Hydrogen binding in coordination compounds of 3(5)-(4-methoxyphenyl)pyrazole

Trinuclear Diamagnetic Nickel(II) Complexes with Bridging 3‐Arylpyrazolato Ligands

“…A few years ago, we investigated the coordination chemistry of 3(5)‐aryl‐functionalized pyrazoles with a special focus on hydrogen‐bond interactions between the pyrazole N–H unit and other ligands in the coordination sphere of a series of transition‐metal sites 12. With Ni(ClO 4 ) 2 (H 2 O) 6 , a very stable hexacoordinate complex was obtained wherein four 3‐arylpyrazole ligands attached to the nickel(II) center pairwise are hydrogen bonded to the trans ‐coordinated perchlorate anions.…”

Ruthenium Complexes Bearing N–H Acidic Pyrazole Ligands

“…Both pyrazole rings act as proton‐donating (N1) and ‐accepting (N2) sites for intermolecular hydrogen bonds. This results in the formation of a complex three‐dimensional network structure, wherein pyrazole tetramers3,9d,10 are involved as the linking centres (Figure 1, centre). The network contains three‐dimensional pores, filled by the butyl chains.…”

“…Coordination of these ligands brings this NH group in close proximity to the metal site, and it becomes even more acidic due to the coordination of the Lewis‐acidic metal site to the pyrazole moiety. We recently could show that such a coordination motif provides a proton donor site for the formation of strong hydrogen bonds 3. This effect should also be beneficial for an improved catalyst–substrate interaction according to the metal–ligand‐bifunctional hydrogenation pathway (Scheme ).…”

From a Simple Pyrazole‐Derived 1,2‐Amino Alcohol to Mono‐ and Multinuclear Complexes by Tailoring Hydrogen Bond Patterns

“…A similar behaviour was previously observed for the dichlorocobalt(II) and dichloronickel(II) complexes of 3 (5)-(4-methoxyphenyl)pyrazole. [18] In the following section, the solid-state structure of the cobalt(II) complex 6 (Figure 4) shall be discussed; the structural data of the nickel(II) complex 7 can be found in the Supporting Information. [12] The blue colour of crystalline 6 is typical for tetrahedrally coordinated cobalt(II) sites, such as Co2.…”