The anionically all‐boron‐based colorless anti‐ perovskites Cs 3 [BH 4 ][B 12 H 12 ] and Cs 3 [BF 4 ][B 12 H 12 ] can be obtained by isothermal evaporation from aqueous solutions of the underlying pseudo ‐binary components Cs 2 [B 12 H 12 ] and Cs[BH 4 ] or Cs[BF 4 ]. At ambient conditions, Cs 3 [BH 4 ][B 12 H 12 ] crystallizes with the lattice parameters a = 1054.89(8) and c = 1197.12(9) pm ( Z = 3) in the trigonal space group R m . According to differential scanning calorimetry studies, it transforms reversibly into a cubic structure ( a = 744.50(6) pm, space group: Pm m , Z = 1) above 310°C. Both forms of Cs 3 [BH 4 ][B 12 H 12 ] represent derivatives of the cubic anti‐ perovskite arrangement, while the orthorhombic crystal structure of Cs 3 [BF 4 ][B 12 H 12 ] ( a = 874.69(5), b = 1052.71(6) and c = 1724.52(9) pm, space group: Pnma , Z = 4) adopts the hexagonal anti‐ perovskite motif. So quasi ‐icosahedral [B 12 H 12 ] 2– anions and Cs + cations assemble to a mixed cubic or hexagonal closest packed framework, respectively, in which the quasi ‐tetrahedral [BH 4 ] – or [BF 4 ] – anions ( A ) occupy the quasi ‐octahedral voids erected only by cations in a way that {[ A Cs 6/2 ] 2+ } or {[ A Cs 6/2 ] 2+ } substructures of all ‐vertex connected [ A Cs 6 ] 5+ octahedra occur in the first, but trans ‐face sharing ones in the second case.

The anionically all-boron-based colorless anti-perovskites Cs-3[BH4][B12H12] and Cs-3[BF4][B12H12] can be obtained by isothermal evaporation from aqueous solutions of the underlying pseudo-binary components Cs-2[B12H12] and Cs[BH4] or Cs[BF4]. At ambient conditions, Cs-3[BH4][B12H12] crystallizes with the lattice parameters a = 1054.89(8) and c = 1197.12(9) pm (Z = 3) in the trigonal space group R (3)overbarm. According to differential scanning calorimetry studies, it transforms reversibly into a cubic structure (a = 744.50(6) pm, space group: Pm(3)overbarm, Z = 1) above 310 degrees C. Both forms of Cs-3[BH4][B12H12] represent derivatives of the cubic anti-perovskite arrangement, while the orthorhombic crystal structure of Cs-3[BF4][B12H12] (a = 874.69(5), b = 1052.71(6) and c = 1724.52(9) pm, space group: Pnma, Z = 4) adopts the hexagonal anti-perovskite motif. So quasi-icosahedral [B12H12](2-) anions and Cs+ cations assemble to a mixed cubic or hexagonal closest packed framework, respectively, in which the quasi-tetrahedral [BH4](-) or [BF4](-) anions (A) occupy the quasi-octahedral voids erected only by cations in a way that infinity(3){[ACs(6/2)](2+)} or infinity(1){[ACs(6/2)](2+)} substructures of all-vertex connected [ACs(6)](5+) octahedra occur in the first, but trans-face sharing ones in the second case.

Three novel anti-perovskite compounds, formulated as Cs3X[B12H12] (X− = [NO3]−, [ClO3]−, and [ClO4]−), were successfully synthesized through the direct mixing of aqueous solutions containing Cs2[B12H12] and CsX (X−: [NO3]−, [ClO3]−, [ClO4]−), followed by isothermal evaporation. All three compounds crystallize in the orthorhombic space group Pnma, exhibiting relatively similar unit-cell parameters (e.g., Cs3[ClO3][B12H12]: a = 841.25(5) pm, b = 1070.31(6) pm, c = 1776.84(9) pm). The crystal structures were determined using single-crystal X-ray diffraction, revealing a distorted hexagonal anti-perovskite order for each. Thermal analysis indicated that the placing oxidizing anions X− into the 3 Cs+ + [B12H12]2− blend leads to a reduction in the thermal stability of the resulting anti-perovskites Cs3X[B12H12] as compared to pure Cs2[B12H12], so thermal decomposition commences at lower temperatures, ranging from 320 to 440 °C. Remarkably, the examination of the energy release through DSC studies revealed that these compounds are capable of setting free a substantial amount of energy, up to 2000 J/g, upon their structural collapse under an inert-gas atmosphere (N2). These three compounds represent pioneering members of the first ever anti-perovskite high-energy compounds based on hydro-closo-borates.

