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- Coordination Compounds Synthesis and Medical Application
- Reactions and Applications of Coordination Compounds | Boundless Chemistry
- Reactions and Applications of Coordination Compounds
Based on these strategies, syntheses of various SAAC ligands were investigated. Dissertations - ALL. Physical Sciences and Mathematics Commons. Advanced Search. Skip to main content. Title Coordination Chemistry in Biology and Medicine. Author Christopher Chu , Syracuse University. Subject Categories Physical Sciences and Mathematics. Included in Physical Sciences and Mathematics Commons.
Digital Commons. The emergence of electrochemical synthesis brings into focus a fast and continuous production of large amounts of metal organic framework crystals with the use of metal ions in synthesis instead of metal salts. Transition-metal coordination polymers are generally prepared using three general methods.
These methods include the following; use of ligands capable of simultaneously coordinating to two metal atoms to generate the desired polymer, use of performed polymers to which metal atoms are attached to yield polymers of useful properties and the use of transition-metal coordination complexes containing at least one of the ligands with functional group useful in polymer formation [18,19]. The use of ligands capable of simultaneously coordinating to two metal atoms to generate the desired polymer could be represented using equation 1. Figure 8a: Coordinating polymer formed from monoden-tate halide or pseudohalide ligands.
M the metal atom and Y the ligand. For a monodentate halide or pseudohalide ligands, coordinating polymer illustrated in Figure 8a is formed. In a case where the ligand is multidentate, structures such as that in Figure 8b could be formed from bis-chelating agents like Salen, rubeanate or squarate. Grubbs et al. Recently, the use of transition- metal coordination complexes in which at least one of the ligands has functional group that can be used in polymer formation is on the increase.
Much interest has been on this method in recent years and substituted metallocenes have been the most interesting in this research. Pittman et al. In a similar faction, acid chlorides of various metallocenes undergo condensation with alkanols to form polyesters as shown in Figure 10b. Condensation complexes such as, Pt [P n-C4H9 3]2Cl condenses with but-1,3-diene to form rigid rod like polymer illustrated in Figure 10c. Generally, porous coordination polymers PCPs are prepared in the liquid phase by using solvent as a medium to induce the self-assembly of a regular framework.
This type of reaction can be carried out by mixing the metal ion solution with the chelating ligand solution at room temperature or under hydrothermal or solvothermal conditions . Metal ion and ligand, solvent and counter ions must be involved to get porous coordination polymers of desired property. The limitation of flexible ligand products complexes of been structurally amorphous therefore allows the use of rigid or semi-rigid ligands for such purposes. The rigidity of aromatic ligands which may be neutral, cationic and anionic other than the aliphatic ones gives them an edge in the synthesis.
Initially, the prepared porous coordination polymers do not have void space because the guests filled all the cavities and these guests may be solvent molecules, excess ligands or counter ions. To make the void spaces usable, the guest molecules are substituted with sufficiently volatile or exchangeable solvent molecules.
Notwithstanding the relevance of vacant spaces, some porous coordination polymers cannot exist without the guest molecule. In some porous coordination polymers the solvents collapses after and are removed. In such a case, the solvent are likely to be unimportant in the use ofthe polymer as it will be eliminated after the preparation of the polymer. Solvent play notable role in the preparation and characteristics of porous coordination polymers such as the size and shape of pore and can be controlled by using different solvents .
The evolution of another branch of coordination polymers, the supramolecular polymers as shown in Figure 10e. The monomeric units are held together through highly directional and reversible non-covalent bonding relationship which subsequently defines their properties. Similarly, building frame work template and formation of open molecular structure is feasible eliminating catenation.
Sareeya et al. Figure 11 a,b : Structures of a [ Co 3 ndc 3 bipyen 1. C6H 6 ]n where ndc is naphthalinedicarboxylate Sareeya et al, Specifically, Cd NO3 2 1,2-bis 4-pyridyl ethyne 1. Similarly, [[Cd NO3 2 1,2-bis 4-pyridyl ethene 1. Figure Coordination environment around the cadmium atom in [Cd NO3 2 1,2-bis 4-pyridyl ethyne 1. Figure Coordination environment around the cadmium atoms in [Cd NO3 2 2 1,2-bis 4-pyridyl ethene 1.
This coordination polymer forms square units that are connected through the two Cd II centers to give infinite linear chains  as shown in Figure Figure Coordination environment around the cadmi-um atoms in [Cd NO3 2 2 1,2-bis 4-pyridyl ethane 1. Coordination polymers have been synthesized and used for a wide range of applications including gas storage, nonlinear optics, drug delivery, catalysis and chemical sensing but recent works has been extended to templates synthesis of silica nanoshells nanoporous carbon and metallic nanoparticles  bearing in mind that most nanoparticles contain either only organic or only inorganic components.
A typical template is represented in Figure Many methods abounds for the synthesis of nanoparticles of coordination polymers or nanoparticles of metal organic frameworks but all of the processes takes advantage of reduced solubility of the particles in comparison of the individual components.
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Common methods rountinely used include solvothermal synthesis, simple mixing of precursor solutions, precipitation by rapid addition of a poor solvent, high-temperature surfactant-assisted synthesis and reverse microemulsion synthesis [1,2,26]. Another group of coordination polymers regarded as cyanometallates is composed of relevant building blocks for series of one, two and three dimensional coordination polymeric networked structures with transition metal templates.
Some authors  noted that this group of strikingly important compound possesses clathrate hosts' structure with properties not limited to spin-crossover phenomena and molecular magnetism. In a typical synthesis, Dursun et al. H 2 O cyanometallate by mixing the stoichiometric amounts of N iCl 2. H 2 O and cadmium compound of 3-aminomethylpyridine.
The coordination polymer of 3D conformation crystallizes in the orthorhombic crystal system with the asymmetric unit containing one Cd II ion, one Ni II ion, one amine, four cyano and bis monodentate bridging ampy ligands having Ni II ion coordinated in square-pyramidal geometry as illustrated in Figure Notable unique properties attributed to coordination polymers makes these groups of compounds very useful in various applications. This has increased research in coordination polymers where transition metals are linked with suitable ligands in the past years.
Notable excellent properties not limited to semiconducting and catalytic properties, protective coating properties, waste water treatment for metal recovery, as antifouling paints and anti-microbial properties. Coordination polymers with efficient ionophores have been of much interest and constant consideration owing to their efficient therapeutic and fluorescence properties [31,32].
Some coordination polymers containing ionosphores of 8-Hydroxyquinoline are important in areas of metal recovery from waste water as they exhibit complexing ability, as water disinfectants, protective coatings, ion-exchange resin, gels and ointment for medical applications, antifouling paints, antimicrobial agents, surgical materials. Coordination polymers exhibit electrical conductivity as one of their important properties. Some coordination polymers have short inorganic and conjugate organic bridges in their structure which provide pathways for electrical conduction.
Coordination polymers could also exhibit semi-conductive property and a typical example is the three dimensional structures that comprise sheets of silver containing polymers when the metal centers are aligned. The conduction decreases as the silver atoms move from parallel to perpendicular direction. Magnetism is one ofthe major properties exhibit by coordination polymers. They show three types of magnetism a consequence of cooperative phenomena of the magnetic spins within a solid and which include antiferromagnetism, ferromagnetism and Ferrimagnetisms.
The property results from the coupling between the spins of the paramagnetic centers. Research [2,33] has shown that efficient magnetic property is obtained when metal ion is bridged by small ligands thereby allowing short metal- metal contacts as exemplified in cyano, or oxo, azido bridges. Luminescent coordination polymers typically contain organic chromophoric ligands that absorb light and then transmit the excitation energy to the metal ion. Coordination polymers are the most versatile, efficient and effective luminescent species potentially because of their emission properties being couples with guest exchange relationship [2,34].
Of recent, luminescent supramolecular architecture has been of much interest and great deal of work has been on the high gear on their potential applications in optoelectronic devices or as fluorescent sensor and probes since they are stable, both thermo and solvent resistant in comparison to organic species. Katz et al. This further explained the fact that increase in rigidity and asymmetry of the ligand upon coordination to the metal center increases the fluorescence of the specie. Of notable interest in the property of coordination polymers is the change in colour upon the change of solvent molecule mixed into the guest structure.
