Mononuclear precursor

Kockerling, M. and Henkel, G. (2000) Synthesis and structure of [Ni4(S2C7Hio)4], the first tetranuclear cyclic nickel complex with bifunctional thiolate ligands and of the mononuclear precursor compound Na2[Ni(S2C7Hio)2]- 4MeOH. (PrOH)-Pr-i, Inorg. Chem. Commun., 3, 117-9. 

There are several synthetic pathways that permit the synthesis of undecanuclear clusters. The reduction of the mononuclear precursor [AuI(PPh3)] or the dinuclear precursor [Au2X2(BINAP)] with NaBH4 leads to clusters [ ( 3)713] [28] and [Aun(BINAP)4X2] [29] (X = C1 or Br BINAP = 2,2 -bis(diphenylphosphino)-1,1 -binaphthyl), respectively reaction of gold vapor with complex [Au(SCN)(PPh3)] in ethanol leads to cluster [Auu(PPh3)7(SCN)3]3+ [30] the photolytic reduction of... 

This synthesis provides another example, comparable to that of [Fe4S3(NO)7] , of the spontaneous self-assembly of a tetranuclear species 4 from a mononuclear precursor in a one-stage procedure. 

Rhodium OFCOT Complex from the Mononuclear Precursor... 

The 2 1 02 binding by tmpa and bpqa complexes may also be compared to that seen for peroxo-dicobalt(III) compounds derived from mononuclear precursors, where the molecularity of reaction is analogous. Thus, k is calculated... 

Table X lists examples of clusters in which a p3 group such as Ni(C5H5), Co(C5H5), Rh(C6HsMe), Co(CO)3, Ir(CO)3, Pt(PR3)2, Pt(CO)(PR3), or W(C5H5)(CO)2 caps a triangle of osmium atoms to which it is attached only by metal-metal bonds. Many are made by direct reaction of Os3H2(CO)10 with an appropriate mononuclear precursor, but less systematic routes are clearly also available. Two of the examples are paramagnetic.

In this case, the best results were obtained by precipitating the dinuclear metal complexes as the PF6 salts. Elemental analysis suggests, as already indicated above, that the products are isolated as sodium salts such as Na3[Ru(dcb)2(bpt)]-3H20 for the mononuclear precursor and Na3[Ru(dcb)2(bpt)0s(bpy)2](PF6)2-3H20 for the Ru-Os dyad. The number of sodium atoms incorporated is, however, not always the same but appears to depend on the manner in which the materials are precipitated. Nevertheless, the uncertainty in the composition of the compounds in the solid state does not affect the measurements, since in all cases the protonation state of the compounds in solution is controlled by the pH of the solutions. 

Molecularly or ionically dispersed metal carbonyl clusters on metal oxides have been prepared in high yields by reaction of metal carbonyl clusters with support surfaces or by syntheses on support surfaces from mononuclear precursors (Gates and Lamb, 1989 Iwasawa, 1993 Ichikawa, 1992 Gates, 1994). Synthesis of supported metal carbonyl clusters has been reviewed recently (Gates, 1995,1998), and only a few examples are included here. 

The binding situation in 1-methylcytosine blues is not clear, although there is strong indication that base deprotonation (hence N(3),N(4)-bridg-ing) is involved and that a blue (or actually purple ) product forms from the mononuclear precursor ds-[Pt(NH3)2(l-MeC-Af3)(OH)]+ (1-MeC = 1-methylcytosine) [80] (see also below). 

Both pyridine (pyr) and quinoline (quin) compounds are efficient cross-linking agents but not potent cytotoxic agents. Interstrand cross-linking is thus not by itself a sufficient requirement for cytotoxicity. These results were also of considerable interest because the mononuclear precursors were found to be similar in cytotoxicity to cisplatin itself, violating the classical structure-activity relationship of platinum compounds. Yet incorporation into the dinuclear structure did not produce active compounds ... 

Costes J. P. and Laurent J. P., Solution properties of dinuclear copper and nickel complexes and their mononuclear precursors, Inorg. Chim. Acta, 134 (1987) pp.245-248. 

The mononuclear precursor [Mn°(phen)2Cl2] has two cis arranged labile Cl ligands and, as such, is an appropriate building block for the preparation of squares or TBPs (Scheme 1). Nevertheless, the combination of this precursor with the mononuclear complex traK.y-[M° bpb)(CN)2] (M = Cr, Fe) resulted in the formation of the dinuclear compounds [Mn phen)2Cl] [M °(bpb)(CN)2] (71) (Fig. 7). Crystallization of the latter species from polar solvents used in the reaction is driven by electroneutrality of these complexes. 

Dunbar and co-workers (153) prepared a homologous series of isostructural neutral square complexes [(triphos)Co (CN)2]2[M Cl2] (Fig. 26) by combining the mononuclear precursor [(triphos)Co (CN)2j with dichlorides of the first-row transition metals (M = Mn, Co, Fe, Ni, Zn). An interesting aspect of these complexes is the rarely encountered combination of SP ions [in this case... 

The use of terminal CN functionalities represents an attractive means to extend the nuclearity of clusters. The pentanuclear TBP complexes described in Section II. D contain six dangling cyanide ligands (Fig. 37) that can be used for the attachment of additional metal ions. Mallah and co-workers (216) successfully employed this strategy by starting with the mononuclear precursors, [(i-Prtacn)Ni Cl2] and K3[Cr CN)6]. The product was precipitated by the addition of NaBPh4, and... 

The ID compound [TpFe VCN)3][Mn (dmf)2]2( X-OTs)2] o (147) (Fig. 80) provides yet another example of an extended structure derived from discrete cyanide-bridged clusters. In this compound, the OTs anions serve to connect the [TpFe (CN)3]2[Mn(dmf)4]2 squares into an infinite chain by forming bridges between the Mn(II) comers of the square. The material was obtained from mononuclear precursors, but the square [TpFe (CN)3]2[Mn (dmf)4]2 (OTf)2... 

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