Abstract N,N′,N′′-peralkylated guanidinium chlorides and N,N′,N′′-peralkylated guanidines were prepared from N,N′-peralkylated chloroformamidinium chlorides. The alkylation of the guanidines affords N,N′,N′′-persubstituted guanidinium chlorides bromides, iodides, alkylsulfates, and tetrafluoroborates. Guanidinium tricyanomethanides and tetracyanopropenides were prepared from the chlorides and iodides by anion metathesis. The reaction of guanidinium halogenides with borontrifluoride etherate, triethyloxonium tetrafluoroborate or sodiumtetrafluoroborate delivers guanidinium tetrafluoroborates. Guanidinium saccharinides, cyanates, thiocyanates, trifluoromethansulfonates, bis(trifluormethansulfonyl)imides, hexacyanoferrates(II/III), tetracyanonickolates and tetrathiocyanatocobaltates were prepared from the corresponding guanidinium chlorides and tetrafluoroborates by anion exchange.

N,N',N ''-peralkylated guanidinium chlorides and N,N',N ''-peralkylated guanidines were prepared from N,N'-peralkylated chloroformamidinium chlorides. The alkylation of the guanidines affords N,N',N ''-persubstituted guanidinium chlorides bromides, iodides, alkylsulfates, and tetrafluoroborates. Guanidinium tricyan omethanides and tetracyanopropenides were prepared from the chlorides and iodides by anion metathesis. The reaction of guanidinium halogenides with borontrifluoride etherate, triethyloxonium tetrafluoroborate or sodiumtetrafluoroborate delivers guanidinium tetrafluoroborates. Guanidinium saccharinides, cyanates, thiocyanates, trifluoromethansulfonates, bis(trifluormethansulfonyl)imides, hexacyanoferrates(II/III), tetracyanonickolates and tetrathiocyanatocobaltates were prepared from the corresponding guanidinium chlorides and tetrafluoroborates by anion exchange.

Bis[bis(dibutylamino)methylen]hydrazine 8 is prepared from N,N,N',N'-tetrabutylchloroformamidinium chloride (4c) and hydrazine. Bromine transforms 8 to the heterocyclic guanidinium salt 15a which is isolated as tetraphenylborate. From N,N,N',N'-tetraalkylchloroformamidiniumchlorides and ethylendiamine the diguanidines are prepared which are alkylated to give diguanidinium salts, From these salts guanidinium salts can be prepared by anion metathesis with tetraphenylborate-, iodide-, hexafluorphosphate-, trifluoromethansulfonat-, bis(trifluormethansulfonyl)imide and tricyanmethanide as counteranions. The structure of the compounds 15 and 17b is confirmed by crystal structure analyses.

Thermoanalytic DSC and temperature-dependent X-ray diffraction investigations on the cesium dodecahalogeno-closo-dodecaborates Cs-2[B12X12] (X = Cl-I) have revealed solid-solid phase transitions from their trigonal room-temperature a-forms (e.g. a-Cs-2[B12Cl12]: a = 959.67(3) pm, c = 4564.2(2) pm, Z = 6, space group R (3) over bar) into cubic high-temperature modifications. The isotypic title compounds crystallize in the space group Pm (3) over barn (e.g. beta-Cs-2[B12Cl12]: a = 1051.98(6) pm, Z = 2) with a W3O-type defect structure. The statistic occupation of six possible positions with only four Cs+ cations results in a cation-deficient A(2)B arrangement for Cs-2[B12X12]. Upon cooling the beta-phase, a third polymorph was observed, which also crystallizes in the cubic system, but now in the space group Ia3c1 (e.g. y-Cs-2[B12Cl12]: alpha = 2102.2(3) pm, Z = 16), and has to be regarded as a phase with only a partially disordered cation substructure. In this crystal structure the [B12X12](2-) anions exhibit a NaTl-type arrangement, in which the Cs' cations occupy suitable interstices. The phase transitions of the differently halogenated cesium salts follow no specific trend as the transition from the trigonal alpha- to the cubic beta-form occurs at 178 degrees C for the chlorinated, at 270 degrees C for the iodinated and at 325 degrees C for the brominated examples. On further heating however, beta-Cs-2[B2I12] starts to decompose at 945 degrees C first, followed by beta-Cs-2[B12Br12] and beta-Cs-2[B12Cl12] at 959 degrees C and 983 degrees C, respectively.

