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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.
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.
Here, we report the remarkable stability at the nanoscale matrix-filler interface in a series of overall low coefficient of thermal expansion (CTE) zinc cyanide (ZC)/epoxy resin composites. These interfaces demonstrate the stability of highly contrasting materials. These composites are designed to optimize the properties of both materials: epoxy resins are valued for their high strength, superb chemical resistance, low dielectric properties, and adhesive abilities. ZC, a model flexible framework, exhibits negative thermal expansion (NTE) behavior and compensates for the epoxy resin’s detrimentally large thermal expansion values. Filled resins minimize the native 65 ppm/°C CTE values to 19 ppm/° C over a wide temperature range while maintaining linearity, yielding composites compatible with typical metal and ceramic substrates’—commonly bonded to the resin— 0–20 ppm/° C CTE values. Additionally, with significant intrinsic differences in the materials, we use wide-angle X-ray diffraction and atomic force microscopy to elucidate thermal movement. The ZC/epoxy interface is surprisingly resilient over 1,000 cycles between -55° C and 75° C, extremes typical to aerospace applications. Further, we show that the resin viscosity remains less than 21 Pa*s at up to 30 vol% ZC, an important consideration for workability. We also discuss settling distribution, glass transition temperature, flexural strength, and longevity. All results point favorably towards practical implementation in low thermal expansion application needs: filling the gap in component design.
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(Fe)2(Zn(CN)4)3 is Corundum structured and crystallizes in the trigonal R-3c space group. The structure is zero-dimensional and consists of twelve iron molecules and eighteen Zn(CN)4 clusters. In each Zn(CN)4 cluster, Zn2+ is bonded in a tetrahedral geometry to four N3- atoms. There is two shorter (1.96 Å) and two longer (1.97 Å) Zn–N bond length. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to 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 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 distorted 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.
(Rh)2Zn(Zn(CN)6)2 crystallizes in the tetragonal P-4m2 space group. The structure is zero-dimensional and consists of two rhodium molecules, two Zn(CN)6 clusters, and one zinc molecule. In each Zn(CN)6 cluster, Zn2+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Zn–N bond distances ranging from 2.11–2.17 Å. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. There are three 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. In the third N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C2+ atom.
Heating [Zn(S 2 CN i Bu 2 ) 2 ] in oleylamine affords high aspect ratio nanowires of ZnS and in situ XAS studies of the decomposition of [Zn(S 2 CNMe 2 ) 2 ] give insight into mechanistic aspects of the molecular transformations.
Zn(CoZn(CN)6)2 is High-temperature superconductor-derived structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional and consists of one CoZn(CN)6 framework and one zinc molecule. In the CoZn(CN)6 framework, there are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in an octahedral geometry to six C+2.17+ atoms. All Co–C bond lengths are 1.87 Å. In the second Co2+ site, Co2+ is bonded in an octahedral geometry to six C+2.17+ atoms. All Co–C bond lengths are 1.87 Å. Zn2+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Zn–N bond distances ranging from 2.08–2.17 Å. There are three inequivalent C+2.17+ sites. In the first C+2.17+ site, C+2.17+ is bonded in a linear geometry to one Co2+ and one N3- atom. The C–N bond length is 1.17 Å. In the second C+2.17+ site, C+2.17+ is bonded in a linear geometry to one Co2+ and one N3- atom. The C–N bond length is 1.17 Å. In the third C+2.17+ site, C+2.17+ is bonded in a linear geometry to one Co2+ and one N3- atom. The C–N bond length is 1.17 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C+2.17+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C+2.17+ atom. In the third N3- site, N3- is bonded in a linear geometry to one Zn2+ and one C+2.17+ atom.
Zn(CN)6(CN)6(AsF6)2 crystallizes in the trigonal R-3 space group. The structure is zero-dimensional and consists of eighteen hydrogen cyanide molecules, six AsF6 clusters, and three Zn(CN)6 clusters. In each AsF6 cluster, As is bonded in an octahedral geometry to six F1- atoms. There is three shorter (1.77 Å) and three longer (1.78 Å) As–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As atom. In each Zn(CN)6 cluster, Zn2+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Zn–N bond lengths are 2.15 Å. C+3.83+ 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 Zn2+ and one C+3.83+ atom.
