Distorted tetrahedral geometry

Active site geometry Distorted tetrahedral Distorted tetragonal Tetragonal Trigonal planar P4-S tetracopper cluster... 

Copper(I) tends towards a tetrahedral coordination geometry in complexes. With 2,2 -bipyr-idine as a chelate ligand a distorted tetrahedral coordination with almost orthogonal ligands results. 2,2 -Bipyridine oligomers with flexible 6,6 -links therefore form double helices with two 2,2 -bipyridine units per copper(I) ion (J. M. Lehn, 1987,1988). J. M. Lehn (1990 U. Koert, 1990) has also prepared such helicates with nucleosides, e.g., thymidine, covalently attached to suitable spacers to obtain water-soluble double helix complexes, so-called inverted DNA , with internal positive charges and external nucleic bases. Cooperative effects lead preferentially to two identical strands in these helicates when copper(I) ions are added to a mixture of two different homooligomers. 

M(NO)2(PPh3)2]+. The coordination number of the metal in both is four, in a distorted tetrahedral geometry. The position of i/(N—O) in the IR spectrum is essentially the same, and the rhodium and iridium compounds have similar slight bending of the M—N—O linkage. 

Other paramagnetic bis(amidinate) iron(II) complexes of the type [But(NR)2]2Fe (R = Cy, Pr ) have been prepared analogously from the lithium amidinate salts and FeCl2- The coordination geometry around Fe is distorted tetrahedral (Scheme 137). 

The lithium derivatives Li[Me3SiNC(Ph)N(CH2) NMe2] ( = 2, 3) crystallize as dimers with each of the Li atoms bonding to two N atoms of an amidinate fragment in one ligand and to two N atoms of the other ligand in the dimer. The coordination geometry around the Li atoms is distorted tetrahedral (Scheme 176). ... 

The compounds formed were studied by esr spectroscopy, with the magnetic parameters being used to determine the geometries. Mn02 is linear, whereas MnOa is trigonal planar (Dsh), and Mn04 is distorted tetrahedral with Csv symmetry. 

X-ray crystallographic analysis of Fe[0Si(0 Bu)3]3THF revealed a distorted tetrahedral geometry (toward a trigonal pyramid) at the Fe center. Related alkyl siloxide complexes of Fe(III) with dimeric structures, [Fe(OSiMe3)3]2 and [Fe(OSiEt3)3]2, have been reported by Schmidbaur and Richter [98]. 

The structural information on the alkaline earth metal derivatives of the heavier group 14 elements is markedly limited. The first silyhnagnesium compound to be structurally characterized was (Me3Si)2Mg (DME), which is monomeric with distorted tetrahedral geometry of the Mg atom and Si-Mg bond length of 2.630(2)... 

Bhalla el al. synthesized and studied the zinc complex of bis(l -methyl-4,5-diphenylimidaz-2-oyl) carbinol. The ligand coordinates as bidentate resulting in a slightly distorted tetrahedral geometry, [ZnL2]2+. 

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