Search

The ansa indenyl ligand precursors CH2CH2CH2(C9H6R)2 (R = Me (7), Et (8), Pr (9)) have been prepared by the reaction of the corresponding lithium indene, Li(C9H6R-1) (R = Me (4), Et (5), Pr (6)), with 1,3-dibromopropane. Compounds 7–9 were converted, by the reaction with butyllithium, to the dilithium compounds, Li2{CH2CH2CH2(C9H5R-3)2} (R = Me (10), Et (11), Pr (12)). The three carbon atom bridge ansa-bis(indenyl)zirconium complexes, [Zr{CH2CH2CH2(η5-C9H5R-3)2}Cl2] (R = Me (13), Et (14) Pr (15)) were synthesized from the reaction of 10–12 with zirconium tetrachloride. Compounds 13–15 have been tested as homogeneous catalysts in the polymerization of ethylene. The molecular structures of 14 and 15 have been determined by single-crystal X-ray diffraction studies.

The organotin compounds, [SnPh 3 (C 5 H 4 R)] (R = Bu t ( 1 ), CMe 2 (CH 2 CH 2 CH CH 2 ) ( 2 )) and [SnPh 3 (C 5 Me 4 R)] (R = H ( 3 ), SiMe 3 ( 4 )), were prepared by the reaction of SnPh 3 Cl with the lithium derivative of the corresponding cyclopentadiene. 1 – 4 have been characterized by multinuclear NMR spectroscopy ( 1 H, 13 C{ 1 H} and 119 Sn{ 1 H}). In addition, the molecular structures of 1 , 2 and 4 were determined by single-crystal X-ray diffraction studies. The cytotoxic activity of the organotin(IV) complexes ( 1 – 4 ) was tested against human tumour cell lines 8505C anaplastic thyroid cancer, A253 head and neck tumour, A549 lung carcinoma, A2780 ovarian cancer, DLD-1 colon carcinoma. Compounds 1 – 4 present higher activities than cisplatin in all the studied cells. The highest sensitivity of the synthesized tin(IV) complexes was observed against A2780 ovarian cancer and DLD-1 colon carcinoma. Complex 3 presents the highest cytotoxic activity of all the studied complexes in all the cancer cells, with IC 50 values from 0.037 to 0.085 μM, however, its trimethylsilyl-substituted analogue ( 4 ), showed the lowest activity against all the studied cells with IC 50 values from 0.163 to 0.351 μM. Complexes 1 and 2 presented very similar activities on all the cancer cells (IC 50 values from 0.044 to 0.119 μM).

The following ansa -ligand precursors, Et(H)Si(C 5 H 5 ) 2 ( 1 ), Et(H)Si(C 5 HMe 4 )Cl ( 2 ), Et(H)Si(C 5 HMe 4 )(C 5 H 5 ) ( 3 ), Ph(H)Si(C 5 HMe 4 )Cl ( 4 ), Ph(H)Si(C 5 HMe 4 )(C 5 H 5 ) ( 5 ), Ph(H)Si(C 5 HMe 4 ) 2 ( 6 ), CH 2 CHCH 2 (H)Si(C 5 HMe 4 )Cl ( 7 ), CH 2 CHCH 2 (H)Si(C 5 HMe 4 )(C 5 H 5 ) ( 8 ), CH 2 CHCH 2 (H)Si(C 5 HMe 4 ) 2 ( 9 ), and their lithium derivatives, Li 2 {Et(H)Si(C 5 H 4 ) 2 } ( 10 ), Li 2 {Et(H)Si(C 5 Me 4 )(C 5 H 4 )} ( 11 ), Li 2 {Ph(H)Si(C 5 Me 4 )(C 5 H 4 )} ( 12 ), Li 2 {Ph(H)Si(C 5 Me 4 ) 2 } ( 13 ), Li 2 {CH 2 CHCH 2 (H)Si(C 5 Me 4 )(C 5 H 4 )} ( 14 ) and Li 2 {CH 2 CHCH 2 (H)Si(C 5 Me 4 ) 2 } ( 15 ) have been prepared. The group 4 metal complexes, [M{Et(H)Si(η 5 -C 5 H 4 ) 2 }Cl 2 ] (M = Ti ( 16a ), Zr ( 16b ), Hf ( 16c )), [M{Et(H)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] (M = Ti ( 17a ), Zr ( 17b ), Hf ( 17c )), [M{Ph(H)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] (M = Ti ( 18a ), Zr ( 18b ), Hf ( 18c )), [M{Ph(H)Si(η 5 -C 5 Me 4 ) 2 }Cl 2 ] (M = Ti( 19a ), Zr ( 19b ), Hf ( 19c )), M{CH 2 CHCH 2 (H)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] (M = Ti ( 20a ), Zr ( 20b )) and [M{CH 2 CHCH 2 (H)Si(η 5 -C 5 Me 4 ) 2 }Cl 2 ] (M = Ti ( 21a ), Zr ( 21b ), Hf ( 21c )) were synthesized from the reaction of the lithium ansa -derivatives and the tetrachloride salts of the transition metal. The reactivity of the group 4 metal complexes in hydrosilylation processes has been studied. The reaction of 16b , 17a and 17b with tetravinylsilane gave [Zr{(CH 2 CH) 3 SiCH 2 CH 2 (Et)Si(η 5 -C 5 H 4 ) 2 }Cl 2 ] ( 22b ) and [M{(CH 2 CH) 3 SiCH 2 CH 2 (Et)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] (M = Ti ( 23a ), Zr ( 23b )), respectively. The reaction of 17a and 17b with dimethyldivinylsilane yielded the hydrosilylation products [M{(CH 2 CH)Me 2 SiCH 2 CH 2 (Et)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] (M = Ti ( 24a ), Zr ( 24b )), respectively. 23b and 24b reacted with the silane reagent HSiEt 3 to form, via hydrosilylation, [Zr{(Et 3 SiCH 2 CH 2 ) 3 SiCH 2 CH 2 (Et)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] ( 25b ) and [Zr{(Et 3 SiCH 2 CH 2 )Me 2 SiCH 2 CH 2 (Et)Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 4 )}Cl 2 ] ( 26b ), respectively.