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A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPhR)2], R = CH3 (1a), H (1b), F (1c), Cl (1d), cta = condensed thioamide, have been prepared under similar conditions and thoroughly characterized by 1H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state. Chemical reduction of 1a with [Cp2Co] yielded [Cp2Co]2[Pt(ctaPhCH3)2], [Cp2Co]2[1a], which has been similarly characterized with the addition of EPR spectroscopy and SQUID magnetization. The singly reduced form containing [1a]1-, (nBu4N)[Pt(ctaPhCH3)2], has been generated in situ and characterized by UV-vis and EPR spectroscopies. DFT studies of 1b, [1b]1-, and [1b]2- confirm the location of additional electrons in exclusively ligand-based orbitals. A detailed analysis of this redox-active ligand, with emphasis on the characteristics that favor noninnocent behavior in six-membered chelate rings, is included.

Isocyanide coordination networks (ISOCNs), which consist of multitopic isocyanide linker groups and transition-metal-based secondary building units (SBUs), are a promising class of organometallic f...

The structure of the title compound exhibits a folded conformation with the three arms all on the same side of the tertiary N atom. The crystal packing features π–π inter­actions., The structure of the title compound, C29H26N4O6, exhibits a folded conformation with the three arms all on the same side of the tertiary N atom. The two phthalimide units make a dihedral angle of 12.18 (12)° and the dihedral angles between the benzyl plane and the phthalimide units are 68.08 (7) and 67.71 (7)°. The crystal packing features π–π inter­actions.

The synthesis and characterization of a series of Sn(II) and Sn(IV) complexes supported by the highly electron-withdrawing dianionic perfluoropinacolate (pinF) ligand are reported herein. Three analogs of [SnIV(pinF)3]2− with NEt3H+ (1), K+ (2), and {K(18C6)}+ (3) counter cations and two analogs of [SnII(pinF)2]2− with K+ (4) and {K(15C5)2}+ (5) counter cations were prepared and characterized by standard analytical methods, single-crystal X-ray diffraction, and 119Sn Mossbauer and NMR spectroscopies. The six-coordinate SnIV(pinF) complexes display 119Sn NMR resonances and 119Sn Mossbauer spectra similar to SnO2 (cassiterite). In contrast, the four-coordinate SnII(pinF) complexes, featuring a stereochemically-active lone pair, possess low 119Sn NMR chemical shifts and relatively high quadrupolar splitting. Furthermore, the Sn(II) complexes are unreactive towards both Lewis bases (pyridine, NEt3) and acids (BX3, Et3NH+). Calculations confirm that the Sn(II) lone pair is localized within the 5s orbital and reveal that the Sn 5px LUMO is energetically inaccessible, which effectively abates reactivity.

The reaction of [PtCl2(P–P)] (P–P = PPh3, dppp) with [R2Sn(SeC5H4N)2] (R = Me, Et) afforded an orange co-crystallized product [{Pt(κ2-SeC5H4N)(P–P)}{R10Sn5(μ-O)3Cl5}] (P–P = PPh3, dppp; R = Me, Et). The latter complexes can also be obtained by the treatment of [Pt(SeC5H4N)2(dppp)] with R2SnCl2 (R = Me, Et). These co-crystallized complexes displayed a completely separated core of the platinum selenolate complex along with an organo-oxotin cage compound in the same lattice. These complexes were characterized by elemental analyses, NMR (1H, 31P, 77Se, 119Sn) spectroscopy and scalar relativistic density functional theory (DFT) calculations. The crystal structures of compounds [{Pt(κ2-SeC5H4N)(dppp)}{Me10Sn5(μ-O)3(μ-Cl)Cl4}]HCONMe2 (2a) and [{Pt(Cl)(SeC5H4N)(P–P)}{Et10Sn5(μ-O)3Cl5}] (2b) were established by single crystal X-ray diffraction analyses. Natural bond orbital (NBO) and energy decomposition analysis (EDA) were carried out in detail to establish the nature of bonding in both cocrystals. Their molecular structure contains nearly the same platinum fragment; however, the only variation that can be observed with the organo-oxotin cage fragment is that the methyl-substituted oxotin compound 2a is Cl-capped and the ethyl substituted one 2b is an O-capped type cluster.

