The synthesis and structural, photophysical, electrochemical, and electroluminescent properties of a class of platinum(II) complexes bearing sigma-alkynyl ancillary ligands, namely [(C/N/N)Pt(C[triple bond]C]nR] [H(C/N/N) = 6-aryl-2,2'-bipyridine; n = 1-4; R = aryl, alkyl, or trimethylsilyl], have been studied. Substituents with different steric and electronic properties were introduced into the tridentate cyclometalating and arylacetylide ligands, and the pi-conjugation length of the oligoynyl moiety was homologously extended from ethynyl to octatetraynyl. The X-ray crystal structures of several derivatives confirm the Pt-(CC) ligation and reveal various intermolecular interactions, such as pi-pi, Pt...Pt, and C-H...F-C. The complexes display good thermal stability and intense phosphorescence in fluid and glassy solutions with high quantum yields and microsecond lifetimes. Their emission energies are sensitive to solvent polarity, the electronic affinities of the substituents on both the cyclometalating and arylacetylide groups, and the length of the oligoynyl ligand. By choosing appropriate cyclometalating and sigma-alkynyl ligands, the emission color of this class of platinum(II) complexes can be tuned from green-yellow to saturated red. In addition to (3)MLCT [Pt(5d) --> pi*(C/N/N)] and (3)IL(C/N/N), intriguing (3)IL(alkynyl) excited states localized on -(C[triple bond]C)(4)- and -(C[triple bond]Cpyrenyl-1) moieties that afford narrow-bandwidth emissions have been observed. Selected Pt(II) complexes were doped into the emissive region of multilayer, vapor-deposited organic light-emitting diodes. The tunable electrophosphorescence energy resembles that recorded in fluid solutions for these emitters, and the devices exhibit high luminance and efficiencies (up to 4.2 cd A(-1)).

The synthesis and structural, spectroscopic, and electrochemical properties of a series of trinuclear tridentate cyclometalated platinum(II) complexes tethered by bis(diphenylphosphinomethyl)phenylphosphine (dpmp) have been studied and compared with their mono- and binuclear homologues and a propeller-like congener. The X-ray crystal structures of several derivatives show the presence of a variety of intramolecular Pt.Pt, pi-pi, and C-H...O(crown ether) and intermolecular pi-pi interactions. The trinuclear complexes display strong absorption in the 400-600 nm region and show intense red to near-infrared phosphorescence with microsecond lifetimes in fluid and glassy solutions and in the solid state. These emissions are generally assigned as (3)MMLCT [dsigma-->pi(CNN)] in nature. The close similarities between the emission energies in acetonitrile solution and in the solid state at 298 K indicate that comparable Pt.Pt and pi-pi configurations are maintained in both media, and hence a relationship between the photophysical behavior of these lumophores and their solid-state structural features is proposed. The tendencies of the absorption and emission energies to red-shift from mono- to linearly tethered bi- and trinuclear Pt(II) species are evident. A light-emitting electrochemical cell using a trinuclear Pt(II) derivative as emitter has been demonstrated.

A series of mono-and multinuclear dicyclometalated platinum(II) complexes, namely, [Pt-(C ∧ N ∧ C)L 1 ] [HC ∧ N ∧ CH ) 2,6-diphenylpyridine; L 1 ) 4-tert-butylpyridine (1), 1-methyl-4,4′bipyridinium (MQ + ) hexafluorophosphate (2(PF 6 )), 2,6-dimethylphenylisocyanide (4), tricyclohexylphosphine (5), triphenylphosphine ( 7) pyrazine (pyr; 3), bis(dicyclohexylphosphino)methane (dcpm; 6), bis(diphenylphosphino)methane (dppm; 8)], and [Pt 3 (C ∧ N ∧ C) 3 (µ 3 -dpmp)] [dpmp ) bis(diphenylphosphinomethyl)phenylphosphine (9)], were synthesized from [Pt(C ∧ N ∧ C)dmso] (dmso ) dimethyl sulfoxide). The X-ray crystal structures of 1, 3‚CHCl 3 , 4, 6‚CHCl 3 ‚CH 3 OH‚4H 2 O, 7, 8 (yellow form), and 8‚CHCl 3 (orange form) have been determined. For complex 1, the Pt(C ∧ N ∧ C) units are oriented into pairs in a head-to-tail fashion with an interplanar separation of 3.40 Å. For complex 4, dimeric π-π overlap between Pt(C ∧ N ∧ C) and phenyl moieties in a head-to-tail manner is observed, with interplanar stacking at 3.39 Å. There are two crystal forms for complex 8. Only one intramolecular Pt(C ∧ N ∧ C)-phenyl π-π interaction (separation 3.381 Å) is apparent in the yellow form. For the orange form (8‚CHCl 3 ), there are two intramolecular Pt(C ∧ N ∧ C)-phenyl π-π contacts (separations 3.115 and 3.287 Å). For 3‚CHCl 3 , the dihedral angles between the pyrazine and the two Pt(C ∧ N ∧ C) planes are 124.0°and 130.5°, which allows the possibility for partial orbital interaction between the (5d)Pt and pπ*(pyrazine) orbitals. Complexes 1 and 4-9 display vibronically structured emission (λ max of most intense band ) 508-526 nm) in 77 K methanol/ethanol (1:5, v/v) glass, which are assigned to 3 IL excited states. For 1, 4-6, 8, and 9, the 77 K structureless emission at λ max 596-636 nm in methanol/ethanol glasses is assigned as ππ* excimeric in nature. These excimeric emissions are concentrationdependent for 1 and 4-6 and concentration-independent for 8 and 9. The 298 K solid emission spectra of 1, 4-6, 8, and 9 are characterized by a broad, unstructured band at λ max 566-633 nm, which red-shift in energy upon cooling to 77 K. These bands are comparable in energy to the 77 K glassy emissions and are similarly assigned. Complexes 2 and 3 show an intense absorption at λ max 410 (shoulder) and 456 nm, which are ascribed to the MLCT (5d)Pt f π*(1-methyl-4,4′-bipyridinium/pyrazine) transition, respectively. Likewise, the solid-state emissions of 2 and 3 at λ max 686 and 658 nm, respectively, are assigned as MLCT. The vapochromism of complex 8 has been investigated.

