Square-planar rhodium(I) complexes with aromatic bent terdentate nitrogen ligands as candidates for rod-like extended materials †

Abstract

The crystal structure of 2,6-bis(1-methylbenzimidazol-2-yl)pyridine (L 4 ) evidenced a quasi trans-trans conformation of the unsubstituted nitrogen atoms of the aromatic rings which is maintained in solution on the NMR timescale. Reactions of L 4, or of its lipophilic analogue 2,6-bisrevealed that the terdentate aromatic unit adopts a distorted trans-trans conformation and acts as a bridging ligand connecting two [Rh(NBD)Cl] units through the nitrogen atoms of the benzimidazole side arms. Solution studies (ES-MS, NMR) indicate that (i) the dimetallic structure is maintained in solution, (ii) the complicated fluxional behaviour observed at room temperature is blocked at 210 K on the NMR timescale and (iii) the bent aromatic core cannot act as a meridional terdentate chelate toward Rh I . The consequences of this co-ordination behaviour on the molecular anisometry of extended complexes is discussed.

Synthesis, Characterization, and Pharmacological Evaluation of Silicon-Containing Aminoquinoline Organometallic Complexes As Antiplasmodial, Antitumor, and Antimycobacterial Agents

“…The molecular structure confirms that the planar aminoquinoline motif coordinates to the metal center through the quinoline nitrogen in a monodentate manner. The geometrical parameters around the rhodium atom are comparable to those found in analogous reported mononuclear Rh(I)-cyclooctadienyl complexes. , Complex 11 crystallizes with a monoclinic system.…”

Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near‐Infrared Luminescence

“…Am ore successful approach used double Stille-type cross-coupling reactions between 2,6-dibromopyridine 15 [36] and stannylated 5-methylpyridine 11 [37] and 5-ethylpyridine 14 (Scheme 4). [38] As observed previously in the crystal structures of L4 [39] and L7, [40] the three connected heterocyclicu nits in L5-L6 and L8-L9 adopt pseudo-twofold transoid-transoid arrangements of the nitrogen donor atoms (Figure 1, and Ta bles S1-S13 and Figure S1 in the SupportingI nformation). Variable interplanar angles between the connected aromatic heterocycles (7.2 w 42.88)r esult from specific intermolecular inter-aromatic packing interactions observed in the crystals ( Figure S2, Supporting Information).…”

“…As observed previously in the crystal structures of L4 and L7 , the three connected heterocyclic units in L5 – L6 and L8 – L9 adopt pseudo‐twofold transoid – transoid arrangements of the nitrogen donor atoms (Figure , and Tables S1–S13 and Figure S1 in the Supporting Information). Variable interplanar angles between the connected aromatic heterocycles (7.2≤ ω ≤42.8°) result from specific intermolecular inter‐aromatic packing interactions observed in the crystals (Figure S2, Supporting Information).…”

Introducing Bulky Functional Lanthanide Cores into Thermotropic Metallomesogens: A Bottom‐Up Approach

“…The domain of existence of the mesophase thus shrinks, and we did not observe LC behavior for the complexes [Ln(Lk)(NO 3 ) 3 ] (k = 5,7,8,14). [17,18,25,26] …”