We investigate the relationship between structure (crystal and molecular) and tert-butyl and methyl group dynamics in 2-(tert-butyl)-9-(4-(tert-butyl)phenyl)anthracene. Powder and single-crystal X-ray diffraction, taken together, show that different polycrystalline samples recrystallized from different solvents have different amounts of at least four polymorphs (crystallites having different crystal structures), of which we have identified three by single crystal X-ray diffraction. The molecules in the asymmetric units of the different crystal structures differ by the dihedral angle the tert-butylphenyl group makes with the anthracene moiety. Ab initio electronic structure calculations on the isolated molecule show that very little intramolecular energy is required to change this angle over a range of about 60° which is probably the origin of the concomitant polymorphism (crystals of more than one polymorph in a polycrystalline sample). Solid state 1 H nuclear magnetic resonance (NMR) spin-lattice relaxation experiments support the powder and single-crystal X-ray results and provide average NMR activation energies (closely related to rotational barriers) for the rotation of the tert-butyl groups and their constituent methyl groups. These barriers have both an intramolecular and an intermolecular component. The latter is sensitive to the crystal structure. The intramolecular components of the rotational barriers of the two tert-butyl groups in the isolated molecule are investigated with ab initio electronic structure calculations.

Relative to other cyclic poly-phosphorus species (that is, cyclo-Pn ), the planar cyclo-P4 group is unique in its requirement of two additional electrons to achieve aromaticity. These electrons are supplied from one or more metal centers. However, the degree of charge transfer is dependent on the nature of the metal fragment. Unique examples of dianionic mononuclear η4 -P4 complexes are presented that can be viewed as the simple coordination of the [cyclo-P4 ]2- dianion to a neutral metal fragment. Treatment of the neutral, molybdenum cyclo-P4 complexes Mo(η4 -P4 )I2 (CO)(CNArDipp2 )2 and Mo(η4 -P4 )(CO)2 (CNArDipp2 )2 with KC8 produces the dianionic, three-legged piano stool complexes, [Mo(η4 -P4 )(CO)(CNArDipp2 )2 ]2- and [Mo(η4 -P4 )(CO)2 (CNArDipp2 )]2- , respectively. Structural, spectroscopic, and computational studies reveal a similarity to the classic η6 -benzene complex (η6 -C6 H6 )Mo(CO)3 regarding the metal-center valence state and electronic population of the planar-cyclic ligand π system.

A new series of heterobimetallic lantern complexes, [PtM(SAc)4(pySMe)] (M = Mn (1), Fe (2), Co (3), Ni (4), Zn (5)), as well as additions to the previously reported series, [PtM(SAc)4(pyNH2)] (M = Mn (6), Fe (7)), have been synthesized and thoroughly characterized. Notably, compounds 1 and 6 are the first crystallographically characterized, neutral Pt-Mn containing lantern complexes. Compounds 2 and 7 are the first examples of Pt-Fe containing lantern complexes with a pyridine based axial ligand. These newly synthesized complexes have been characterized by single-crystal X-ray diffraction and UV–vis (1–7), 1H and 13C NMR spectroscopies (5), and solution magnetic susceptibility (1–4 and 6–7) and analyzed in comparison to our previously reported lantern families. Compounds 2–4 are isomorphous and contain two crystallographically independent dimers with the same staggered conformations. One dimer has a typical Pt⋯Pt metallophilic interaction ranging from 3.2198(6) to 3.2913(6) A while the other has a much longer contact ranging from 3.3212(6) to 3.4533(6) A. These latter contacts suggest metallophilic interactions that are the longest reported to date in any system. Solid state variable-temperature magnetic susceptibility studies suggest antiferromagnetic coupling between the 3d metal centers in the two lantern complexes of the dimeric forms of 2, 3, and 4.

