Studies on dehydration and thermal decomposition of Tris(2,2′-Bipyridyl) ruthenium(II) chloride and sulphate

Unusual Frequency Dispersion Effects of the Nonlinear Optical Response in Highly Conjugated (Polypyridyl)metal−(Porphinato)zinc(II) Chromophores

“…TGA−DTA studies indicate that T d for Ru-PZn exceeds 325 °C, consistent with literature precedent (see refs and ).…”

“…Figure highlights a series of bis- and tris(chromophoric) supermolecules consisting of (porphinato)zinc(II) [P(Zn)], Ru(tpy) 2 , and Os(tpy) 2 units in which an ethynyl moiety bridges the meso -macrocycle and 4‘-terpyridyl positions. These species were synthesized from porphyrinic and terpyridyl precursor molecules bearing either ethynyl or bromo functional groups via metal-catalyzed cross-coupling reactions. ,− Key design elements of these species exploit the facts that (1) ruthenium polypyridyl compounds possess significant optical nonlinearities, outstanding thermal stabilities, − and electronically excited states characterized by multidirectional metal-to-ligand charge transfer (MLCT); (2) appropriate polypyridyl ethyne derivatization gives rise to a singly degenerate, low-energy electronically excited CT state; and (3) coupling such an ethynylated metal polypyridyl moiety to a PZn meso -carbon position enforces a head-to-tail alignment of the corresponding transition dipoles of the two chromophoric entities, ,− ,, ,, defining a supermolecular structure having an initially prepared singly degenerate excited state polarized along this vector.

1 Comparative electronic absorption spectra of (A) Ru-PZn, Os-PZn; (B) Ru-PZn-A, Os-PZn-A; and (C) Ru-PZn-Os, D-PZn-A.

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“…In summary, this work highlights that: (i) Coupled oscillator photophysics and metal-mediated cross-coupling can be exploited to elaborate high β 0 supermolecules. (ii) High-stability metal polypyridyl compounds constitute an attractive alternative to electron releasing dialkyl- and diaryl-amino groups, the most commonly used donor moieties in a wide range of established NLO dyes and long recognized to be the moiety that often limits dye thermal stability. −, (iii) Given the NLO response highlighted by Ru-PZn and the fact that its β λ value determined at 1300 nm exceeds by a factor of 2.5 that determined for any other chromophore at this energy, this design strategy clearly enables ready elaboration of extraordinarily large β λ chromophores at telecommunication-relevant wavelengths. (iv) An important new effect has been delineated in this series of compounds, namely that B - and Q -state-derived β 0 values can be designed to have the same or opposite sign; because the sign of the resonance enhancement factor is frequency dependent, appropriate engineering of the relative contributions of these CT states at a given wavelength provides a new means to regulate the magnitude of dynamic hyperpolarizabilities and, thus, may enable the development of novel materials with enhanced and more selective electrooptic and NLO properties.…”