Biimidazole

Biimidazole and bibenzimidazole with [(ri -2-RC3H )Pd(p-Cl)]2 (R = H, Me) taken in the 2 1 molar ratio in the presence of methanolic potassium hydroxide give complexes of the type 146 (83JCS(D)1729) and with [(ti -2-RC3H ) Pd(Mc2C0) ](C10 ) - 147. When the ratio of 2,2 -biimidazole or 2,2 -bibenz-imidazole and [(Ti -2-RC3H )Pd(p-Cl)]2 (R = H, Me) is 1 1, the homo-tetranuclear species 148 result. Heterotetranuclear palladium(II)-rhodium(I) complexes 149 (L2 = cod) follow from [(TiLcod)Rh(Hbim)] and [(ri -2-R-C3H )Pd(acac)]. They are readily carbonylated with complete substitution of... 

AyV -Carbonyl-2,2 -biimidazole (A V7-carbonyl-2,2 -biimidazyl) prepared from 2,2 -biimidazole and phosgene is relatively unreactive on hydrolysis, and shows reduced reactivity in reactions with carboxylic acids.[19],[2]... 

The synthesis of (80) from [Ircp Cl2]2 and 2,2 -biimidazole has been detailed.119 The X-ray structure of (80) shows the expected three-legged piano-stool arrangement round the Ir center. 

In the homodinuclear complex [ Pd(dppp) 2(//-biim)](OTf)2 (dppp = bis(diphenylphosphino)-propane, biim = 2,2 -biimidazole, 0Tf=0S02CF3) a biim2 ligand spans the two palladium(II) centers.535... 

The biphenyl ligand functionalized with two imidazoles (6) was used to produce distorted tetrahedral complexes of zinc.119 2,2 -Biimidazole can act as a bidentate ligand coordinating to one zinc ion (7) or as a bridging ligand in the formation of dimeric species (8) with X-ray structures of both binding motifs.120... 

Dinitroazetidine salts were studied as explosives nitrate, dinitroimidate, 2,4-dinitroimidazolate, 4,4, 5.5 -tctranitro-2.2 -biimidazolate, 5-nitro-l,2,4-triazolonate... 

Replacement of both pyridine rings of bipyridine by imidazole has a much greater effect than replacement by thiazole and the [Fe N6]2+ derivative of 2,2 -biimidazole 34 (Dq(Ni2+)=1080 cm-1) is purely high spin [41]. The spin-crossover behaviour of tris(2,2/-bi-imidazoline)iron(II) salts seems somewhat unexpected in light of this and the relatively low a-donor power as indicated by the small Dq(Ni2+) value (1030 cm-1) for 36. 

Muetterties has suggested that the dimeric hydride [RhH(P OiPr 3)2]2 catalyzes alkene and alkyne hydrogenation via dinuclear intermediates [91]. However, no kinetic evidence has been reported to prove the integrity of the catalysts during the reactions. On the other hand, studies of the kinetics of the hydrogenation of cyclohexene catalyzed by the heterodinuclear complexes [H(CO) (PPh3)2Ru((u-bim)M(diene)] (M = Rh, Ir bim=2,2 -biimidazolate) suggested that the full catalytic cycle involves dinuclear intermediates [92]. 

Whereas the synthesis of 2,2 -biimidazoles has been very well developed, that of 4,4 -biimidazoles has not. Pyne et al. revealed that the Pd(0)-catalyzed homocoupling of 4-iodo-l-(triphenylmethyl)imidazole (5a) or its 2-methyl analog 5b delivered the 4,4 -biimidazoles 6a and 6b, respectively [6],... 

The Ni(II) complex of a 16-membered macrocycle, 2,7-dimethyl-3,6 -(1,1 - (2,2 - biimidazole) -1,3,6,8,11,14 - hexaazacyclohexadeca -1,7 -diene, 22, was synthesized by Schiff base condensation of the Ni(II)-triethylenetetramine complex and 1,1 -diacetyl-2,2 -bisimidazole (29). The Ni(II) complex formed square-planar geometry with iodide or perchlorate anions and an octahedral structure with chloro or bromo ligands. 

Dihydro-5-isonitro-4,-methyl-4-methylene-1,1, 5 -trinitro-2,2 -biimidazole Methyl Ester or 4-Methyf-4,-methylene-1,1l,5I-trinitro-2,2 -biimidazole-5 -nitronic Acid Methyl Ester,... 

---