Trinuclear ruthenium dendrons based on bridging PHEHAT and TPAC ligands

Abstract

Novel polynuclear compounds, the trinuclear precursor complex cis-{[(phen)(2)Ru(PHEHAT)](2)Ru(CH(3)CN)(2)}(6+) 4 and the trinuclear TPAC (tetrapyrido[3,2-a:2',3'-c:3'',2'-h:2''',3'''-j]acridine) complex {[(phen)(2)Ru(PHEHAT)](2)Ru(TPAC)}(6+) 5 have been prepared. Their electrochemistry and photophysics indicate that the (3)MLCT (metal to ligand charge transfer) emissions involve the external {Ru(PHEHAT)} moieties for both complexes and there is no spectro-electrochemical correlation. The trinuclear dendron with the TPAC ligand represents a key compound for future constructions of much larger species thanks to the TPAC that could bridge another polynuclear precursor. For decreasing the length of preparation of these compounds, microwave assisted syntheses have been tested and used not only for the targeted complexes but also for the precursors ((phen)(2)RuCl(2), {(phen)(2)Ru(phendione)}(2+), {(phen)(2)Ru(PHEHAT)}(2+) (PHEHAT = 1,10-phenanthrolino[5,6-b]1,4,5,8,9,12-hexaazatriphenylene), (DMSO)(4)RuCl(2)), and for the bridging TPAC ligand itself. The microwave method allows a drastic decrease of the preparation times, especially in the case of the TPAC, from 8 days to 60 min.

Fundamental Factors Impacting the Stability of Phosphonate-Derivatized Ruthenium Polypyridyl Sensitizers Adsorbed on Metal Oxide Surfaces

“…The following ligands were prepared according to literature methods: 5,5′-dimethoxy-2,2′-bipyridine, 2,2′-bipyrazine, 4,4′-dibromo-2,2′-bipyridine, 4,4′-trifluoromethyl-2,2′-bipyridine, 2,2′-bipyridine-4,4′-diphosphonic acid, , and 2,2′-bipyridine-4,4′-dimethylenephosphonic acid . The following complexes we prepared according to literature methods: poly-Ru­(1,4-cyclooctadiene)­Cl 2 , [Ru­(phen) 2 Cl 2 ], Ru­(MeObpy)­(bz)­(Cl)]·Cl, [Ru­(bpz) 2 Cl 2 ] RuP , RuP 2 , RuP 3 , RuCP , RuCP 2 , RuCP 3 , RuP4Me , RuP5Me , RuP4OMe , RuP t Bubpy , RuPBr , and RuPCF 3 . See Figure for associated structures.…”

Large π‐Conjugated Chromophores Derived from Tetrathiafulvalene

“…Unless otherwise stated, all reagents were purchased from commercial sources and used without additional purification. The precursors Ru-A C H T U N G T R E N N U N G (phen) 2 Cl 2 [13] and 2- [5,6-diamino-4,7-bis(4-pentylphenoxy)-1,3-benzodithiol-2-ylidene]-4,7-bis(4-pentylphenoxy)-1,3-benzodithiole-5,6-diamine (1) [8] were prepared according to the literature procedures. 1 H NMR spectra were recorded at 300 MHz.…”

Pyridoacridines in the 21st Century

“…Reaction of 5‐amino‐1,10‐phenanthroline 208 with formaldehyde and acid produced the tetrapyrido[3,2‐ a :2′,3′‐ c :3′′,2′′‐ h :2′′′,3′′′‐ j ]acridine 209 subsequently designated “tpac” (Scheme ) . The use of microwave heating reduced the synthesis reaction time from a week to 60 minutes – 70 % yield . The extended polycyclic bis‐phenanthroline ligand led to the use of tpac in the formation of several metal complexes, in a monodentate or bidentate fashion (see below).…”

“…[129] The use of microwave heating reduced the synthesis reaction time from a week to 60 minutes -70 % yield. [130] The extended polycyclic bis-phenanthroline ligand led to the use of tpac in the formation of several metal complexes, in a monodentate or bidentate fashion (see below). Note: the structure of tpac comprises two pyrido[3,2-a]acridine units and also two pyrido[2,3-c]acridine units.…”