Inter- and intra-molecular pathways in polyamine synthesis from diamines

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Inter- and intra-molecular pathways in polyamine synthesis from

diamines†

Min-Ho Choi,^aBok Jo Kim,^bIl-Chool Kim,^cSeo-Hyang Kim,^aYang Kim,^a

Jack M. Harrowﬁeld,*^dMan-Kil Lee,^aMauro Mocerino,^eElisabeth Rukmini,^a

Brian W. Skelton^fand Allan H. White^f

^aDepartment of Chemistry, Kosin University, Yeongdo-gu, Pusan, 606-701, Korea

^bDepartment of Environmental Engineering, Kyung Woon University, Kumi, Korea

^cDepartment of Food and Biotechnology, Joong Bu University, Chung-Nam, Korea

^dSpecial Research Centre for Advanced Mineral and Materials Processing and

Department of Chemistry, University of Western Australia, Nedlands, WA 6907, Australia

^eSchool of Applied Chemistry, Curtin University of Technology, Bentley, WA 6102, Australia

^fCrystallography Centre and Department of Chemistry, University of Western Australia,

Nedlands, WA 6907, Australia

Received 19th October 2000, Accepted 18th December 2000

First published as an Advance Article on the web 12th February 2001

Characterisation, largely through crystal structure determinations of their metal complexes, of the polyamine

products of several reactions between (in all but one case) polyalcohol benzenesulfonates and 1,2- and 1,3-diamines,

conﬁrmed that intramolecular reaction pathways are important only in the 1,2-diamine reactions. Even under

conditions where the amine reactants are in large excess, however, it is possible to obtain products resulting from

alkylation of a diamine by more than one molecule of sulfonate (or, in one case, of a bromochloroalkane). In metal

ion complexes formed by the new ligands there are examples of only partial coordination of the N-donor sites, giving

species which might be suitable for further, selective functionalisation at the unbound centres. Conversion of the

complexes into macrocyclic derivatives also suited to further functionalisation is straightforward.

at 125.8 MHz) spectrometers. Chemical shifts are expressed in

Introduction

ppm relative to an internal standard of acetone, taken as

The structural variety of polyamines and the stability of their

1

being δ 2.22 for H and δ 30.89 for ¹³C spectra (relative to

complexes is reﬂected in a remarkable coordination chemistry.¹

TMS). Elemental microanalyses were carried out by the

It is this, paradoxically, which provides the impetus for further

Chemistry Centre of Western Australia, the Australian

investigation of their syntheses and their applications. The bio-

National University Microanalytical Service, and Kosin Uni-

logical activity of the proton complexes of many polyamines

versity Microanalytical Service. All samples were thoroughly

is well known²and the synthesis of rigidiﬁed analogues of

dried under vacuum (0.1 mmHg) at 50 ЊC for 4 hours prior to

naturally occurring polyamines is of potential therapeutic

their analysis. Ion exchange chromatography was performed

signiﬁcance.³We have sought to prepare new polyamines

under gravity ﬂow using H^ϩform Dowex 50W × 2 (200–400

which, in particular, might be used to provide functionalised

mesh) or Na^ϩform SP Sephadex C25 (200–400 mesh) cation

macro(poly)cyclic species suitable, amongst other things, for

exchange resins. All eluate evaporations were performed at

immobilisation on solid supports. The syntheses are based

predominantly upon the reactions of various diamines with

reduced pressure (≈ 20 mmHg) using a Büchi rotary evaporator

and a water aspirator. The Schlenk technique using high purity

polyol arylsulfonates (Fig. 1) and the product distributions

argon or nitrogen was employed wherever it was necessary to

reﬂect diﬀering degrees of competition between inter- and

exclude oxygen from preparative mixtures. UV-visible absorp-

intra-molecular pathways, as has been established in related

tion spectra (200–800 nm) were recorded on a Hewlett-Packard

earlier work.^4–8In the present publication we provide basic

characterisation of several amine families diﬀering with respect

8452A Diode Array or a Hitachi 3200 spectrophotometer.

Circular dichroism (CD) spectra were recorded using a JASCO

to donor atom separation, denticity and chirality, largely

J-200 Automatic Spectropolarimeter.

through structural characterisation of metal complexes of the

new amines.

Preparative chemistry

Glycerol (1,2,3-propanetriol), neopentyl glycol (2,2-dimethyl-

propane-1,3-diol), pentaerythritol (2,2-bis(hydroxymethyl)-

propane-1,3-diol), 1-bromo-3-chloro-2-methylpropane, ethane-

Experimental

Analytical and spectroscopic instrumentation

1,2-diamine,

propane-1,3-diamine,

(1R),(2R)-trans-cyclo-

Nuclear magnetic resonance spectra were acquired, usually in

hexane-1,2-diamine and benzenesulfonyl chloride were

purchased from Aldrich and used as received. The alcohols

were all converted into their benzene sulfonates (benzene-

sulfonyl esters) by literature procedures.^9,10All organic solvents

were distilled prior to use.

D₂O solvent, using Varian Gemini 200 (¹H at 200 MHz and ¹³

at 50.3 MHz) or Bruker ARX 500 (¹H at 500.13 MHz and ¹³

C

† Electronic supplementary information (ESI) available: unit-cell con-

tents for compounds 1, 5, 6, 8 and 12. See http://ww w .rsc.org/suppdata/

dt/b0/b008452m/

With one exception (see below) polyamine formation reac-

tions were all conducted by the common procedure of reaction

DOI: 10.1039/b008452m

J. Chem. Soc., Dalton Trans., 2001, 707–722

This journal is © The Royal Society of Chemistry 2001

707

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Fig. 1 Reaction pathways observed in some reactions of poly(benzenesulfonates) (benzenesulfonate = Bs) and one related material with diamines.

under nitrogen of a given polyalcohol poly(benzenesulfonate)

with a large excess (twentyfold molar ratio) of a given diamine

at the boiling point of the diamine, no solvent being added.

After cooling the reaction mixture, suﬃcient methanolic KOH

to neutralise the theoretical stoichiometric amount of acid

released was added and, after cooling again, any precipitated

potassium benzenesulfonate was ﬁltered out and washed with

diethyl ether. The ﬁltrate mixture was then distilled under

reduced pressure to remove as much as possible of the excess

of diamine (along with the methanol and ether). Initially,

following a procedure described in earlier literature,⁸the residue

was then treated with Co^IIunder oxidising conditions to give

a mixture of cobalt() complexes which was subjected to

cation exchange chromatography to achieve species separation.

Although this generally worked well to separate cleanly the

reaction products, the existence of isomeric forms of the com-

plexes of a given ligand occasionally led to a chromatographic

separation of much greater complexity than was necessary for

this purpose alone. As the ligands could in general be far more

easily removed from the copper() than their cobalt() com-

plexes, in later studies the product mixtures were separated

through cation exchange chromatography of their copper()

complexes. The “free” ligands were then isolated by treatment

of the complexes with an excess of HCl and precipitation of

their hydrochlorides by addition of ethanol. In achronological

order, the particular systems (Fig. 1) investigated were as

follows.

(i) Neopentyl glycol bis(benzenesulfonate) and ethane-1,2-

diamine. The crude amine mixture obtained from 4.8 g of the

sulfonate was added to a solution of CuSO₄ؒ5H₂O (3.2 g) in

water (200 mL) and the deep blue solution formed absorbed on

a column of Na^ϩform SP Sephadex C25 cation exchange resin.

Elution with 0.3 mol L^Ϫ1sodium chloride revealed six com-

ponents. F1, a minor component, contained only ethane-1,2-

diamine as the amine ligand and was discarded. The violet F2

was visually the major component and the complex in it was

obtained by evaporating the eluate to dryness and extracting

with ethanol to leave NaCl behind. Two further cycles of

evaporation and extraction of the residue with ethanol gave a

product (3.7 g) practically free of NaCl. F3 and F4 were trace

components and, because their green colour suggested they

were not amine complexes, both were discarded. The violet,

slowly eluting F5 and F6 were also present in small quantities

but treatment of their eluates as described for F2 provided 60

mg (F5) and 280 mg (F6). The hydrochlorides of the ligands

present in F2 (L¹), F5 and F6 (both L²) were isolated by dissolv-

ing the complexes in an excess of 0.5 mol L^Ϫ1HCl, adsorbing

the solution formed on H^ϩform Dowex 50W × 2 cation

exchange resin, removing Cu^IIby elution with 1 mol L^Ϫ1HCl,

708

J. Chem. Soc., Dalton Trans., 2001, 707–722

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the protonated ligands by elution with 3 mol L^Ϫ1HCl,

evaporation of the latter eluates to dryness under vacuum,

and crystallisation of the residues by trituration with ethanol.

Vapour diﬀusion of ethanol into solutions of ligand L²in

dilute HCl was used to produce crystals of 5 suitable for the

(50 mL) gave a pale blue solution which was diluted with water

(450 mL) and passed through H^ϩform Dowex 50W × 2. Free

Cu^IIwas removed by elution with 0.5 mol L^Ϫ1HBr, then the

protonated ligand was eluted with 3 mol L^Ϫ1HBr. The eluate

was taken to near dryness under vacuum and the ligand hydro-

bromide precipitated as a white powder by the addition of

ethanol. Found C, 18.7; H, 5.8; N, 7.7. [H₄L³]Br₄ؒHBrؒ

5H₂O = C₁₁H₄₃Br₅N₄O₅requires C, 18.58; H, 6.10; N, 7.98%.

1

X-ray work. H NMR spectra (D₂O solvent): F2 ligand (L¹),

δ 1.23 (s, CH₃, 6H), 3.21 (s, CH₂, 4H) and 3.48 (br s, CH₂, 8H);

F5 and F6 ligands (of L²), 1.23 (s, CH₃, 12H), 3.22 (s, CH₂, 8H),

3.49 (br s, CH₂, 8H) and 3.61 (s, CH₂, 4H). The complex present

in F2 was precipitated by addition of NaClO₄to its concen-

trated aqueous solution and cooling at 4 ЊC for 12 h and then

recrystallised similarly. Found C, 23.8; H, 5.2; N, 12.4. [Cu(L¹)]-

[ClO₄]₂= [Cu(C₉H₂₄N₄)][ClO₄]₂1 requires C, 23.98; H, 5.37;

N, 12.43%. As shown by a crystal structure determination (see

ahead), precipitation of the complex in the presence of high

concentrations of chloride resulted in deposition of a chloride

perchlorate, 4.

