Despite being disparaged for their malodorous and toxic demeanour, compounds of selenium, a bio-essential element, and tellurium, offer possibilities as therapeutic agents. Herein, their potential ...use as drugs, for example, as anti-viral, anti-microbial, anti-inflammatory agents,
etc
., will be surveyed along with a summary of the established biological functions of selenium. The natural biological functions of tellurium remain to be discovered.
The potential of selenium (a bio-essential element) and tellurium compounds as therapeutics (
e.g.
as anti-viral and anti-inflammatory agents) are surveyed.
A new era of metal-based drugs started in the 1960s, heralded by the discovery of potent platinum-based complexes, commencing with cisplatin (H₃N)₂PtCl₂, which are effective anti-cancer ...chemotherapeutic drugs. While clinical applications of gold-based drugs largely relate to the treatment of rheumatoid arthritis, attention has turned to the investigation of the efficacy of gold(I) and gold(III) compounds for anti-cancer applications. This review article provides an account of the latest research conducted during the last decade or so on the development of gold compounds and their potential activities against several cancers as well as a summary of possible mechanisms of action/biological targets. The promising activities and increasing knowledge of gold-based drug metabolism ensures that continued efforts will be made to develop gold-based anti-cancer agents.
Molecular crystals by design? Tiekink, Edward R. T
Chemical communications (Cambridge, England),
2014-Oct-04, Letnik:
5, Številka:
76
Journal Article
Recenzirano
In this Viewpoint, the impact of the paper published by Gautam R. Desiraju and Angelo Gavezzotti (
J. Chem. Soc., Chem. Commun
., 1989, 621) upon the development of
Crystal Engineering
, now ...recognised a key discipline in contemporary chemical/pharmaceutical/materials science, is discussed.
In this Viewpoint, the impact of the paper published by Gautam R. Desiraju and Angelo Gavezzotti (
J. Chem. Soc., Chem. Commun
., 1989, 621) upon the development of
Crystal Engineering
, now recognised a key discipline in contemporary chemical/pharmaceutical/materials science, is discussed.
Five new anionic aqueous dioxidovanadium(V) complexes, {VO2L1,2}A(H2O) n α (1–5), with the aroylhydrazone ligands pyridine-4-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H2L1) and ...furan-2-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)hydrazide (H2L2) incorporating different alkali metals (A = Na+, K+, Cs+) as countercation were synthesized and characterized by various physicochemical techniques. The solution-phase stabilities of 1–5 were determined by time-dependent NMR and UV–vis, and also the octanol/water partition coefficients were obtained by spectroscopic techniques. X-ray crystallography of 2–4 confirmed the presence of vanadium(V) centers coordinated by two cis-oxido-O atoms and the O, N, and O atoms of a dianionic tridentate ligand. To evaluate the biological behavior, all complexes were screened for their DNA/protein binding propensity through spectroscopic experiments. Finally, a cytotoxicity study of 1–5 was performed against colon (HT-29), breast (MCF-7), and cervical (HeLa) cancer cell lines and a noncancerous NIH-3T3 cell line. The cytotoxicity was cell-selective, being more active against HT-29 than against other cells. In addition, the role of hydrophobicity in the cytotoxicity was explained in that an optimal hydrophobicity is essential for high cytotoxicity. Moreover, the results of wound-healing assays indicated antimigration in case of HT-29 cells. Remarkably, 1 with an IC50 value of 5.42 ± 0.15 μM showed greater activity in comparison to cisplatin against the HT-29 cell line.
Supramolecular aggregates featuring Se N contacts have been identified in 88 crystals containing two, three or four selenium atoms, corresponding to 9% of crystals where Se N contacts have the ...potential to form. Molecules with two selenium atoms make up the majority of examples (58) followed by molecules with three (12) and four (18) selenium atoms. A wide range of supramolecular aggregation patterns has been identified in the 88 crystals featuring Se N contacts with one- (42%) and two- (31%) dimensional aggregation forming the majority compared with zero- (17%) and three- (10%) dimensional aggregation making up the rest. The overwhelming majority of Se N contacts correspond to chalcogen-bonding interactions based on σ-hole interactions. Correlations in intermolecular separations were evident for isostructural crystals which showed that a comparable Te N interaction was stronger than the equivalent Se N interaction, and the Se N interaction was always stronger than the equivalent S N interaction. When compared to crystals of mono-nuclear selenium compounds, a very similar adoption rate was observed in their crystals but with a bias towards smaller aggregation patterns,
i.e.
