Nonaxial Hydrogen Bond in the Na<sup>+</sup>(12-Crown-4)<sub>2</sub>SCN·HOMe Complex

Schultz, Philip W.; Ward, Donald L.; Popov, and Alexander I.; Leroi, G. E.

doi:10.1021/jp961724t

Cited by 3 publications

(4 citation statements)

References 29 publications

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“…The BDEs are consistent with the fact that the N 3 ‐side‐on structures M‐2 a (M=Li–Cs) and M‐2 b (M= K–Cs) are more stable than their corresponding N 3 ‐end‐on structures M‐1 a (M=Li–Cs) and Li‐1 b . Consistent with the literature, a relationship between the BDE values and the distances between the alkali metal and the terminal N atoms (M−N1), for the N 3 ‐end‐on and N 3 ‐side‐on [M(cyclen)N 3 ] structures (M=Li–Cs), is observed along the alkali metal series. In general, the BDE values, associated with process (1), decrease with a systematic lengthening of the M−N1 bond necessitated by an increase in the size of the ionic radii of the M + ions (0.60, 0.98, 1.33, 1.49 and 1.69 Å, respectively) on going from Li + →Cs +…”

Section: Resultssupporting

confidence: 86%

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Bhakhoa

Rhyman

Lee

et al. 2016

Chemistry A European J

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Can cyclen (1,4,7,10‐tetraazacyclododecane) bind alkali metal azides? This question is addressed by studying the geometric and electronic structures of the alkali metal azide‐cyclen [M(cyclen)N3] complexes using density functional theory (DFT). The effects of adding a second cyclen ring to form the sandwich alkali metal azide‐cyclen [M(cyclen)2N3] complexes are also investigated. N3− is found to bind to a M+(cyclen) template to give both end‐on and side‐on structures. In the end‐on structures, the terminal nitrogen atom of the azide group (N1) bonds to the metal as well as to a hydrogen atom of the cyclen ring through a hydrogen bond in an end‐on configuration to the cyclen ring. In the side‐on structures, the N3 unit is bonded (in a side‐on configuration to the cyclen ring) to the metal through the terminal nitrogen atom of the azide group (N1), and through the other terminal nitrogen atom (N3) of the azide group by a hydrogen bond to a hydrogen atom of the cyclen ring. For all the alkali metals, the N3‐side‐on structure is lowest in energy. Addition of a second cyclen unit to [M(cyclen)N3] to form the sandwich compounds [M(cyclen)2N3] causes the bond strength between the metal and the N3 unit to decrease. It is hoped that this computational study will be a precursor to the synthesis and experimental study of these new macrocyclic compounds; structural parameters and infrared spectra were computed, which will assist future experimental work.

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Section: Resultssupporting

confidence: 86%

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Bhakhoa

Rhyman

Lee

et al. 2016

Chemistry A European J

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“…[5] Ref. [5] 1 Na(NCS)(14-crown-4) [9] MeNCS [8] We found in most samples of 1 an IR band at 2050 cm…”

Section: Bncsmentioning

confidence: 67%

“…The band at 2050 cm Ϫ1 is most likely due to the presence of NCS Ϫ , as can be deduced from the band found at 2045 cm Ϫ1 observed in Na(NCS) (15-crown-5). [9] In order to make reliable assignments we performed DFT calculations at the B3LYP/6-311**G(d,p) level. There should be two IR-active BϪH stretching frequencies at 2355 and 2358 cm…”

