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Synthesis and Reactivity of the Tl I salts of [TCNE] .− and [TCNE] 2− : The Structural Determination of Tl I [TCNE] and [TDAE][TCNE] 2 and Evidence for a Chelated [TCNE] .−
Author(s) -
Johnson Mitchell T.,
Campana Charles F.,
Foxman Bruce M.,
Desmarais William,
Vela Michael J.,
Miller Joel S.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/(sici)1521-3765(20000515)6:10<1805::aid-chem1805>3.0.co;2-l
Subject(s) - chemistry , crystallography , denticity , angstrom , triclinic crystal system , dimer , synthon , crystal structure , monoclinic crystal system , stereochemistry , organic chemistry
Abstract Synthons Tl I [TCNE] . − ( 1 ) and Tl I 2 [TCNE] 2− ( 2 ), for [TCNE] . − and [TCNE] 2− , respectively, in metathesis reactions have been quantitatively prepared and characterized. The structure of 1 was solved and refined in a monoclinic unit cell at 27 °C [ C 2/ c , a =12.6966 (12) Å, b =7.7599 (7) Å, c =15.5041 (15) Å, β =96.610 (5)°, V =1517.4 (2) Å 3 , D calcd =2.911 g cm −3 , Z =8, R 1 =0.0575, wR 2=0.0701] and exhibits ν CN absorptions at 2191 (s) and 2162 (s) cm −1 consistent with metal‐bound [TCNE] . − . The structure of 1 consists of a distorted square antiprismatic octacoordinate Tl I bound to six monodentate [TCNE] . − s with TlN separations ranging from 2.901 to 3.171 Å averaging 3.020 Å, and one bidentate [TCNE] . − with TlN separations averaging 3.279 Å. The TlN bonding is attributed to electrostatic bonding. The [TCNE] . − s form dimerized zigzag chains with intra‐ and interdimer separations of 2.87 and 3.29 Å, respectively. The tight π‐[TCNE] 2 2− dimer is diamagnetic and has the shortest intradimer [TCNE] . − distance reported. These synthons for [TCNE] . − and [TCNE] 2− in metathesis reactions lead to the precipitation of, for example, Tl I X (X=Cl, Br, OAc). Reaction of 1 with Mn III (porphyrin)X (X=Cl, OAc) forms the molecule‐based magnets of [Mn III (porphyrin)][TCNE] composition, while the reaction of [Cr I (C 6 H 6 ) 2 ]Br and (Me 2 N) 2 CC(NMe 2 ) 2 Cl 2 , [TDAE]Cl 2 , with 1 forms [Cr I (C 6 H 6 ) 2 ][TCNE] and [TDAE][TCNE] 2 , respectively. The structure of [TDAE][TCNE] 2 ⋅ MeCN was solved and refined in an orthorhombic unit cell at 21 °C [ I 222, a =10.2332(15), b =13.341(6), c =19.907(8) Å, V =2717.7 Å 3 , Z =4; D calcd =1.216 g cm −3 , R =0.083, Rw =0.104] and exhibits ν CN absorptions at 2193 (m), 2174 (s), and 2163 (s) cm −1 consistent with isolated [TCNE] 2 2− , in contrast to the aforementioned Tl I bound [TCNE] 2 2− . The reaction of 2 with [TDAE]Cl 2 forms [TDAE] 2+ [TCNE] 2− .