The variation or replacement of the solvent in the coordination sphere leads to change in the geometry of the polymer necessary in sensor application. A typical example when two cobalt coordination polymers of the type [ReS CN ]4- - cluster contains water ligands coordinated to the cobalt atoms. Replacement of water with tetrahydrofuran changes the original orange solutions to either purple or green while on addition of diethylether, the colour changes to blue [2,36]. Coordination polymers in this case act as solvent sensor capable of physically changing color in the presence of certain incoming solvents displacing the water ligands on the cobalt atoms resulting in a change of their geometry from octahedral to tetrahedral.
Non-linear optical behavior one of the striking properties of coordination polymers describes the ability of a material or materials to convert frequency and intensity modulation. Research [34,37] has shown that one of the best known non-linear optical materials is a one dimensional coordination polymer, potassium titanyl phosphate KTP. KTP characteristically has high non-linear optical co-efficient, low threshold power, high optical damage threshold and low phase matching sensitivity  and could be a good replacement for silicon solar cells which is limited in mobile applications and processing cost.
This very unique property peculiar to third generation porous coordination polymers because they showcase flexible framework and dynamic functionalities is highly sought in industrial polymer materials. Thus, the guest molecules serve as the stimuli capable of transformation of flexible porous coordination polymers with the rotation of the bridging ligands possible due to uncommon high flexibility of the coordination polymer. The presence of high void space provides more applicable and efficient function for this group of compounds as they are more dynamic than other non-porous solids as enough space allows ligand rotation.
Typically, a 3-dimensional porous coordination polymer [ Zn3 nbt 2 EtOH ].
Similarly, rotation of the O-C-O plane of the carboxylate part geometrically changes the structure. Thermal stability of coordination polymers is one of the most striking properties of this group of compounds. They are notably of low thermal conductivity, low density and exhibit phonon phenomena energy carriers are linked with the vibration modes of crystal lattices making them dielectric materials [2,7]. The thermal conductivity of porous coordination polymers rely on the mode of phonon scattering which could be phonon-grain boundary, scattering defect-phonon scattering or phonon scattering.
Recently research by Huang et al. Within the range of 35 to l00K of temperature, phonon-phonon scattering mechanism becomes prominent leading to rapid thermal conductivity decrease with temperature increase whereas above K of temperature, thermal conductivity is mostly independent of temperature indicating minimum phonon mean free path. This is an advantage of porous coordination polymers for gas storage application.
Coordination Compounds Synthesis and Medical Application
This property has given them edge over their non- porous counterpart in industrial applications. Coordination polymers are resistant to solvents compared with purely organic species . Coordination polymers especially the Shiskabob class of transition-metal coordination polymers  of typical example the non-planar metalloporphyrins with non-symmetrical bridging ligands carry a net and aligned dipole moment along the stacking axes as shown in Figure This dipole moment originate from the change separation between the bowl shaped porphyrinato core and the metal atom.
The metal atom tends to be pulled out of the porphyrin plane by a stronger axial ligand. Figure The schematic representation of ferroelectric coordination polymer and dipole moment switching in response to an externa! Coordination polymer an organometallic or inorganic polymer or a coordination compound with coordination complexes asrepeating units are important in inorganic and organic chemistry, material science, pharmacology and electrochemistry because of the stunning variety of their structure, compositions and easy tailoring widening their applications in most areas of modern society [7,40,41].
Specifically, they are used as commercial dyes, in separation of hydrocarbons, as molecular sieves, light emitting diodes and other miscellaneous applications. Coordination polymers are used mainly in the commercial form as dyes. XH2O is also commercially used as dye. The compound is easy to make, cheap, non-toxic and intensely colored and widely used as a pigment in oil and water color and dyeing as pigments in the production of black and bluish inks and a common pigment in paint .
Among the early commercialized coordination polymers are the Hofmann compounds which crystallize with small aromatic guests such as some xylenes, benzene and of the formula Ni CN Ni NH .
The selectivity of this material has been applied in the separation of hydrocarbons. This is one of the most important applications of coordination polymers. Many coordination polymers are used in materials science as electrical conductors and semiconductors. Metal conductivity is generally higher than semiconductors with temperature dependence defining the difference as increase in temperature increases electrical conductivity in metals unlike the semiconductors in which increase in temperature decreases their conductivity.
The interest in superconducting materials is solely in synthetic metals and of interest are dimensional coordination polymers that conduct electricity.