(iv) Neopentyl glycol bis(benzenesulfonate) and (1R),(2R)-

trans-cyclohexane-1,2-diamine. Chromatography as above of

the copper() complexes of the product revealed six blue

species but the ﬁrst was present in quantities too small for it to

be characterised and the second and fourth proved to be just

complexes of (1R),(2R)-trans-cyclohexane-1,2-diamine. The

third band contained far more material (4.14 g from 3.85 g of

sulfonate) than either of the ﬁfth and sixth fractions, though

suﬃcient material was present in these for it to be possible to

isolate the ligands present and show the two to have identical

(ii) 1-Bromo-3-chloro-2-methylpropane and ethane-1,2-

diamine. The commercial availability of this mixed-halide

alkylating agent was exploited for comparison with a closely

related tosylate as used above. A mixture of 1-bromo-3-chloro-

2-methylpropane (4.3 g) and ethane-1,2-diamine (30 g) was

heated under N₂at 120 ЊC for 72 h. After neutralisation with

NaOH and removal of NaCl/NaBr, the product mixture was

treated in exactly the same way as those obtained from the

benzenesulfonates. Chromatography of the copper() com-

plexes (SP Sephadex/0.3 mol L^Ϫ1NaCl) revealed three

components, the ﬁrst eluted being simply [Cu(en)₂]^2ϩ(trace), the

second [Cu(L^1Ј)]^2ϩand the third [Cu(L^2Ј)]^2ϩ. The eluate contain-

ing [Cu(L^1Ј)]^2ϩwas evaporated to dryness, the complex freed

from NaCl by extraction into ethanol (giving, on evaporation,

8.0 g of crude [Cu(L^1Ј)]Cl₂) and then crystallised from its

concentrated aqueous solution by addition of NaClO₄and

cooling to ≈4 ЊC. Found C, 21.6; H, 5.3; N, 12.7. [Cu(L^1Ј)]-

[ClO₄]₂= [Cu(C₈H₂₂N₄)][ClO₄]₂2, 3 requires C, 22.00; H, 5.08;

N, 12.83%. L^1Јwas isolated as its hydrochloride from the

complex as described above for L¹. NMR spectra (0.5 mol L^Ϫ1

DCl): ¹H δ 1.22 (d, J 9 Hz, CH₃, 3H), 2.49 (br m, CH, 1H), 3.16

(m), 3.31 (m) (CH₂of 3-carbon link, 4H) and 3.50 (br m,

NHCH₂CH₂NH₂, 8H); ¹³C δ 16.7 (CH₃), 30.9 (CH), 37.6, 47.1,

53.1 (CH₂). Similar treatments of the third eluate gave the crude

copper() chloride complex of L^2Ј(2.9 g) and subsequently the

ligand hydrochloride. NMR spectra (0.5 mol L^Ϫ1DCl): ¹H

δ 1.22 (d, J 12 Hz, CH₃, 6H), 2.52 (br m, CH, 2H), 3.18 (m),

3.32 (m) (CH₂of 3-carbon link, 8H) and 3.50 (m, “external”

NCH₂CH₂N, 8H) and 3.59 (br s, “internal” NCH₂CH₂N,

4H); ¹³C δ 16.1 (CH₃), 30.4 (CH), 36.9, 45.3, 46.4, 52.5, 52.6

(CH₂).

1

¹H NMR spectra. H NMR spectra (D₂O solvent): F3 ligand

(L⁴), δ 1.22 (s, CH₃, 6H); 1.3–2.4 (ill resolved multiplets, cyclo-

hexyl CH₂, 16H); 3.15, 3.37 (q, neopentyl CH₂, 4H, J_AB12 Hz);

3.42–3.64 (m, cyclohexyl CH, 4H); F5, F6 ligands, 0.98–2.40

(ill resolved multiplets with an intense singlet at 1.22); 3.00–3.60

(overlapping multiplets). For microanalysis, the copper()

complex of L⁴present in F3 was precipitated by addition of

NaClO₄to its concentrated solution in water. Found C, 35.2; H,

6.5; N, 9.5. [Cu(L⁴)][ClO₄]₂ؒH₂O = [Cu(C₁₇H₃₆N₄)][ClO₄]₂ؒH₂O

requires C, 35.39; H, 6.64; N, 9.71%.

(v) Glycerol tris(benzenesulfonate) and ethane-1,2-diamine.

The orange-brown colour of the crude amine mixture obtained

here appeared to be associated with poor yields of simple

polyamine products and the presence of seemingly large quan-

tities of dark brown to black materials in the cobalt() com-

plexes mixture which adhered very strongly to cation exchange

resins and which we have not succeeded in characterising. The

crude amine mixture obtained from 10.3 g of glycerol tris-

(benzenesulfonate) after 48 h reaction under N₂with boiling

ethane-1,2-diamine was dissolved in methanol (100 mL) con-

taining glacial acetic acid (1 mL) and CoSO₄ؒ7H₂O (5.7 g), and

air drawn through the solution for 3 h. The resulting brown

solution was acidiﬁed with concentrated HCl (10 mL) and

evaporated to near dryness on a steam bath. The residue was

dissolved in water (100 mL) and the solution absorbed on a

column of H^ϩform Dowex 50W × 2 cation exchange resin

to give a dark brown band at the head of the column. Elution

with 2 mol L^Ϫ1HCl rapidly removed a large quantity of Co^II,

followed by trace amounts of purple and green materials which

were possibly just bis(ethane-1,2-diamine)cobalt() species and

not further characterised. Continued elution removed a broad

yellow band which, after evaporation to dryness under vacuum,

was rechromatographed on SP Sephadex C-25 cation exchange

resin using 0.1 mol L^Ϫ1trisodium citrate as eluent. This pro-

vided four components, from which the complex cations

present were isolated by absorption of the eluate fractions on

H^ϩform Dowex 50W × 2, re-elution with HCl and evaporation

of these eluates to dryness under vacuum. Yields: F1(red), 0.33

g; F2(orange), 0.16 g; F3(yellow), 0.06 g and F4(yellow), 0.28 g

(ethanol-washed residues, vacuum dried). F3 was identiﬁed as

(iii) Neopentyl glycol bis(benzenesulfonate) and propane-1,3-

diamine. Chromatography as above of the copper() complexes

of the reaction products from 7.7 g of sulfonate revealed four

blue components. The ﬁrst eluted was by far the dominant

species and provided 5.6 g of solid after removal of NaCl. The

second band was a simple propane-1,3-diamine complex, and

the third and fourth very slowly eluted bands contained such

small amounts of complex that they could not be further

characterised. ¹H NMR spectrum (D₂O solvent): F1 ligand

(L³), δ 1.17 (s, CH₃, 6H); 2.05, 2.09, 2.13, 2.15, 2.17, 2.21 (m,

CH₂, 4H); 3.04, 3.08, 3.12, 3.18, 3.22 (m, δ 3.12 peak strongest,

CH₂, 12H). Addition of NaClO₄to a concentrated aqueous

solution of F1 gave a blue, crystalline precipitate which was

then converted back (anion exchange resin) into the chloride:

Found C, 34.0; H, 8.8; N, 14.5. [Cu(L³)]Cl₂ؒ2H₂O = [Cu(C₁₁-

H₂₈N₄)]Cl₂ؒ2H₂O requires C, 34.15; H, 8.34; N, 14.48%. Some

of this puriﬁed chloride was reprecipitated with perchlorate to

give crystals suitable for a structure determination, showing

that material to be a chloride perchlorate, [Cu₄(L³)₄Cl₂(OH₂)₂]-

[ClO₄]₆6. Dissolution of the chloride (0.5 g) in 1 mol L^Ϫ1HCl

1

[Co(en)₃]Cl₃on the basis of its H and ¹³C NMR spectra, and

discarded. All the other fractions showed very complicated

¹H NMR spectra with strongly overlapped multiplets in the

region δ ≈ 2–3.5 but the ¹³C spectra were all well resolved and

reﬂected the lack of any symmetry in the three molecules. ¹³C

NMR: F1, δ 40.57, 42.35, 43.98, 44.02, 44.75, 44.82, 51.08,

54.54 and 58.40 (CH); F2, 44.65, 44.96, 46.01, 47.40, 52.45,

53.21, 55.17, 60.27 (CH) and 62.89; F4, 40.81, 44.90, 46.35,

46.69, 46.82, 51.31, 51.50, 56.32 and 61.97 (CH) (all CH₂reson-

ances except where indicated). Found C, 24.3; H, 6.5; N, 18.9.

J. Chem. Soc., Dalton Trans., 2001, 707–722

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[Co(L⁵)(en)Cl]Cl₂ؒHClؒH₂O = [Co(C₇H₁₈N₄)(C₂H₈N₂)Cl]Cl₂ؒ

HClؒH₂O 7 requires C, 24.67; H, 7.13; N, 19.18%. Crystals of

F1 suitable for X-ray diﬀraction studies were grown by vapour

diﬀusion of ethanol into a solution of the complex in dilute

HCl. The hexamine nature of the ligand, L⁶, in F4 was inferred

from the conversion of F4 into a cage complex, structural

characterisation of which is reported elsewhere.¹¹

steam bath for 5 minutes to give a deep blue solution. This was

ﬁltered, diluted with ethanol (15 mL) and then with acetone

(50 mL). Deep blue microcrystals rapidly deposited and were

collected and washed with acetone and ether. Yield: 0.20 g.

Crystals of 9 suitable for X-ray crystallography were obtained

by slow evaporation of an aqueous solution, the nitrate 10

being obtained via anion exchange.

(vi) Glycerol tris(benzenesulfonate) and propane-1,3-diamine.

Reaction of the sulfonate (10.3 g) with propane-1,3-diamine (30

g) at reﬂux over 48 h again produced, after removal of as much

as possible of the excess of diamine by vacuum distillation,

a viscous, brownish oil which was then converted into its

cobalt() complexes as above. The mixture was directly

adsorbed onto Na^ϩform SP Sephadex C25 resin and the

various species present eluted using 0.1 mol L^Ϫ1trisodium

citrate. Co^IIwas ﬁrst removed, followed by a bis(propane-1,3-

diamine)cobalt() species, then a major band of a red-orange

complex. This third eluate fraction was resorbed on Dowex

50W × 2 and the complex present isolated by elution with 5 mol

L^Ϫ1HCl and evaporation of the eluate to dryness under

vacuum. The deliquescent residue was converted into the

chloride perchlorate by passage of its aqueous solution through

a column of perchlorate form Dowex 1 anion exchange resin, to

provide an air stable red-orange powder (2.8 g), the cobalt()

complex of L⁷. Visible spectrum in 1 mol L^Ϫ1HCl: λ_max481 nm,

ε_max103 M^Ϫ1cm^Ϫ1. δ ¹³C (in 1 mol L^Ϫ1DCl): 23.62, 26.78, 28.22,

39.04, 39.80, 40.89, 47.99, 49.21, 51.91, 55.18, 55.66 and 64.93

(CH). Found C, 26.1; H, 5.9; N, 14.5. [Co(L⁷)]Cl[ClO₄]₂= [Co-

(C₁₂H₃₂N₆)]Cl(ClO₄)₂requires C, 26.03; H, 5.82; N, 15.18%.

(viii) Pentaerythritol tetrakis(benzenesulfonate) and (1R),(2R)-

trans-cyclohexane-1,2-diamine. Reaction of 2.8 g of the sulf-

onate led ultimately to a green solution of cobalt() complexes

which was absorbed on a column of Dowex 50W × 2 cation

exchange resin. Elution with HCl solutions of concentrations

increasing from 0.2 to 4 mol L^Ϫ1revealed six components. The

ﬁrst eluted was Co^II, while the second, third and sixth species

were bis- and tris-cyclohexanediamine complexes of Co^III(as

Ϫ

revealed by isolation of the “free” ligand after BH₄reduction

in acid). The fourth and major green component provided a

green powder (1.1 g) on evaporation of its eluate to dryness.

The trace of material in the ﬁfth, purple band oﬀ the column

was not identiﬁed. To obtain crystals of the fourth fraction

suitable for X-ray diﬀraction, it was recrystallised from dilute

HCl by vapour diﬀusion of ethanol. Found C, 38.0; H, 7.9;

N, 11.6. [Co(H₂L⁹)Cl₂]Cl₃ؒ4.5H₂O = [Co(C₂₃H₄₆N₆)Cl₂]Clؒ

2HClؒ4ؒ5H₂O 11 requires C, 37.80; H, 8.00; N, 11.67%. Visible

spectrum (in 1 mol L^Ϫ1HCl): λ_max615 nm, ε = 47.9 M^Ϫ1cm^Ϫ1

Circular dichroism: 630, ∆ε = ϩ1.43; 563, ∆ε = Ϫ0.17; 450,

∆ε = ϩ0.55; 391 nm, ∆ε = Ϫ0.25 M^Ϫ1cm^Ϫ1

.

