(2,2′-bipyridine-κ2 N,N′)copper(II)] 5-carboxy­benzene-1,3-dicarboxyl­ate 2,2′-bipyridine solvate trideca­hydrate 
The asymmetric unit of the title complex, [Cu2(C9H4O6)(C10H8N2)4](C9H4O6)·C10H8N2·13H2O, comprises two formula units. The two CuII centres are bridged by a 5-carb­oxy­benzene-1,3-dicarboxyl­ate (Hbtc) ligand. Each of the metal centres is bonded to four N atoms of two bidentate 2,2′-bipyridine ligands (bpy) and one O atom of the Hbtc ligand in a highly distorted square-pyramidal geometry. The secondary structure is stabilized by a variety of O—H⋯O hydrogen bonds and π–π stacking inter­actions connecting the complex cations, Hbtc anions, bpy and water mol­ecules of crystallization. Three water molecules are disordered over two positions, with site occupancy factors of ca 0.8 and 0.2.
doi:10.1107/S1600536808001852
PMCID: PMC2960318  PMID: 21201338
23.  Aqua­(4-methyl­quinoline-κN)[N-(2-oxidobenzyl­idene)glycinato-κ3 O,N,O′]copper(II) hemihydrate 
The title complex, [Cu(C9H7NO3)(C10H9N)(H2O)]·0.5H2O, crystallizes with two independent formula units in the asymmetric unit; the solvent mol­ecule is located on a twofold axis of symmetry. The CuII atom is coordinated by one tridentate N-salicylideneglycinate Schiff base ligand, one 4-methyl­quinoline ligand and one water mol­ecule, leading to a slightly distorted square-pyramidal N2O3 geometry. In the crystal structure, the mol­ecules are linked by O—H⋯O hydrogen bonds into linear chains in the [100] direction. The structure is further stabilized by inter­molecular C—H⋯O inter­actions and C⋯C contacts with C⋯C = 3.3058 (2), 3.3636 (2) and 3.3946 (2) Å.
doi:10.1107/S1600536807067852
PMCID: PMC2960168  PMID: 21201263

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