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Colloidal COF-300 synthesis with substituted benzoic acid catalysts demonstrates that acidity plays a role in reaction kinetics and the resulting particle's colloidal stability.

Platinum(II) compounds were synthesized with both chelate cyclometalated ligands and chelate diphosphine ligands. The cyclometalated ligands include phenylpyridine and a benzothiophene-containing ligand. The three new benzothiophene compounds were characterized by nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HR-MS), and photophysical measurements. In the case of one compound, L1-DPPM, the structure was determined by single crystal X-ray diffraction. The structural coherence of the noncrystalline emissive solid state was measured by X-ray total scattering real space pair distribution function analysis. Quantum yield values of all of the platinum compounds measured in the solid state and in PMMA films were much greater than in solution.

A library of thio- and selenourea derivatives is used to adjust the kinetics of PbE (E = S, Se) nanocrystal formation across a 1000-fold range (kr = 10−1 to 10−4 s−1), at several temperatures (80–120 °C), under a standard set of conditions (Pb[thin space (1/6-em)]:[thin space (1/6-em)]E = 1.2[thin space (1/6-em)]:[thin space (1/6-em)]1, [Pb(oleate)2] = 10.8 mM, [chalcogenourea] = 9.0 mM). An induction delay (tind) is observed prior to the onset of nanocrystal absorption during which PbE solute is observed using in situ X-ray total scattering. Density functional theory models fit to the X-ray pair distribution function (PDF) support a Pb2(μ2-S)2(Pb(O2CR)2)2 structure. Absorption spectra of aliquots reveal a continuous increase in the number of nanocrystals over more than half of the total reaction time at low temperatures. A strong correlation between the width of the nucleation phase and reaction temperature is observed that does not correlate with the polydispersity. These findings are antithetical to the critical concentration dependence of nucleation that underpins the La Mer hypothesis and demonstrates that the duration of the nucleation period has a minor influence on the size distribution. The results can be explained by growth kinetics that are size dependent, more rapid at high temperature, and self limiting at low temperatures.

Primary amines and benzothiophene-3-carboxaldehyde were reacted to give four large, bulky imine ligands. These imine ligands were reacted with a tetramethyl platinum dimer and by heteroatom-assisted C–H activation, both monometalated compounds and bismetalated compounds were synthesized. In all cases, five-membered platinacycles were formed. The compounds were characterized by NMR spectroscopy, and one bismetalated compound was characterized by single-crystal X-ray diffraction. The UV–vis absorption and emission spectra and the excited-state lifetimes were recorded for these complexes. Density functional theory (DFT) and time-dependent-DFT calculations were performed to aid in the assignment of the absorption and emission spectra of the newly synthesized complexes.

Benzothiophene-based ligands containing quinoline or pyridine moieties were synthesized through Suzuki Coupling reactions and subsequently reacted with the binuclear Platinum compound, [Pt2Me4 (μ-SMe2)2], PtA, in order to study chelate-assisted C H activation. The preparation and characterization of CˆN cyclometalated products, including η2 intermediates, monometalated, and bismetalated species, are reported. The photophysical properties of the complexes were studied and compared to TD-DFT computational results.

Thermolysis of a pair of dibenzo-7-phosphanorbornadiene compounds is shown to lead to differing behaviors: phosphinidene sulfide release and formation of amorphous P2S. These compounds, tBuP(S)A (1, A = C14H10 or anthracene; 59% isol. yield) and HP(S)A (2; 63%), are available through thionation of tBuPA and the new secondary phosphine HPA (5), prepared from Me2NPA and DIBAL-H in 50% yield. Phosphinidene sulfide [ tBuP═S] transfer is shown to proceed efficiently from 1 to 2,3-dimethyl-1,3-butadiene to form Diels-Alder product 3 with a zero-order dependence on diene. Platinum complex (Ph3P)2Pt(η2- tBuPS) (4, 47%) is also accessed from 1 and structurally characterized. In contrast, heating parent species 2 (3 h, 135 °C) under vacuum instead produces an insoluble, nonvolatile yellow residual material 6 of composition P2S that displays semiconductor properties with an optical band gap of 2.4 eV. Material 6 obtained in this manner from molecular precursor 2 is in a poorly characterized portion of the phosphorus-sulfur phase diagram and has therefore been subjected to a range of spectroscopic techniques to gain structural insight. X-ray spectroscopic and diffraction techniques, including Raman, XANES, EXAFS, and PDF, reveal 6 to have similarities with related compounds including P4S3, Hittorf's violet phosphorus. Various possible structures have been explored as well using quantum chemical calculations under the constraint that each phosphorus atom is trivalent with no terminal sulfide groups, and each sulfur atom is divalent. The structural conclusions are supported by data from phosphorus-31 magic angle spinning (MAS) solid state NMR spectroscopy, bolstering the structural comparisons to other phosphorus-sulfur systems while excluding the formulation of P2S as a simple mixture of P4S3 and phosphorus.