Abstract Thermoanalytic DSC and temperature-dependent X-ray diffraction investigations on the cesium dodecahalogeno-closo-dodecaborates Cs2[B12 X 12] (X = Cl–I) have revealed solid-solid phase transitions from their trigonal room-temperature α-forms (e.g. α-Cs2[B12Cl12]: a = 959.67(3) pm, c = 4564.2(2) pm, Z = 6, space group R 3 ¯ $\overline{3}$ ) into cubic high-temperature modifications. The isotypic title compounds crystallize in the space group Pm 3 ¯ $\overline{3}$ n (e.g. β-Cs2[B12Cl12]: a = 1051.98(6) pm, Z = 2) with a W3O-type defect structure. The statistic occupation of six possible positions with only four Cs+ cations results in a cation-deficient A 2 B arrangement for Cs2[B12 X 12]. Upon cooling the β-phase, a third polymorph was observed, which also crystallizes in the cubic system, but now in the space group Ia 3 ¯ $\overline{3}$ d (e.g. γ-Cs2[B12Cl12]: a = 2102.2(3) pm, Z = 16), and has to be regarded as a phase with only a partially disordered cation substructure. In this crystal structure the [B12 X 12]2− anions exhibit a NaTl-type arrangement, in which the Cs+ cations occupy suitable interstices. The phase transitions of the differently halogenated cesium salts follow no specific trend as the transition from the trigonal α- to the cubic β-form occurs at 178 °C for the chlorinated, at 270 °C for the iodinated and at 325 °C for the brominated examples. On further heating however, β-Cs2[B12I12] starts to decompose at 945 °C first, followed by β-Cs2[B12Br12] and β-Cs2[B12Cl12] at 959 °C and 983 °C, respectively.

Abstract N,N,N′,N′-Tetraalkylchlorformamidiniumchlorides 1a, b react with ω-dimethylaminoalkylamines 19, 20 to give mixtures of N-(ω-dimethylammonioalkyl)-guanidinium salts 12, 13 and N-(ω-dimethylaminoalkyl)-guanidinium salts 21, 22. These mixtures are transformed to mixtures of the ureas 15, 17 and N-(ω-dimethylaminoalkyl)-guanidines 23, 25 on treatment with aqueous sodium hydroxide. The reaction of N-(3-dimethylammoniopropyl)-guanidin 25a with dimethylsulfate in a molar ratio of 1:1 delivers a mixture of the N-(3-dimethylaminopropyl)-N,N,N′,N′,N″,N″-pentamethyl-guanidinium salt 29a and the N-(3-dimethylammoniopropyl)-N,N′,N′,N″,N″-pentamethyl-guanidinium-bis (methylsulfate) 33a. The action of dimethylsulfate on the guanidines 23a, 25a in a molar ratio of 2:1 affords the bisquarternary salts 32a, 33a. Alkylating reagents as methyliodide, benzylbromide, allylbromide and chloroacetonitrile attack N-(2-dimethylaminoethyl)-N′,N′,N″,N″-tetraethylguanidine (23b) in a molar ratio of 1:1 cleanly at the dimethylaminoethylgroup to give the ammonium salts 30a–d. As a strong base the guanidine 23b dehydrochlorinates β-Chlorpropionitrile and chloroacetone under formation of the guanidinium salt 21c. In contrast to this the reaction of ethyl bromoacetate with the N-(2-dimethylaminoethyl)guanidine 23b occurs at the guanidinogroup giving the guanidinium salt 28c. The methylation of the guanidinium chlorides 21a, 22a with dimethyl sulfate affords the bis-quaternary salts 35b, 36b with mixed anions. From the heterocyclic guanidines 14, 16 and the alkylating reagents benzylbromide and ethyl bromoacetate the heterocyclic guanidinium salts 37a, b, 39a, b can be obtained. The reactions with ethyl chloroformiate proceed in an analogous way giving the guanidinium salts 37c, 39c. The N-alkyl-N,N,N′,N′-tetramethyl-(3-ureidopropyl)guanidinium salts 41a, b can be prepared from the N′,N′,N″,N″-tetramethyl-N′′-(3-ureidopropyl) guanidine 17a and the alkylating compounds dimethyl sulfate and benzyl bromide. Several compounds obtained that way were transformed to the corresponding tetraphenyloborates and bis(tetraphenylborates), respectively.

