Plane Of Ring Research Articles

Identifying Shadowing Signatures of C Ring Ringlets and Plateaus in Cassini Data from Saturn’s Ionosphere

For orbits 288 and 292 of Cassini’s Grand Finale, clear dips (sharp and narrow decreases) are visible in the densities measured by the Ion and Neutral Mass Spectrometer (INMS). In 2017, the southern hemisphere of Saturn was shadowed by its rings and the substructures within. Tracing a path of the solar photons through the ring plane to Cassini’s position, we can identify regions in the ionosphere that were shadowed by the individual ringlets and plateaus (with increased optical depths) of Saturn’s C ring. The calculated shadowed altitudes along Cassini’s trajectory line up well with the dips in the data when adjusting the latter based on a detected evolving shift in the INMS timestamps since 2013, illustrating the potential for verification of instrument timings. We can further estimate the mean optical depths of the ringlets/plateaus by comparing the dips to inbound densities. Our results agree well with values derived from stellar occultation measurements. No clear dips are visible for orbits 283 and 287, whose periapsides were at higher altitudes. This can be attributed to the much longer chemical lifetime of at these higher altitudes, which in turn can be further used to estimate a lower limit for the flow speed along Cassini’s trajectory. The resulting estimate of ∼0.3 km s−1 at an altitude of ∼3400 km is in line with prior suggestions. Finally, the ringlet and plateau shadows are not associated with obvious dips in the electron density, which is expected due to their comparatively long chemical (recombination) lifetime.

Dynamics of CTAB micelle mediated reaction of fuchsin degradation in alkaline medium

Abstract Cetyltrimethylammonium bromide (CTAB) micelles catalyzed the degradation of fuchsin in the entire surfactant concentration range investigated. The pseudo first order rate constants increased with CTAB concentrations. However, there was a decrease in the rate constant at higher concentrations of CTAB. Increase in the rate constant was attributed to the incorporation of fuchsin and hydroxide ion in the stern layer of the CTAB micelles. The kinetics involved the removal of the π-conjugation in fuchsin due to its attack by hydroxide ion on the central C atom of the planar ring which led to the formation of carbinol. The reaction showed first order each to fuchsin and OH-. Menger-Portnoy and Piszkiewicz cooperative models were used to explain the micellar and kinetic effects.

Extremely low barrier activation of methane on spin-polarized ferryl ion [FeO]2+ at the four-membered ring of zeolite

The Panov's α-O center in ZSM-5 zeolite revealing extraordinary activity in the oxidation of methane to methanol has been a subject of intense experimental and theoretical studies. Consensus on the structure and the origin of α-O superactivity seems to be achieved only in that α-O represents the ferryl group [FeO]2+ (bound by four lattice oxo sites) in cation-exchange position at some zeolite ring containing two framework Al atoms. Among rings with various sizes only three ones (four-, five-, and six-membered) can provide the ferryl ion with the necessary four number of oxo ligands (in the “plane” of ring) at reasonable Fe-O distance of about 2.0 Å. The six-membered ring is considered as the most probable one due to the 29Si MAS NMR data on Al pairs distribution on zeolite rings. However, the six-membered model in ZSM-5 has not been checked on behalf of the possibility of axial Fe-O coordination along Fe and terminal oxygen axis. By means of plane-wave DFT modeling, the present work shows that this coordination in fact takes place for six-membered ring unlike the four- and five-membered ones in which the Fe cation appears well above the plane of ring making the axial coupling impossible. Therefore, by known strong negative effect of axial oxo ligand on the ferryl species oxidizing activity, the six-membered model has to be discarded. Instead, a model of [FeO]2+ at four- or five-membered ring is to be put forward. In this work the four-membered model is shown to form the oxyl ground state Fe(III)–O• with the radical-like β-spin polarized oxygen. Calculated barrier of hydrogen abstraction from methane on this center is as low as 1.7 kcal/mol. The obtained prediction opens a way for other reactions to be probed on this center, particularly, the condensation of methane and oxidative dehydrogenation of hydrocarbons at low temperatures.

Planar Optofluidic Integration of Ring Resonator and Microfluidic Channels.

