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Zn(CN)2 is Tungsten structured and crystallizes in the tetragonal P4_2nm space group. The structure is zero-dimensional and consists of two Zn(CN)2 clusters. Zn2+ is bonded in a water-like geometry to two equivalent N3- atoms. Both Zn–N bond lengths are 1.99 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom.
Mg(CN)2 is Tungsten structured and crystallizes in the tetragonal P4_2nm space group. The structure is zero-dimensional and consists of two Mg(CN)2 clusters. Mg2+ is bonded in a water-like geometry to two equivalent N3- atoms. Both Mg–N bond lengths are 2.05 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Mg2+ and one C2+ atom.
Au2Zn(CN)4 crystallizes in the hexagonal P6_422 space group. The structure is three-dimensional and consists of two Au2Zn(CN)4 frameworks. Au1+ is bonded in a distorted linear geometry to two C2+ atoms. Both Au–C bond lengths are 1.99 Å. Zn2+ is bonded in a tetrahedral geometry to four N3- atoms. All Zn–N bond lengths are 1.98 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. In the second C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom.
Li(CN)2 crystallizes in the monoclinic C2/m space group. The structure is one-dimensional and consists of two Li(CN)2 ribbons oriented in the (0, 0, 1) direction. Li1+ is bonded to four N3- atoms to form a mixture of edge and corner-sharing LiN4 tetrahedra. There are two shorter (2.08 Å) and two longer (2.13 Å) Li–N bond lengths. There are two inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.20 Å. In the second C+2.50+ site, C+2.50+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.20 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted T-shaped geometry to two equivalent Li1+ and one C+2.50+ atom. In the second N3- site, N3- is bonded in a trigonal planar geometry to two equivalent Li1+ and one C+2.50+ atom.
CoAu2(CN)4 crystallizes in the hexagonal P6_422 space group. The structure is three-dimensional and consists of two CoAu2(CN)4 frameworks. Co2+ is bonded in a tetrahedral geometry to four N3- atoms. All Co–N bond lengths are 1.93 Å. Au1+ is bonded in a distorted linear geometry to two C2+ atoms. Both Au–C bond lengths are 1.99 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. In the second C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Co2+ and one C2+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Co2+ and one C2+ atom.
Au2Zn(CN)4 crystallizes in the hexagonal P6_222 space group. The structure is three-dimensional and consists of two Au2Zn(CN)4 frameworks. Au1+ is bonded in a distorted linear geometry to two C2+ atoms. Both Au–C bond lengths are 1.99 Å. Zn2+ is bonded in a tetrahedral geometry to four N3- atoms. All Zn–N bond lengths are 1.98 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. In the second C2+ site, C2+ is bonded in a distorted single-bond geometry to one Au1+ and one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom.
Ba3Rh(CN)3 crystallizes in the hexagonal P6_3/m space group. The structure is zero-dimensional and consists of two Ba3Rh(CN)3 clusters. Ba2+ is bonded in a 1-coordinate geometry to one N3- atom. The Ba–N bond length is 2.78 Å. Rh3+ is bonded in a trigonal planar geometry to three equivalent C atoms. All Rh–C bond lengths are 1.93 Å. C is bonded in a distorted linear geometry to one Rh3+ and one N3- atom. The C–N bond length is 1.23 Å. N3- is bonded in a distorted single-bond geometry to one Ba2+ and one C atom.
BaH15Te3(CN)3 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of two BaH15Te3(CN)3 sheets oriented in the (1, 0, 0) direction. Ba2+ is bonded in a 3-coordinate geometry to three N3- and five Te2- atoms. There are a spread of Ba–N bond distances ranging from 2.88–2.95 Å. There are a spread of Ba–Te bond distances ranging from 3.61–3.81 Å. There are three inequivalent C+0.67- sites. In the first C+0.67- site, C+0.67- is bonded in a tetrahedral geometry to one N3- and three H1+ atoms. The C–N bond length is 1.47 Å. All C–H bond lengths are 1.10 Å. In the second C+0.67- site, C+0.67- is bonded in a tetrahedral geometry to one N3- and three H1+ atoms. The C–N bond length is 1.47 Å. There is two shorter (1.10 Å) and one longer (1.11 Å) C–H bond length. In the third C+0.67- site, C+0.67- is bonded in a tetrahedral geometry to one N3- and three H1+ atoms. The C–N bond length is 1.47 Å. All C–H bond lengths are 1.10 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+, one C+0.67-, and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+, one C+0.67-, and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the third N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+, one C+0.67-, and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. There are fifteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+0.67- atom. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Te2- atoms. There are one shorter (2.85 Å) and one longer (3.22 Å) Te–Te bond lengths. In the second Te2- site, Te2- is bonded in a 2-coordinate geometry to two Te2- atoms. The Te–Te bond length is 2.94 Å. In the third Te2- site, Te2- is bonded in a 5-coordinate geometry to three equivalent Ba2+ and two Te2- atoms.
