Synthesis and Spectroscopic and Electronic Characterization of New Cis-Configured Di- to Multiplatinum Alkynyls

Abstract

Utilization of Sonogashira coupling reactions with cis-[Pt(dppe)Cl2] and varying amounts of the alkynyl ligands HC⋮CRC⋮CH (where R = p -C6H4, p -C6H4-p -C6H4) afford the monoplatinum complexes cis-[Pt(dppe)(C⋮CRC⋮CH)2] (R = p -C6H4 (1a), p -C6H4-p -C6H4 (1b)), the diplatinum complexes cis-[(HC⋮CRC⋮C)Pt(dppe)(C⋮CRC⋮C)Pt(dppe)(C⋮CRC⋮CH)] (R = p -C6H4 (2a), p -C6H4-p -C6H4 (2b)), the triplatinum complexes cis-[(HC⋮CRC⋮C)Pt(dppe)(C⋮CRC⋮C)Pt(dppe)(C⋮CRC⋮C)Pt(dppe)(C⋮CRC⋮CH)] (R = p -C6H4 (3a), p -C6H4-p -C6H4 (3b)), and the respective oligomeric species 4a,b, all in reasonable yields. X-ray diffraction studies of 2a reveal the presence of two independent diplatinum molecules in the asymmetric unit, each with C i symmetry. All the complexes have been fully characterized by NMR and mass spectrometry, and GPC analysis of 4a,b indicate their oligomeric nature, with a degree of polymerization of ca. 4. Electronic spectral studies indicate that the optical band gap decreases with increasing chain length but that the intensity of the triplet state emission increases with the number of repeating units. As expected, there is less effective π-conjugation along the chain in the cis configuration as compared to the analogous trans-oriented species.

Organometallic Complexes for Nonlinear Optics. 42. Syntheses, Linear, and Nonlinear Optical Properties of Ligated Metal-Functionalized Oligo(p-phenyleneethynylene)s

“…14, 2009 6535 mixed valence states, and such complexes have been examined for molecular electronics and liquid crystal applications. 16,17 Despite this interest, the physical properties of well-defined series of systematically varied metal-terminated OPEs are yet to be explored; although there have been a large number of reports of ligated-metal-capped 1,4-diethynylarenes (A, Chart 1), and their corresponding polymers (in which the ligated metals are in the repeat units: B, Chart 1), [43][44][45][46][47][48][49][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] there are considerably fewer reports of well-characterized "dimers" (C, Chart 1) [50][51][52]64,[67][68][69][70][71] or well-defined higher oligomers. Noteworthy series of the latter include (PhCtC){Pt-( PBu n 3 ) 2 (CtC-4-C 6 H 4 CtC)} n Pt(PBu n 3 ) 2 (CtCPh) (n=1-4, 6) from Schanze and co-workers 72,73 74 Excluding the "monomer" case (A, Chart 1), the literature for metal termination of OPEs is sparse, specific examples being (triphenylphosphine)gold and cluster-capped tri(phenyleneethynylene) 75 (D, Chart 1) and platinum-tri(aryleneethynylene) polymers (E, Chart 1).…”

Dual ligand-based fluorescence and phosphorescence emission at room temperature from platinum thioxanthonyl complexes

“…[46][47][48][49][50][51] Particularly abundant are trans-bis(alkynyl)bis-(trialkylphosphine)platinum(II) complexes trans-Pt (CuCR) 2 (PR 3 ) 2 . 52,53 Such complexes have, for example been used as constituents of luminescent coordination oligomers and polymers featuring platinum atoms in the conjugated main chain [54][55][56][57][58][59][60][61][62][63] or for two-photon absorption (TPA). 64 Other representatives have organic dyes as the substituents at the alkynyl ligands.…”

Trace amount CuII(ppm) and mixture design of CuII/PdIIcatalyzed Suzuki cross-coupling reactions based on the cooperative interaction of metal with a conjugated pyridylspirobifluorene

“…S14 †), which could result from the Cu(II)psf coordination interaction, probably along with some d(Cu 2+ ) / p*(pyridyl) MLCT (metal-to-ligand charge transfer) character. 26,27 Upon adding lm layers, Cu 2+ ion deposition resulted in the absorbance increase. The absorbance increases were close to linear with R 2 ¼ 0.9803 between the optical absorption at l max ¼ 345 nm and the number of bilayers, suggesting that the psf ligands were incorporated into the multilayer lms PEI-(Cu 2+ /psf) n for the rst ten layers.…”