We report an optofluidic hybrid silicon-polymer planar ring resonator with integrated microfluidic channels for efficient liquid delivery. The device features a planar architecture of intersecting liquid-core waveguides and microfluidic channels. A low-loss integration of microfluidic channels is accomplished by exploiting the interference pattern created by the self-imaging effect in the multimode interference-based coupler waveguides. Numerical simulations have been performed in order to minimize the propagation losses along the ring loop caused by the integration of microfluidic channels. The device has been fabricated and optically characterized by measuring the quality factor, obtaining a value of 4 × 103. This result is comparable with the quality factor of an optofluidic ring with the same optical layout but without integrated microfluidic channels, thus, confirming the suitability of the proposed approach for microfluidics integration in planar optofluidic design.

Planar π-extended cycloparaphenylenes featuring an all-armchair edge topology.

The [n]cycloparaphenylenes ([n]CPPs)-n para-linked phenylenes that form a closed-loop-have attracted substantial attention due to their unique cyclic structure and highly effective para-conjugation leading to a myriad of fascinating electronic and optoelectronic properties. However, their strained topology prevents the π-extension of CPPs to convert them either into armchair nanobelts or planarized CPP macrocycles. Here we successfully tackle this long-standing challenge and present the bottom-up synthesis and characterization of atomically precise in-plane π-extended [12]CPP on Au(111) by low-temperature scanning probe microscopy and spectroscopy combined with density functional theory. The planar π-extended CPP is a nanographene with an all-armchair edge topology. The exclusive para-conjugation at the periphery yields delocalized electronic states and the planarization maximizes the overlap of p orbitals, which both reduce the bandgap compared to conventional CPPs. Calculations predict ring currents and global aromaticity in the doubly charged system. The intriguing planar ring topology and unique electronic properties make planar π-extended CPPs promising quantum materials.

A Planar Five-Membered Aromatic Ring Stabilized by Only Two π-Electrons.

Many chemicals known today are partially or fully aromatic, since a ring framework experiences additional stabilization through the delocalization of π‐electrons. While aromatic rings with equal numbers of π‐electrons and ring atoms such as benzene are particularly stable, those with the minimally required two π‐electrons are very rare and yet remain limited to three‐ and four‐membered rings if not stabilized in the coordination sphere of heavy metals. Here we report the facile synthesis of a dipotassium cyclopentagallene, a unique example of a five‐membered aromatic ring stabilized by only two π‐electrons. Single‐crystal X‐ray diffraction revealed a planar Ga5 ring with almost equal gallium–gallium bond lengths, which together with computational and spectroscopic data confirm its aromatic character. Our results prove that aromatic stabilization goes far beyond what has previously been assumed as minimum π‐electron count in a five‐atom ring fragment.

Crystal structure and Hirshfeld surface analysis of 4-bromo-2-[3-methyl-5-(2,4,6-tri-methyl-benz-yl)oxazolidin-2-yl]phenol.

The title compound, C20H24BrNO2, is chiral at the carbon atoms on either side of the oxygen atom of the oxazolidine ring and crystallizes as a racemate. The 1,3-oxazolidine ring adopts an envelope conformation with the N atom in an endo position. The mean plane of the oxazolidine ring makes dihedral angles of 77.74 (10) and 45.50 (11)°, respectively, with the 4-bromo-phenol and 1,3,5-tri-methyl-benzene rings. In the crystal, adjacent mol-ecules are connected via C-H⋯O hydrogen bonds and C-H⋯π inter-actions into layers parallel to the (200) plane. The packing is strengthened by van der Waals inter-actions between parallel mol-ecular layers. A Hirshfeld surface analysis shows that H⋯H (58.2%), C⋯H/H⋯C (18.9%), and Br⋯H/H⋯Br (11.5%) inter-actions are the most abundant in the crystal packing.

Syntheses and crystal structures of a nitro-anthracene-isoxazole and its oxidation product.

The syntheses and structures of an unexpected by-product from an iodination reaction, namely, ethyl 5-methyl-3-(10-nitro-anthracen-9-yl)isoxazole-4-carb-oxy-l-ate, C21H16N2O5, (I), and its oxidation product, ethyl 3-(9-hy-droxy-10-oxo-9,10-di-hydro-anthracen-9-yl)-5-methyl-isoxazole-4-carboxyl-ate, C21H17NO5 (V) are described. Compound (I) crystallizes with two mol-ecules in the asymmetric unit in which the dihedral angles between the anthracene fused-ring systems and isoxazole ring mean planes are 88.67 (16) and 85.64 (16)°; both mol-ecules feature a disordered nitro group. In (V), which crystallizes with one mol-ecule in the asymmetric unit, the equivalent dihedral angle between the almost planar anthrone ring system (r.m.s. deviation = 0.029 Å) and the pendant isoxazole ring is 89.65 (5)°. In the crystal of (I), the mol-ecules are linked by weak C-H⋯O inter-actions into a three-dimensional network and in the extended structure of (V), inversion dimers linked by pairwise O-H⋯O hydrogen bonds generate R 2 2(14) loops.