Abstract Bis[bis(dibutylamino)methylen]hydrazine 8 is prepared from N,N,N′,N′-tetrabutylchloroformamidinium chloride (4c) and hydrazine. Bromine transforms 8 to the heterocyclic guanidinium salt 15a which is isolated as tetraphenylborate. From N,N,N′,N′-tetraalkylchloroformamidiniumchlorides and ethylendiamine the diguanidines are prepared which are alkylated to give diguanidinium salts, From these salts guanidinium salts can be prepared by anion metathesis with tetraphenylborate-, iodide-, hexafluorphosphate-, trifluoromethansulfonat-, bis(trifluormethansulfonyl)imide and tricyanmethanide as counteranions. The structure of the compounds 15 and 17b is confirmed by crystal structure analyses.

The asymmetric unit of the title salt, C 7 H 18 N 3 + ·C 7 HN 4 − , comprises one cation and one anion. The N , N , N ′, N ′, N ′′, N ′′-hexamethylguanidinium ion shows orientational disorder and two sets of N- and C-atom positions were found, with an occupancy ratio of 0.535 (3):0.465 (3). The C—N bond lengths in the guanidinium ion range from 1.339 (16) to 1.35 (2) Å, indicating partial double-bond character pointing towards charge delocalization within the NCN planes. The negative charge in the 1,1,3,3-tetracyanoprop-2-en-1-ide ion is delocalized within the CCC planes with the C—C bonds ranging in length from 1.379 (3) to 1.427 (3) Å, also indicating partial double-bond character.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The asymmetric unit of the title salt, C 12 H 24 N 4 2+ .2C 24 H 20 B − , comprises half a cation and one tetraphenylborate ion. An inversion centre is situated at the mid-point of the triple C[triple-bond]C bond in the cation. The bisamidinium C—N bonds [1.3249 (11) and 1.3267 (11) Å] have double-bond character and both positive charges are delocalized between the dimethylamino groups. The bonds between the N atoms and the terminal C-methyl groups all have values characteristic for a typical single bond [1.4656 (12)–1.4687 (12) Å]. The acetylenic bond length [1.1889 (18) Å] is consistent with a triple C[triple-bond]C bond and the butyne carbon chain is almost linear. C—H...π interactions between the bisamidinium methyl H atoms and the phenyl C atoms of the tetraphenylborate ions are present. The phenyl rings form aromatic pockets, in which the cations are embedded. This leads to the formation of a two-dimensional supramolecular pattern in the ab plane.

