Pakistan Research Repository Home

Title of Thesis

Khadija Shahid
Institute/University/Department Details
Department of Chemistry/ Quaid-i-Azam University Islamabad
Inorganic Chemistry
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
nmr studies, organotin, organosilicon, organoboron, silanes, ligand

This thesis consists of two parts (A and B) of the research work. Part A contains the synthesis and 1, 1-organoboration of various alkynylsilanes and part B includes the synthesis and characterization of organotin carboxylates.

Silanes of the type C1Me2SiC≡CR/C1MeHSiC≡CR (R = nBu, CH2NMe2, Me3Si) [1-4], HC12SiC≡CR (R = nBu, Me3Si) [5,6], HMe2SiC≡CR (R = CH2NMe2) [7], symmetrically substituted di-alkynyl silanes Me2Si(C≡CR)2/MeHSi(C≡CR)2 (R = CH2NMe2) [8,9], unsymmetrically substituted di-alkynyl silanes Me2Si(C≡CR12/MeHSi(C≡CR)2 (R = nBu, CH2NMe2, Me3Si) [10-13], Cl2HSiC≡CR (R ≡ CH2NMe2) [14], ClHSi(C≡CR) (R = CH2NMe2) [15], unsymmetrically substituted C1HSi(C≡CRR1) (C=CR1) (R = CH2NMe2, R1 = nBu, CH2NMe2, Me3Si) [17, 18], as well as symmetrically substituted trialkyl silanes HSi(C≡CR)3 (R = CH2NMe2) [16] were prepared and treated with BEt3. Unsymmetrically substituted trialkynyl silanes HSi(C≡CR) (C≡CR1) (R = CH2NMe2 and R1 = nBu, CH2NMe2, Me3Si) [19, 20], and silanes with tri and dichloro function C13SiC≡CR (R = nBu) [21], C12Si(C≡CR)2 (R = nBu) [22] were prepared and their reactivity towards triethylborane, BEt3, was studied.

Unsymmetrically substituted tri-/dialkynyl silanes were synthsized in order to find out which Si-C≡ bond is attacked preferably by BEt3.

In case of mono-alkynyl silanes, the final products of 1, 1-ethylboration were alkenes [23a, b, 24b, 25a, b, 26b, 28a, 29b, 30b, 31a, band 67]. The 1, 1-ethylboration of alkyn-1-yl-chloro(methyl)silanes, Me2Si(C1)-C≡C-R (1) and Me(H)Si(C1)-C≡C-R (2) [R = nBu, CH2NMe2] requires harsh reaction conditions (-20 days boiling in triethylborane), and leads to alkenes in which the boryl and silyl groups occupy cis (E)-isomers: 23a, 23b, 25a, 25b) or trans positions (Z)-isomers in smaller quantities: 24b and 26b). The alkenes are destabilized in the presence of SiH(C1) and CH2NMe2 units (25b, 26b). NMR data indicate hyper coordinated silicon by intramolecular N-Si coordination in 23b and 25b, by which, at the same time, weak Si-C1-B bridges.

The 1,l-ethylboration of dichloro(hexyn-1-y1) silane, C12Si(H)-C≡C-Bu, affords selectively an alkene which is the first example with dialkylboryl and dichlorosilyl groups in eis-positions at the C≡C bond. The analogous reaction of dichloro(trimethylsilylethynyl)silane, C12(H)Si-C≡C-Si Me3, leads to a 4:1 mixture of alkenes, in one of which the boryl groups are in trans-positions. The alkenes were characterized by a consistent set of NMR data.

As well as in case of 1,1-ethylboration of di- and trialkylsilanes the final products, sila-2,4-cyclopentadienes (siloles) [32, 33, 36-43, 47, 49, 50, 52-56, 59-68] were obtained respectively bearing a diethylboryl group in 3- or 4-position. If the CH2NMe2 and the boryl group are in neighboured positions, the Me2N group is always coordinated to the boron atom. Side products and intermediates 34, 35, 45 and 46, 48, 51, 57, 58, containing an electron-deficient Si-H-B bridge could be detected by NMR spectroscopy. Azoles [69, 70] were prepared for synthesis of heterocyclic compounds [71-82] with reaction of alkenes. The molecular structure of tricyclic compound 76 has also been determined by the single crystal X-ray analysis. On the other hand 1, l-ethylboration of alkyne, C12Si(C≡CR)2, gives interesting results due to cleavage of Et2BH. The proposed structures of all products, side products and intermedidates follow from a consistent set of multinuclear magnetic resonance data 1H, 11B, 13C and 29Si NMR), IR and Mass spectrometry.