Macrocycle formation reactions based on the well established

template reaction of a linear tetramine complex with nitro-

ethane and formaldehyde^1b,12,13were investigated for the

copper() complexes of L¹and L^1Ј.

(vii) Pentaerythritol tetrakis(benzenesulfonate) and propane-

1,3-diamine. A remarkably large number of components (at

least 12) was observed on chromatography of the cobalt()

complexes of the polyamine product mixture but it was

apparent that this was at least partly a consequence of aquation

reactions of the initial complexes which occurred at a rate

similar to that of the chromatographic separation. By reduction

of the isolated cobalt() species with NaBH₄under acidic

conditions to release the attached ligands, it was found that

essentially only one product ligand was present along with

some unchanged propane-1,3-diamine. Fortunately, complexes

of the diamine eluted from Dowex 50W × 2/HCl as two bands

immediately following a cobalt() band and well separated

from slower-moving components, so that, although the various

cobalt() species were not identiﬁed, chromatography of the

complexes was useful for ligand puriﬁcation. Thus, all eluate

fractions subsequent to the ﬁrst three were combined and

evaporated to dryness under vacuum. The residue was dissolved

in water and an excess of NaBH₄, followed by enough concen-

trated HCl to make its concentration in the mixture ≈1 mol

(ix) The copper(II) complex of 6,6,13-trimethyl-13-nitro-

1,4,8,11-tetraazacyclotetradecane, L¹⁰. Nitroethane (0.85 g),

triethylamine (2.5 g) and aqueous formaldehyde (37%, 8 mL)

were added to a solution of [Cu(L¹)]Cl₂(4.1 g) in methanol (50

mL) and the mixture was heated and stirred at 50 ЊC for 5 h.

After evaporation to dryness and redissolution of the product

mixture in water, chromatography (SP Sephadex/0.3 mol L^Ϫ1

NaCl) provided separation of two components, the purple

leading band being reactant and the trailing reddish purple

band the desired macrocyclic product. Its eluate was taken

to dryness and the complex isolated as its chloride (3.2 g)

by extraction into ethanol and evaporation of this extract.

Crystals suitable for structure determinations were obtained

from this crude chloride both by addition of NaPF₆to its con-

centrated aqueous solution (and extended storage at ≈4 ЊC,

resulting in the chloride hexaﬂuorophosphate 12) and by con-

version into the nitrate 13 via anion exchange followed by pre-

cipitation from water by vapour diﬀusion of ethanol. Found C,

28.8; H, 5.7; N, 12.7. [Cu(L¹⁰)]Cl[PF₆]ؒ1.5H₂O = [Cu(C₁₃H₂₉-

N₅O₂)]Cl[PF₆]ؒ1.5H₂O requires C, 28.31; H, 5.82; N, 12.68%.

Found, C, 31.8; H, 6.1; N, 20.0; [Cu(C₁₃H₂₉N₅O₂)][NO₃]₂ؒH₂O

requires C, 31.67; H, 6.34; N, 19.89%.

L

^Ϫ1, was added to reduce Co^IIIto Co^II(indicated by vigorous

eﬀervescence and the deposition of a black precipitate which

slowly redissolved to give a pinkish solution). This solution was

absorbed on a column of Dowex 50W × 2 cation exchange

resin, free Co^IIeluted with 0.5 mol L^Ϫ1HCl and the colourless

protonated polyamine eluted with 5 mol L^Ϫ1HCl. The second

eluate was taken to near dryness, then triturated with ethanol to

give a white, crystalline solid. From 7.0 g of the tetrakis(benz-

enesulfonate), 4.8 g of the hydrochloride of L⁸were thereby

obtained. Crystals of the product suitable for X-ray diﬀraction

studies were grown by vapour diﬀusion of ethanol into a

concentrated aqueous solution. Analysis of the dried solid

corresponded to a considerably lower degree of hydration than

that deduced from the crystal structure (see ahead, 8). Found C,

29.6; H, 8.6; N, 15.6. L⁸ؒ8HClؒ2H₂O = C₁₇H₄₄N₈ؒ8HClؒ2H₂O

requires C, 29.67; H, 8.20; N, 16.27%. To prepare the copper()

complex of L⁸, the hydrochloride (0.35 g), Li₂CO₃(0.07 g) and

CuCO₃(0.12 g) were slurried with water (5 mL). After the

initial eﬀervescence had subsided, the mixture was heated on a

(x) The copper(II) complex of 6,13-dimethyl-6-nitro-1,4,8,11-

tetraazacyclotetradecane, L¹¹. Substituting [Cu(L^1Ј)]Cl₂(3.3 g)

for the reactant in preparation (ix), essentially identical

observations were made, though the product ultimately

obtained by recrystallisation (ethanol plus ether) of what was

presumed to be the crude chloride actually proved to be a tetra-

chlorocuprate, [Cu(L¹¹)][CuCl₄] 14 (6.1 g). Found C, 26.1;

H, 5.8; N, 12.2. [Cu(L¹¹)][CuCl₄]ؒ0.5H₂O = [Cu(C₁₂H₂₇N₅O₂)]-

[CuCl₄]ؒ0.5H₂O requires C, 26.15; H, 5.12; N, 12.70%.

Structure determinations

At the University of Western Australia diﬀraction data were

acquired in a number of modes, at the speciﬁed temperature,

710

J. Chem. Soc., Dalton Trans., 2001, 707–722

View Article Online

all instruments being equipped with monochromatic Mo-Kα

radiation, λ = 0.7107₃Å. Using a single counter instrument in

2θ–θ scan mode, N unique reﬂections were measured within

the speciﬁed 2θ_maxlimit, N_owith I > 3σ(I) being considered

‘observed’, Gaussian absorption corrections being applied

(structures 7–11). Data were also measured using a Bruker AXS

CCD instrument (structures 1, 2, 4–6, 12, 13) (2θ_max= 58Њ),

N_t(otal)reﬂections within a full sphere being merged to N unique,

R_intas speciﬁed after ‘empirical’/multiscan absorption cor-

rection within the proprietary/preprocessing software, the

‘observed’ criterion applicable being F > 4σ( F ). Anisotropic

thermal parameter forms were reﬁned in a full matrix context

for non-hydrogen atoms, (x, y, z, U_iso)_Hbeing constrained at

estimated values. Conventional residuals R, R_w(statistical

weights) on |F| are quoted at convergence. Neutral atom

complex scattering factors were employed within the Xtal 3.4

program system.¹⁴Reﬁnement in almost all determinations was

seriously impeded by disorder/‘thermal motion’/site occupancy

problems and ambiguities. Straightforward reﬁnements are

noted as such! Pertinent results are given in the Figures and

Tables below; individual variations in procedure/diﬃculties/

idiosyncrasies are cited as ‘variata’. For the room temperature

determinations, 20% displacement ellipsoids are shown, for the

low temperature, 50%. Hydrogen atoms, where shown, have

arbitrary radii of 0.1 Å. Two structure determinations (3, 14)

at Pukyong National University were performed (by BJK)

at room temperature using four-circle diﬀractometer data

(Mo-Kα radiation), with data collection, cell reﬁnement and

data reduction based on STOE proprietary software, while

the structure solution was obtained with SHELXS 97¹⁵and the

structure reﬁnement performed with SHELXL 97.¹⁵

[Cu(L^1Ј)(OؒClO₂ؒO)]_(∞|∞)ClO₄3. C₈H₂₂Cl₂CuN₄O₈, M = 436.7.

STOE instrument, T ca. 293 K. Monoclinic, space group P2₁/n

(C⁵_2h, no. 14 (variant)), a = 9.567(2), b = 13.745(3), c = 12.562(3)

Å, β = 91.26(3)Њ, V = 1652 Å³, D_c(Z = 4) = 1.75₆g cm^Ϫ3

,

µ_Mo= 16.9 cm^Ϫ1, specimen 0.30 × 0.30 × 0.20 mm, ‘T’_min,max

0.59, 0.81, N = 3780, N_o= 2774, R = 0.058, R_w= 0.14,

|∆ρ_max| = 0.5 e Å^Ϫ3

=

.

Variata. The bridging perchlorate was modelled as dis-

ordered over two sites of equal occupancy.

[Cu(L¹)Cl]ClO₄4. C₉H₂₄Cl₂CuN₄O₄, M = 386.8. CCD

instrument, T ca. 300 K. Orthorhombic, space group Pnma

16

2h

(D , no. 62), a = 11.246(1), b = 9.373(2), c = 15.291(2) Å,

V = 1612 Å³, D_c(Z = 4) = 1.59₄g cm^Ϫ3, µ_Mo= 17.0 cm^Ϫ1

,

specimen 0.40 × 0.20 × 0.18 mm; ‘T’_min,max= 0.75, 0.91,

N_t= 19214, N = 2235 (R_int= 0.022), N_o= 1847, R = 0.031,

R_w= 0.040; |∆ρ_max| = 0.44 e Å^Ϫ3

.

Variata. (x, y, z, U_iso)_Hwere reﬁned throughout; the perchlor-

ate was modelled with O(22,23) disordered, site occupancies

0.72(1) and complements.

[H₆L²]Cl₆.2H₂O 5. [(H₃N(CH₂)₂NH₂CH₂C(Me₂)CH₂NH₂-

CH₂)₂]Cl₆ؒ2H₂O ≡ C₁₆H₅₀Cl₆N₆O₂, M = 571.3. CCD instrument,

T ca. 153 K. Monoclinic, space group P2₁/c , a = 7.0501(8),

b = 18.946(2), c = 11.005(1) Å, β = 105.383(1)Њ, V = 1417 Å³, D_c

(Z = 2) = 1.33₉g cm^Ϫ3, µ_Mo= 6.3 cm^Ϫ1, specimen 0.45 × 0.35 ×

0.30 mm, ‘T’_min,max= 0.65, 0.96, N_t(CCD data) = 15638,

N = 3519 (R_int= 0.028), N_o= 3181, R = 0.026, R_w= 0.037,

|∆ρ_max| = 0.47 e Å^Ϫ3

.

Variata. Reﬁnement was straightforward, all hydrogen atoms

reﬁning in (x, y, z, U_iso).

Cu(L¹)(ClO₄)₂

؍

[Cu(L¹)(OؒClO₂ؒO)]_(∞|∞)ClO₄1. C₉H₂₄Cl₂-

CuN₄O₈, M = 450.8. CCD instrument, T ca. 153 K. Mono-

[{Cu(L³)(OH₂)}₂Cl][{Cu(L³)}₂Cl][ClO₄]₆6. C₄₄H₁₁₆Cl₈Cu₄-

N₁₆O₂₆, M = 1823.3. CCD instrument, T ca. 300 K. Mono-

clinic, space group C2/c (C⁶_2h, no. 15), a = 42.632(3),

b = 9.9729(8), c = 18.659(1) Å, β = 101.365(1)Њ, V = 7778 Å³, D_c

(Z = 4) = 1.55₇g cm^Ϫ3, µ_Mo= 14.3 cm^Ϫ1, specimen 0.40 × 0.25 ×

clinic, space group P2₁/c (C₂⁵_h

,

no. 14), a = 13.791(1),

b = 9.1815(8), c = 27.573(2) Å, β = 90.524(2)Њ, V = 3491 Å³,

D_c(Z = 8) = 1.71₅specimen

cm^Ϫ3µ_Mo= 16.0 cm^Ϫ1

g

,

0.45 × 0.40 × 0.36 mm, ‘T’_min,max= 0.51, 0.75, N_t= 51632,

0.20 mm, ‘T’_min,max= 0.70, 0.91, N_t= 34329, N = 9754 (R_int

=

N = 13588 (R_int= 0.036), N_o= 10597, R = 0.049, R_w= 0.059,

0.035), N_o= 5964, R = 0.043, R_w= 0.047, |∆ρ_max| = 0.65 e Å^Ϫ3

.

|∆ρ_max| = 1.6(1) e Å^Ϫ3

.