Ba3Ir(CN)3 crystallizes in the hexagonal P6_3/m space group. The structure is zero-dimensional and consists of two Ba3Ir(CN)3 clusters. Ba2+ is bonded in a 1-coordinate geometry to one N3- atom. The Ba–N bond length is 2.78 Å. Ir5+ is bonded in a trigonal planar geometry to three equivalent C+0.67- atoms. All Ir–C bond lengths are 1.91 Å. C+0.67- is bonded in a 1-coordinate geometry to one Ir5+ and one N3- atom. The C–N bond length is 1.24 Å. N3- is bonded in a distorted single-bond geometry to one Ba2+ and one C+0.67- atom.
Al(CN)3 is alpha Po structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three Al(CN)3 clusters. Al3+ is bonded in a distorted T-shaped geometry to three equivalent N3- atoms. All Al–N bond lengths are 1.97 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Al3+ and one C2+ atom.
Abstract Carbon nitrides featuring three‐dimensional frameworks of CN 4 tetrahedra are one of the great aspirations of materials science, expected to have a hardness greater than or comparable to diamond. After more than three decades of efforts to synthesize them, no unambiguous evidence of their existence has been delivered. Here, the high‐pressure high‐temperature synthesis of three carbon–nitrogen compounds,tI14‐C 3 N 4 ,hP126‐C 3 N 4 , andtI24‐CN 2 , in laser‐heated diamond anvil cells, is reported. Their structures are solved and refined using synchrotron single‐crystal X‐ray diffraction. Physical properties investigations show that these strongly covalently bonded materials, ultra‐incompressible and superhard, also possess high energy density, piezoelectric, and photoluminescence properties. The novel carbon nitrides are unique among high‐pressure materials, as being produced above 100 GPa they are recoverable in air at ambient conditions.
Here, we report the observation of a small, yet remarkably stable, metal-free hexacyanodiborate dianion [B 2 (CN) 6 ] 2– in the gas phase. Negative ion photoelectron spectroscopy (NIPES) was employed to measure its spectra at multiple laser wavelengths, yielding a 1.9 eV electron binding energy (EBE) —a remarkably high value of electronic stability and a ~2.60 eV repulsive Coulomb barrier (RCB) for electron detachment. This rationalizes the observation of this dianion, although homolytic charge-separation dissociation into two [B(CN) 3 ] •– is energetically favorable. Quantum chemical calculations demonstrate a $D_{3d}$ staggered conformation for both the dianion and radical monoanion, and the calculated EBE and RCB match the experimental values well. The simulated density of states spectrum reproduces all measured electronic transitions, while the simulated vibrational progressions for the ground state transition cover a much narrower EBE range compared to the experimental band, indicating appreciable auto-photodetachment via electronically excited dianion resonances
An azadithiolate bridged CN — bound pentacarbonyl bis-iron complex, mimicking the active site of [Fe–Fe] H 2 ase is synthesized. The geometric and electronic structure of this complex is elucidated using a combination of EXAFS analysis, infrared and Mössbauer spectroscopy and DFT calculations. The electrochemical investigations show that complex 1 effectively reduces H + to H 2 between pH 0–3 at diffusion-controlled rates (10 11 M —1 s —1 ) i.e. 10 8 s —1 at pH 3 with an overpotential of 140 mV. Electrochemical analysis and DFT calculations suggests that a CN— ligand increases the p K a of the cluster enabling hydrogen production from its Fe(I)–Fe(0) state at pHs much higher and overpotential much lower than its precursor bis-iron hexacarbonyl model which is active in its Fe(0)–Fe(0) state. The formation of a terminal Fe–H species, evidenced by spectroelectrochemistry in organic solvent, via a rate determining proton coupled electron transfer step and protonation of the adjacent azadithiolate, lowers the kinetic barrier leading to diffusion controlled rates of H 2 evolution. The stereo-electronic factors enhance its catalytic rate by 3 order of magnitude relative to a bis-iron hexacarbonyl precursor at the same pH and potential.
