4,5-Dicyanoimidazole

In the title tricyano-nitrile compound, C(8)H(5)N(5), the N-substituted cyano-ethyl group is offset to the imidazole ring [dihedral angle = 75.41 (15)°].

In this report, monolithic silica-based capillary columns were produced by the sol-gel process and subsequently silanized with gamma-glycidoxypropyltrimethoxysilane to form on the surface of the monolith a reactive gamma-glycidoxypropylsilyl sublayer to which an interactive top layer can be covalently attached. The interactive top layer consisted of either an immobilized lectin or polar cyano functions to perform lectin affinity chromatography (LAC) of glycoproteins or normal phase chromatography (NPC) of glycans, respectively. Two lectins were immobilized, namely Con A and wheat germ agglutinin (WGA) due to their utility in LAC of a wide range of glycoconjugates. On the other hand, 1H-imidazole-4,5-dicarbonitrile was covalently attached to the silica monolith to yield polar silica monolith referred to as 2CN-OH monolith. The two lectin monolithic columns were evaluated in Nano-LC with standard glycoproteins over a wide range of conditions and proved useful in capturing the glycoforms bearing the pertinent saccharidic motifs for interaction with the given lectin.

Crystal structures are reported for three substituted 1H-imidazole-4,5-dicarbonitrile compounds used as catalysts for the coupling reaction of nucleoside methyl phosphonamidites, namely 2-(3',5'-dimethylbiphenyl-2-yl)-1H-imidazole-4,5-dicarbonitrile, C19H14N4, (I), 2-(2',4',6'-trimethylbiphenyl-2-yl)-1H-imidazole-4,5-dicarbonitrile, C20H16N4, (II), and 2-[8-(3,5-dimethylphenyl)naphthalen-1-yl]-1H-imidazole-4,5-dicarbonitrile, C23H16N4, (III). The asymmetric unit of (I) contains two independent molecules with similar conformations. There is steric repulsion between the imidazole group and the terminal phenyl group in all three compounds, resulting in the nonplanarity of the molecules. The naphthalene group of (III) shows significant deviation from planarity. The C-N bond lengths in the imidazole rings range from 1.325 (2) to 1.377 (2) Å. The molecules are connected into zigzag chains by intermolecular N-H···N(imidazole) [for (I)] or N-H····N(cyano) [for (II) and (III)] hydrogen bonds.

Two polar ligands, namely 3-hydroxypropionitrile and 1H-imidazole-4,5-dicarbonitrile (IDCN) were covalently attached to epoxy-activated silica-based monolithic capillary columns via an epoxide ring-opening reaction to yield CN-OH-Monolith and 2CN-OH-Monolith, respectively. The silica monolith was prepared by a sol-gel process, and the resulting "rod-like" stationary phase was subjected to pore tailoring with an alkaline solution to convert small pore domains to mesopore domains, thus yielding a monolith with bimodal pore structure consisting of flow through pores (i.e., flow channels for mobile-phase flow) and mesopores that provide most of the adsorption capacity of the monolith toward the separated solutes. The two polar monoliths, CN-OH-Monolith and 2CN-OH-Monolith, were evaluated in normal-phase CEC with organic-rich mobile phases less polar than the stationary phase. The 2CN-OH-Monolith bearing more polar functions than the CN-OH-Monolith exhibited more retention and improved selectivity toward model polar solutes.