Desalination of brackish water sources is critical to addressing the growing global freshwater demand. One promising approach is electrically driven desalination using intercalation electrodes. While intercalation electrodes have been widely researched for energy storage applications, only a small subset of those materials is suitable for desalination. In this work, we report the synthesis, characterization, and in-device testing of three Prussian blue analogue intercalation compounds: copper, manganese, and zinc hexacyanoferrate with formulas K x M[Fe(CN) 6 ] z ·nH 2 O (M = Cu, Mn, Zn). The desalination performance for each of these materials against carbon electrodes is reported for Na + intercalation and for Ca 2+ intercalation using 1000 ppm NaCl and 1000 ppm CaCl 2 feed solutions, respectively. While the copper and manganese analogs showed promising performance for Na + and Ca 2+ intercalation, the zinc compound was unstable and underwent rapid dissolution. Manganese hexacyanoferrate showed the best desalination performance in terms of salt removal capacities and salt removal rates with NaCl while copper hexacyanoferrate performed the best with CaCl 2 . The manganese analog proved to be the most stable intercalation material, retaining 83% and 72% of its salt removal capacity after 280 cycles in NaCl and CaCl 2 feed solutions respectively.
(B)2Zn(CN)6(CN)2 crystallizes in the trigonal P-3m1 space group. The structure is zero-dimensional and consists of two boron molecules, two hydrogen cyanide molecules, and one Zn(CN)6 cluster. In the Zn(CN)6 cluster, Zn2+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Zn–N bond lengths are 2.16 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 Zn2+ and one C2+ atom.
K2Zn(CN)4 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional and consists of one K(CN)2 framework and eight zinc molecules. In the K(CN)2 framework, K1+ is bonded to six equivalent N3- atoms to form edge-sharing KN6 octahedra. All K–N bond lengths are 2.94 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 to three equivalent K1+ and one C2+ atom to form a mixture of distorted corner and edge-sharing NK3C tetrahedra.
While the bis(trifluoromethylsulfonyl)imide anion (TFSI – ; formula [N(SO 2 CF 3 ) 2 ] – ) has been noted for its practical utility, the use of TFSI – salts as sources of Lewis acidic metal cations for studies of cation-driven tuning effects has not been reported. Here, the effective Lewis acidity of mono-, di-, and trivalent cations (namely, K + , Na + , Li + , Ba 2+ , Ca 2+ , Mg 2+ , Zn 2+ , La 3+ , Y 3+ , Lu 3+ , and Sc 3+ ) in the form of their TFSI – salts is described, along with quantitative comparisons to salts of several other weakly coordinating anions (namely, SO 3 CF 3 – , PF 6 – , and BArF 24 – ). Triphenylphosphine oxide (TPPO) was used as a 31 P NMR probe in titration experiments for quantification of key parameters describing the effective Lewis acidity of the salts in acetonitrile (CH 3 CN) solutions. Notably, the TFSI – salts of di- and trivalent cations were found to display strong binding to TPPO with significant speciation and were found to be quite hygroscopic. Taken together, the measurements demonstrate that TFSI – salts are systematically better/stronger effective Lewis acids than their triflate analogues. And, considering the excellent solubility of TFSI – salts, these materials appear attractive for further use and development in Lewis-acidity-dependent applications, including catalysis and tuning of multimetallic materials.
K2Zn(CN)4 crystallizes in the trigonal R-3c space group. The structure is three-dimensional and consists of one K(CN)2 framework and twelve zinc molecules. In the K(CN)2 framework, there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six N3- atoms to form distorted edge-sharing KN6 pentagonal pyramids. There are a spread of K–N bond distances ranging from 2.87–3.02 Å. 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 2.86 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to 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 1-coordinate geometry to three K1+ and one C2+ atom. In the second N3- site, N3- is bonded to three equivalent K1+ and one C2+ atom to form distorted corner-sharing NK3C tetrahedra.
Zn4P3O13(CN)3 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional and consists of six hydrogen cyanide molecules and one Zn4P3O13 framework. In the Zn4P3O13 framework, there are four inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO4 tetrahedra and corners with three PO4 tetrahedra. There are a spread of Zn–O bond distances ranging from 1.94–2.03 Å. In the second Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO4 tetrahedra and corners with three PO4 tetrahedra. There is three shorter (1.95 Å) and one longer (2.03 Å) Zn–O bond length. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO4 tetrahedra and corners with three PO4 tetrahedra. There are a spread of Zn–O bond distances ranging from 1.95–2.05 Å. In the fourth Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO4 tetrahedra and corners with three PO4 tetrahedra. There is three shorter (1.95 Å) and one longer (2.03 Å) Zn–O bond length. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four ZnO4 tetrahedra. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four ZnO4 tetrahedra. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four ZnO4 tetrahedra. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Zn2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Zn2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Zn2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Zn2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Zn2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a tetrahedral geometry to four Zn2+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom.