Silver pyrazolates as coordination-polymer luminescent metallomesogens.
Silver pyrazolates with columnar liquid-crystal phases that are stable at room temperature have been prepared by reaction of silver nitrate with 3,5-diarylpyrazolates. The complexes consist of open-chain oligomers, despite the fact that the most common structural type for homoleptic coinage metal pyrazolates is the trimeric metallacycle [M(μ-pz)](3). The special characteristics of silver in forming reversible metal-ligand bonds in solution, evidenced experimentally, leads to supramolecular organizations in which the silver cations promote self-organization of the nonmesomorphic pyrazolates into helical 1D polymers that exhibit columnar mesophases. The materials are readily soluble in common organic solvents and are liquid-crystalline over a broader temperature range than their gold counterparts, which are known to form discrete cyclic trinuclear species. Thin films of the silver complexes show luminescence at room temperature. The compounds described here are the first examples of luminescent metallomesogens formed by a main-chain coordination polymer.
Department of Organic Chemistry, Facultad de Ciencias, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza, CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
Joaquín
J
Barberá
Ignacio
I
Lantero
Sandra
S
Moyano
José Luis
JL
Serrano
Anabel
A
Elduque
Raquel
R
Giménez
D050866:Liquid Crystals; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013696:Temperature
D009942:Organometallic Compounds; D011108:Polymers; D011720:Pyrazoles; D012834:Silver