The ferrocene-hormone conjugate 16-ferrocenylidene-17β-estra-1,3,5-triene-3,17-diol crystallizes in a monoclinic unit cell, space group P21. The asymmetric unit cell contains two ferrocene-hormone conjugates, co-crystallized with two water and one acetonitrile molecules. The crystal structure shows a hydrogen bonding network within the hormone residues and the co-crystallized water and acetonitrile molecules. Hirshfeld surface and two-dimensional fingerprint plots were performed for each of the ferrocene-hormone conjugates in order to analyse weak intermolecular contacts. Particular attention is placed on hydrogen bond interactions in the crystal structure. A noncovalent OH-π intermolecular interaction was found in the crystal structure. DFT studies were employed using the long-range functional ωB97XD and 6–311 g** basis set to study such interactions. The existence of this OH-π intermolecular interaction contributes with −2.32 kcal/mol to the total energy of the crystalline structure.

In order to stabilize a 10–P–3 species with C2v symmetry and two lone pairs on the central phosphorus atom, a specialized ligand is required. Using an NCN pincer, previous efforts to enforce this planarized geometry at P resulted in the formation of a Cs-symmetric, 10π-electron benzazaphosphole that existed as a dynamic “bell-clapper” in solution. Here, OCO pincers 1 and 2 were synthesized, operating under the hypothesis that the more electron-withdrawing oxygen donors would better stabilize the 3-center, 4-electron O–P–O bond of the 10–P–3 target and the sp3-hybridized benzylic carbon atoms would prevent the formation of aromatic P-heterocycles. However, subjecting 1 to a metalation/phosphination/reduction sequence afforded cyclotriphosphane 3, resulting from trimerization of the P(I) center unbound by its oxygen donors. Pincer 2 featuring four benzylic CF3 groups was expected to strengthen the O–P–O bond of the target, but after metal–halogen exchange and quenching with PCl3, unexpected cyclization with loss of CH3Cl was observed to give monochlorinated 5. Treatment of 5 with (p-CH3)C6H4MgBr generated crystalline P-(p-Tol) derivative 6, which was characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. The complex 19F NMR spectra of 5 and 6 observed experimentally, were reproduced by simulations with MestreNova.

A systematic study of arene-perfluoroarene interactions in solution is presented. Using a combination of NMR titration experiments, X-ray crystallography, and computational analysis, we analyze the effects of fluorination, substituents, ring size, and solvation on the arene-perfluoroarene interaction. We find that fluorination, extension of the π systems, and enhancement of solvent polarity greatly stabilize the stacking energy up to 3 orders of magnitude (K(a) =

To identify the genesis of the differing magnetic behaviors for the ferro- (FO) and metamagnetic (MM) polymorphs of [FeCp*2][TCNQ] (Cp* = pentamethylcyclopentadienide; TCNQ = 7,7,8,8-tetracyano-p-quinodimethane) the low temperature (18 ± 1 K) structures of each polymorph were determined from high-resolution synchrotron powder diffraction data. Each polymorph possesses chains of alternating S = 1/2 [FeCp*2]˙+ cations and S = 1/2 [TCNQ]˙+, but with differing relative orientations. These as well as an additional paramagnetic polymorph do not thermally interconvert. In addition, the room and low (

The new PtVO(SOCR)4 lantern complexes, 1 (R = CH3) and 2 (R = Ph) behave as neutral O-donor ligands to Ln(OR)3 with Ln = Ce, Nd. Four heterotrimetallic complexes with linear {LnOVPt} units were prepared: [Ln(ODtbp)3{PtVO(SOCR)4}] (Ln = Ce, 3Ce (R = CH3), 4Ce (R = Ph); Nd, 3Nd (R = CH3), 4Nd (R = Ph); ODtbp = 2,6-ditertbutylphenolate). Magnetic characterization confirms slow magnetic relaxation behaviour and suggests antiferromagnetic coupling across {Ln-O[double bond, length as m-dash]V} in all four complexes, with variations tunable as a function of Ln and R.

This work reports the synthesis and characterization of a new C^N-based cycloplatinated(II) fluorido complex [Pt(ppy)PPh3)F] involving a Pt‒F bond. The new complex is highly luminescent in green area with a high quantum yield of 94.6% at 77K. A comparison study of the heavier of halogen derivatives reveals a descending emission quantum yield order of F > Cl > Br > I. Time-dependent density functional theory (TD-DFT) calculations ascribe the decreased emission efficiency to the decreasing trend of ILCT transition from F to I, which accounts for the major radiative pathway.