Reactions and Applications of Coordination Compounds | Boundless Chemistry
Other ambient pressure superconductors based on electron transfer , metal -metal distance, periodical variation of the charge density along radical donor and polymeric anions in such compounds has electron transfer donor molecules alternating layers in their crystal structure and polymeric anions . Luminescent polymers are used as fluorescent sensors and probes because of the presence of organic chromophoric ligands which absorbs light and then pass the excitation energy to the metal ion.
Potentially, coordination polymers are the most versatile luminescent species because of their emission properties together with guest exchange and are efficient materials for light emitting diodes [2,35,37]. The application of coordination polymers in medicine is currently on the rise with special emphasis on nanoparticle drug delivery.
Reactions and Applications of Coordination Compounds
Photolytically sensitive caged compounds have been examined as containers for releasing a drug or reagent [42,43]. This nanoparticle metal organic framework is important in x-ray computed tomography CT a type of biomedical imaging that is capable of providing three-dimensional images with excellent spatial resolution.
CT is mainly and recently used to image a wide range of structures within and throughout the whole body not limited to organs, blood vessels, and bones. The technique is a relevant tool for diagnosing and monitoring abnormal health conditions and ailments throughout the body with conditions such as tumors, calcifications, embolisms, aneurysms, and inflammation efficiently and effectively treated [2,44,8].
Similarly, one of the cyanide complexes, Fe4[Fe CN 6]3. XH2O has the ability to incorporate mono-cations and this makes it an important separating agent for certain heavy metal poison including but not limited to patients who have ingested radioactive caesium or thallium. One of the recognized, common, honoured, effective and efficient coordination polymers used in histopathology stain to detect iron presence in biopsy specimens by pathologists in bone marrow samples is Fe4[Fe CN 6]3.
XH2O . The deposits of iron in the tissue form purple Prussian blue dye in place and are seen as blue or purple deposits.
- Bibliographic Information.
- Online Coordination Compounds Synthesis And Medical Application 1987;
- Medicine in the Making of Modern Britain: 1700-1920 (Historical Connections).
- Coordination Compounds: Synthesis And Medical Application by Allen Bulman.
- Archives of Organic and Inorganic Chemical Sciences.
- Introduction to Topological Quantum Matter & Quantum Computation.
Flexible porous coordination polymers have attracted attention as gas storage vessel recently because of their high porosity and surface area. Fuel gases like hydrogen H2 and methane CH4 due to their economic, environmental balanced benefits have been realized as vehicle fuels and have attracted much interest as replacements of petroleum and diesel power source. However, Kesanli et al. Storage of these gases in adsorbate phase has been observed to increase the volumetric density and this has been efficiently done at room temperature and pressure of atm using porous coordination polymer .
In the same way, Zn4O-based MOF compounds are well known for their application to fuel gas storage because of their high porosity and large surface area. Though, some of the MOFs are too large for effective adsorption of hydrogen due to presence of large void space, however the unused space increases the volumetric density and hence smaller pores are favorable but controllable by the use of nonvolatile guests. The intercalation of nonvolatile guests in the porous coordination polymers decreases the void space and pore size making the active surface guests an adsorbent as well.
Decrease in pore size is better probably because the interaction between the aromatic ring of the donor ligand and the fuel gas leads to increase in storage ability . Recently, coordination polymers with pillared layers structures are applied in adsorption to tune the pore size to that ofthe adsorbed gas and are effective for stabilizing the explosive gases like acetylene.
Since they are structurally transformable, pore shape and size can be adjusted towards the most stable state with guest to improve host -guest interaction. The molecular interaction between the acetylene molecules placed in porous coordination polymer and acetylene molecule and the wall of the flexible porous coordination polymers is reduced and the system is stabilized a consequence of the large surface area of the flexible porous coordination polymers. The world is becoming more complex with an ever increasing search for a more efficient, effective, energy-saving and environmentally friendly procedure for separation and adsorption of gases and this calls for the design of tailored structures with tunable surface properties.
The flexible porous coordination polymers and metal organic frameworks are promising candidates as adsorbents for gas separations owing to their thermal stability, large surface areas, adjustable pore sizes and tunable properties [47,48]. Flexible porous coordination polymer shows unequalled high selective guest sorption even though interpenetration results in porosity reduction. The combination of the flexibility of flexible porous coordination polymer and functional surface activity enables effective selectivity.