Variata. (x, y, z, U_iso) were reﬁned for all hydrogen atoms

except those associated with the water molecule which were

not located. Perchlorates 4,5 were modelled as rotationally

disordered about Cl(n)–O(n1), O(n2–4) having site occupancies

reﬁning to 0.79(1), 0.81(1) and complements respectively.

(These values are so similar that the disorder may be con-

certed.) Three quarters of a sphere of data were measured.

Variata. (x, y, z, U_iso) were reﬁned for all hydrogen atoms.

Anionic perchlorate oxygen atoms (O(42–44)) were modelled as

a pair of rotationally disordered components about Cl–O(41),

site occupancies 0.5; perchlorate 1 within the polymer was

modelled with the coordinated oxygen atoms O(11,12) ordered,

albeit with elongated displacement envelopes, while the remain-

ing ClO₂component was disordered over two sets of sites,

occupancies 0.5. 2θ_maxwas 68Њ. Since there is, not infrequently,

interest in the temperature-dependent behaviour of copper()

structures, we note that in this particular case a preliminary

determination was undertaken at room temperature (T ca. 300

K) (wherein the perchlorate disorder was not resolved). Cu–N

(room, low temperature) did not diﬀer signiﬁcantly at the

3σ level; Cu–O diﬀered rather more but, even so, by no more

than 0.02 Å. Data for the room temperature determination are

deposited. (Cell dimensions etc.: a = 13.887(1), b = 9.2532(9),

c = 27.778(3) Å, β = 90.634(2)Њ, V = 3569 Å³, R, R_w= 0.052,

0.069 for N_t= 40411, N = 8745 (R_int= 0.023), N_o= 6577

(2θ_max= 58Њ), |∆ρ_max| = 0.88(3) e Å^Ϫ3).

[Co(HL⁵)(en)Cl]Cl₃ؒH₂O 7. C₉H₂₉Cl₄CoN₆O, M = 438.1.

Single-counter instrument, T ca. 295 K. Triclinic, space group

1

¯

P1 (C_i, no. 2), a = 11.265(4), b = 10.177(2), c = 8.382(2) Å,

α = 97.91(2), β = 97.51(3), γ = 107.01(2)Њ, V = 895 Å³, D_c

(Z = 2) = 1.62₅g cm^Ϫ3, µ_Mo= 15.6 cm^Ϫ1, specimen 0.48 × 0.26 ×

0.41 mm, T_min,max= 0.52, 0.69, 2θ_max= 65Њ, N = 6056, N_o=

5347, R = 0.031, R_w= 0.041, |∆ρ_max| = 1.25 e Å^Ϫ3

.

Variata. Reﬁnement was straightforward, all hydrogen atoms

reﬁning in (x, y, z, U_iso).

[H₈L⁸]Cl₈ؒ7.5H₂O 8. C₁₇H₆₇Cl₈N₈O_7.5, M = 787.4. Single

counter instrument, T ca. 295 K. Monoclinic, space group C2/c,

a = 21.636(6), b = 17.446(5), c = 10.360(4) Å, β = 94.82(3)Њ,

[Cu(L^1Ј)(OClO₃)₂] 2. C₈H₂₂Cl₂CuN₄O₈, M = 436.7. CCD

instrument, T ca. 153 K. Monoclinic, space group P2₁(C ₂², no.

4), a = 8.368(1), b = 24.884(4), c = 8.508(1) Å, β = 114.917(3)Њ,

V = 3897 Å³, D_c(Z = 4) = 1.34₂g cm^Ϫ3, µ_Mo= 6.2 cm^Ϫ1

,

specimen 0.32 × 0.55 × 0.65 mm, T_min,max= 0.77, 0.83,

N(hemisphere) = 9154, N = 4439 (R_int= 0.033), N_o= 3142,

V = 1607 Å³, D_c(Z = 4) = 1.80₅g cm^Ϫ3, µ_Mo= 17.4 cm^Ϫ1

,

R = 0.057, R_w= 0.060, |∆ρ_max| = 0.69 e Å^Ϫ3

.

specimen 0.12 × 0.10 × 0.06 mm, ‘T’_min,max= 0.74, 0.89, N_t=

Variata. (x, y, z, U_iso)_Hwere reﬁned for the ligand; hydrogen

atoms were located in diﬀerence maps for O(1–3) and included

in the reﬁnement with constrained parameters. Other residues

O(4–6) were modelled as oxygen atoms only, occupancy 0.5,

0.25, 0.25, ‘Cl(5)’ also having occupancy 0.5 (caveat: cf. O),

with high ‘thermal motion’ evident among Cl(4,5), O(1–4).

16230, N = 4227 (R_int= 0.047), N_o= 3150, R = 0.042,

R_w= 0.041, |∆ρ_max| = 0.6(1) e Å^Ϫ3

.

Variata. An initial reﬁnement of x_abswith ‘Friedel pair’ data

preserved distinct gave a value of ca. 0.5. Accordingly, the

data were merged.

J. Chem. Soc., Dalton Trans., 2001, 707–722

711

View Article Online

[(CuCl)₂L⁸]Cl₂ؒ2H₂O 9. C₁₇H₄₈Cl₄Cu₂N₈O₂, M = 665.5.

Single counter instrument, T ca. 295 K. Triclinic, space group

N_o= 2383, R = 0.039, R_w= 0.095 (preferred hand), |∆ρ_max| = 0.5

e Å^Ϫ3

CCDC reference number 186/2308.

See http://ww w .rsc.org/suppdata/dt/b0/b008452m/ for crys-

tallographic ﬁles in .cif format.

.

¯

P1, a = 12.531(4), b = 12.271(2), c = 10.075(2) Å, α = 99.22(1),

β = 112.61(2), γ = 90.64(2)Њ, V = 1407 Å³, D_c(Z = 2) = 1.57₁g

cm^Ϫ3

,

µ_Mo= 19.2 cm^Ϫ1

,

specimen 0.65 × 0.75 × 0.48 mm,

T_min,max= 0.25, 0.47, 2θ_max= 56Њ, N = 6779; N_o= 5569, R =

0.047, R_w= 0.052, |∆ρ_max| = 0.91 e Å^Ϫ3

.

Results and discussion

1 Polyamines derived from propane-1,3-diamine

Variata. (x, y, z, U_iso)_Hwere reﬁned throughout except for the

water molecules for which they were not located.

Although propane-1,3-diamine units are commonly found as

constituents of polyamines and macrocycles,^1,16and linear

polyamines in particular have often been synthesized by

reactions similar to those of the present work,¹⁷little inform-

ation is available on direct comparison of 1,2- and 1,3-diamines

with respect to the competition between intra- and inter-

molecular pathways in reactions with electrophilic polyol

derivatives. As reaction of two sulfonate ester groups of the

same molecule with a diamine must result in the formation of

a larger ring from a 1,3- than from a 1,2-diamine, it might be

expected that intramolecular processes in the present systems

would be less prominent for 1,3- than for 1,2-diamines.¹⁸

Indeed, we have observed no evidence of cyclic products from

propane-1,3-diamine, meaning that the reaction products were

relatively simple to characterise and it is for this reason that we

have chosen to describe ﬁrst their syntheses.

[(CuONO₂)₂L⁸][NO₃]₂ؒ3H₂O 10. C₁₇H₅₀Cu₂N₁₂O₁₅, M =

789.8. Single counter instrument, T ca. 295 K. Orthorhombic,

15

2h

space group Pbca (D , no. 61), a = 22.843(9), b = 18.422(6),

c = 15.489(5) Å, V = 6518 Å³, D_c(Z = 8) = 1.60₉g cm^Ϫ3

,

µ_Mo= 13.9 cm^Ϫ1, specimen 0.95 × 0.35 × 0.23 mm, T_min,max

=

0.53, 0.68, 2θ_max= 50Њ, N(hemisphere) = 9636, N = 5735

(R_int= 0.082), N_o= 3810, R = 0.049, R_w= 0.061, |∆ρ_max| = 0.79

e Å^Ϫ3

.

Variata. (x, y, z, U_iso)_Hwere reﬁned throughout the ligand;

hydrogen atoms were located for water molecule 1 only and

constrained. O(3) was modelled as disordered over a pair

of sites, occupancies set at 0.5 after trial reﬁnement. The pro-

jection of the Figure does not show the elongation of the

ellipsoid of C(45), suggestive of conformational disorder in

that ring, resulting in associated torsion angle anomalies.

Reaction between the bis(benzenesulfonate) of neopentyl

glycol and propane-1,3-diamine gave essentially a single

product, L³(Fig. 1). Trace amounts of at least two other species

were observed as their copper() complexes but, on the basis

of results obtained for the ethane-1,2-diamine products (see

ahead), we assume that these were likely to have been derived

from a reaction pathway in which the initial steps are consecu-

tive reactions of propane-1,3-diamine with two molecules of

sulfonate. (While in all present reactions a large excess of

diamine was always used, it may be noted that the solutions

were actually moderately concentrated in polysulfonate.) The

¹H nuclear magnetic resonance spectrum of the bulk product

is completely consistent with a reaction in which amino groups

of two independent diamine molecules displace the sulfonate

groups of a single diol derivative molecule (Fig. 1). That the

product is a quadridentate amine of the “333-tet” type^1a,19

was conﬁrmed by the remarkable structure determined for its

copper() complex, 6, [Cu₄(L³)₄Cl₂(OH₂)₂][ClO₄]₆(Fig. 2). The

solid contains a pair of binuclear cations with (L³)Cu units

bridged in both by chloride entities, each disposed on a crystal-

lographic symmetry element, one a twofold axis, the other an

inversion centre. Cu(2)–Cl(2)–Cu(2) is thus (obligate) linear and

Cu(1)–Cl(1)–Cu(1) bent (162.49(6)Њ). Cu(2) is ﬁve-coordinate

but Cu(1) six-coordinate due to the approach of a residue

modelled as a water molecule oxygen (Cu(1)–O(01) 2.986(5) Å),

having little other apparent impact on the geometry about the

Cu (Tables 1(c), 2). Ligands of the 333-tet type are known to be

relatively unsuited to chelation of a single transition metal ion

because of the steric problems associated with the adoption

of the favoured chair conformation by all three fused six-

membered chelate rings,^1a,19though [Cu(333-tet)(ClO₄)]ClO₄

[3,3,3-tet = N,NЈ-bis(3-aminopropyl)-1,3-diamine] does contain

the chair–chair–chair form in the crystal,²⁰presumably because

the N₄donor atom array is able to distort well away from

planarity. A similar conclusion may apply in the present system,

since all four tetramine entities are bound in the chair–chair–

chair mode but again in association with marked deviations of

the N₄units from planarity.