Abstract [Fe-(pyrazine){Pd(CN) 4 }] (pyrazine = pz) thin films were fabricated using a layer-by-layer assembly approach, a method known to be tunable, versatile, and scalable, since thin films are better-suited for industrial applications. In this study, [Fe-(pz){Pd(CN) 4 }] powder was synthesized, and the results obtained from a vibrating sample magnetometer verified the presence of an abrupt hysteresis loop with widths of 45 K centered around 300 K, indicating good cooperativity. Super conducting quantum interference device magnetometry results indicated a slow spin transition with temperature but with evidence of hysteresis for thin film samples. X-ray absorption analysis provided further support of the spin crossover behavior but differs from the magnetometry because the spin state transition at the surface differs from the bulk of the thin film. X-ray photoelectron spectroscopy provided some insight into issues with the film deposition process and multiplex fitting was used to further support the claim that the surface of the film is different than the bulk of the film.
The dimer Mott insulator kappa - (BEDT-TTF) 2 - Cu 2 (CN) 3 can be tuned into metallic and superconducting states on applying pressure of 1.5 kbar and more. We have performed dielectric measurements (7.5 kHz to 5 MHz) on kappa - (BEDT-TTF) 2 - Cu 2 (CN) 3 single crystals as a function of temperature (down to T = 8 K) and pressure (up to p = 4.3 kbar). In addition to the relaxor-like dielectric behavior seen below 50 K at p = 0, that moves toward lower temperatures with pressure, a second peak emerges in ε 1 (T) around T = 15 K. When approaching the insulator-metal boundary, this peak diverges rapidly reaching ε 1 ≈ 10 5 . Our dynamical mean-field theory calculations substantiate that the dielectric catastrophe at the Mott transition is not caused by closing the energy gap, but due to the spatial coexistence of correlated metallic and insulating regions. We discuss the percolative nature of the first-order Mott insulator-to-metal transition in all details.
Abstract Molecular polaritons, hybrid light-matter states resulting from strong cavity coupling of optical transitions, may provide a new route to guide chemical reactions. However, demonstrations of cavity-modified reactivity in clean benchmark systems are still needed to clarify the mechanisms and scope of polariton chemistry. Here, we use transient absorption to observe the ultrafast dynamics of CN radicals interacting with a cyclohexane ( c -C 6 H 12 ) and chloroform (CHCl 3 ) solvent mixture under vibrational strong coupling of a C–H stretching mode of c- C 6 H 12 . By modulating the c -C 6 H 12 :CHCl 3 ratio, we explore how solvent complexation and hydrogen (H)-abstraction processes proceed under collective cavity coupling strengths ranging from 55 to 85 cm −1 . Reaction rates remain unchanged for all extracavity, on-resonance, and off-resonance cavity coupling conditions, regardless of coupling strength. These results suggest that insufficient vibrational cavity coupling strength may not be the determining factor for the negligible cavity effects observed previously in H-abstraction reactions of CN with CHCl 3 .
By photographically averaging time sequences of high-resolution CN 3883-A spectroheliograms, the noise level due to the rapidly fluctuating intensity of the solar background has been reduced significantly. Very faint faculae that are lost in the noise on a single frame are easily visible on such an enhanced picture. A comparison between these enhanced spectroheliograms and a photoelectric magnetogram suggests that the brightness-magnetic field correlation extends to much weaker field strengths and fainter faculae than can be detected on a single, high quality CN spectroheliogram.
The quenching of the B (super 2)Sigma-plus fluorescence from the CN radical has been studied as a function of the relative velocity of the quenching collision and the total pressure in the fluorescence cell. The rate constant for the quenching of the CN fragment by ICN vapor was found to be directly proportional to the relative velocity of the quenching collision. Electronic quenching was also observed for methane, diatomic hydrogen, Kr, and Ar.