50, 44, 5 and 1% for zero-, one-, two- and three- dimensional, respectively. This observation is clearly consistent with the greater opportunity for multi-nuclear selenium molecules to form more interactions. However, as exemplified by the 18 tetra-nuclear molecules, not all selenium atoms participated in a Se N contact as two, 10, two and four selenium atoms, out of a possible four, formed a Se N contact in their crystals.
The importance of Se N chalcogen-bonding in supramolecular assembly is demonstrated.
A systematic analysis of the Cambridge Crystallographic Database has been made for supramolecular architectures sustained by C-I π(chelate ring) interactions where the iodide atom is directed towards ...the ring centroid, Cg, of the arene ring,
i.e.
with the angle subtended at the iodide atom, C-I Cg (
) being ≥160°. The majority of the 181 identified aggregates are one-dimensional chains of varying topology (100 examples) followed by zero-dimensional aggregates (71 examples) with only a small number of two-dimensional arrays (4 examples). The overall likelihood for the formation of these delocalised interactions is around 4%, a number that increases to around 15% when the angle
restriction is relaxed to 90°. A comparison has been made with the formation of C-X π(chelate ring) interactions for the lower X = bromide, chloride and fluoride congeners. This shows these interactions are more likely to form in the order X = I > Br > Cl > F.
A survey of delocalised C-I π(chelate ring) interactions is presented.
The analysis of atom-to-atom and/or residue-to-residue contacts remains a favoured mode of analysing the molecular packing in crystals. In this contribution, additional tools are highlighted as ...methods for analysis in order to complement the `crystallographer's tool',
PLATON
Spek (2009).
Acta Cryst
. D
65
, 148–155. Thus, a brief outline of the procedures and what can be learned by using
Crystal Explorer
Spackman & Jayatilaka (2009).
CrystEngComm
11
, 19–23 is presented. Attention is then directed towards evaluating the nature,
i.e
. attractive/weakly attractive/repulsive, of specific contacts employing
NCIPLOT
Johnson
et al.
(2010).
J. Am. Chem. Soc
.
132
, 6498–6506. This is complemented by a discussion of the calculation of energy frameworks utilizing the latest version of
Crystal Explorer
. All the mentioned programs are free of charge and straightforward to use. More importantly, they complement each other to give a more complete picture of how molecules assemble in molecular crystals.
Dibenzo1,5diazocine scaffolds are present in a wide range of organic building blocks, for example in pharmaceuticals, materials and structural chemistry. However, the development of these structural ...frameworks has not received significant attention owing to limited synthetic protocols and strategies. Herein, a summary of the attractive synthetic approaches for the construction of dibenzo1,5diazocines, epiminodibenzo1,5diazocines and epoxydibenzo1,5diazocines developed over the past two decades is presented. The spectroscopic, synthetic mechanisms for the formation of the heterocyclic rings and remarkable structural features, including in the solid-state, are discussed.
Recent synthetic approaches and functionalisation of dibenzo1,5diazocines, epiminodibenzo1,5diazocines and epoxydibenzo1,5diazocines are reviewed.
The Cambridge Crystallographic Database has been searched for the presence of intermolecular C-H π(chelate ring) interactions, known to be stabilising, in the crystals of the first-row transition ...metal dithiocarbamates,
i.e.
containing anionic ligands of the type
−
S
2
CNR
2
, R = H, alkyl and aryl. A significant propensity to form C-H π(chelate ring) interactions is noted, especially in crystals of nickel and copper dithiocarbamates. The participating hydrogen atoms are characterised as being near an electronegative atom/substituent encouraging their engagement in this supramolecular synthon. The survey shows that an open, square-planar geometry is not a prerequisite for a C-H π(chelate ring) interaction but, allows, on average, more of these contacts leading to one- and two-dimensional architectures. It is concluded that a search for a C-H π(chelate ring) supramolecular synthon should be included in any detailed analysis of the molecular packing of metal-containing crystals.
C-H π(chelate ring) interactions play an important role in assembling first-row transition metal dithiocarbamates in their crystals.
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