Abstract
Three mercaptoamines have been lithiated in the presence of various Lewis bases. 2-Mercaptopyrimidine (I), containing a = NC(= S)NH- (as an amine)/ = NC(-SH)= N- (as a thiol) unit, affords [N activated = CHCH = CH(N..C..S)Li.hmpa]n 1. 2-Mercaptothiazoline (II), with a -SC(= S)NH-/-SC(-SH) = N- unit, gives [S activated CH2CH2(N..C..S)Li.tmen]n 2. 2-Mercaptobenzimidazole (III), having a -NHC(= S)NH-/-NHC(-SH) = N- unit, gives, when dilithiated, { activated C6H4[N..C(..S)..N]Li2.3hmpa}n 3 [hmpa = hexamethylphosphoramide, (Me2N)3P = O; tmen = Me2NCH2CH2NMe2]. The solid-state structures of complexes 1-3 were solved by X-ray crystallography. Complex 1 is polymeric (n = infinity): each unit contains a (N..C..S)Li chelate feature with a terminal hmpa molecule on Li, and these units are then associated via intermolecular N-->Li co-ordinations using the third (N) heteroatom of the organic anion. Complex 2 is a dimeric (n = 2) S-Li compound with each Li bearing a tmen molecule; dimerisation is achieved by N-->Li intermonomer interactions, but the third (ring S) heteroatom is not involved with metal centres. The dilithiated species 3 is also a dimer (n = 2) and each Li is chelated by an N..C..S unit of its organic dianion; the two end-Li atoms of the dimer are each co-ordinated to two terminal hmpa molecules, while the two central Li atoms are linked by two mu-hmpa molecules, which effect dimerisation. The structural diversities displayed by 1-3 have been probed, and thereby in part rationalised, by ab initio (6-31G basis set) and MNDO molecular-orbital calculations on the amine/thiol isomers of I-III, and on their uncomplexed and complexed lithiated derivatives (as monomers). In particular, the optimised structures predict and reproduce the (N..C..S)Li chelating modes found in 1 and 3, and help to explain why direct S-Li bonding is found in 2.
| Language | English |
|---|---|
| Pages | 765-776 |
| Number of pages | 12 |
| Journal | Journal of the Chemical Society, Dalton Transactions |
| Issue number | S |
| DOIs | |
| Publication status | Published - 1991 |
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Keywords
- arbinitio mo calculations
- lithium amide chemistry
- solid-state
- basis sets
- reactivity
- energies
- complexes
- diphenylamide
- aggregation
- solvation
Cite this
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Lithiations of mercaptoamines containing NC(S)NH–,–NHC(S)S– and –NHC(S)NH– units: syntheses, crystal structures and model molecular-orbital calculations. / ARMSTRONG, D R ; Mulvey, Robert; BARR, D ; PORTER, R W ; RAITHBY, P R ; SIMPSON, T R E ; SNAITH, R ; WRIGHT, D S ; GREGORY, K ; MIKULCIK, P .
