Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Abstract

Four new diorganotin(IV) complexes of N-(3,5-dibromosalicylidene)tryptophane, R 2 Sn[3,5-Br 2 -2-OC 6 H 2 CH NCH(CH 2 Ind)COO] [Ind = 3-indolyl; R = Et (1); n-Bu (2); Cy (3); Ph (4)], were synthesized and characterized by elemental analysis and IR, NMR ( 1 H, 13 C and 119 Sn) spectra. The crystal structures of complexes 1-3 were determined by X-ray single crystal diffraction. The tin atom is five-coordinated and its coordination geometry is best described as an intermediate between trigonal bipyramidal and square pyramidal. Intermolecular weak interactions in the complexes 1-3 connect molecules into a one-dimensional helical chain and a two-dimensional array. The dibutyltin complex 2 has potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complex 1 displays weak cytotoxic activity.

Synthesis, structure and cytotoxic activity of diethyltin N‐[(2‐oxyphenyl)methylene]phenylalaninates

“…Complexes 1 , 2 , 3 , 4 all display in vitro activity against A549 and CoLo205, in which the activity of 3 is the best, but their activity is weaker than clinically used cisplatin. This result is similar to that of our previously reported diethyltin analogues Et 2 Sn(5‐Cl‐2‐OC 6 H 3 CHNCH(CH 2 Ind)COO), Et 2 Sn(5‐Br‐2‐OC 6 H 3 CHNCH(CH 2 Ind)COO) and Et 2 Sn(3,5‐Br 2 ‐2‐OC 6 H 2 CHNCH(CH 2 Ind)COO) . Several groups have reported that the dibutyltin and diphenyltin complexes of the Schiff base ligand derived from substituted salicylaldehyde and α‐amino acid have potentially good inhibition activity for some tumor cells, namely MCF‐7, EVSA‐T, WiDr, IGROV, MI9 MEL, A498, H226, HeLa, CoLo205, HCT‐15 and NCI‐522, and the IC 50 values of some of them against the cell lines are less than 0.05 µg ml −1 .…”

“…This is quantified by the value of τ (=0.10), which compares with τ = 0.00 for an ideal square pyramid and τ = 1.00 for an ideal trigonal bipyramid . The Sn(1)O(1) (2.2073(19) Å) and Sn(1)O(3) (2.1761(18) Å) bond distances are consistent with those found in the analogues Et 2 Sn(5‐Cl‐2‐OC 6 H 3 CHNCH(CH 2 Ind)COO) (2.1754(15) and 2.1022(16) Å) and Et 2 Sn(3,5‐Br 2 ‐2‐OC 6 H 2 CHNCH(CH 2 Ind)COO) (2.191(5) and 2.142(5) Å) …”

“…Bioassay studies showed that the diorganotin complexes possess significant cytotoxic activity against some human tumor cell lines . To expand the chemistry and therapeutic potential of the diorganotin complexes of the ligand, we previously reported the synthesis, structure and biological activity of some diorganotin complexes with N ‐(substituted salicylidene)‐α‐amino acid . In those investigations, more attention was paid to the di‐ n ‐butyl‐ and diphenyltin complexes, and less to the diethyltin complexes.…”

Tin(IV) Schiff base complexes derived from pyridoxal: Synthesis, spectroscopic properties and cytotoxicity

“…Their coordination geometry is best described as an intermediate between trigonal bipyramidal and square pyramidal, with bond angles O(11)–Sn(12)–O(13) of 156.7(1)° ( 3b ), 156.9(2)° ( 3d ) and 155.6(8)° ( 3e ). The distortion is quantified by the value of τ (0.00 for an ideal square pyramid and 1.00 for an ideal trigonal bipyramid) . In our case, τ = 0.61, 0.25 and 0.18 for 3b , 3d and 3e , respectively.…”

Synthesis, structure and property of diorganotin N‐[(3‐methoxy‐2‐oxyphenyl)methylene]tyrosinates

“…Because the steric hindrance of the cyclohexyl group is larger than that of methyl, ethyl and butyl group, in the crystal of 4 there does not exist the intermolecular interaction between Sn(1) and O(1A) (symmetry operation A = −x + 1/2, −y + 1, z ) and O(4A) from the adjacent ligand (Sn(1)⋅⋅⋅O(1A) 5.988(2) Å and Sn(1)⋅⋅⋅O(4A) 5.647(2) Å), and it is only present as a monomer. The tin atom is in a distorted trigonal bipyramid involving the tridentate ONO ligand and a axial bond angle, O(1)‐Sn(1)‐O(2), of 155.9(3)°, which is comparable with that observed in Cy 2 Sn(3,5‐Br 2 –2‐OC 6 H 2 ‐ CH=NCH (CH 2 Ind)COO), Cy 2 Sn(3,5‐Br 2 –2‐OC 6 H 2 CH=NCH ( i ‐Pr)COO), and Cy 2 Sn(5‐Cl‐2‐OC 6 H 3 CH=NCH ( i ‐Pr)COO) . Complex 4 is linked into a one‐dimensional zigzag chain through intermolecular O −H⋅⋅⋅O hydrogen bonds involving phenolic hydroxyl of tyrosinate and O(2) i atom of carbonyl (symmetry code i = x ‐1/2, − y + 1, z ) with Sn⋅⋅⋅Sn distance of 7.45(2) Å (Table , Figure ).…”