Crystal structure and Hirshfeld surface analysis of 2-chloro-N-(4-meth-oxy-phen-yl)acetamide.

In the title mol-ecule, C9H10ClNO2, the meth-oxy group lies very close to the plane of the phenyl ring while the acetamido group is twisted out of this plane by 28.87 (5)°. In the crystal, a three-dimensional structure is generated by N-H⋯O, C-H⋯O and C-H⋯Cl hydrogen bonds plus C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis of the inter-molecular inter-actions was performed and indicated that C⋯H/H⋯C inter-actions make the largest contribution to the surface area (33.4%).

Non-contrast computed tomography versus cinefluoroscopy for the assessment of mechanical prosthetic valve leaflet motion

Introduction: valve replacement remains the definitive treatment of most cases with severe valvular heart disease. Mechanical prosthetic valves remain the main option in younger patients. Objective: evaluation of mechanical prosthetic valve function by comparing the feasibility of leaflet motion assessment by cinefluoroscopy vs. CT. Materials and methods: Leaflet motion was assessed in 30 bileaflet mechanical prostheses (21 mitral and 9 aortic) by cinefluoroscopy and non-contrast CT. Assessment was considered feasible when the ‘in profile’ projection (with the radiographic beam parallel to both the valve ring plane and the tilting axis of discs) could be achieved. Results: Overall feasibility of fluoroscopic assessment was 74% (mitral, 66% vs. aortic, 93%; p=0.071), while feasibility of CT assessment was 100% (p=0.003). Among prostheses with unfeasible fluoroscopic assessment, CT suggested an extreme C-arm angulation to achieve the “in profile” projection (RAO: 76.0±5.8°, LAO: 122.7±32.5°, CRA: 51.4±16.0°, CAU: 57.0±18.2°). Among prostheses with feasible assessment by both techniques, fluoroscopy and CT yielded similar opening and closing angles (intraclass correlation coefficient, 0.959 - 0.998) with lower irradiation with CT as compared with fluoroscopy (26.2[21.1-29.3] vs. 289[179-358] mGy, p<0.001). While CT scan took 8.7±0.5 seconds, fluoroscopy required 2.64±1.56 minutes to achieve and record the “in profile” projection.

Design and synthesis of multi-stimuli responsive π-extended phenothiazine aldehydes: Solvatochromism, acidochromism, moisture detection and fluorochromic sensing of amine vapors

A series of phenothiazine-based A-π-D-A type ‘push-pull’ molecules containing sites sensitive to external stimuli was designed and synthesized by phase transfer Heck coupling reaction. A positive solvatochromism was observed with an increase in solvent polarity resulting in an enhanced intramolecular charge transfer (ICT). The existence of TICT was prominent in highly polar media such as methanol and water. Single crystal X-ray diffraction revealed the existence of two structures of VPTZ, with torsional angles of 145.92⁰ and −161.04⁰, respectively along C–N–S–C plane of the phenothiazine rings. These compounds were used as probes for quantitative measurement of moisture present in three organic solvents, namely CH3CN, THF, and DMSO. The probes could detect moisture as low as 0.0034% (v/v) in CH3CN. Further, these compounds displayed reversible acidochromism in both solution and solid-state. VPTZ, containing pyridine ring as the receptor, displayed excellent sensing of trifluoroacetic acid (TFA) with a detection limit of 91.4 nM. A detailed mechanism involved in reversible acid sensing was studied by 1H NMR. Finally, silica-coated TLC plates were used to fabricate test strips by coating them with VPTZ and then were used as a portable device for selective turn-on sensing of triethyl amine (TEA) and n-dibutyl amine (DBA). TEA and DBA exhibited exceptional fluorochromic turn-on response from purplish-pink to yellow-green and mustard yellow, respectively.

