Synthesis , Characterization and Crystal Structure Determination of a New Indium ( III ) Complex : [ In ( 5 , 5 ’-DiMeBiPy ) Cl 3 ( DMSO ) ] . 2 ( DMSO )

[In(5,5’-DiMeBiPy)Cl3(DMSO)].2(DMSO) complex (5,5’-DiMeBiPy is 5,5’-Dimethyl-2,2’bipyridine) was prepared from reaction of InCl3.4H2O with 5,5’-DiMeBiPy in 1.1 molar ratio in DMSO. This compound has been characterized by IR, 1H NMR, UV-Vis spectroscopy as well as X-ray crystallography. This compound crystallizes in the space group P+ of the triclinic system. The unit cell dimensions is: a = 8.6695(8) Å, b = 12.8456(14) Å, c = 13.0877(12) Å, a = 78.258(8)o, b = 85.270(8)o, g = 74.932(8)o. According to X-ray structure determination, there are one molecules of the complex and two DMSO solvent molecules in the asymmetric unit. In this complex the geometry at the indium (III) center is octahedral, formed by two nitrogen atom of 5,5’-DiMeBiPy ligand, three chloride ions and one DMSO molecule in trans position to chloride ion.

On the other hand, the chemistry of indium compounds is of interest owing to their important application in catalysts, electronics and optics 10-

ExPERIMENTAL Materials and instruments
All chemicals were purchased from Merck and Aldrich.Infrared spectra (4000-250 cm -1 ) of solid samples were taken as 1% dispersion in KBr pellets using a Shimadzu-470 spectrometer. 1 H-and 13 C-NMR spectra were recorded on a Bruker AC-300 MHz spectrometer operating in the quarter mode.

Crystal structure determination and refinement
The X-ray diffraction measurements were made on a Bruker SMART 1000 CCD area detector diffractometer at 298 K (Mo-Ka radiation, graphite monochromator, λ = 0.71073 Å).The structure was solved by SHELX-97 and SHELXTL and absorption correction was done using the SADABS and APEX2 programs [24][25] .Data collection, cell refinement and data reduction were done by APEX2, SAINT, SHELXTL, PLATON and MERCURY [24][25][26][27] .The suitable crystal for X-ray diffraction experiment was obtained by slow evaporation of DMSO in room temperature after three weeks.Synthesized complex was thoroughly characterized by elemental analysis, IR and 1 H-NMR spectroscopy.

Fig. 2 :
Fig. 2: Crystal packing diagram of [In(5,5'-DiMeBiPy)Cl 3 (DMSO)].2(DMSO)showing the C-H…Cl and C-H…O hydrogen bonds and π…π stacking interactions between adjacent molecules title complex.A comparison between 1 H and 13 CNMR spectra of title complex and 5,5'-dmbpy ligand, clearly indicated the coordination of ligand to In(III).It can be deduced from NMR data that in the solution, the 5,5'dmbpy ligand have a symmetrical environment.As expected, the 1 H NMR spectrum exhibited a singlet at 2.63 ppm for methyl, a doublet at 8.40 ppm, a doublet at 8.83 ppm and a singlet at 9.28 for the aromatic rings.The 13 C NMR spectrum showed a singlet at 19.3 ppm, for CH 3 groups and five singlets at 126.1 to 152.6 ppm for the aromatic rings.
. The complex have distorted octahedral geometry.In this complex indium has pseudo-octahedral coordination with facarrangement of chlorine atoms.In-Cl bond lengths differ strongly around indium center.The bond lengths In1-Cl3 (chlorine atom is trans to oxygen) is longer than distances In1-Cl1 and In-Cl2 [C11 and Cl2 atoms are trans to nitrogen atoms].