[Co(H₂L⁹)Cl₂]Cl₃ؒ≈4.5H₂O 11. C₂₃H₅₇CoCl₅N₆O_4.5

, M =

438.1. Single counter instrument, T ca. 295 K. Orthorhombic,

space group P2₁2₁2₁(D₂⁴, no. 19), a = 17.339(7), b = 15.529(4),

c = 12.625(4) Å, V = 3399 Å³, D_c(Z = 4) = 1.41₈g cm^Ϫ3

,

=

µ_Mo= 9.4 cm^Ϫ1, specimen 0.42 × 0.32 × 0.75 mm, T_min,max

0.68, 0.75, 2θ_max= 60Њ, N = 5459, N_o= 4124, R = 0.046, R_w=

0.048 (preferred hand), |∆ρ_max| = 0.7 e Å^Ϫ3

.

Variata. Site occupancy of O(5) was constrained to 0.5 after

trial reﬁnement. Hydrogen atoms were not located for O(3–5),

the remainder being included with parameters constrained at

estimates.

[Cu(L¹⁰)Cl(OH₂)]PF₆ؒ0.5H₂O 12. C₁₃H₃₂ClCuF₆N₅O_3.5P,

M = 558.4. CCD instrument, T ca. 153 K. Monoclinic, space

group P2₁/n, a = 6.5904(8), b = 17.471(2), c = 19.014(2) Å,

β = 96.038(2)Њ, V = 2177 Å³, D_c(Z = 4) = 1.70₃

g

cm^Ϫ3

,

µ_Mo= 12.8 cm^Ϫ1, specimen 0.15 × 0.10 × 0.06 mm, ‘T’_min,max

=

0.76, 0.93, N_t= 21705, N = 5523 (R_int= 0.055), N_o= 3592,

R = 0.051, R_w= 0.056, |∆ρ_max| = 0.73(9) e Å^Ϫ3

.

Variata. The hexaﬂuorophosphate was disordered, resolved

residues for F(2) – F(6) being modelled as pairs of components,

site occupancies set at 0.5 after trial reﬁnement. Hydrogen

atoms were not resolved in association with a further residue,

modelled as half a water molecule oxygen, nor with the

coordinated water molecule oxygen.

[Cu(L¹⁰)(ONO₂)₂]ؒH₂O 13. C₁₃H₃₁CuN₇O₉, M = 493.0. CCD

instrument, T ca. 153 K. Monoclinic, space group C2/c,

a = 19.018(3), b = 9.015(2), c = 12.256(2) Å, β = 97.504(2)Њ,

V = 2083 Å³, D_c(Z = 4) = 1.57₂g cm^Ϫ3, µ_Mo= 11.1 cm^Ϫ1

,

specimen 0.45 × 0.40 × 0.05 mm, ‘T’_min,max= 0.60, 0.86,

N_t= 9784, N = 2559 (R_int= 0.029), N_o= 2227, R = 0.038,

R_w= 0.042, |∆ρ_max| = 0.65 e Å^Ϫ3

.

Variata. Modelling in space group C2/c entails disorder of

the molecule, and the lattice water, about inversion centres,

manifest in half-weighting of the nitro and methyl-12 moieties,

hydrogen atoms in association with the latter not being

resolved. Other hydrogens were reﬁned in (x, y, z, U_iso)_H.

Unlike the sulfonate of neopentyl glycol (and those of related

polyols such as pentaerythritol and 1,1,1-tris(hydroxymethyl)-

ethane), the trisulfonate of glycerol can undergo base-catalysed

elimination as an alternative to nucleophilic substitution and

we assume this is the reason for the relatively poor yields of

substitution products in the reactions we have studied of this

sulfonate. Nonetheless, it is possible in the case of reaction with

[Cu(L¹¹)][CuCl₄] 14. C₁₂H₂₇Cl₄Cu₂N₅O₂, M = 542.3. STOE

instrument, T ca. 298 K. Monoclinic, space group Cc (C_s⁴,

no. 9), a = 17.439(4), b = 8.037(2), c = 15.946(3) Å, V = 2063 Å³,

D_c(Z = 4) = 1.74₆g cm^Ϫ3, µ_Mo= 26.0 cm^Ϫ1, specimen 0.50 ×

0.30 × 0.20 mm, ‘T’_min,max= 0.62, 0.74, 2θ_max= 55Њ, N = 2383,

712

J. Chem. Soc., Dalton Trans., 2001, 707–722

View Article Online

Fig. 3 The [H₈L⁸]^8ϩcation, in the octachloride salt, 8, projected

normal to the crystallographic 2 axis which lies horizontal in the page.

A ﬁgure showing the unit cell contents, projected down c, is deposited

as ESI.

methylene units between every basic site,²³though the crystal

structure (Fig. 3) shows an extended array which is presumably

partly determined by repulsions between the charge centres.

One half of the formula unit comprises the asymmetric unit of

the structure, the cation disposed with the central quaternary

carbon atom lying on a crystallographic 2 axis. Torsion angles

in the branches, outwards from C(1)–N(2) are 177.7(3),

Ϫ178.3(3), 177.4(3), Ϫ169.6(3) (branch 1) and 179.9(3),

Ϫ172.1(3), Ϫ66.9(6), Ϫ67.3(6)Њ (branch 2), predominantly

trans, so that the cation is sprawling rather than compact.

Despite the high charge, one of the anions is ill deﬁned, as is a

substantial water complement, these moieties being disordered/

partly occupied. Hydrogen bonding is extensive but again

dominated by a few short contacts, most especially anion-

protonated amine group (speciﬁed by N ؒ ؒ ؒ Cl (< 3.5 Å) rather

than H ؒ ؒ ؒ Cl distances in view of the relatively imprecise

hydrogen locations here): Cl(1) ؒ ؒ ؒ N(12,22,26), N(26)(1¹ Ϫ x,

Fig. 2 (a),(b) Projections of the two cations of [{Cu(L³)(OH₂)}₂Cl]-

[{Cu(L³)}₂Cl][ClO₄]₆, 6, cation 1 lying on a crystallographic 2 axis, and

2 about an inversion centre. A ﬁgure showing the unit cell contents,

projected down b, is deposited as Electronic Supplementary Material

(ESI).

¯

²

propane-1,3-diamine to isolate a hexamine species, L⁷(Fig. 1),

in acceptable yield, with no evidence being obtained for the

presence of other substitution products. The cobalt() complex

of this hexamine has the pinkish yellow colour typical of

tris(1,3-diamine) complexes (and distinguishing them from

yellow tris(1,2-diamine species) but there is evidence from its

¹³C nuclear magnetic resonance spectrum that it may exist in

two diastereomeric forms, unlike the complex of the analogous

hexamine (“stn”) derived from reaction of 1,1,1-tris(hydroxy-

methyl)ethane derivatives.^4,21Eﬀorts to obtain crystals of

the material suitable for a structure determination were

unsuccessful.

Analysis of the products of the reaction of the tetrakis-

(benzenesulfonate) of pentaerythritol with propane-1,3-

diamine by formation and chromatography of their cobalt()

complexes proved unfortunate because of the (unsurprising)

lability^21,22of these complexes, although the chromatography

was still seemingly useful in enabling separation of simple

propane-1,3-diamine complexes from others. As ﬁrst demon-

strated by a crystal structure determination of the hydro-

chloride of the “free” ligand 8, once again a single polyamine,

an octamine L⁸derived by substitution involving four

independent diamine units (Fig. 1), was the only signiﬁcant

product. Ready isolation of the fully protonated octamine

is consistent with the minimum separation of at least three

1¹ Ϫ y, 1 Ϫ z) 3.058(4), 3.195(4), 3.187(5) (quasi-tridentate)

¯

²

3.267(4); Cl(2) ؒ ؒ ؒ N(22), N(16)(x, 1 Ϫ y, z Ϫ ¹), (1¹ Ϫ x, ¹ ϩ y,

¯

²

¯

²

¯

²

¹ Ϫ z), N(26) (1¹ Ϫ x, 1¹ Ϫ y, 1 Ϫ z) 3.385(4), 3.368(5), 3.129(5),

3.320(4); Cl(3) ؒ ؒ ؒ N(16)(x, 1 Ϫ y, z Ϫ ¹), N(26)(1¹ Ϫ x, 1¹ Ϫ y,

1 Ϫ z) 3.186(5), 3.129(4) Å. Cl(4), disposed on a crystal-

lographic axis, is surrounded by water molecules:

Cl(4) ؒ ؒ ؒ O(01)(1 Ϫ x, 1 Ϫ y, 1 Ϫ z) (x, 2 Ϫ y, ¹ ϩ z), O(02)(x,

¯

²

¯

²

¯

²

¯

²

¯

²

¯

²

2

¯

²

y, z), (1 Ϫ x, y, 1¹ Ϫ z) 2.996(5) (× 2), 2.908(5) (× 2), as is

¯

²

the half-occupied ‘Cl(5)’, Cl(5) ؒ ؒ ؒ O(04), O(05)(1 Ϫ x, y,

1¹ Ϫ z), (1 Ϫ x, 1 Ϫ y, 1 Ϫ z), O(06) (1 Ϫ x, y, 1¹ Ϫ z) 3.06(1),

¯

²

¯

²

3.17(2), 2.82(2), 2.64(2), the latter also contacting N(12) (x, y, z)

(1 Ϫ x, 1 Ϫ y, 1 Ϫ z) 3.059(6), 3.106(7) Å. O ؒ ؒ ؒ O, N contacts

also are found (< 3 Å): O(01) ؒ ؒ ؒ O(01) (1 Ϫ x, y, ¹ Ϫ z),

¯

²

O(02)(1 Ϫ x, y, ¹ Ϫ z) 3.010(7), 2.726(7), N(22) 2.826(6);

O(02) ؒ ؒ ؒ O(03) (1 Ϫ x, y, ¹ Ϫ z) 2.731(8); O(03) ؒ ؒ ؒ O(04),

N(16) (x, 1 Ϫ y, ¹ ϩ z) 2.700(9), 2.893(8); O(04) ؒ ؒ ؒ O(05) (x, y,

z) (1 Ϫ x, y, 1¹ Ϫ z) 2.246(2) Å.