Clinical study of digital six-axis external fixation frame based on CT data for tibiofibular fractures

Objective: To investigate the clinical effect of applying the digital six-axis external fixation frame based on CT data in the treatment of tibiofibular fractures. Methods: The clinical data of 43 patients with tibiofibular fractures treated by the self-developed digital six-axis external fixation frame based on CT data at Integrated Orthopedic Department of Traditional Chinese Medicine (TCM) and Western Medicine,HongHui Hospital from January 2018 to January 2021 were retrospective analysis.There were 27 males and 16 females,aged (36.0±9.4) years(range:25 to 50 years).AO classification:15 cases of 42A,11 cases of 42B, and 17 cases of 42C.There were 7 open fractures and Gustilo fracture classification:2 cases of type Ⅰ,4 cases of type Ⅱ,and 1 case of type Ⅲ.The two or three plane rings were connected with six connecting rods to form a complete six-axis external fixation frame,and the distal and proximal fracture blocks were connected to the distal and proximal rings by fixation pins,and the lengths of the six connecting rods needed to be adjusted were calculated by using the supporting software according to the CT data after surgery,and then the lengths of the connecting rods were adjusted one by one to complete the reduction of the fracture. The reduction accuracy of this six-axis external fixation brace was evaluated by measuring postoperative radiographs; postoperative recovery and complications were collected,the time of brace removal was recorded,and the function of the affected limb was evaluated according to the Johner-Wruhs score at the final follow-up. Results: Postoperative radiographs showed that all patients achieved satisfactory reduction with lateral displacement(M(IQR)) of 2.3(2.5) mm (range:0.3 to 7.3 mm),anteroposterior displacement of 2.1 (2.4) mm (range:0.3 to 5.7 mm),anteroposterior angulation of 2.5(2.4)°(range:0 to 5°),internal and external angulation of 2.1(1.5)°(range:0 to 4°), and no significant internal or external rotational deformity was detected on the exterior.On the second postoperative day,all patients were able to walk with partial weight-bearing on crutches. All 43 patients were followed up for more than 6 months,with a follow-up period of (33.3±7.3) weeks (range:24 to 42 weeks).The external fixation frame was removed after the fracture healed.The external frame was removed at 20(3)weeks (range:18 to 25 weeks) postoperatively. Up to the final follow up, no secondary fracture occurred in any of them.The Johner-Wruhs score of the affected limb at the last follow-up was excellent in 39 cases and good in 4 cases. Conclusion: The digital six-axis external fixator based on CT data for tibiofibular fractures has the advantages of precise reduction,firm fixation,simple operation,rapid fracture healing,and minimal trauma, which is a minimally invasive method for treating tibiofibular fractures,especially suitable for patients with poor skin and soft tissue conditions such as open injuries.

Exploiting aromaticity in fatty terephthalate diesters to enhance melting point and prevent polymorphism

Saturated aliphatic diesters sourced from vegetable oils present phase change properties particularly suitable for latent heat thermal energy storage (LHTES). However, inherent ester group flexibility, weak intermolecular attractions and intramolecular steric repulsions between the electronic clouds of the two ester groups, which lead to degraded packing and polymorphism, prevent these molecules from achieving optimal functionality as phase change materials (PCM). The present work demonstrates that the incorporation of a planar benzene ring between the two ester groups restricts intramolecular steric repulsion, increases the intermolecular attractions and effectively limits molecular flexibility, leading to the formation of stable monomorphs and enhancement of the thermal properties. The terephthalate diesters prepared in this work crystallized in the most stable triclinic β -polymorph regardless of cooling rate, demonstrated melting temperatures up to 86 °C and enthalpies up to 260J/g as well as higher thermal stabilities than corresponding aliphatic diol and diacid diesters. The enhanced thermal properties are mainly attributed to the π-π intermolecular attractions established between planar benzene rings inherent quadrupole moment and resonance effect from the delocalization of π-electrons within the extended conjugated π-system formed between the benzene ring and ester groups. The π-π intermolecular attractions and resonance stabilized ester group contributed to a higher energy barrier for rotation to occur at the center molecules and resulted in the stiffening of the fatty chains, facilitating periodic crystal packing. • Terephthalates are excellent PCMs for medium temperature thermal energy storage. • High melting point (86 °C) and thermal energy storage density (260J/g) achieved. • Rapidly store/release heat via sharp phase transitions with low supercooling. • Planar ring, π-π interaction and resonance effect instrumental performance. • Molecular packing constrained into the most stable monomorph regardless of kinetics.