Four groups of rare-earth complexes, comprising 11 new compounds, with fluorinated O-donor ligands ([K(THF)6][Ln(OC4F9)4(THF)2] (1-Ln; Ln = Ce, Nd), [K](THF)x[Ln(OC4F9)4(THF)y] (2-Ln; Ln = Eu, Gd, Dy), [K(THF)2][Ln(pinF)2(THF)3] (3-Ln; Ln = Ce, Nd), and [K(THF)2][Ln(pinF)2(THF)2] (4-Ln; Ln = Eu, Gd, Dy, Y) have been synthesized and characterized. Single-crystal X-ray diffraction data were collected for all compounds except 2-Ln. Species 1-Ln, 3-Ln, and 4-Ln are uncommon examples of six-coordinate (Eu, Gd, Dy, and Y) and seven-coordinate (Ce and Nd) LnIII centers in all-O-donor environments. Species 1-Ln, 2-Ln, 3-Ln, and 4-Ln are all luminescent (except where Ln = Gd and Y), with the solid-state emission of 1-Ce being exceptionally blue-shifted for a Ce complex. The emission spectra of the six Nd, Eu, and Dy complexes do not show large differences based on the ligand and are generally consistent with the well-known free-ion spectra. Time-dependent density functional theory results show that 1-Ce and 3-Ce undergo allowed 5f → 4d excitations, consistent with luminescence lifetime measurements in the nanosecond range. Eu-containing 2-Eu and 4-Eu, however, were found to have luminescence lifetimes in the millisecond range, indicating phosphorescence rather than fluorescence. The performance of a pair of multireference models for prediction of the Ln = Nd, Eu, and Dy absorption spectra was assessed. It was found that spectroscopy-oriented configuration interaction as applied to a simplified model in which the free-ion lanthanide was embedded in ligand-centered Lowdin point charges performed as well (Nd) or better (Eu and Dy) than canonical NEVPT2 calculations, when the ligand orbitals were included in the treatment.

In a pair of earlier papers, the existence of long directional interaction bonds, LDI bonds, was postulated on the basis of data for cofacial oligomeric siloxysilicon phthalocyanines from this laboratory and data for other cofacial oligomeric phthalocyanines from the literature. However, the combined data are not fully suited to the purpose for which they were used. Here an alternative approach is taken in which a carefully chosen group of dimeric cofacial siloxysilicon phthalocyanines is used. Structural data derived from these phthalocyanines is examined in some detail to determine where it conforms to normal expectations and where it does not. To a high degree of certainty, consideration of the results obtained shows that long directional (LDI) bonds exist in dimeric cofacial siloxysilicon phthalocyanines. The new data also provide an opportunity for other research on chemical bonds.

[Y(N(SiMe3)2)3] reacts with (Ad,MeArOH)3mes to form the Y3+ complex [((Ad,MeArO)3mes)Y], 1-Y. This complex reacts with potassium metal in the presence of 2.2.2-cryptand to give a cocrystallized mixture of [K(2.2.2-cryptand)][((Ad,MeArO)3mes)Y], 2-Y, and [K(2.2.2-cryptand)][((Ad,MeArO)3mes)YH], 3-Y. The electron paramagnetic resonance spectrum of this crystalline mixture exhibits an isotropic signal at 77 K (giso = 2.000, Wiso = 1.8 mT), suggesting that 2-Y is best described as a Y3+ complex of the tris(aryloxide)mesitylene radical ((Ad,MeArO)3mes)4–. Evidence of the hydride ligand in 3-Y was obtained by 89Y–1H heteronuclear multiple quantum coherence NMR spectroscopy, and a coupling constant of JYH = 93 Hz was observed. A single crystal of 3-Y was also obtained in pure form and structurally characterized for comparison with the crystal data on the mixed component 2-Ln/3-Ln crystals. The origin of the hydride in 3-Ln is unknown, but further studies of the reduction of 1-La, previously found to form 2-La, r...