¯

²

¯

²

¯

²

¯

²

In complexes of L⁸with both copper() chloride, 9, and

nitrate, 10, the ligand functions as a binucleating species,

binding two ﬁve-coordinate CuN₄X (X = Cl or NO₃) units in

which the geometry may be considered intermediate between

square-pyramidal and trigonal bipyramidal. Although in both

species the mean CuN₄planes are close to coplanar, there is an

interesting diﬀerence between the two in that unidentate nitrate

ligands bind on the same side (“cis”) while chloride ligands

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Table 1 Copper atom environments (distances in Å, angles in Њ) of N₄Cu(X)(Y) entities in complexes of L¹and L³

(a) [Cu(L¹)(OClO₂O)]_(∞|∞)ClO₄1, [Cu(L^1Ј)(OClO₃)₂] 2 and [Cu(L^1Ј)(OClO₂O)]_(∞|∞)ClO₄3. Values are for molecules 1 and 2 of 2, ‘cations’ 1 and 2 of 1,

and 3

Atom

r

N(n6)

N(n3Ј)

N(n6Ј)

O(n1)^a

O(n 1 2)

N(n3)

2.045(5), 1.991(6)

2.011(2), 2.020(2)

2.010(4)

84.4(2), 85.9(2)

85.54(9), 85.36(9)

84.9(2)

93.0(2), 93.9(2)

93.25(9), 93.60(8)

94.4(2)

179.0(2), 179.0(2)

179.1(1), 175.9(1)

177.9(2)

88.3(2), 89.9(2)

96.8(1), 98.58(8)

101.2(8)

94.9(2), 90.3(2)

84.13(8), 82.12(8)

93.3(8)

N(n6)

N(n3Ј)

N(n6Ј)

O(n1)

O(n1Ј)

2.016(5), 2.031(5)

2.011(2), 2.007(3)

2.003(5)

2.024(4), 2.018(5)

2.018(2), 2.009(2)

2.007(4)

1.978(5), 2.024(5)

2.014(2), 2.012(3)

2.009(5)

2.540(6), 2.518(6)

2.572(3), 2.551(2)

2.69(2)

176.4(3), 177.6(2)

176.26(9), 178.10(9)

178.7(2)

96.4(2), 95.0(2)

95.4(1), 95.9(1)

95.4(2)

86.2(2), 85.2(2)

85.83(9), 85.3(1)

85.2(2)

93.0(2), 92.8(2)

98.82(9), 92.52(9)

100.2(6)

89.5(2), 89.6(2)

84.82(9), 86.06(8)

78.8(6)

91.2(2), 90.5(2)

83.0(1),85.3(1)

76.7(5)

87.4(2), 86.4(2)

82.58(8), 84.41(9)

73.0(8)

90.3(2), 91.2(2)

93.78(7), 97.03(8)

108.2(8)

85.6(2), 89.4(2)

96.05(9), 94.1(2)

88.9(8)

176.8(2), 179.2(2)

178.37(8), 176.79(8)

164(1)

2.517(6), 2.556(6)

2.577(2), 2.591(2)

2.50(2)

1

b

1

–

(b) [Cu(L )Cl]ClO₄4. Primed atoms are generated by the mirror plane through the copper atom; Cl(1*) is generated by (x Ϫ ₂, 1₂Ϫ y, ₂Ϫ z)

Atom

r

N(3)

N(6)

Cl(1*)

N(3Ј)

N(6Ј)

Cl(1)

N(3)

N(6)

2.6885(7)

2.013(1)

2.023(2)

2.908(7)

92.55(5)

94.62(7)

85.27(7)

171.14(2)

(81.40(5))

(91.33(7))

81.40(5)

93.11(6)

(172.71(8))

91.33(7)

172.71(8)

95.45(8)

Cl(1*)

(94.62(7))

(c) [{Cu(L³)(OH₂)}₂Cl][{Cu(L³)}₂Cl][ClO₄]₆6. Values for cation n = 2 are given italicised below those for cation n = 1^c

Atom

r

N(n3)

N(n7)

N(n3Ј)

N(n7Ј)

Cl(n)

O(01)

N(n3)

2.986(5)

2.065(3)

2.063(3)

2.019(4)

2.057(4)

2.067(3)

2.060(3)

2.064(4)

2.036(4)

2.5808(5)

2.5887(4)

74.3(1)

80.8(2)

92.3(2)

85.7(1)

97.2(1)

95.6(1)

96.0(1)

171.1(1)

153.0(1)

82.9(2)

157.2(2)

170.2(1)

84.9(2)

84.6(2)

86.2(2)

165.31(9)

93.26(9)

91.06(8)

92.2(1)

112.4(1)

91.6(1)

94.49(8)

109.5(1)

91.4(1)

N(n7)

N(n3Ј)

N(n7Ј)

Cl(n)

93.2(1)

^aFor Cu(2) of structure 1 read O(21) (1 ϩ x, y, z). Angles subtended by the pairs of heavy atoms at O(11), O(12) are 122.6(5)/124.0(5), 127.4(5)/

128.3(4) and at O(21,22) are 131.7(1), 129.5(1)Њ. The entry for 3 corresponds to the array with the shorter pair of Cu–O distances, O(12Ј), O(14Ј)

1

2

1

–

᎐

–

(₂Ϫ x, ϩ y, 1 Ϫ z) ᎐ O(n1), O(n 1 2). For the other perchlorate component, Cu ؒ ؒ ؒ O(13), O(14) (₂Ϫ x, ₂ϩ y, 1₂Ϫ z) are 3.00(1), 2.755(8) Å.

᎐

^bCu lie²s 0.127(1) Å out of the (exact) N₄plane; Cl–Cu–Cl* is 167.95(3)Њ. ^cCl(2) lies on a crystallographic inversion centre, Cl(1) at twofold axis;

Cu(1)–Cl(1)–Cu(1Ј) is 162.49(6)Њ. Atom deviations from the N₄‘planes’ (χ²4837, 10266) are (N(3,3Ј,7,7Ј)Cu) Ϫ0.100(4), 0.116(4), 0.224(6),

Ϫ0.264(6), 0.224(1) (Cu(1)), Ϫ0.162(4), 0.155(4), 0.318(4), 0.270(5), Ϫ0.241(1) Å (Cu(2)).

Table 2 Ligand torsion angles (Њ) for structures 1 (‘cations’ 1,2), 2 (molecules 1,2), 3, 4 and 6 (‘cations’ 1,2)^a

Atoms

1

2

3

4

6

C(2Ј)–C(1)–C(2)–N(3)

C(2)–C(1)–C(2Ј)–N(3Ј)

C(1)–C(2)–N(3)–C(4)

C(1)–C(2Ј)–N(3Ј)–C(4Ј)

C(1)–C(2)–N(3)–Cu

C(1)–C(2Ј)–N(3Ј)–Cu

C(2)–N(3)–C(4)–C(5)

C(2Ј)–N(3Ј)–C(4Ј)–C(5Ј)

Cu–N(3)–C(4)–C(5)

Cu–N(3Ј)–C(4Ј)–C(5Ј)

N(3)–C(4)–C(5)–N(6)

N(3Ј)–C(4Ј)–C(5Ј)–N(6Ј)

C(4)–C(5)–C,N(6)–Cu,N(7)

C(4Ј)–C(5Ј)–C,N(6Ј)–Cu,N(7Ј)

Ϫ66.0(5), Ϫ66.3(5)

66.4(5), 66.6(5)

Ϫ179.34(4), Ϫ179.6(3)

176.8(4), 179.6(3)

56.9(4), 56.2(4)

Ϫ57.9(4), Ϫ56.3(4)

Ϫ172.1(4), Ϫ170.73(3)

168.1(4), 173.8(4)

Ϫ42.7(4), Ϫ40.5(4)

37.6(4), 44.0(4)

Ϫ69.5(8), Ϫ67.2(8)

67.0(8), 71.3(8)

Ϫ177.6(6), 179.9(6)

Ϫ179.9(6), 175.0(6)

59.9(7), 55.6(8)

Ϫ55.8(7), Ϫ61.5(7)

Ϫ171.2(6), Ϫ172.2(6)

171.1(6), 167.1(6)

Ϫ43.5(7), Ϫ42.0(7)

40.8(7), 39.0(7)

Ϫ69.2(7)

70.2(7)

179.4(5)

179.9(6)

54.9(6)

Ϫ56.7(7)

Ϫ174.7(5)

174.9(5)

Ϫ44.5(5)

45.4(5)

Ϫ65.9(2)

—

Ϫ178.3(2)

—

57.6(2)

—

Ϫ175.1(2)

—

Ϫ44.9(2)

—

55.3(2)

—

Ϫ37.0(2)

—

Ϫ69.9(5), Ϫ70.4(4)

72.8(4), 70.1(4)

Ϫ179.9(4), 180.0(3)

178.4(3), 178.0(3)

46.7(5), 51.2(4)

Ϫ52.5(4), Ϫ50.1(4)

170.8(4), 163.9(4)

Ϫ163.9(4), Ϫ171.1(4)

Ϫ54.9(4), Ϫ64.9(4)

64.4(5), 56.1(4)

55.0(5), 54.9(5)

56.0(8), 53.3(8)

56.1(6)

72.0(6), 63.3(5)

Ϫ52.6(5), Ϫ53.7(5)

Ϫ39.4(5), Ϫ41.8(4)

40.6(4), 36.6(5)

Ϫ54.6(8), Ϫ53.9(8)

Ϫ39.9(7), Ϫ37.5(7)

40.6(7), 41.6(7)

Ϫ56.8(7)

Ϫ39.4(6)

38.6(6)

Ϫ66.1(4), Ϫ75.8(5)

Ϫ67.7(7), Ϫ64.3(5)

64.8(6), 66.8(5)

^aFor compound 6, C(5)–C(6)–N(7)–Cu are 53.3(6), 69.6(3) with primed counterparts Ϫ67.3(5), Ϫ45.8(5)Њ.

714

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Fig. 4 Projections of the cations of [(CuX)₂L⁸]X₂ؒnH₂O (a) 9, X = Cl, n = 2, and (b) 10, X = NO₃, n = 3 normal to the moiety ‘plane’. (c) Schematic

diagram of the intra-ring torsion angles as descriptors of ring conformations for the two complexes (s.u.’s typically 0.3, 0.6 Њ).

Table 3 Selected cation geometries (distances in Å, angles in Њ) of [(CuX)₂L⁸]^2ϩ(X = Cl 9 or ONO₂10). Values for the nitrate are given in italics below

those for the chloride. Segments 1/2 and 3/4 pertain to the environs of Cu(1) and Cu(2) respectively

Segment 1/2 (n = 1 or 2)

Segment 3/4 (n = 3 or 4)

Cu(1)–X(1)

Cu(1)–N(n2)

Cu(1)–N(n6)

2.685(1)

2.371(4)

2.086(4), 2.028(3)

2.068(4), 2.020(5)

1.994(3), 2.035(6)

1.980(5), 2.014(6)

Cu(2)–X(2)

Cu(2)–N(n2)

Cu(2)–N(n6)

2.700(1)

2.506(5)

2.076(3), 2.054(4)

2.032(4), 2.048(4)

2.023(5), 2.025(3)

2.016(6), 1.987(7)

X(1)–Cu(1)–N(n2)

X(1)–Cu(1)–N(n6)

N(n2)–Cu(1)–N(n6)

N(n2)–Cu(1)–N(nЈ6)

N(12)–Cu(1)–N(22)

N(16)–Cu(1)–N(26)

C(n1)–N(n2)–C(n3)

Cu(1)–N(n2)–C(n3)

Cu(1)–N(n2)–C(n1)

Cu(1)–N(n6)–C(n5)

111.19(9), 93.21(9)

107.7(2), 85.4(2)

88.1(1), 98.2(1)

87.0(2), 106.4(2)

90.3(2), 90.0(2)

90.0(2), 93.5(2)

150.5(2), 178.2(2)

145.9(2), 172.2(2)

90.4(1)

X(2)–Cu(2)–N(n2)

X(2)–Cu(2)–N(n6)

N(n2)–Cu(2)–N(n6)

N(n2)–Cu(1)–N(nЈ6)

N(32)–Cu(2)–N(42)

N(36)–Cu(2)–N(46)

C(n1)–N(n2)–C(n3)

Cu(1)–N(n2)–C(n3)

Cu(2)–N(n2)–C(n1)

Cu(2)–N(n6)–C(n5)

108.28(8), 93.03(9)

81.8(2), 91.9(2)

87.2(1), 91.8(1)

111.3(2), 90.3(2)

90.0(1), 91.7(2)

89.9(2), 91.4(3)

159.8(1), 179.5(1)

171.4(3), 156.8(2)

89.5(1)

90.5(2)

88.6(2)

90.4(2)

92.4(2)

88.7(2)

89.6(3)

108.1(3), 109.8(3)