Generation and Characterization of the Charge-Transferred Diradical Complex CaCO2 with an Open-Shell Singlet Ground State

The CaCO2 complex is generated via the reaction of excited-state calcium atom with carbon dioxide in a solid neon matrix. Infrared absorption spectroscopy and quantum chemical calculations reveal that the complex has a planar four-membered ring structure with a strongly bent CO2 ligand side-on coordinated to the calcium center in an η2-O, O manner. The complex has an open-shell singlet ground state, which can be described as the bonding interactions between a Ca+ (4s1) cation in the doublet ground state and a doublet ground state CO2- anion. The analysis of the bonding situation suggests that the Ca-O2C bonds have a large (75%) electrostatic character. The covalent (orbital) interactions come from the coupling of the unpaired electrons of Ca+ and CO2- giving rise to electron-sharing bonding and a stronger contribution from dative bonding (Ca+)←(CO2-). The atomic orbitals (AOs) of Ca+ that are engaged in the covalent bonds are the 4s AO for the electron-sharing bonds and the 3d AOs for the dative bonds. This is further evidence for the assignment of the heavier alkaline-earth atoms as transition metals rather than main-group elements.

Internal dynamics of methyl p-tolyl sulfoxide in the gas phase: Rotational spectroscopy and theoretical studies.

A pure rotational spectrum of methyl p-tolyl sulfoxide (MTSO) was studied using chirped-pulse Fourier transform microwave spectroscopy in the frequency range of 18-26GHz. A single conformer was unambiguously observed in the supersonic jet expansion, which is consistent with the conformational analysis performed using quantum-chemical calculations. Rotational transitions were split into two components of A and E symmetries due to the low-barrier internal rotation of the ring methyl group [V3 = 11.0178(23) cm-1]. The low energy barrier for the methyl top internal rotation implies an electron-withdrawing effect of the group at the opposite side of the phenyl ring, in comparison with other para-substituted toluenes. The effective ground state (r0) geometry was derived using the rotational constants from the parent species and the 34S and eight 13C singly substituted isotopologues. Compared to two other sulfoxides, methyl phenyl sulfoxide and methyl 4-nitrophenyl sulfoxide, the sulfoxide group in MTSO is slightly more twisted with respect to the plane of the phenyl ring, which could be attributed to the moderate electron-donating effect of the p-methyl group. Furthermore, the pyramidal inversion that interconverts the handedness at the sulfur stereogenic center was explored in the electronic ground (S0) and excited (S1) states with nudged elastic band and time-dependent density functional theory methods. It was found that the pyramidal inversion in S1 is easier than in S0, showing that optical excitation to S1 will facilitate an effectively barrier-free inversion.

Probing the electronic nature of Co centers forming the planar ring in octa-nuclear Co complexes using X-ray absorption spectroscopy

The formation of octanuclear cobalt core has been studied in the Co complexes Na[Co8{O2CCH3}8(OCH3)16]NO3(1), Na[Co8{O2CC(CH3)3}8(OCH3)16]NO3(2), Na[Co8{O2CC(CH3)3}8 (OC2H5)16]NO3(3) by analysing the X-ray absorption spectra at the Co K-edge. Analysis of EXAFS confirmed octahedral coordination around the Co atoms. The presence of neighbouring Co atoms has been associated to the octanuclear nature of the complexes. The XANES features have been correlated with the oxidation state of the absorbing Co atoms and their coordination in the complexes. XANES spectra have been simulated by ab-initio XANES calculations performed for the Co centres forming the planar ring in order to investigate and compare the electronic nature of these metal centres. Co density of states (DOS), i.e., s-, p- and d-DOS have also been calculated to explain the different features of XANES spectra. The simulated XANES spectra are further compared with the experimental spectra to probe the effect of different ligands present in the complexes.

Synthesis, experimental and computational characterizations of 8,9-dimethoxybenzo[b]naphtho[2,3-d] thiophene (DBNT) crystals for electro-mechano utilities

