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Complexation of organotin chlorides with selected N,N' and N,O- donor ligands
Author
Ouyang, Jiexiang
Supervisor
Khoo, Lian Ee
Abstract
This thesis described the complexation reaction of selected ligands with organotin chlorides.
In the first chapter, the basic concepts of organotin compounds, ligands and multi-dentate ligands were described. Organotin complexes, with examples, were classified into several categories according to their structures. The second part of this chapter is a review on the factors that affect the formation of adducts.
In the second chapter, the reactions of 8-aminoquinoline (Aq) with diorganotin dichlorides (R2SnCl2, R = Ph, Me, Bu) were described in the first part. With Ph2SnCl2, a stable adduct, Aq-Ph2SnCl2, was obtained. However, the reaction of BU2SnCl2 with Aq, irrespective of the solvent used, gave hydrolytic products, [(BU2SnCl)2O]2 and HCI, which subsequently protonated the ligand to form Aq-HCI. Depending on the solvent used, Me2SnCl2 reacted with Aq and yielded either an adduct, Aq-Me2SnCl2, or hydrolytic and protonated products, [(Me2SnCl)2O]2 and Aq-HCI. Additionally, the adduct, Aq-Me2SnCl2 was found to decompose into Aq-HCI and [(Me2SnCl)2O]2 upon recrystallisation in a commercial solvent. The adducts, Aq-Ph2SnC12 and Aq-Me2SnCl2, were characterised with various physical methods including X-ray crystallography. These results confirmed that the decreasing sequence of acceptor strength for diorganotin dichlorides with respect to Aq is Ph2SnC12 > Me2SnC12 > Bu2SnC12.
,br>The second part of Chapter 2 was concerned about the reactions of 8-methyl-aminoquinoline (MeAq) with R2SnC12 (R = Ph, Me, Bu) in commercial chloroform. The reaction of Me2SnC12 with MeAq gave (HMeAq)2Me2SnC14, together with [(Me2SnC1)2O]2 while MeAq-HCI and [(Bu2SnC1)2O]2 were isolated from the reaction with Bu2SnC12. Diphenyltin dichloride reacted with MeAq and afforded an unstable adduct, MeAq-Ph2SnC12, which was easily decomposed into (HMeAq)2Ph2SnC14 and [(Ph2SnC1)2O]2 upon recrystallisation in hot CHC13. The adduct, MeAq-Ph2SnC12, and the complex salts, (HMeAq)2R2SnC14 (R = Ph, Me), were characterised. All the products isolated revealed that the hydrolytic rate of R2SnC12 followed the order of Ph2SnC12 < Me2SnC12 < Bu2SnC12 . In addition, results derived from product studies showed that the electron-donating ability of MeAq was reduced compared to that of Aq. It indicated that the methylation on donor atom (N) of a ligand reduced the coordination ability of this ligand.
The reactions of 8-methoxyquinoline (Mq) with R2SnC12 (R = Ph, Me, Bu) and Ph3SnC1 were discussed in the third chapter. All these RSnC12 reactions yielded not adduct but complex salts and protonated compounds, together with the corresponding distannoxanes. The reactions of Bu2SnC12, irrespective of the solvent used, gave Mq-HC1 and [(Bu2SnC1)2O]2 while (HMq)2Me2SnC14 and [(Me2SnC1)2O]2 were isolated from the Mq reaction with Me2SnC12. When Mq reacted with Ph2SnC12 in chloroform and it yielded (HMq)2Ph2SnC14 and [(Ph2SnC1)2O]2 . However, when the same reaction was carried out in cyclohexane, an additional complex salt (Mq-HMq)Ph2SnC13, besides (HMq)2Ph2SnC14 and [(Ph2SnC1)2O]2, was isolated. Furthermore, (Mq-HMq)Ph2SnC13 was found to decompose into (HMq)2Ph2SnC14, [(Ph2MSnC1)2O]2 and Mq-HCI. All the protonated products wre characterised, including X-ray structural analyses of (Mq-HMq)Ph2SnC13 and (HMq)2Ph2SnC14. Isolation of these products reaffirmed that the hydrolytic rate of R2SnC12 followed the sequence of Ph2SnC12 < Me2SnC12 < Bu2SnC12. Additionally, the composition of (Mq-HMq)Ph2SnC13 displayed that the [Ph2SnC13] anion disproportionated into [Ph2SnC14]2-, a dianion, and Ph2SnC12.
An outer-sphere coordination adduct, Mq-H2O-Ph3SnC1, with a different structure as usual, was prepared and characterised with various physical methods through the reaction of Mq and Ph3SnC1.
The reactions of 3-methyladenine (3-MeAd) and N,N,9-trimethyladenine (Me3Ad) with R2SnC12 (R = Ph, Me, Bu) were depicted in the fourth chapter. Dimethyltin dichloride reacted with 3-MeAd and produced a 2:1 adduct, (3-MeAd)2Me2SnC12, irrespective of the ratio of the donor and acceptor used. The reaction of Bu2SnC12 with 3-MeAd gave [(Bu2SnC1)2O]2 and 3-MeAd-HCI. However, the reaction of Ph2SnCI2 with 3-MeAd only afforded, besides Ph3SnC1 and 3-MeAd-HCI, the disproportionated product, (3-MeAd)2PhSnC12, which cannot be characterised probably due to its hydrolysis. From the structural characterisation of (3-MeAd)2Me2SnC12, the coordination site of 3-MeAd was confirmed to be at the N7 atom.
Me3Ad reacted with R2SnC12 (R = Ph, Me, Bu) and yielded Me3Ad-HCI, together with the corresponding distannoxanes, [(R2SnC1)2O]2. These results reaffirmed that the methylation on donor atom (N) of a ligand reduced the coordination ability of this ligand.
