Organotin (IV) Compounds: Chemistry, Properties and Uses

Organo sack (IV) Compounds Chemistry, Properties and UsesIntroduction1.1 Tin ElementIt is undeniably that many research and studies had been done in the field of organo stool alchemy for the past half century. Sn which is symbol b atomic number 18d by bottom which is called as stannum in La ass. It is placed on mathematical group 14 and period 5 in the periodic table with atomic number of 50. It has an electronic configuproportionn of Kr 4d10 5s2 5p2. The table 1.1 below show properties of tin (Davies, et al., 2008).The chemical properties was sh ard similarity with germanium and chasten. Moreover, tin form compounds which has +2 and +4 as its oxidisation number with +4 has slightly extravagantlyer stability. Hence, formation of tetrahedral tin atoms occur when four valence electrons relate in the sp3 hybridization.Table 1.1 Tin Properties (Davies, et al., 2008)Based on Tin Chemistry Fundamentals, Frontiers and Application, it was stated that tin has the invariable isotopes of ten and also with the highest number of any element in the periodic table of isotopes. Thus, tin endanger vary characteristic of the mass spectra. From on the table 1.2 shown below, it reckon that twain isotopes of 117 and 119 with spin of argon utilize in the Nuclear Magnetic Resonance (NMR) spectroscopy (Davies, et al., 2008).Table 1.2 Stable isotopes of Tin (Davies, et al., 2008. p. 3)It is found that antimonial tin occur in two states which is -tin and -tin. The -tin exists as distorted cubic structure and function as electric conductor. Whereas, -tin is formed when -tin is converted slowly at temperature below 10C. as well as that, -tin exits as a diamond structure which have the properties as a semiconductor. The physical appearances of tin is white and get inertness at ambient temperature. However, tin will completely undergo oxidation to SnO2 at 200C since it is a malleable post transition metal (Davies, et al., 2008).1.2 History of TinTin has been discovered a round 3500 BC and it is known as an element that strengthen copper by forming copper-tin alloy which actually begin as early as Bronze Age civilization. The tin present in sur impertinence of Earth is only approximately 2 ppm which is far lesser compared to zinc, copper and lead. The production of tin master(prenominal)ly from mining and smelting (Davies, 2004).In 1849, gives the birth of the first organotin(IV) compound, diethyltin diiodide synthesized by Edward Frankland which ultimately devise as a new era in the field of tin chemistry. Frankland basically studies the behavior of the reaction between ethyl iodide and zinc inflameed in a sealed tube. It was that time found out that the decomposition of iodide of ethyl is unnatural by tin at the range of temperature between 150C to 200C (Davies, 2004). Threfore, his research practically preen as a seed for progress studies and was further stimulated around 1949 when various application of tin was discovered.Truly structural c hanges of compounds between the solution and solid states plays a crucial subprogram in the organotin(IV) chemistry and its applications. In early studies of the 60s and 70s, Mssbauer spectrosocopy was used to determine the sturcture of the complexes. Nevertheless, it is now been dominantly used with X-ray crstallography and 119Sn NMR collect to better technology and resolution (Davies, 2004).1.3 Preparation of Organotin(IV) CarboxylatesOrganotin(IV) carboxylatess formula is RnSn(O2CR)4-n . The complexes give the sack be produced by reacting organotin(IV) oxide or hyrdroxide with comparable carboxylic sulphurous. (equation 1.1 to1.3)R3SnOH or (R3Sn)2O + RCOOH R3SnOOCR + H2O (1.1)R2SnO + 2RCOOR R2Sn(OOCR)2 + H2O (1.2)RSn(O)OH + 3RCOOH RSN(OOCR)3 (1.3)Esterification reaction is accomplished between organotin(IV) oxides or hydroxides and carboxylic acids by azeotrophic dehydration. The above equations reactions will depend on the mixing of different mole ratio of acid and base wi th appropriate solvent. The side products, water was removed by Dean-Stark apparatus and molecular sieve.Furthermore, organotin(IV) carboxylates can be prepared by reacting organotin(IV) chloride with metal carboxylates. (equation 1.4). Meanwhile, when a tin-carbon cleaved with carboxylic acid, it can also produce organotin(IV) carboxylates or cleaved with mercury(I) or mercury (II), or lead (IV) carboxylate as shown below (Davies, 2004). (equation 1.5-1.6)RnSnCI4-n + 4-nRCOOM RnSn(OOCR)4-n + 4-nMCI (1.4)R4Sn + RCOOH R3SnOOCR +RH (1.5)R4Sn + RCOOM R3SnOOCR +RM (1.6)1.4Structures of Triorganotin(IV) ComplexesBasically the general formula for triorganotin(IV) complexes would be R3SnX and it is widely studied. This is due to the higher biological activity of triorganotin(IV) complexes compared to diorganotin(IV) complexes. The R group highly influence the biocidal activities as it contains three Sn-C whereas their volatility and solubility is affected by the X group (Kizlink, 2001). The toxicity also decreases with a decrease of organic groups bind to the tin atom. However, reviews indicated that X group itself is active biologically and an increased of aqueous solubility will lead to increased of activity (Davies, et al., 2008).Meanwhile, chelation of triorganotin monomer or polymer with a five coordination leads to a decreased of activities (Davies, et al., 2008). 