Metallomesogens

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

“…[1] On the other hand, metal atom clusters are versatile building blocks for the design of hybrid nanomaterials with potential applications, for instance,inthe fields of lighting,displays,and biolabeling technologies. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, propyl), were employed as co-ligands besides the other mesogenic ligands.R ecently,i th as been shown that the triphenylphosphine oxide core can be successfully used as ascaffold to obtain columnar liquid crystals that can interact easily with alkali metals to allow aswitch between columnar and cubic phases. [3] In the light of recent findings,q uantum yields of nanometer-sized octahedral clusters can reach values above 60 %.…”

“…[3] In the light of recent findings,q uantum yields of nanometer-sized octahedral clusters can reach values above 60 %. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, propyl), were employed as co-ligands besides the other mesogenic ligands.R ecently,i th as been shown that the triphenylphosphine oxide core can be successfully used as ascaffold to obtain columnar liquid crystals that can interact easily with alkali metals to allow aswitch between columnar and cubic phases. Combining such nanoobjects with liquid-crystalline ordering is achallenging task [5] and so far,s everal strategies based on covalent binding or ionic self-assembly (ISA) were successfully employed to induce liquid crystalline (LC) properties in systems containing bulky entities,s uch as fullerene [6] and polyoxometalates.…”

“…[7,8] On the other hand, phosphine or phosphine oxide ligands were scarcely used in the design of liquid-crystalline materials,mainly due to their inappropriate geometry concerning the molecular requirements to generate mesomorphic behavior. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, propyl), were employed as co-ligands besides the other mesogenic ligands.R ecently,i th as been shown that the triphenylphosphine oxide core can be successfully used as ascaffold to obtain columnar liquid crystals that can interact easily with alkali metals to allow aswitch between columnar and cubic phases. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, propyl), were employed as co-ligands besides the other mesogenic ligands.R ecently,i th as been shown that the triphenylphosphine oxide core can be successfully used as ascaffold to obtain columnar liquid crystals that can interact easily with alkali metals to allow aswitch between columnar and cubic phases.…”

From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores

“…[9] Moreover,e ven if they are widely used as ligands in coordination chemistry only few examples of phosphine-oxide-containing metallomesogens (metal-containing liquid crystals) are known. [10] Generally,o nly less bulky phosphines,s uch as trialkylphosphine (alkyl = methyl, ethyl, propyl), were employed as co-ligands besides the other mesogenic ligands.R ecently,i th as been shown that the triphenylphosphine oxide core can be successfully used as ascaffold to obtain columnar liquid crystals that can interact easily with alkali metals to allow aswitch between columnar and cubic phases. [11] In this Communication, we show that cholesteryl-and cyanobiphenyl-based phosphine oxide ligands constitute av aluable class of compounds that can be successfully used to design LC hybrid materials and in particular clustomesogens.B yu sing long flexible alkyl chains to link the mesogenic groups to the coordinating unit, we prove that it is possible to decouple the mesogenic entities motion from the bulky metallic (M 6 Cl i 8 ) 4+ cluster core within the [(M 6 Cl i 8 )L a 6 ] 4+ building blocks,further abbreviated as ML 1-4 (M = Mo and W).…”

Discotic Liquid Crystals Based on Cu(I) Complexes with Benzoylthiourea Derivatives Containing a Perfluoroalkyl Chain

“…Liquid crystalline compounds (LC) based on metal complexes (metallomesogens) represent a special class of liquid crystals with interesting properties related to metal ions employed, such as luminescence, magnetism, redox properties, and so on [1,2]. e unique properties of thermotropic liquid crystals, in particular their electrooptical properties [3][4][5][6][7], have led to various applications (LCD, molecular sensors and detectors, optical switches, spatial light modulator, etc.)…”