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confidence: 99%

Sodium Hydro(isothiocyanato)borates: Synthesis and Structures

Nöth

Warchhold

2004

Eur J Inorg Chem

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Sodium thiocyanate reacts in THF solution with 18‐crown‐6 to give the molecular compound Na(18‐crown‐6)(THF)NCS (3) with the N atom of the NCS anion oriented towards Na+. The same reaction with 15‐crown‐5 yields the ion pair Na(15‐crown‐5)NCS (4). In contrast, Na(NCS)(py)4, obtained by treating a solution of Na(H3BNCS) in THF with pyridine, yields Na(py)4(NCS) (5), which has a chain structure with hexacoordinate Na atoms coordinated to five N atoms and an S atom. Na(NCS) in THF adds 1 equiv. of BH3 to give Na(H3BNCS)·nTHF. Addition of 18‐crown‐6 to this solution yields crystals of the salt [Na(18‐crown‐6)(THF)2][H3BNCS] (1), as shown by X‐ray crystallography. Both the cation and the anion show site disorder. However, when 15‐crown‐5 is used for complexation, the salt [Na(15‐crown‐5)(THF)][H3BNCS] (2) can be isolated. Its anion shows an almost linear B−N−C−S unit. Only a mixture of (catecholato)(isothiocyanato)borates results on treating Na(NCS) in THF with catecholborane. However, the borate Na[catB(NCS)2] is readily formed by adding Na(NCS) to B‐(isothiocyanato)catecholborane. Single crystals of this compound were obtained as the salt [Na(18‐crown‐6)(THF)2][catB(NCS)2] (6). On the other hand, the reaction of Na(NCS) with 9‐borabicyclo[3.3.1]nonane (9‐BBN) in THF yields Na[(9‐BBN)NCS)]·nTHF, and, on addition of 18‐crown‐6, the complex [Na(18‐crown‐6)(THF)2][(9‐BBN)NCS] was isolated. Suitable crystals for X‐ray structure determination were, however, only obtained by crystallization from tetrahydropyran. This solvate has the rather unusual structure [Na(18‐crown‐6)(thp)2][{(9‐BBN)NCS}2Na(thp)4] (8). The sodiate anion has an Na atom coordinated by two S and four O atoms. DFT calculations support these experimental results: The (isothiocyanato)borates are more stable than the thiocyanato isomers. For the latter a bent structure of the B−S−C−N unit with a B−S−C bond angle of 105.7° is predicted. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…On the other hand, a nonaxial hydrogen bonded complex will be characterized by a red-shift for the ν CN stretch and a slight blue-shift in the ν CS stretch . In the infrared spectrum of this solvate the ν CN mode lies 12 cm -1 below that of the ν CN stretch in Na + (12C4) 2 SCN - .…”

Section: Resultsmentioning

confidence: 98%

Solvation of SCN^- and SeCN^- Anions in Hydrogen-Bonding Solvents

1996

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The primary solvation sphere surrounding the thiocyanate or the selenocyanide anion in protic solvents, such as methanol, N-methylformamide and formamide, forms intimate hydrogen bonds with these anions. These interactions perturb the electron density and vibrational modes of these anions and can therefore be studied by NMR and infrared spectroscopies. In neat solutions, these solvents form hydrogen bonds to the nitrogen end along the molecular axis and nonaxially to the π cloud of the C−N bond, although a substantial proportion of the anions is not hydrogen bonded. In nitromethane solutions, the thiocyanate and selenocyanide anions form weak complexes with methanol and the amide solvents (K < 1 M-1), which is an order of magnitude smaller than that of OCN- with the same solvents, determined in our previous investigation of the cyanate anion. The remarkable differences in the solvation of these singly charged anions can be understood by theoretical calculations of their electrostatic potentials.

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Nonaxial Hydrogen Bond in the Na⁺(12-Crown-4)₂SCN·HOMe Complex

Cited by 3 publications

References 29 publications

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Sodium Hydro(isothiocyanato)borates: Synthesis and Structures

Solvation of SCN^- and SeCN^- Anions in Hydrogen-Bonding Solvents

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Nonaxial Hydrogen Bond in the Na+(12-Crown-4)2SCN·HOMe Complex

Cited by 3 publications

References 29 publications

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Can Cyclen Bind Alkali Metal Azides? A DFT Study as a Precursor to Synthesis

Sodium Hydro(isothiocyanato)borates: Synthesis and Structures

Solvation of SCN- and SeCN- Anions in Hydrogen-Bonding Solvents

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Product

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Nonaxial Hydrogen Bond in the Na⁺(12-Crown-4)₂SCN·HOMe Complex

Solvation of SCN^- and SeCN^- Anions in Hydrogen-Bonding Solvents