11 molar ratio of carboxylic acid and triorganoitn(IV) base are used to prepare triorganotin(IV) complexes (IMTIAZ-UD-DIN and BADSHAH, 2010 Win, 2012).There are two main types of structures possess by triorganotin(IV) complexes which is chain and separate structures. Figure 1.1 shows frequent occuring stuctures of triorganotin(IV) complexes with different coordination geometries (Hadjikakou and Hadjiliadis, 2009).Figure 1.1 Frequent occurring structures in triorganotin(IV) complexes (A-C) (Hadjikakou and Hadjiliadis, 2009. p. 236)At telephone number 1.1, complexes A to C falls on the category of discrete structures. It is habitually found that Ar3SnO2CR exhibit discrete structures such as triphenyltin carboxylates. Complexes A shows possible dicarboxylate ligand that can form a var.ar polymer by bridging triorganotin(IV) groups. Complexes B is a structure that closely resemble to trigonal bipyramid containing two equivalent CO bonds with facial alkyl group groups whereas complexes C shows tetrahedral geometry with two non-equivalent CO bonds. The axial commits for complexes A to C are all occupied by O-Sn-O electronegative substituents (Davies, et al., 2008).1.5Tin ApplicationIt is undeniably that tin compounds have contributed and played a crucial role in various fields such as its property as an anticancer agent, in vitro anti-bacterial, wood preservatives, pesticides and so forth(Davies, et al., 2008). The main focus of tin application would be its organotin complexes due to its biologically active compounds in potentially threatening cancerous cells. Therefore, t remendous focus have actually diverted to anti-cancer field though its smooth have a wide applications.Table 1.3Industrial uses of organotin(IV) compounds (Omae, 2002)1.5.1AgricultureTriorganotin(IV) compounds are proven to be extremely useful in agricultural and industry as they act as fungicides, molluscides, acaricides ,biocides and pesticides based on the research and reviews conducted (Kizlink, 2001 Nath, et al., 2013). For examples, toxicity towards insects and mammals are contributed by trimethyltins whereas Gram-negative bacteria are affected by tri-n-propyltins. In addition, tri-n-butyltin and triphenyltin compounds are effective against fungi. mien of triorganotins pose as a lethal to mosquitoes and their larvae.Moreover,tributytin chloride act as an strong repellent for rodents in crops. Besides that, snails control is affected by both triphenyltin acetate and triphenyltin chloride as molluscicides. This will help to prevent descent fluke infections in human (Piver, 1 973). According to Kizlink studies, the presence of n-butyl, phenyl and cyclohexyl groups will greatly increase the biocidal activity (Davies, et al., 2008).Tricyclohexyltin hydroxide and trineophenyltin oxide acts as a acaricides which are used on citrus and vegetable crops though they are not in condition(p) to defense environment (Batt, 2006). Whereas triphenyltin(IV) hydroxide and triphenytltin(IV) acetate are used in high value crops when on that point is potential for the crops to be infected such as early blight, Alternaria solani (GUENTHNER, et al., 2000). Therefore, the common crops used for fungicides are potatoes, pecans etc.With all the advantageous as biocides, ,little did people know that when triorganotin(IV) compunds are capable of adsorbed into the soil. This will eventually lead to contamination of surface water due to runoff (Okoro, et al., 2011).1.5.2 Anti-cancer ActivityIn 1965, platinum complexes which is known as cis-diamminedichloroplatinum or cisplatin tha t characterized anti-proliferative activity has been discovered by Rosenberg (Alama, et al., 2009). Since then, platinum (II) complexes has been used as anti-cancer agent (Lippard and Jamieson, 1999). Regardless of its success, conducted studies has shown that it possess side effects (Langer, et al., 2013). Therefore, a non-platinum metal complexes field has been been prompted to studied with continual investigation of new complexes as antitumor drugs.Besides that, there has been many reviews and studies on organotin carboxylates due to its antitumor potential. Generally, triorganotin(IV) complexes had been