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The [FeFe]-hydrogenase can be matured using a defined semisynthetic approach in which the synthetic complex [2Fe] E bypasses the need for HydE and HydG, and glycine cleavage system components synthesize DTMA on [2Fe] E while it is bound to HydF.
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
Recently, Urai et al. reported that an antiferromagnetic long-range-ordered state in κ-(ET) 2 Cu[N(CN) 2 ]Cl changes into a quantum spin liquid via an unconventional spin glass-like state as randomness is introduced by x-ray irradiation. In this work, we focused on the spin glass-like state and conducted a detailed investigation into it using 13 C-NMR measurements on 150-h x-ray-irradiated κ-(ET) 2 Cu[N(CN) 2 ]Cl. We found that the spin glass-like state is composed of two components: the major component inherits the spin structure of nonirradiated κ-(ET) 2 Cu[N(CN) 2 ]Cl, whereas the minor component differs from that of nonirradiated κ-(ET) 2 Cu[N(CN) 2 ]Cl. We also found that in the spin glass-like state, spin moments fluctuate very slowly around stable directions even at low temperatures, which is very likely related to the Griffiths physics.
Abstract A series of isostructural Ln 3 O 2 (CN 3 ) (Ln=La, Eu, Gd, Tb, Ho, Yb) oxoguanidinates was synthesized under high‐pressure (25–54 GPa) high‐temperature (2000–3000 K) conditions in laser‐heated diamond anvil cells. The crystal structure of this novel class of compounds was determined via synchrotron single‐crystal X‐ray diffraction (SCXRD) as well as corroborated by X‐ray absorption near edge structure (XANES) measurements and density functional theory (DFT) calculations. The Ln 3 O 2 (CN 3 ) solids are composed of the hitherto unknown CN 3 5− guanidinate anion—deprotonated guanidine. Changes in unit cell volumes and compressibility of Ln 3 O 2 (CN 3 ) (Ln=La, Eu, Gd, Tb, Ho, Yb) compounds are found to be dictated by the lanthanide contraction phenomenon. Decompression experiments show that Ln 3 O 2 (CN 3 ) compounds are recoverable to ambient conditions. The stabilization of the CN 3 5− guanidinate anion at ambient conditions provides new opportunities in inorganic and organic synthetic chemistry.
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.
Be(CN)2 is Tungsten structured and crystallizes in the tetragonal P4_2nm space group. The structure is zero-dimensional and consists of two Be(CN)2 clusters. Be2+ is bonded in a water-like geometry to two equivalent N3- atoms. Both Be–N bond lengths are 1.69 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.16 Å. N3- is bonded in a linear geometry to one Be2+ and one C2+ atom.
Cd(CN)2 is Tungsten structured and crystallizes in the tetragonal P4_2nm space group. The structure is zero-dimensional and consists of two Cd(CN)2 clusters. Cd2+ is bonded in a water-like geometry to two equivalent N3- atoms. Both Cd–N bond lengths are 2.23 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 Cd2+ and one C2+ atom.
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.
Zn(CN)2 is Tungsten structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one Zn(CN)4 cluster and one zinc molecule. In the Zn(CN)4 cluster, Zn2+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Zn–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 Zn2+ and one C2+ atom.
Cd(CN)2 is Tungsten structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one cadmium molecule and one Cd(CN)4 cluster. In the Cd(CN)4 cluster, Cd2+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Cd–N bond lengths are 2.19 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 Cd2+ and one C2+ atom.
Hg(CN)2 is Potassium Silver Cyanide-derived structured and crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Hg2+ is bonded in a 4-coordinate geometry to two equivalent C2+ and four equivalent N3- atoms. Both Hg–C bond lengths are 2.05 Å. There are two shorter (2.82 Å) and two longer (3.16 Å) Hg–N bond lengths. C2+ is bonded in a linear geometry to one Hg2+ and one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a distorted single-bond geometry to two equivalent Hg2+ and one C2+ atom.
RbB(CN)2 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Rb1+ is bonded in a square co-planar geometry to four equivalent N3- atoms. There are two shorter (2.90 Å) and two longer (3.04 Å) Rb–N bond lengths. B3+ is bonded in a linear geometry to two equivalent C1+ atoms. Both B–C bond lengths are 1.44 Å. C1+ is bonded in a distorted linear geometry to one B3+ and one N3- atom. The C–N bond length is 1.20 Å. N3- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Rb1+ and one C1+ atom.