Polycondensation via direct C–H arylation of thiophene derivatives gave thiophene- and bithiophene-based alternating copolymers in good yields. The optimization of the reaction conditions was investigated in terms of a catalytic system and reaction time. Under optimized conditions, the polycondensation reaction of 3,3′,4,4′-tetramethylbithiophene with 2,7-dibromo-9,9-dioctylfluorene gave poly[2,7-(9,9-dioctylfluorene)-alt-5,5′-(3,3′,4,4′-tetramethyl-2,2′-bithiophene)] with a molecular weight of 31 800 in 91% yield. The polycondensation reaction proceeded with 2 mol % of Pd(OAc)2 without the addition of a phosphine ligand in a short reaction time (3 h). Six kinds of π-conjugated polymers were synthesized by the polycondensation reaction without the use of bifunctional organometallic reagents as monomers.

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Ion desorption efficiency and internal energy transfer were probed and correlated in carbon-based surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using benzylpyridinium (BP) salt as the thermometer chemical. In a SALDI-MS experiment with a N(2) laser (at 337 nm) used as the excitation light source and with multiwalled carbon nanotubes (CNT), buckminsterfullerene (C(60)), nanoporous graphitic carbon (PGC), non-porous graphite particles (G), highly oriented pyrolytic graphite (HOPG), or nanodiamonds (ND) as the SALDI substrate, both the desorption efficiency in terms of ion intensity of BP and the extent of internal energy transfer to the ions are dependent on the type and size of the carbon substrates. The desorption efficiency (CNT approximately C(60) > PGC > G > HOPG > ND) in general exhibits an opposite trend to the extent of internal energy transfer (CNT < C(60) approximately PGC < G approximately HOPG < ND), suggesting that increasing the extent of internal energy transfer in the SALDI process may not enhance the ion desorption efficiency. This phenomenon cannot be explained by a thermal desorption mechanism, and a non-thermal desorption mechanism is proposed to be involved in the SALDI process. The morphological change of the substrates after the laser irradiation and the high initial velocities of BP ions (1100-1400 ms(-1)) desorbed from the various carbon substrates suggest that phase transition/destruction of substrates is involved in the desorption process. Weaker bonding/interaction and/or a lower melting point of the carbon substrates favor the phase transition/destruction of the SALDI substrates upon laser irradiation, consequently affecting the ion desorption efficiency.

Alternating conjugated polymers of ethylenedioxythiophene and fluorene are prepared using three different synthetic methods to investigate the effects of these synthetic methods on the purity, field‐effect transistor (FET) performance, and organic photovoltaic (OPV) performance of the polymer. In this study, microwave‐assisted direct arylation polycondensation is used to obtain a high‐purity, high‐molecular‐weight (147 kDa) polymer. This pure polymer exhibits a high FET hole mobility of 1.2 × 10−3 cm2 V−1 s−1 and high OPV performance with a power conversion efficiency of 4%, even though the polymer forms an amorphous film, which absorbs in a limited region of the spectrum.

Latent fingerprint (LFP) detection is a top-priority task in forensic science. It is a simple and effective means for the identification of individuals. Development of nanomaterials which maximize the surface interaction with endogenous substances on the ridges to enhance the contrast of the fingerprints is an important application of nanotechnology in LFP detection. However, most developments in this area have mainly focused on the visualization of the physical pattern of the fingerprints and failed to explore the molecular information embedded in LFPs. Here, we have integrated certain distinctive properties of gold nanoparticles (AuNPs) with imaging mass spectrometry for both the visualization and molecular imaging of LFPs. Two contrasting colors (blue and pink), arising from different surface plasmon resonance (SPR) bands of the AuNPs, reveal the optical images of LFPs. The laser desorption/ionization property of the AuNPs allows the direct analysis of endogenous and exogenous compounds embedded in LFPs and imaging their distributions without disturbing the fingerprint patterns. The simultaneous visualization of LFP and the recording of its molecular images not only provide evidence on individual identity but also resolve overlapping fingerprints and detect hazardous substances.