We report the synthesis of two isomeric Pt(II) complexes ligated by doubly deprotonated 1,1′-bis(o-carborane) (bc). The κ2-C,C-bound isomer (3a) is generated through salt metathesis of K2[bc] and Pt(dtb-bpy)Cl2 (dtb-bpy = 4,4′-di-tert-butyl-2,2′-bipyridine), whereas the κ2-B,C-bound isomer (3b) forms after the addition of K[H-bc] to a reaction mixture containing the Pt(II) starting material and an alkyl lithium reagent. The structures of both isomers were confirmed with 1H NMR spectroscopy and single crystal X-ray crystallography. A cathodic shift is observed for both oxidation (>260 mV) and reduction (∼130 mV) potentials of 3b versus those of 3a, which is corroborated by DFT calculations of both complexes. While photophysical studies reveal similar quantum yields and excited state lifetimes for both isomers, emission spectra for 3b in a PMMA film, frozen solution at 77 K, and as a neat solid are slightly blue-shifted relative to the corresponding emission spectra for 3a. Ultimately, this work provides a ...

Reported here is the isolation of a dianionic cobalt terminal carbyne derived from chemical reduction of an encumbering isocyanide ligand. Crystallographic, spectroscopic and computational data reveal that this carbyne possesses a low-valent cobalt center with an extensively filled d-orbital manifold. This electronic character renders the cobalt center the primary site of nucleophilicity upon reaction with protic substrates and silyl electrophiles. However, reactions with internal alkynes result in [2+2] cycloaddition with the carbyne carbon to form a new C-C bond.

The fluorine-substituted branched oligogermane (Ph3Ge)3GeF was successfully synthesized from (Ph3Ge)3GeH and [Ph3C][BF4] after several unfruitful attempts using other synthetic methods and was formed as a mixture with Ph3GeF. Pure (Ph3Ge)3GeF could be obtained from the reaction mixture by successive recrystallizations and was characterized by elemental analysis and NMR (1H, 13C, and 19F) spectroscopy, including a variable-temperature 19F NMR study to investigate the presence or absence of hydrogen bonding in this species. The oligogermane (Ph3Ge)3GeF is indefinitely stable in the solid state under an inert atmosphere, but gradually decomposes to Ph3GeF and other unidentified products in solution. The X-ray crystal structure of (Ph3Ge)3GeF was obtained and represents the only crystallographically characterized germanium–fluorine compound having unsupported Ge–Ge bonds. The Ge4 framework of the oligogermane (Ph3Ge)3GeF is isostructural with the other previously prepared halogen-substituted analogues (Ph3Ge)...

Multimetallic clusters have long been investigated as molecular surrogates for reactive sites on metal surfaces. In the case of the μ4 -nitrido cluster [Fe4 (μ4 -N)(CO)12 ]- , this analogy is limited owing to the electron-withdrawing effect of carbonyl ligands on the iron nitride core. Described here is the synthesis and reactivity of [Fe4 (μ4 -N)(CO)8 (CNArMes2 )4 ]- , an electron-rich analogue of [Fe4 (μ4 -N)(CO)12 ]- , where the interstitial nitride displays significant nucleophilicity. This characteristic enables rational expansion with main-group and transition-metal centers to yield unsaturated sites. The resulting clusters display surface-like reactivity through coordination-sphere-dependent atom rearrangement and metal-metal cooperativity.

A quantitative assessment of the substituent, hybridization, and crystal-packing effects on the electronic, structural, and vibrational properties of halogen bonded systems is presented. Through a combined experimental and theoretical approach employing Raman spectroscopy, X-ray crystallography, and density functional theory, a series of solid-state iodobenzene and iodoethynylbenzene derivatives substituted with electron withdrawing groups (-F2, -(CF3)2, -F5, and -(NO2)2) and their complexes with two pyridine-based building blocks are characterized. Structural analysis via X-ray crystallography and density functional theory computations suggests that these 1:1 molecular assemblies are not only driven by halogen bonding, but also by other energetically competitive noncovalent interactions, such as π-stacking. The magnitude of the σ-hole localized around the C–I bond in the isolated halogen bond (XB) donors and the interaction strength in the complexes unambiguously depend on the nature of the substituents ...