Thermolysis of a pair of dibenzo-7-phosphanorbornadiene compounds is shown to lead to differing behaviors: phosphinidene sulfide release and formation of amorphous P

Imine N^N^C-type pincer ligands were reacted with palladium(II) acetate and palladium(0) bis(dibenzylideneacetone) and the regioselective C–H and C–X activation was studied. C–X bonds that formed six-membered rings were selectively activated over C–H bonds; in addition sp2 C–H bonds were selectively activated over sp3 CH bonds. The formation and regioselectivity of the cyclometalated palladium(II) complexes were characterized by NMR, MS, and XRD. Photoluminescence studies of cyclopalladated complexes were conducted.

A mixture of seven-membered and five-membered platinacycle complexes are eventually formed after a series of substitution, oxidative addition, and reductive elimination reactions between the platinum dimer, cis -[Pt 2 Me 4 ( μ -SMe 2 ) 2 ] and the naphthyl-derived CˆN chelate ligands, (8-XC 10 H 6 CH = N-R), X = I, Br; R = phenyl and 4-Cl-benzyl. From the tethered ligand, either an sp 2 C H bond can be activated forming a five-membered ring or an sp 3 C H bond can be activated forming a seven-membered ring. All compounds have the imine included in the platinacycle. The ratio of complexes as a function of ring size varies depending on ligand architecture of the chelate ligand and the nature of other ligands in the coordination sphere. The cyclometalated platinum complexes have been characterized by NMR spectroscopy. One complex with a seven-membered ring was characterized crystallographically. Reductive elimination reactions of isolated and/or identified cyclometalated, six-membered platinum(IV) compounds [PtMe 2 Br{C 10 H 6 CH = NCH 2 (4-ClC 6 H 4 )}L] and [PtMe 2 Br{C 10 H 6 CH = N(C 6 H 5 )}L] (L = SMe 2 ) to form C sp3 C sp2 bonds, followed by competition between C sp2 H and C sp3 H bond activation are also reported.

Several naphthyl-based N^N^C ligands were synthesized by strategically incorporating a bromide or iodide at the 8-position of the naphthyl ring. When allowed to react with the platinum tetra methyl dimer, PtMe 4 (μ-SMe 2 ) 2 , the more rare six-membered platinum(IV) platinacycles were formed by oxidative addition of the C(sp 2 )–X bond. In a separate case, C–H activation at the 8-position was encouraged by having the 2-position ‘blocked’ with a methyl group thus a six-membered platinum(II) platinacycle was formed by C(sp 2 )–H activation at the 8-position. Products were characterized by XRD, NMR, UV/vis, emission spectroscopy, and HRMS. The platinum(IV) compounds were inert to thermolysis. The complexes appear to exhibit dual fluorescence and phosphorescence at room temperature in solution.

Several thiophene-based N^C ligands were synthesized. Strategically, a bromide was incorporated on the 2-position of the thiophene ring. When allowed to react with the platinum tetramethyl dimer, [Pt2Me4(µ-SMe2)2], platinum(IV) platinacycles were formed by oxidative addition of the C(sp2)-X bond. These platinum(IV) compounds were characterized by NMR and HRMS. The platinum (IV) compounds were subsequently subjected to thermolysis. A series of reactions occurred, including selective C-C reduction elimination and selective C-H oxidative addition, giving mixtures of platinum(II) products with varying degrees of regioselectivity.