Tetrahedral molecular geometry

About: Tetrahedral molecular geometry is a research topic. Over the lifetime, 1795 publications have been published within this topic receiving 30706 citations.

Molecular structure and DFT investigations on new cobalt(II) chloride complex with superbase guanidine type ligand

Abstract: The new [Co(btmgn)Cl 2] complex and the 1,8-bis(tetramethylguanidino)naphthalene (btmgn) ligand were synthesized and characterized. The X-ray single crystal investigation showed distorted tetrahedral geometry around the Co(II) ion. The geometry of the btmgn and [Co(btmgn)Cl 2] complex was optimized using the B3LYP/6–311G(d,p) method. The calculated geometric parameters at the optimized structure of the [Co(btmgn)Cl 2] complex showed good agreement with our reported X-ray structure. The two tetramethylguanidino groups are in a cis-type position to the naphthalene ring plane both in the free and coordinated btmgn. The large red shift of the υ C=N mode upon coordination indicates the strong ligand–metal interactions. The calculated natural charges using natural bond orbital (NBO) analysis at the two coordinated Cl-atoms are not equivalent. Also the two LP(4)Cl →LP*(3)Co intramolecular charge transfer interaction energies (E (2)) are 29.00 and 39.17 kcal/mol, respectively. The two Co-Cl bonds are not equivalent where the longer Co-Cl bond has more electronegative chlorine atom than the shorter one. Molecular electrostatic potential (MEP) study of the btmgn ligand showed that the N4 and N7 atoms are the most reactive nucleophilic centers for the coordination with the Co 2+ ion. The [Co(btmgn)Cl 2] complex has higher polarizability (α 0), first hyperpolarizability (β 0) and lower energy gap (ΔE) than the free ligand. The TD-DFT calculations predicted the transition bands at 337.2 nm (f =0.2299, H →L) and 342.6 nm (f =0.1465, H-2/H →L) for the btmgn and [Co(btmgn)Cl 2], respectively.

Synthesis and Characterization of Cobalt(II), Nickel(II), and Zinc(II) Complexes with N,N′‐bis(2‐nitrocinnamaldehyde)‐1,2‐diiminoethane Ligand. Crystal Structure of Zn(nca2en)Br2

Abstract: A series of complexes of the type M(nca2en)X2, where nca2en=/N,N′‐bis(2‐nitrocinnamaldehyde)‐1,2‐diiminoethane, M(II) =Co, Ni or Zn and X=Cl, Br, I have been synthesized and characterized. The crystal and molecular structure of Zn(nca2en)Br2 8 was determined by X‐ray crystallography from single‐crystal data. The complex 8 crystallizes in monoclinic system, having Zn ion in distorted tetrahedral geometry, Br(1)‐Zn(1)‐ Br(2), 117.37(4)°; N(3)‐Zn(1)‐N(2), 82.57(18)°. This structure consists of intermolecular hydrogen bond of the type C‐H‐X. The formation of the C‐H‐M weak intramolecular hydrogen bonds due to the trapping of C‐H bonds in the vicinity of the metal atoms is reported for 8. The 1H NMR study of Zn complexes gives further evidence for the presence of such interactions. The spectral properties of the above complexes are also discussed.

Synthesis and X-ray crystal structure of a complex formed by reaction of 1,2-bis(2′-pyridylethynyl)benzene and mercury(II) chloride

Abstract: The X-ray crystal structure of the complex formed between 1,2-bis(2′-pyridylethynyl) benzene and mercuric(II) chloride is described. The complex (C40H24Cl6Hg3N4) crystallized in the triclinic space group P-1 with a=9.0414(6), b=9.4631(7), c=12.1134(9) A, α=97.4680(10), β=94.8130(10), γ=105.4700(10)°. The structure reveals that the ligand is distorted from planarity to accommodate the mercury cation and a third mercuric chloride moiety is held between two ligand-mercury coordination complexes. The central mercury cation has octahedral coordination geometry surrounded by six chlorides while the other two mercury cations have distorted tetrahedral geometry each coordinated by two pyridyl nitrogen atoms and two chlorides.