107.6(4), 109.7(5)

109.8(3), 114.7(3)

106.8(3), 114.2(4)

110.5(2), 110.5(2)

115.2(3), 110.2(4)

115.4(3), 118.9(4)

116.9(4), 117.6(5)

108.9(3), 110.1(3)

108.5(4), 108.0(4)

110.1(2), 116.2(3)

112.7(4), 111.8(4)

110.9(2), 110.4(3)

112.8(3), 112.0(3)

113.5(3), 119.5(3)

117.7(5), 128.3(9)

bind on opposite sides (“trans”) (Fig. 4) of the average plane,

concomitant with diﬀerences in associated chelate ring torsion

angles. Thus, in the chloride, the rings fused through the spiro-

carbon atom derived from pentaerythritol adopt the skew-boat

conformation, as does one “terminal” chelate ring about each

copper. In the nitrate the two terminal rings on one Cu may be

considered to be in chair conformations, while one is chair and

the other skew-boat on the other Cu. Despite such diﬀerences,

N–Cu–N bond angles are regular and very close to 90Њ,

although there is a greater disparity of Cu–N distances for the

terminal skew-boat than for the terminal chair chelate rings

(Table 3). The range of Cu–N distances is, however, similar to

J. Chem. Soc., Dalton Trans., 2001, 707–722

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that in various “unconstrained” [Cu(NH₃)₄]^2ϩderivatives^1aand

in [Cu(333-tet)][ClO₄]₂.²⁰In the latter, as noted above, the three

rings all adopt essentially chair conformations but the Cu^IIis

also six-coordinate via perchlorate coordination and it is not

immediately apparent what factors may principally determine

these conformational diﬀerences. Magnetic suceptibility meas-

urements (4–300 K) on both the chloride and nitrate of the

copper() complex of L⁸show Curie–Weiss behaviour and indi-

cate negligible interaction between the copper centres, though

the acetate, presently of unknown structure, is more strongly

antiferromagnetic.

2 Polyamines derived from 1,2-diamines

(a) Ethane-1,2-diamine. The reaction of the bis(benzene-

sulfonate) of neopentyl glycol with ethane-1,2-diamine is

analogous to a large number of reactions which have been used

to produce open-chain quadridentate amines and appears, as in

these earlier studies,^17,19to give essentially just such a product,

1

L¹(Fig. 1) of the “232-tet” type.^1a,19The H nuclear magnetic

resonance spectrum of the major reaction product is com-

pletely consistent with this structure and the assignment is

conﬁrmed by crystal structure determinations of the copper()

complex as its perchlorate, 1, and chloride perchlorate, 4. In

contrast to the analogous complex of 232-tet itself [N,NЈ-bis-

(2-aminoethyl)propane-1,3-diamine],²⁰the perchlorate does not

crystallise as isolated [Cu(L)(ClO₄)₂] units but as a coordination

polymer, [CuL¹(OClO₂O)]_(∞|∞)ClO₄, (Fig. 5a; Tables 1 and 2),

two formula units comprising the asymmetric unit of the

structure. CuN₄units, much closer to planar than in the com-

plexes of L³and L⁸described above, are linked by O(disordered

ClO₂)O perchlorate bridges in their ﬁfth and sixth trans-

co-ordination sites, the two moieties of the asymmetric unit

alternating in the undulating polymer which is generated by the

unit a translation, the asymmetric unit spanning that dimension

of the unit cell. The chloride perchlorate, [CuL¹Cl]ClO₄(Fig.

5b; Tables 1 and 2), has a structure which may be superﬁcially

regarded as made up of mononuclear cations and perchlorate

counter ions, but in fact has the chloride moieties bridging, less

symmetrically, successive CuL¹units stacked up a in a manner

similar to that found in the perchlorate; in both structures

successive L¹ligands are turned end-for-end about the (undulat-

ing) polymer axis. Here, one half of the formula unit makes

up the asymmetric unit of the structure, the polymer lying

in a crystallographic mirror plane which bisects it and the

(disordered) perchlorate counter ion. As for 232-tet, the quad-

ridentate ligand is bound in both cases in its “meso”, R,S form,

with the central chelate ring in its chair form and the ﬂanking

ﬁve-membered chelate rings in mirror-image gauche conform-

ations. As elsewhere,²⁰this seems compatible with near plan-

arity of the CuN₄unit.

Importantly, the very minor additional reaction product

detected was not the diazepam possibly formed by intra-

molecular substitution following the ﬁrst displacement of a

sulfonate group by an ethane-1,2-diamine nitrogen but

a hexamine, L²(Fig. 1), seemingly produced by initial dialkyl-

ation of the diamine with two molecules of disulfonate,

followed by independent nucleophilic substitution of the

remaining sulfonate groups by another two molecules of

diamine. The spacing of the basic sites in this molecule by C₃

units appears to be suﬃcient to allow ready isolation of

the hexahydrochloride (viz. the fully protonated form). A

low-temperature, single-crystal X-ray study of the hexa-

hydrochloride dihydrate, 5, in which all hydrogen atoms were

successfully located and reﬁned, and all nitrogen atoms

deﬁnitively established as such by reﬁnement, conﬁrmed the

ligand structure (Fig. 6). The substance crystallises with one

half of the formula unit comprising the asymmetric unit, an

ionic complex, with all nitrogen atoms fully protonated, the

centre of the central (H₂)C–C(H₂) bond being disposed on a

Fig. 5 (a) Section of the polymeric cation of [CuL¹(OClO₂O)]_(∞|∞)ClO₄,

1; a lies horizontal in the page. A ﬁgure showing the unit cell contents,

projected down b, is deposited as ESI. (b) (i) The unit cell contents

[CuL¹Cl]ClO₄, 4, projected down a, showing the columnar stacking of

the cations and associated perchlorates up that axis. (ii) A side-on view

of a cation stack, a lying vertically in the page.

crystallographic inversion centre, so that one half of the cation,

three counter ions and one water molecule are crystallograph-

ically independent. Torsion angles in the independent half of

the cation string, from the central C–C bond outwards, are:

180(Ϫ), 173.6(1), 164.0(1), Ϫ79.0(1), 177.1(1), 180.0(1),

174.7(1), Ϫ86.3(1)Њ, a mixture of trans and gauche dispositions.

Again, the hydrogen bonding is seemingly dominated by

a limited number of short interactions: anion–protonated

amine and water, Cl(1) ؒ ؒ ؒ H(3bB), N(3b) 2.28(2), 3.128(1),

716

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Fig. 6 Projection of the centrosymmetric [H₆L⁶]^6ϩcation in com-

pound 5. A ﬁgure showing the unit cell contents of [H₆L⁶]Cl₆ؒ2H₂O, 5,

down a, and indicating short hydrogen-bonded contacts is deposited

as ESI.

Cl(1) ؒ ؒ ؒ H(01A), O(01) 2.33(2), 3.128(1); Cl(2) ؒ ؒ ؒ H(3aA),

N(3a) (x Ϫ 1, y, z Ϫ 1) 2.38(1), 3.105(1); Cl(2) ؒ ؒ ؒ H(6aA),

N(6a) (x Ϫ 1, ¹ Ϫ y, z Ϫ ¹) 2.37(2), 3.186(1); Cl(3) ؒ ؒ ؒ H(3bA),

¯

²

¯

²

N(3b) 2.23(2), 3.086(1); and water-protonated amine, O(01) ؒ ؒ ؒ

H(6aC), N(6a) 2.09(2), 2.863(1) Å.

While there are close parallels in the properties of ligands

L¹and L²and L^1Јand L^2Ј, there are also some signiﬁcant

diﬀerences, associated signiﬁcantly with the prochiral nature

of the central carbon atom of the propyl units in L^1Јand L^2Ј.

Seemingly, the complex (CuL^1Ј)(ClO₄)₂can adopt two solid state

structures of comparable energy, since samples drawn on diﬀer-

ent occasions from crystalline masses produced by supposedly

identical procedures contain isomeric species, diﬀering notably

in that structure 2 has the methyl substituent on the central

six-membered (chair) chelate ring in an equatorial orientation,

whereas in structure 3 it is axial (Fig. 7). Given that interconver-

sion of these two species would require not only inversion of all

three chelate rings in the complex but also inversion of the two,

“inner” coordinated nitrogen atoms, it seems unlikely that this

diﬀerence could be associated with the diﬀerent temperatures

for the two structure determinations (especially given the minor

eﬀects of temperature seen in two structure determinations of

[Cu(L¹Ј)(OClO₂O)]_(∞|∞)ClO₄) and thus we ascribe it to chance

selection of diﬀerent crystals from similar syntheses. Structure

2 is very closely similar to that of Cu(232-tet)(ClO₄)₂,²⁰in that

it contains “molecular” [Cu(L^1Ј)(OClO₃)₂] units, whereas struc-

ture 3 is based upon polymeric [Cu(L^1Ј)(OClO₂O)]_nstrands very

similar to those in the complex of L¹(structure 1). A short

amine–perchlorate oxygen hydrogen bond is found in the

molecular structure, linking the two independent molecules

of the asymmetric unit: O(13) ؒ ؒ ؒ H(26a) (2 Ϫ x, y Ϫ ¹, 2 Ϫ z)

2.1₄Å (est.). In the polymeric array the perchlorate is modelled

in terms of weak coordination via two pairs of oxygen atoms,

disordered by rotation about an undisordered Cl–O bond. In

the structure of the nickel() complex of another derivative of

232-tet²⁴an axially oriented methyl substituent is found on the

central atom of an approximately chair-form 6-membered

chelate ring and, interestingly, this central atom is a tertiary

nitrogen which is presumably free to undergo inversion, so that

here at least it appears that the axial orientation must be

thermodynamically preferred. While much structural evidence

indicates that equatorial orientations are favoured for single

substituents on six-membered rings,^1a,25axial orientations are

known even in simple (bidentate) systems²⁶and calculations

indicate that the energy diﬀerences may not be large,²⁷so that

subtle solid state eﬀects may tip the balance. In linear and

macrocyclic quadridentate ligand complexes with similarly

Fig. 7 (a) A single molecule (molecule 1) of [Cu(L^1Ј)(OClO₃)₂], 2

(molecule 2 is similar). (b) Projection of the polymeric cation of

[Cu(L^1Ј)(OClO₂O)]^ϩ_(∞|∞), 3, showing the modelling of the perchlorate in

terms of components rotationally disordered about Cl–O(1), entailing

coordination via O(13,14) or O(12Ј,14Ј).

¯

²

sized methyl and nitro group substituents on the central carbon

of propyl links, stereoselective coordination with both axial and

equatorial methyl group orientations is well established^13,28,29

and this is further discussed ahead in relation to the macrocyclic

ligand complex structures 12–14.

