Structure trinuclear species

A typical ligand capable of generating a dendritic structure is 1,4,5,8,9,12-hexaazatriphenylene (HAT). Photophysical studies of trinuclear species based on HAT have been reported [14 a, 49]. Representative example of complexes of this type are 26, 27, and 28. For some of these complexes, the luminescence, originating from MLCT levels involving the central HAT ligand, was found to decay with multiexponential kinetics. Furthermore, the vibrational modes responsible for the nonradiative decay of the luminescent MLCT states are different in the polynuclear dendritic edifices with respect to the mononuclear [M(L)2(HAT)]2+ compounds [14a]. 

Platination of the N3 position in 1-substituted uracil and thymine derivatives requires proton abstraction and usually occurs only at high pH, but the Pt-N3 bond, once formed, is thermodynamically stable (log K 9.6) [7]. Platinum binding to N3 increases the basicity of 04, which becomes an additional binding site leading to di- and trinuclear complexes. A list of X-ray structurally characterized species is given by Lippert [7]. Pt complexes of uracil and thymine can form intensely colored adducts (e.g. platinum pyrimidine blues), which show anticar-cinogenic activity analogously to the monomeric species [7]. 

Among a series of complexes with sulfur-containing ligands (e.g., WS4 , M0S4 (ethanedithiolate)2, 85 ) is the trinuclear species [(bpy)2RuS2WS2Ru(bpy)2] " " which has been structurally characterized. ... 

As the data summarized in Tables I and II show, both Pd (II) and Co (II) form homometallic trinuclear complexes of the general structure[M (ML2)2]X2. Also, the mononuclear Pd (II) complex has been utilized to form heterometallic trinuclear species—e.g., [Ni(PdL2)2]X2. 

The trinuclear cation Cr,(NH,) 0(OH)45 and the tetranuclear cation Crj(OH),Cr(NH have been prepared similarly by the Cr(II) charcoal catalytic method and were separated by cation-exchange chromatography (40). The trinuclear species was isolated as a bromide salt and has structure 5 in Fig. 1. The tetranuclear species Cr[(0H),Cr(NH,)4[/f has been shown to be a chromium ammonia analog of the so-called Werner s brown salt, Co[(OH)2Co(en),J 3f,f (structure 6 in Fig. 1) (41). 

The structures of the trinuclear species Cr3(OH)45 + and the two tetranuclear species a- and /7-Cr4(OH)6< + have not been established. Linear as well as cyclic trimeric structures (structures 4a, 4b, and 5 in Fig. 1) have been considered (27, 37), as has another cyclic structure such as that shown in Fig. 10. However, the kinetic, thermodynamic, spectroscopic, and magnetic properties appear to provide no evidence to favor the one rather than the other (27). The number of possible... 

Synthesizing blacks such as C.I. Oxidation Base 10, 76060 13007-86-8] (C.I. Developer 13 ) is very complex and depends on the oxidation conditions. The first step with / -phenylenediamine is oxidation top-benzoquinoncdiim incs, then to a trinuclear species called Bandorowski s base (2). The final polymeric dye structure is unknown. 

Fig. 4. Schematic structures of the bi- and trinuclear species ( dimer and trimer ) obtained using the Ru(bpy)2CN+ subunit.

If the M unit is Ru(bpy)2CN+, dinuclear or trinuclear species (thereafter called dimef or trimers ) can be obtained [13], The structures of such species (unknown conformation) are schematically shown in Fig. 4. The trimer structure shown in Fig. 4 is that of one of the three linkage isomers that are possible depending on the orientation of the two bridging cyanides (-NC-Ru-CN-, -NC-Ru-NC-, or -CN-Ru-NC-). 

The reaction of [Cu(pba)] with Nidi) perchlorate in the presence of bapa also affords a trinuclear species of formula [Ni(bapa)(H20)]2-Cu(pba) (C104)2. The structure of the trinuclear cation is shown in Fig. 

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