In part B, organotin (IV) derivatives of the general formulae R2SnL2 and R3SnL where R = Me, n-Bu, n-Oct, Ph and Bz have been synthesized in 1:2 and 1:1 molar ratio by using acids HL 1-HL10 (prepared by the mixing of different anhydrides with different anilines). The synthesis of these complexes has been achieved by either reaction of organotin halides R2SnC12/R3SnCl or organotin oxide R2SnO with triethylammonium salt of 4-(2,5-Dioxo-2,5-dihydro-lH-pyrrol-l-yl)benzoic acid (HL1) or aniline derived acids (H2 -HL10). The coordination around tin in solid as well as in solution has been proposed on the basis of spectroscopic results. The crystal structure of the HL1, C10H8BrNO3, establishes that condensation of 4-bromoaniline with maleic anhydride gives the title compound at room temperature. There are strong intermolecular hydrogen bonding. The carboxyl groups adopt an anti-planar conformation and participate in intramolecular bonding. These complexes were characterized by elemental analyses, infrared, multinuclear 1H, 13C, 119Sn) NMR and Mass spectrometry.

Biological screenings were performed in order to establish their biological activity. These complexes were also tested against different bacteria and fungi to determine their toxicity. LD50 data were also calculated using the Brine Shrimp method. Insecticidal and antileishminial activity was performed for selective complexes by contact toxicity method.

Download Full Thesis
4556.81 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
398.69 KB
2 1 Introduction 1-44
1067.33 KB
  1.1 Organometallic Chemistry 1
  1.2 Organoboron Compounds 6
  1.3 Organosilicon Compounds 9
  1.4 Organotin Compounds 17
  1.5 1, 1-Organoboration 29
3 2 Experimental Section 45-188
3331.59 KB
  2.1 Instrumentation 45
  2.2 Synthesis 45
  2.3 Results And Discussion 46
  2.4 Stepwise Synthesis Of The Unsymmetrically Substituted- Di( Alkyn-1-Yl)Silanes 52
  2.5 Preparation Of Hydrido And Chloro Functions Containing Of Symmetrically Substituted Silanes 55
  2.6 Preparation Of Hydrido And Chloro Functions Containing Of Unsymmetrically Substituted Silanes 56
  2.7 Preparation Of Silanes Containing Trichloro Function 60
  2.8 1 ,1 -Ethylboration Of Alkyn-L-Yl-Chloro (Methyl)Silanes: Alkenes With Chloro(Methyl)Silyl And Diethylboryl Groups In Cis Positions 62
  2.9 1, L-Ethylboration Of Alkyn-L-Yl - ( Dichloro )Silanes: Alkenes Bearing Dichlorosilyl And Diethylboryl Groups 69
  2.10 1, 1-Organoboration Of Silane (7) 71
  2.11 1, 1-Organoboration Of Di( 1-Alkynyl)Silanes 72
  2.12 1, 1-Organoboration Of Compound (15) And Spectroscopic Data( 46,47) 83
  2.13 1 ,1 -Organoboration Of Silane (21) And Spectroscopic Data (67) 94
  2.14 Synthesis Of Cyclic Compounds By The Reaction Of Alkenes With Azo1es 96
  2.15 Instrumentation 117
  2.16 Introduction 119
  2.17 General Procedure For Synthesis Of Ligands (Hl 2 -Hl 10 ) 120
  2.18 Procedure For Synthesis Of Ligand (Hl 1 ) 120
  2.19 Di- And Triorganotin ( IV) Derivatives Of 4-(2,5-Dioxo-2,5- Dihydro-1h-Pyrrol-L-Yl)Benzoic Acid (Hl1) 121
  2.20 Di- And Triorganotin ( IV) Derivatives Of 3-[(4-Bromo- Phenylamido ) ] Propenoic Acid (Hl 2 ) 129
  2.21 Di- And Triorganotin ( IV) Derivatives Of 2-[(4-Bromo- Phenylamido )]Benzoic Acid (Hl 3 ) 137
  2.22 Di- And Triorganotin ( IV) Derivatives Of 3-[(2,2',4-Tribromo- Phenylamido )] Propanoic Acid(Hl 4 ) 143
  2.23 Di- And Triorganotin ( IV) Derivatives Of 2[(2,4-Dinitrophenyl- Amido ) ] Propenoic Acid (Hl 5 ) 148
  2.24 Di- And Triorganotin (Iv) Derivatives Of 3-[( 4-Nitrophenyl)- Amido ] Propenoic Acid And 3-[( 4-Nitrophenyl) Amido ] Propanoic Acid(Hl 6 /Hl 7 ) 154
  2.25 Di- And Triorganotin ( IV) Derivatives Of 2-[(N- Naphthylamido )]Benzoic Acid (Hl 8 ) 165
  2.26 Di- And Triorganotin ( IV) Derivatives Of 2-[(2,4-Dinitrophenyl- Amido )]Benzoic Acid (Hl 9 ) 172
  2.27 Di- And Triorganotin ( IV) Derivatives Of 2-[(2,2'-Dinitrophenyl- Amido )] Benzoic Acid (Hl 10 ) 177
  2.28 Results And Discussion 183
  2.29 References 190-195