NaAg(CN)2 is Potassium Silver Cyanide-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded to six equivalent N3- atoms to form edge-sharing NaN6 octahedra. There are a spread of Na–N bond distances ranging from 2.54–2.60 Å. Ag1+ is bonded in a linear geometry to two equivalent C2+ atoms. Both Ag–C bond lengths are 2.05 Å. C2+ is bonded in a linear geometry to one Ag1+ and one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Na1+ and one C2+ atom.
KAg(CN)2 is Potassium Silver Cyanide structured and crystallizes in the trigonal P-31c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six equivalent N3- atoms to form edge-sharing KN6 octahedra. There are three shorter (2.86 Å) and three longer (2.98 Å) K–N bond lengths. In the second K1+ site, K1+ is bonded to six equivalent N3- atoms to form edge-sharing KN6 octahedra. All K–N bond lengths are 2.92 Å. Ag1+ is bonded in a linear geometry to two equivalent C2+ atoms. Both Ag–C bond lengths are 2.05 Å. C2+ is bonded in a linear geometry to one Ag1+ and one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a 4-coordinate geometry to three K1+ and one C2+ atom.
KAu(CN)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six equivalent N3- atoms to form edge-sharing KN6 octahedra. There are three shorter (2.83 Å) and three longer (2.90 Å) K–N bond lengths. In the second K1+ site, K1+ is bonded to six equivalent N3- atoms to form edge-sharing KN6 octahedra. All K–N bond lengths are 2.85 Å. Au1- is bonded in a linear geometry to two equivalent C3+ atoms. Both Au–C bond lengths are 1.99 Å. C3+ is bonded in a distorted single-bond geometry to one Au1- and one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded to three K1+ and one C3+ atom to form a mixture of distorted edge and corner-sharing NK3C tetrahedra.
KCu(CN)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.82–3.33 Å. Cu1+ is bonded in a distorted trigonal non-coplanar geometry to two C2+ and one N3- atom. There is one shorter (1.90 Å) and one longer (1.92 Å) Cu–C bond length. The Cu–N bond length is 2.00 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Cu1+ and one N3- atom. The C–N bond length is 1.19 Å. In the second C2+ site, C2+ is bonded in a distorted linear geometry to one Cu1+ and one N3- atom. The C–N bond length is 1.18 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to three equivalent K1+ and one C2+ atom. In the second N3- site, N3- is bonded in a distorted bent 150 degrees geometry to three equivalent K1+, one Cu1+, and one C2+ atom.
RbAu(CN)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Rb–N bond distances ranging from 3.02–3.21 Å. In the second Rb1+ site, Rb1+ is bonded in a 7-coordinate geometry to seven N3- atoms. There are a spread of Rb–N bond distances ranging from 3.05–3.29 Å. There are three inequivalent Au1- sites. In the first Au1- site, Au1- is bonded in a distorted linear geometry to two equivalent C3+ atoms. Both Au–C bond lengths are 1.99 Å. In the second Au1- site, Au1- is bonded in a linear geometry to two C3+ atoms. Both Au–C bond lengths are 1.99 Å. In the third Au1- site, Au1- is bonded in a linear geometry to two equivalent C3+ atoms. Both Au–C bond lengths are 1.99 Å. There are four inequivalent C3+ sites. In the first C3+ site, C3+ 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 C3+ site, C3+ is bonded in a single-bond geometry to one Au1- and one N3- atom. The C–N bond length is 1.18 Å. In the third C3+ site, C3+ is bonded in a distorted single-bond geometry to one Au1- and one N3- atom. The C–N bond length is 1.18 Å. In the fourth C3+ site, C3+ is bonded in a single-bond geometry to one Au1- and one N3- atom. The C–N bond length is 1.17 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to three Rb1+ and one C3+ atom. In the second N3- site, N3- is bonded in a distorted single-bond geometry to three Rb1+ and one C3+ atom. In the third N3- site, N3- is bonded in a 1-coordinate geometry to three Rb1+ and one C3+ atom. In the fourth N3- site, N3- is bonded in a 1-coordinate geometry to three Rb1+ and one C3+ atom.