widely known to possess superior activity than diorganotin deriavatives (Baul, et al., 2005 Ali, et al., 2011 Yip, et al., 2012). This rules apply to some of the activties and had been recognized as R3SnL R2SnL2 RSnL3. Literature had indicated that triphenyltin(IV) complexes have remarkable activty in in vitro antitumor against human mamary tumour (MCF-7) and colon carcinoma (W IDR) (Baul, et al., 2009).It is also reported that the actvity of triphenyltin(IV) complexes are higher than otherwise complexes with p-hydroxybenzoic acids. This is because of the high values of half inhibitory tightness (IC50) lipoxygenase stifling compared to organitins(IV) and also reference cisplastin. Besides that, the inhibition of lipoxygenase and the activity of anti-proliferative against smooth muscle tumor, a leiomyosarcoma cells are higher for triorganitin(IV) compounds compared to diorganotin(IV) compounds (Nu, Li and Li, 2014).High lipophilic deportment ,ability to penetrate cell membrane and promotion of binding to biological molecules due to its phenyls group of triorganotin(IV) carboxylates showed high cytotoxic activity further confirms its impressive cytotoxicity in vitro against human lung cell line and human hepatocellular carcinoma cell line (Ma, et al., 2014).Furthermore, spontaneous disproportionation reactions in solution may undergone by triorganotin(IV) derivatives into di- and tetraorganotin(IV) derivatives. In the mean time, lost of alkyl or aryl group may happened in in vivo during interception of aromatase enzyme. Therefore, there is possibility to recognize diorganotin(IV) complexes might be the ultimatum of cytotoxic agent and pharmacokinetic considerations in relation to commonly observed triorganotin(IV) compounds high activity (Alama, et al., 2009).The organotin carboxylates can be further studied by exploring the ligand of the carboxylic acid, coordination number of the central tin atoms which play a crucial role in determine factor of the anti-tumor activity or cytotoxicity properties (Hadjikakou and Hadjiliadis, 2009 Ding, et al., 2012 Thorpe, et al., 2013). In conclusion, simultaneous in researching leads to potential in discovery in designing new anticancer drugs which will greatly help in our publicity in the medical field.1.5.3 AntifoulingExploit of trioganotin(IV) compounds can be used as a biocidal agent in anti -fouling paints for ships. In fact, tri-n-butyltin oxide (TBTO) is the first organotin compound to be discover for its properties. The function of anti-fouling systems is to coat and paint ships that acts as tutelary layer in order to inhibit attachment of Chlamydomas sp. or acorn barnacles. Shipping industry will face a serious problem if marine fouling occur due to increased surface roughness and resistance in water. Therefore, a consumption of 40% of fuel is needed to maintain the normal speed (Omae, 2003).Furthermore, triorganotin(IV) compounds are resistance towards corrosion on aluminum hulls which is why it is favoured. Besides that the ability of tributyltin oxide to mix with pain solvents as a colorationless liquid can be used in many biocidal applications. However, tributyltin oxide is highly soluble in seawater and thus giving a short term protection. Whereas, triphenyltin(IV) fluoride has become a common antifungal paint due to its long life protection from algae and s hells (Omae, 2003).Even though both tributyltin oxide and triphenyltin(IV) fluoride made a good antifouling paint, studies had shown that they contribute contamination to the aquatic environment (Hartl, 2012). It was suggested that biocides release is caused by high pressure hosing activities in which the paint particles become attached with the sediments and also leaching (Konstantinou and Albanis, 2004)1.5.4 Wood preservativesIt is undeniable that wood is a precious gift from the mother nature and serves as as a wide applicant in the world. Specific wood species are needed for construction due its superior physical, mechanical and aesthetically pleasing performance (Jusoh, 2012). However, not all wood species are durable for outdoor activities. Therefore, organotin(IV) compounds are set as a wood preservatives such as tributyltin(IV) oxide and tributyltin(IV) naphthenate.Based on Kizlink research in category 2000, triorganotin(IV) compounds are found to inhibit the growth of myc elium from wood-destroying fungi Coniophora puteana, Serpula lacrymans and mould suspensions. It is reported that butyl group in n-alkyi fetter contained by triorganotin(IV) compounds such as bis(tributyltin) oxide and tributyltin N, N-diethyldithiocarbamate is highly effective against fungi.On the other hand, inhibitory activity of fungicides of triphenyltin(IV) compounds appear to be lower than tributyltin(IV) compounds. This