Ligands symmetric

Few Ni4 complexes with a cubane-like structure and four triply bridging //3-l,l,l-N3 ligands symmetrically bound to three Ni11 ions have been discovered (886),2135,2156 but magnetic data are only reported in the case of [Ni4(dmb)4(EtOH)4(//3-l,l,l-N3)4] (dbm = dibenzoylmethane).2135,2136 Its magnetic behavior was well reproduced by a model with a single 7 = +11.9cm 1. 

Movement of all four ligands symmetrically to one side of the plane yields the square pyramidal 4 structure. The highest two orbitals of the Dm structure, pz = b g and ndz2 = a g, are substantially stabilized, the former by in-phase mixing of the ligand orbitals and the latter by relief of repulsion with the ligand orbitals. In ascending order, the five valence orbitals of the C4t, structure are dxy = a2, (nxz,nyz) = e nz2 = a, and npz = d. ... 

The presence of simple ir-allyl and ir-cyclopentadienyl ligands symmetrically coordinated to an M3 unit seems to be unique. Bridging allyl groups are found in [C3H5Pt(acac)]2 (42) and in the tetrameric [C3H5PtCl]4 (43), but they are linked differently to the platinum atoms, namely mono-hapto to one platinum and dihapto to the other. There is also no metal-metal bond formed in these complexes. 

The trinuclear copper site (see Fig. 6) has eight histidine ligands symmetrically supplied by domain 1 and domain 3 and two oxygen ligands. Seven histidines are ligated by their NE2 atoms to the copper ions, whereas His62 is ligated to CU3 K3 by its NDl atom. In the... 

Metallocene catalysts can be classified into several categories based on ligand symmetrical structures. This includes Cj, Ci-v, Cs, Ci, oscillating structures, and bridged half-metallocenes. The main features of these... 

Besides the blue type-1 copper sites, the blue oxidases contain a trinuclear copper center, which is located between the N- and C-terminal domains. It can be described spectroscopically as a coupled type-2/type-3 copper center. The atomic structure of the trinuclear copper site for oxidized ascorbate oxidase as derived from X-ray crystallography is displayed in Figure 6. The trinuclear cluster has eight histidine ligands symmetrically supplied from... 

MMCT absorption band, but the observation of ligand symmetric ring vibration in the IR " TA, transient absorption measurements, assuming that ACda 0-... 

The phosphorus monoxide ligand symmetrically caps (OsP = 2.294(4)-2.321(3) A) one face of the OS4 tetrahedron in [Et4N]115 (with OsOs bond lengths between 2.811(1)-2.883(1) A). The PO bond length of 1.48(1) A is comparable with that in the free PO molecule (1.46-1.48 thus giving evidence of multiple bonding character of the PO... 

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