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C Bond Angle (c + bond_angle)

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Chemistry	100%

Selected Abstracts

Sodium Hydro(isothiocyanato)borates: Synthesis and Structures

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2004
Heinrich Nöth
Abstract 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) [source]

Diaquatetrakis(tert -butyl isocyanide)cobalt(II) bis(perchlorate): an example of cobalt(II) coordinated by only four alkyl isocyanide ligands

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009
Clifford A. L. Becker
The title compound, [Co(C5H9N)4(H2O)2](ClO4)2, crystallizes in the monoclinic space group C2/m. The cation has space-group-imposed 2/m symmetry, while the perchlorate ion is disordered about a mirror plane. The two slightly non-equivalent Co,C bonds [1.900,(3) and 1.911,(3),Å] form a rectangular plane, with a C,Co,C bond angle of 86.83,(11)°, and the linear O,Co,O C2 axis is perpendicular to this plane. The C[triple-bond]N bond lengths are 1.141,(4),Å and the Co,C[triple-bond]N and C[triple-bond]N,C angles average 175.5,(4)°. The perchlorate counter-ions are hydrogen bonded to the water molecules. The title compound is the first example of four alkyl isocyanide ligands coordinating CoII upon initial reaction of Co(ClO4)2·6H2O/EtOH with alkyl isocyanide. In all other known examples, five alkyl isocyanide molecules are coordinated, as in [(RNC)5Co,Co(CNR)5](ClO4)4 (R = Me, Et, CHMe2, CH2Ph, C4H9 - n or C6H11) or [Co(CNC8H17 - t)5](ClO4)2. This complex, therefore, is unique and somewhat unexpected. [source]

Crystallographic report: Ethyltriphenyltin(IV), Et(Ph)3Sn

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2004
José S. Casas
Abstract The crystal lattice of the title compound comprises isolated molecules. The coordination polyhedron is a slightly distorted tetrahedron with C,Sn,C bond angles ranging from 106.62(17)° to 113.9(3)°. Copyright © 2004 John Wiley & Sons, Ltd. [source]

A comparison of 2,7-dihydro-2,2,7,7-tetramethyl-3,6-diphenyl-1,4,5-thiadiazepine and the corresponding 1,1-dioxide