In the first chapter, the basic concepts of organotin compounds, ligands and multi-dentate ligands were described. Organotin complexes, with examples, were classified into several categories according to their structures. The second part of this chapter is a review on the factors that affect the formation of adducts.
In the second chapter, the reactions of 8-aminoquinoline (Aq) with diorganotin dichlorides (R2SnCl2, R = Ph, Me, Bu) were described in the first part. With Ph2SnCl2, a stable adduct, Aq-Ph2SnCl2, was obtained. However, the reaction of BU2SnCl2 with Aq, irrespective of the solvent used, gave hydrolytic products, [(BU2SnCl)2O]2 and HCI, which subsequently protonated the ligand to form Aq-HCI. Depending on the solvent used, Me2SnCl2 reacted with Aq and yielded either an adduct, Aq-Me2SnCl2, or hydrolytic and protonated products, [(Me2SnCl)2O]2 and Aq-HCI. Additionally, the adduct, Aq-Me2SnCl2 was found to decompose into Aq-HCI and [(Me2SnCl)2O]2 upon recrystallisation in a commercial solvent. The adducts, Aq-Ph2SnC12 and Aq-Me2SnCl2, were characterised with various physical methods including X-ray crystallography. These results confirmed that the decreasing sequence of acceptor strength for diorganotin dichlorides with respect to Aq is Ph2SnC12 > Me2SnC12 > Bu2SnC12.
,br>The second part of Chapter 2 was concerned about the reactions of 8-methyl-aminoquinoline (MeAq) with R2SnC12 (R = Ph, Me, Bu) in commercial chloroform. The reaction of Me2SnC12 with MeAq gave (HMeAq)2Me2SnC14, together with [(Me2SnC1)2O]2 while MeAq-HCI and [(Bu2SnC1)2O]2 were isolated from the reaction with Bu2SnC12. Diphenyltin dichloride reacted with MeAq and afforded an unstable adduct, MeAq-Ph2SnC12, which was easily decomposed into (HMeAq)2Ph2SnC14 and [(Ph2SnC1)2O]2 upon recrystallisation in hot CHC13. The adduct, MeAq-Ph2SnC12, and the complex salts, (HMeAq)2R2SnC14 (R = Ph, Me), were characterised. All the products isolated revealed that the hydrolytic rate of R2SnC12 followed the order of Ph2SnC12 < Me2SnC12 < Bu2SnC12 . In addition, results derived from product studies showed that the electron-donating ability of MeAq was reduced compared to that of Aq. It indicated that the methylation on donor atom (N) of a ligand reduced the coordination ability of this ligand.
The reactions of 8-methoxyquinoline (Mq) with R2SnC12 (R = Ph, Me, Bu) and Ph3SnC1 were discussed in the third chapter. All these RSnC12 reactions yielded not adduct but complex salts and protonated compounds, together with the corresponding distannoxanes. The reactions of Bu2SnC12, irrespective of the solvent used, gave Mq-HC1 and [(Bu2SnC1)2O]2 while (HMq)2Me2SnC14 and [(Me2SnC1)2O]2 were isolated from the Mq reaction with Me2SnC12. When Mq reacted with Ph2SnC12 in chloroform and it yielded (HMq)2Ph2SnC14 and [(Ph2SnC1)2O]2 . However, when the same reaction was carried out in cyclohexane, an additional complex salt (Mq-HMq)Ph2SnC13, besides (HMq)2Ph2SnC14 and [(Ph2SnC1)2O]2, was isolated. Furthermore, (Mq-HMq)Ph2SnC13 was found to decompose into (HMq)2Ph2SnC14, [(Ph2MSnC1)2O]2 and Mq-HCI. All the protonated products wre characterised, including X-ray structural analyses of (Mq-HMq)Ph2SnC13 and (HMq)2Ph2SnC14. Isolation of these products reaffirmed that the hydrolytic rate of R2SnC12 followed the sequence of Ph2SnC12 < Me2SnC12 < Bu2SnC12. Additionally, the composition of (Mq-HMq)Ph2SnC13 displayed that the [Ph2SnC13] anion disproportionated into [Ph2SnC14]2-, a dianion, and Ph2SnC12.
An outer-sphere coordination adduct, Mq-H2O-Ph3SnC1, with a different structure as usual, was prepared and characterised with various physical methods through the reaction of Mq and Ph3SnC1.
The reactions of 3-methyladenine (3-MeAd) and N,N,9-trimethyladenine (Me3Ad) with R2SnC12 (R = Ph, Me, Bu) were depicted in the fourth chapter. Dimethyltin dichloride reacted with 3-MeAd and produced a 2:1 adduct, (3-MeAd)2Me2SnC12, irrespective of the ratio of the donor and acceptor used. The reaction of Bu2SnC12 with 3-MeAd gave [(Bu2SnC1)2O]2 and 3-MeAd-HCI. However, the reaction of Ph2SnCI2 with 3-MeAd only afforded, besides Ph3SnC1 and 3-MeAd-HCI, the disproportionated product, (3-MeAd)2PhSnC12, which cannot be characterised probably due to its hydrolysis. From the structural characterisation of (3-MeAd)2Me2SnC12, the coordination site of 3-MeAd was confirmed to be at the N7 atom.
Me3Ad reacted with R2SnC12 (R = Ph, Me, Bu) and yielded Me3Ad-HCI, together with the corresponding distannoxanes, [(R2SnC1)2O]2. These results reaffirmed that the methylation on donor atom (N) of a ligand reduced the coordination ability of this ligand.
Date Issued
1998
Call Number
QD412.S7 Ouy
Date Submitted
1998