In: Journal of the Chemical Society, Dalton Transactions, No. S, 1991, p. 765-776.Research output: Contribution to journal › Article
TY - JOUR
T1 - Lithiations of mercaptoamines containing NC(S)NH–,–NHC(S)S– and –NHC(S)NH– units: syntheses, crystal structures and model molecular-orbital calculations
AU - ARMSTRONG, D R
AU - Mulvey, Robert
AU - BARR, D
AU - PORTER, R W
AU - RAITHBY, P R
AU - SIMPSON, T R E
AU - SNAITH, R
AU - WRIGHT, D S
AU - GREGORY, K
AU - MIKULCIK, P
PY - 1991
Y1 - 1991
N2 - Three mercaptoamines have been lithiated in the presence of various Lewis bases. 2-Mercaptopyrimidine (I), containing a = NC(= S)NH- (as an amine)/ = NC(-SH)= N- (as a thiol) unit, affords [N activated = CHCH = CH(N..C..S)Li.hmpa]n 1. 2-Mercaptothiazoline (II), with a -SC(= S)NH-/-SC(-SH) = N- unit, gives [S activated CH2CH2(N..C..S)Li.tmen]n 2. 2-Mercaptobenzimidazole (III), having a -NHC(= S)NH-/-NHC(-SH) = N- unit, gives, when dilithiated, { activated C6H4[N..C(..S)..N]Li2.3hmpa}n 3 [hmpa = hexamethylphosphoramide, (Me2N)3P = O; tmen = Me2NCH2CH2NMe2]. The solid-state structures of complexes 1-3 were solved by X-ray crystallography. Complex 1 is polymeric (n = infinity): each unit contains a (N..C..S)Li chelate feature with a terminal hmpa molecule on Li, and these units are then associated via intermolecular N-->Li co-ordinations using the third (N) heteroatom of the organic anion. Complex 2 is a dimeric (n = 2) S-Li compound with each Li bearing a tmen molecule; dimerisation is achieved by N-->Li intermonomer interactions, but the third (ring S) heteroatom is not involved with metal centres. The dilithiated species 3 is also a dimer (n = 2) and each Li is chelated by an N..C..S unit of its organic dianion; the two end-Li atoms of the dimer are each co-ordinated to two terminal hmpa molecules, while the two central Li atoms are linked by two mu-hmpa molecules, which effect dimerisation. The structural diversities displayed by 1-3 have been probed, and thereby in part rationalised, by ab initio (6-31G basis set) and MNDO molecular-orbital calculations on the amine/thiol isomers of I-III, and on their uncomplexed and complexed lithiated derivatives (as monomers). In particular, the optimised structures predict and reproduce the (N..C..S)Li chelating modes found in 1 and 3, and help to explain why direct S-Li bonding is found in 2.
AB - Three mercaptoamines have been lithiated in the presence of various Lewis bases. 2-Mercaptopyrimidine (I), containing a = NC(= S)NH- (as an amine)/ = NC(-SH)= N- (as a thiol) unit, affords [N activated = CHCH = CH(N..C..S)Li.hmpa]n 1. 2-Mercaptothiazoline (II), with a -SC(= S)NH-/-SC(-SH) = N- unit, gives [S activated CH2CH2(N..C..S)Li.tmen]n 2. 2-Mercaptobenzimidazole (III), having a -NHC(= S)NH-/-NHC(-SH) = N- unit, gives, when dilithiated, { activated C6H4[N..C(..S)..N]Li2.3hmpa}n 3 [hmpa = hexamethylphosphoramide, (Me2N)3P = O; tmen = Me2NCH2CH2NMe2]. The solid-state structures of complexes 1-3 were solved by X-ray crystallography. Complex 1 is polymeric (n = infinity): each unit contains a (N..C..S)Li chelate feature with a terminal hmpa molecule on Li, and these units are then associated via intermolecular N-->Li co-ordinations using the third (N) heteroatom of the organic anion. Complex 2 is a dimeric (n = 2) S-Li compound with each Li bearing a tmen molecule; dimerisation is achieved by N-->Li intermonomer interactions, but the third (ring S) heteroatom is not involved with metal centres. The dilithiated species 3 is also a dimer (n = 2) and each Li is chelated by an N..C..S unit of its organic dianion; the two end-Li atoms of the dimer are each co-ordinated to two terminal hmpa molecules, while the two central Li atoms are linked by two mu-hmpa molecules, which effect dimerisation. The structural diversities displayed by 1-3 have been probed, and thereby in part rationalised, by ab initio (6-31G basis set) and MNDO molecular-orbital calculations on the amine/thiol isomers of I-III, and on their uncomplexed and complexed lithiated derivatives (as monomers). In particular, the optimised structures predict and reproduce the (N..C..S)Li chelating modes found in 1 and 3, and help to explain why direct S-Li bonding is found in 2.
KW - arbinitio mo calculations
KW - lithium amide chemistry
KW - solid-state
KW - basis sets
KW - reactivity
KW - energies
KW - complexes
KW - diphenylamide
KW - aggregation
KW - solvation
U2 - 10.1039/DT9910000765
DO - 10.1039/DT9910000765
M3 - Article
SP - 765
EP - 776
JO - Journal of the Chemical Society, Dalton Transactions
T2 - Journal of the Chemical Society, Dalton Transactions
JF - Journal of the Chemical Society, Dalton Transactions
SN - 0300-9246
IS - S
ER -