In the crystal structure of the hydrated double salt, Cs+·[N(CH3)4]+·[B12H12]2−·H2O, the asymmetric unit contains one caesium and one tetramethylammonium cation, one dodecahydrido-closo-dodecaborate anion and one water molecule. The Cs+ cation is coordinated tetrahedrally by four [B12H12]2− clusters, with the water molecule completing the coordination sphere. The tetramethylammonium cation is surrounded distorted octahedrally by six [B12H12]2− anions. The crystal structure is stabilized by a three-dimensional network of O—H...H—B and C—H...H—B dihydrogen bonds.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The asymmetric unit of the solvated title compound, (C 7 H 18 N 3 ) 4 [Bi 4 Cl 16 ]·2CH 3 CN, comprises two cations, one half [Bi 4 Cl 16 ] 4− ion and one acetonitrile molecule. One N , N , N ′, N ′, N ′′, N ′′-hexamethylguanidinium ion shows orientational disorder and two sets of N- and C-atom positions were found, with an occupancy ratio of 0.941 (2):0.059 (2). The second cation is not disordered. The C—N bond lengths in the two guanidinium ions range from 1.334 (17) to 1.341 (17) Å, indicating double-bond character and pointing towards charge delocalization within the NCN planes. The four Bi III ions are coordinated by six chloride ions in distorted octahedral manner. Two [Bi 2 Cl 8 ] 2− dimers are fused together, forming a centrosymmetric tetranuclear [Bi 4 Cl 16 ] 4− cluster. The bond lengths of bismuth to the terminal chlorides [2.4982 (7)–2.5509 (6) Å] are shorter than those of the double and triply bridging ones [2.7052 (6)–3.0320 (6) Å]. The acetonitrile solvent molecule is disordered over two positions, with an occupancy ratio of 0.818 (4):0.182 (4) for the two orientations. The crystal structure is stabilized by a three-dimensional network of C—H...Cl hydrogen bonds.

The asymmetric unit of the title solvated salt, C11H28N42+·2C24H20B−·C3H6O, comprises two cations, four tetraphenylborate anions and two acetone molecules. One cation shows an orientational disorder at the CN3 moiety and two sets of N-atom positions were found related by a 60° rotation, with a refined occupancy ratio of 0.935 (1):0.065 (1). The respective nitrogen-bonded –CH2 and –CH3 groups are included in the disorder model. The C—N bond lengths in the central CN3 units of both guanidinium ions range between 1.3329 (17) and 1.364 (16) Å, indicating a degree of double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and one positive charge is delocalized in the CN3 plane. The C—N bond lengths in the terminal trimethylammonium groups have values close to a typical single bond, and the second positive charge is localized there. In the crystal, the guanidinium ions are connected by C—H...O hydrogen bonds with the acetone molecules. C—H...π interactions are present between the guanidinium and acetone hydrogen atoms and the phenyl rings of the tetraphenylborate ions, leading to the formation of a two-dimensional supramolecular pattern along the bc plane.

In the crystal structure of the title salt, C10H20N3O2+·C24H20B−, the C—N bond lengths in the cation are 1.327 (3), 1.339 (3) and 1.342 (3) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms, indicating only a slight deviation from a trigonal–planar geometry. The positive charge is delocalized in the CN3 plane. The ethoxy group is disordered over two orientations, with an occupancy ratio of 0.60 (1):0.40 (1). C—H...π interactions are present between the guanidinium H atoms and the phenyl C atoms of the tetraphenylborate ions. The phenyl rings form aromatic pockets, in which the cations are embedded. This leads to the formation of a two-dimensional supramolecular pattern along the ac plane.

The asymmetric unit of the title salt, 2C5H12N3O+·SO42−, comprises two cations and one sulfate ion. In both cations, the C, N and O atoms of the morpholine rings are disordered over two sets of sites, with refined occupancies of 0.849 (3):0.151 (3) for cation I and 0.684 (4):0.316 (4) for cation II. The C—N bond lengths in both central C3N units of the carboxamidinium ions range between 1.253 (12) and 1.362 (5) Å, indicating a degree of double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in both CN3 planes. The crystal structure is stabilized by a three-dimensional network of N—H...O hydrogen bonds between the cations and the sulfate ion. Scheme tiny font, charges and delocalized bonds almost invisible

The asymmetric unit of the hydrated title compound, C 26 H 42 N 6 2+ ·2Br − ·1.5H 2 O, comprises one cation, two bromide anions and one and a half water molecules, as one water molecule is fully occupied and the other is only half occupied [0.500 (6)]. Both bromide ions are disordered over two sites with refined occupancies of 0.938 (3):0.062 (3) and 0.520 (9):0.480 (9). The C—N bond lengths in both central C 3 N units of the bisguanidinium ion range between 1.336 (3) and 1.349 (3) Å, indicating a degree of double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in both CN 3 planes. The crystal structure is stabilized by a three-dimensional network of O—H...O, O—H...Br and C—H...Br hydrogen bonds.