Single crystals of organic non-linear optical material, 8,9-Dimethoxybenzo[b]naphtho[2,3-d] thiophene (DBNT) are need to grow as the titled crystals have thiophene, since thiophenes are having potential bio activity and industrial uses. The entitled specimen is well-grown by solution growth method and reported for the first time for computational and experimental study. Characterization of the crystals is made using single crystal X-ray diffraction and compared for the elucidation of structure of DBNT for bond parameters. The titled compound is having the chemical formula C18H14O2S. From the structure, the planar rings are properly identified. The crystal system of DBNT is monoclinic in nature and the space group is P21/n. The lattice constants are 13.0063 Å, 5.9632 Å and 18.3802 Å and β is 104.020° which is determined by XRD analysis. The non-linear optical - NLO characteristics of this material is analyzed and found to be utilized for opto-electronic gadgets and filters because of its nonlinearities and in experimental frequency doubling circuits. The composition of elements present in the grown specimen of DBNT crystal was theoretically and experimentally analyzed. The morphological effect of DBNT is analyzed and reported for the surfaces of crystal with magnifications and the dielectric behavior is studied properly for all polarizations and reported for entitled crystalline DBNT material, in mechano use by preloading data as coated DBNT. The dielectric and crystalline nature of the specimen is by electrical correlation and the thin film influx refers the proper grown confirmation of the DBNT and encompasses the filter usage exclusively of opto-electronic way.

Crystal structure of N-(1H-indol-2-yl-methyl-idene)-4-meth-oxy-aniline.

The mol-ecule of the title compound, C16H14N2O, contains an essentially planar indole ring system and a phenyl ring. In the crystal, the mol-ecules are linked by a weak inter-molecular C-H⋯O hydrogen bond and C-H⋯π inter-actions, forming a one-dimensional column structure along the b-axis direction. These columns are linked by other C-H⋯π inter-actions, forming a two-dimensional network structure.

Synthesis, crystal structure, DFT studies, and Hirshfeld surface analysis of 2,2'-(((methylene-bis(4,1-phenylene))bis(azanylylidene))bis(methanylylidene))diphenol

The synthesis, characterization, and theoretical studies of the title compound has been reported in this study. The molecular structure has been characterized by room-temperature single-crystal X-ray diffraction study which reveals that it has an angular shape with intramolecular and intermolecular hydrogen bonding. Crystal data for the title compound, C27H22N2O2 (M =406.46 g/mol): monoclinic, space group C2/c (no. 15), a = 36.371(10) Å, b = 4.6031(12) Å, c = 12.192(3) Å, β = 94.972(6)°, V = 2033.5(9) Å3, Z = 4, T = 100 K, μ(MoKα) = 0.084 mm-1, Dcalc = 1.328 g/cm3, 8812 reflections measured (2.248° ≤ 2Θ ≤ 49.734°), 1773 unique (Rint = 0.0323, Rsigma = 0.0239) which were used in all calculations. The final R1 was 0.0411 (I > 2σ(I)) and wR2 was 0.1165 (all data). In crystal structure, the molecule exits in the enol form and is located on a two-fold axis of symmetry; where the central methylene carbon atom of the diphenylmethane moiety is displaced from the aromatic ring planes. The Hirshfeld surface analysis of the title compound shows that H···H, C···H, and O···H interactions of 53.3, 13.2, and 5.4%; respectively, which exposed that the main intermolecular interactions were H···H intermolecular interactions. The HOMO-LUMO energy gap in the title compound is 2.9639 eV. Molecular electrostatic potential of the investigated compound has also been studied.

Thermodynamic Driving Forces for Substrate Atom Extraction by Adsorption of Strong Electron Acceptor Molecules.

A quantitative structural investigation is reported, aimed at resolving the issue of whether substrate adatoms are incorporated into the monolayers formed by strong molecular electron acceptors deposited onto metallic electrodes. A combination of normal-incidence X-ray standing waves, low-energy electron diffraction, scanning tunnelling microscopy, and X-ray photoelectron spectroscopy measurements demonstrate that the systems TCNQ and F4TCNQ on Ag(100) lie at the boundary between these two possibilities and thus represent ideal model systems with which to study this effect. A room-temperature commensurate phase of adsorbed TCNQ is found not to involve Ag adatoms, but to adopt an inverted bowl configuration, long predicted but not previously identified experimentally. By contrast, a similar phase of adsorbed F4TCNQ does lead to Ag adatom incorporation in the overlayer, the cyano end groups of the molecule being twisted relative to the planar quinoid ring. Density functional theory (DFT) calculations show that this behavior is consistent with the adsorption energetics. Annealing of the commensurate TCNQ overlayer phase leads to an incommensurate phase that does appear to incorporate Ag adatoms. Our results indicate that the inclusion (or exclusion) of metal atoms into the organic monolayers is the result of both thermodynamic and kinetic factors.