studies indicated and proven that smaller molecular volume of R3Sn have a better establisment to the site of inhibitory action compared to bigger molecular volume.Whereas in the studies of Jusoh, it was suggested that Alstonia schlaris, Macaranga triloba and Hevea brasiliensis were preserved succesfully by organotin(IV) compounds. This results would be further supported by the binding of tin compounds with the wood cell from the FTIR spectra which serves as a preservations of treatability of the particular(prenominal) wood species.1.5.5 Poly (vinyl chloride ) (PVC) stabilizersThe degradation of poly (vinyl chloride) (PVC) or oxygenolysis occur at lower temperature of its processing temperature. Thus, conjugation of double bonds are established and the decomposition will release hydrogen chloride (HCI) which then be reduced by heat stabilizers through absorption (Arkis and Balkose, 2004 Wang, et al., 2014). The stabilizers are composed of mono or di-disubstituted organotin(IV) compounds which usually added to pipes, films and packing materials due to their caloric stability (Nu, Li and Li, 2014).Common PVC stabilizers can be differentiated with their alkyl group of organotins which is methyl, butyl and octyl (Okoro, et al., 2011). Since the toxicity of monoorganotin stabilizers towards mammals are extremely low, they are widely used with an added advantage of low raw material cost. On the other hand, the efficiency of octyltins are lesser due to its lower tin content (Batt, 2006).According to Songwon in 2013 by Tin Intermediates Select ion Guide, the examples of organtin(IV) complex used as a heat stabilizers is butyltin(IV) mercaptide, dibutyltin(IV) dilaurate, monobutyltin tris(2-ethylhexanoate) and dioctyltin mercaptide. Tin mercaptides are found to be the most desired due to its high efficiency acting as a weak acid reacting with labile chloride sites on PVC. Besides that, solubility of the stabilizer and lubrication in polymer processing is compound by the high molecular weights and ester group in mercaptan ligands (Batt, 2006).1.6 Other usage of Organotin(IV) compoundsBesides organotin(IV) compounds acts as an bacteriacide and antifungal agent, it also has mothproofing properties to treated fabrics such as bis(tributyltin) oxide. This is due the advantage of being lacking of color and staining. Staphylococcus aureus, a bacteria found in hospital also can be controlled by chemical bis(tributyltin) oxide (Piver, 1973).Diorganotin(IV) compounds are used as catalysts to in process of forming polyurethane and s ilicon elastomers (Okoro, et al., 2011). Dibutyltin(IV) compounds such as diibutytin(IV) dilaurate is responsible in controlling tapeworms for poultry such as Raillietina cesticillus.1.7 Effects of Organotin(IV) compoundsHumans are affected by organotins consumption of contaminated food, waters from pipelines of PVC or inhalation from agricultural activities and industry processes. The symptoms includes liver damage, loss of weight and neurological disorder.Birds are affected by their uptake of food in which their torso structure, diet and metabolism of butyltin determines the accumulation in their tissues. Tri-n-butyltin oxide will greatly impact the immunological system and hormones activities of the birds.Whereas the doorway of organotins to fishes is through uptake of water from the gills and diet factor. The toxic effects would be on the red blood cells, gills and liver in the presence of tributyltin(IV) compounds(Namiesnik, et al., 2013).Another evidence was proved by study ing chronic toxicity of organotin(IV) compounds by observing gastropods as subjects. It was found that gastropods exhibit imposex which can be defined as having priapic organs such as penis in a female species even with low concentration of tributyltins. This literally means that contamination of organotins greatly affects all biological living species (Omae. 2002)1.8 ObjectivesThe main objectives of this research is to synthetic thinking (4-amino-3,5-dichlorobenzoato)triphenyltin(IV) from the reaction between 4-amino-3,5-dichlorobenzoic acid with triphenyltin(IV) oxide.The second objective of this research is to study the characterization of the synthesized complexes through last of melting point, carbon, hydrogen, nitrogen elemental analysis, Fourier Transform Infrared spectrometry (FTIR) as KBR dics, 119Sn, 1H and 13C Nuclear Magnetic Spectroscopy (NMR) with the means of quantitatively and qualitatively.The third objective for this study is to determine the structure and coord ination geometry of the tin moiety carboxylates. wedge ratio of the reactants, polarity of solvent, temperature of refluxing etc. will contribute to the effects of coordination number and binding mode of the ligand to the tin atom which will be investigated.