| 总结: | The objective of the research study is to synthesize novel compounds through substitution process. The carbonyl ligand on chromium complexes is replaced by different ligands in order to produce a novel organometallic monocrystal compound. The crystal is characterized in terms of its structure, physical and chemical properties. Derivatives of chromium carbonyl are prepared by reaction with a number of group 15 complex ligands which have the potential to result in novel organometallic compounds. Five different ligands were used to produce novel organometallic monocrystal compounds namely Ethylenebis diphenyl-arsine,P-bromophenyldiphenylphosphane,Bis(diphenylphosphino)hexane,Bis(diphenylphosphino)pentane, and Triphenylarsine. From these, the substitution reaction using Ethylenebis diphenyl-arsine and Pbromophenyldiphenyiphosphane both resulted in the formation of sticky light pale yellow crystals, and a fine bright yellow crystal respectively. From the monocrystal Xray diffraction analysis, the resulting novel crystal structure is determined as [cis-1,2-
bis(diphenylarsinyl)ethane] tetracarbonylchromium with molecular formula Cr(CO)4(C26H24As2) denoted as Al and trans-bis [(4-bromophenyldiphenyl) phosphane] tetracarbonylchromium with molecular formula Cr(CO)4 (P2C36H28Br2 ) denoted as A2. Infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) further compliment the X-ray diffraction results. For the Al novel structure, the Cr atom is octahedrally coordinated by four carbonyl ligands and single bidentate arsenic ligand, which are bonded in a trans position to each other. The compound crystallizes in the orthorhombic system with an average Cr-As bond length of 2.44865A and average Cr-CO bond length of 1.86975A. For the A2 novel structure, the Cr atom is octahedrally coordinated by four carbonyl ligands and two monodentate tertiary phosphine ligand, which are bonded in a cis position to each other. The compound crystallizes in the triclinic system with an average Cr-P bond length of 2.3509A and average Cr-CO bond length of 1.8895A. Melting point test is also used to determine the melting point of both crystals with Al at 185°C and A2 at 182°C.
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