The structure of hexamine ligand L^2Ј, though established on

the basis of spectroscopic evidence only, shows that, as also

indicated by earlier work,⁸the product distribution may be

markedly dependent on whether sulfonate or halide groups are

displaced by the amine. The yield of L^2Јrelative to that of the

tetramine (L^1Ј) greatly exceeds that of its analogue L², though it

is conceivable that this reﬂects simply the high reactivity of the

bromo substituent leading to reaction during the initial stage of

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Table 4 Selected geometries of [Co(HL⁵)(en)Cl]Cl₃ؒH₂O 7. The cobalt

environment. r/Å is the metal–ligand atom distance; other entries are

the angles (Њ) subtended by the relevant atoms at the head of the row

and column

Atom

r

N(1)

N(2)

N(11)

N(14)

N(17)

Cl(1) 2.2651(8) 88.84(6) 87.29(6) 177.93(4) 93.90(5) 90.75(5)

N(1) 1.958(2)

N(2) 1.967(1)

N(11) 1.961(2)

N(14) 1.959(1)

N(17) 1.989(1)

85.83(7) 92.08(7) 176.67(7) 96.71(6)

90.93(8) 92.39(6) 176.76(7)

85.12(7) 90.98(7)

85.16(6)

Also: Co–N–C at N(1,2,11) are 110.4(1), 109.1(1), 112.0(1); Co–N(14)–

C(13,15) are 108.1(1), 111.1(1), and Co–N(17)–C(16,18) are 106.37(8),

121.2(1)Њ. Torsion angles in the bonds around the C₄N₂ring beginning

with the C(16)–N(17) bond are 59.3(2), Ϫ58.0(2), 56.6(3), Ϫ55.2(3),

54.8(2), Ϫ57.4(2)Њ, around the ﬁve-membered C₂N₂Co rings,

beginning with N(1)–C(1), N(11)–C(12) and N(14)–C(15) are Ϫ34.5(2),

46.9(3), Ϫ37.5(2), 14.9(2), 11.1(2); Ϫ19.4(2), 41.3(2), Ϫ44.7(2), 27.5(1),

Ϫ4.5(1); and Ϫ22.5(2), 45.7(2), Ϫ47.1(2), 28.4(1), Ϫ3.5(1)Њ.

Fig. 8 Projection of the [Co(HL⁵)(en)Cl]^3ϩcation in complex 7.

of the en amine moieties: O(01) ؒ ؒ ؒ H(11a), N(11) 2.19(3),

2.915(3) Å.

mixing the reagents, when in fact the diamine was gradually

1

added to the dihalide. Although the H and ¹³C NMR spectra

Formation of the piperazine derivative L⁵must be the result

of an intramolecular reaction, though there is at present

no evidence as to whether such a step follows one or two

intermolecular substitutions (or both). Note that this red

complex, [Co(HL⁵)(en)Cl]Cl₃ؒH₂O, is clearly diﬀerent in colour

to the yellow second and fourth chromatographic fractions, so

that although it is presumably possible for isomers of it to be

present, it is for this reason that the second is presumed to be a

diastereomer of the fourth and not the ﬁrst (although if L⁵

binds as a quadridentate species along with en, then of course

this argument would be invalid). In all, there is a complete lack

of symmetry as shown by the detection of nine resonances

in the ¹³C nuclear magnetic resonance spectrum of each. For

present purposes, it suﬃces to recognise that cyclic and open

chain amines are produced in similar amounts. Owing to the

overall ineﬃciency of the reaction, the analogous synthesis with

the less readily accessible diamine (1R),(2R)-trans-cyclohexane-

1,2-diamine was not investigated.

indicate that L^2Јis a single species, it is not obvious why there

should be a marked preference for one possible isomer over

another (R*,R* or R*,S*) and we presume that either the

spectral diﬀerences are extremely small or that isolation of the

ligand by formation of the copper() complex may have led to

fractionation.

The reaction of the tris(benzenesulfonate) of glycerol with

ethane-1,2-diamine does not seem to be an eﬃcient pathway to

polyamine formation. Nevertheless, nucleophilic substitution

can be detected and it is clear that in this system intramolecular

reaction following the initial or second step of substitution is

at least as important as further intermolecular reaction. Full

characterisation of the reaction products (L⁵and L⁶; Fig. 1) was

complicated by the apparent presence of diastereomers of the

cobalt() complex of the hexamine product component and

only the more abundant of these two isomers (the fourth

fraction of the chromatographic separation of the cobalt()

complexes of the product mixture) has been unambiguously

identiﬁed as the hexamine L⁶by a structure determination of its

cage derivative which will be reported elsewhere.¹¹The structure

of the complex cation containing L⁵(and ethane-1,2-diamine,

presumably arising from its use in large excess in the synthesis)

found in the ﬁrst fraction of the chromatographic separation

and crystallised as its trichloride monohydrate, 7, is shown

in Fig. 8. The determination is precise, to the extent of reﬁning

all hydrogen atom parameters and establishing nitrogen

(versus carbon) atom locations deﬁnitively. Monoprotonated L⁵

coordinates in this complex as a fac-N₃-tridentate ligand, with,

among the various remaining possible modes of co-ordination

of the remaining ligands, the chloride anion coordinating trans

to the acyclic peripheral nitrogen. The metal atom environment

is summarised in Table 4; the C₄N₂six-membered ring is a

relatively unperturbed ‘chair’, while the two fused chelate rings

are envelopes, C(12,15) as ‘ﬂaps’ unsymmetrically disposed

distal and adjacent to the ‘central’ nitrogen, N(14). The ethane-

1,2-diamine has quasi-2 symmetry about the line through N(2)

and the midpoint of the N(1)–C(1) bond. Bond lengths and

angles about the metal hold no surprises; hydrogen bonding is

dominated by a relatively few quite short contacts, notably

between the halide counter ions and the protonated amine

Cl(2) ؒ ؒ ؒ H(110a), N(110a) (x, y Ϫ 1, z) 2.16(2), 3.098(2),

Cl(3) ؒ ؒ ؒ H(110b), N(110b) 2.24(4), 3.200(2) Å, and the other

coordinated amine groups of the cation, Cl(4) ؒ ؒ ؒ H(1bN), N(1)

(1 Ϫ x, 2 Ϫ y, 2 Ϫ z) 2.30(2), 3.160(2), Cl(4) ؒ ؒ ؒ H(17), N(17)

2.37(2), 3.198(2), and, more distantly, the water molecule,

Cl(2) ؒ ؒ ؒ H(01b), O(01) (x, 1 ϩ y, z Ϫ 1) 2.56(4), 3.118(3) Å.

The water molecule oxygen is also hydrogen-bonded by one

(b) (1R),(2R)-trans-Cyclohexane-1,2-diamine. The reaction of

the bis(benzenesulfonate) of neopentyl glycol with (1R),(2R)-

trans-cyclohexane-1,2-diamine appeared closely to parallel that

with ethane-1,2-diamine in giving a dominant product showing

a ¹H nuclear magnetic resonance spectrum fully consistent with

it being an open chain tetramine produced by displacement of

both sulfonates by separate diamine molecules (Fig. 1). The

scale of the synthesis with the cyclohexanediamine was such

that other trace components observed as their copper() com-

plexes could not fully be characterised and it is assumed that

they may be analogous to the hexamine species detected in the

ethane-1,2-diamine system (and that the use of a sulfonate

reactant has minimised their production). Given that the con-

ﬁguration of (1R),(2R)-trans-cyclohexane-1,2-diamine ﬁxes

its chelate rings in a λ conformation, a square planar array of

the four N donor atoms of L⁴would require that, unlike the

unsubstituted 232-tet ligand complex (where the outer rings are

enantiomeric), the central six-membered chelate ring should

adopt a chiral, λ, skew-boat conformation, as is observed in the

cobalt() complex 10 of the related ligand L⁹(see below).

Unfortunately, attempts to conﬁrm both the nature of L⁴and

this predicted conformation by determination of the crystal

structure of [Cu(L⁴)][ClO₄]₂were unsuccessful due to the

unsatisfactory nature of the crystals.

Although the reactions of various derivatives of penta-

erythritol with ethane-1,2-diamine appear to diﬀer to some

degree depending on the exact nature of the leaving group,^4–8

the product distributions all reﬂect signiﬁcant competition of

718

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Table 5 The metal environment (distances in Å, angles in Њ) of

[Co(H₂L⁹)Cl₂]Cl₃ؒ4.5H₂O 11

Atom

r

Cl(2)

N(12)

N(14)

N(22)

N(24)

Cl(1)

Cl(2)

N(12) 1.986(4)

N(14) 1.941(4)

N(22) 1.953(4)

N(24) 1.947(4)

2.261(1) 176.64(6) 88.8(1) 89.8(1)

93.8(1)

88.7(1)

91.8(2) 176.1(2)

87.9(1)

90.1(1)

2.249(2)

93.3(1) 87.7(1)

87.0(2)

176.1(2)

95.1(2)

86.3(2)

ations upon the whole molecule, so that the six-membered

chelate ring is δ-skew-boat and the inner coordinated nitrogen

atom conﬁgurations are S,S, rather than chair and R,S as in the

analogue. There appears to be no signiﬁcant systematic diﬀer-

ence between the distances from the metal to the inner (N(n2))

and outer (N(n4)) nitrogens (Table 5). In the present case the

asymmetric unit of the structure is the full formula unit, devoid

of crystallographic symmetry, though the chiral cation has

quasi-2 symmetry. The complex crystallises in orthorhombic

space group P2₁2₁2₁, so that the individual crystal is enantio-

merically pure. The coordinated chloride ions are approached

by water molecules, Cl(1) ؒ ؒ ؒ O(01) 3.392(4); Cl(2) ؒ ؒ ؒ O(05)

3.37(1) Å, the others by protonated amine groups and water

molecules, Cl(3) ؒ ؒ ؒ N(32), N(42) (x Ϫ ¹, ¹ Ϫ y, 1 Ϫ z), O(01)

¯ ¯

² ²

(x Ϫ ¹, ¹ Ϫ y, 1 Ϫ z), O(05) 3.076(4), 3.190(4), 3.274(4),

¯

²

¯

²

2.73(2) (O(05) being reﬁned with site occupancy 0.5),

Cl(4) ؒ ؒ ؒ O(02) (1¹ Ϫ x, y¯ , z Ϫ ¹), O(03), O(4) (¹ ϩ x, ¹ Ϫ y, 1 Ϫ z)

3.063(4), 3.201(5), 3.075(5), Cl(5) ؒ ؒ ؒ N(32), O(01) (1¹ Ϫ x,

1 Ϫ y, ¹ ϩ z), O(03) (x Ϫ ¹, ¹ Ϫ y, 1 Ϫ z), O(04) 3.134(4),

3.348(4), 3.371(5), 3.172(5) Å, with water–water contacts

O(01) ؒ ؒ ؒ O(04) (1¹ Ϫ x, 1 Ϫ y, z Ϫ ¹) 3.102(6), O(02) ؒ ؒ ؒ O(03)

¯

²

¯

²

¯

²

¯

²

¯

²

¯

²

¯ ¯

² ²

¯

²

¯

²

2.681(6) Å, in an extended hydrogen-bonding array.

3 Template formation of functionalised tetraazamacrocycles

Reactions between metal complexes of linear polyamines,

formaldehyde and nitroethane¹²are well established as highly

stereoselective pathways to functionalised azamacrocycles^1b,13,30

and appear to work smoothly in the case of copper() com-

plexes of L¹(12, 13) and L^1Ј(14). Here, the product, L¹¹, derived

from L^1Јappears to be a single diastereomer, with both

methyl substituents equatorial in the tetrachlorocuprate of its

copper() complex, 14, the NO₂(axial)/CH₃(eq) conﬁguration

also being found for the single asymmetric carbon atom in both

the chloride/hexaﬂuorophosphate, 12, and nitrate, 13, of the

copper() complex of the macrocycle, L¹⁰, derived from L¹

(Fig. 10). The basic macrocycle in each of 12–14, disposed

about the Cu atom as [(L^10,11)Cu], takes the same and familiar

form usually seen in the bound parent macrocycle “cyclam”,³¹

of symmetry quasi 2/m, in each of the three complexes, with

similar geometrical and conformational parameters (Table 6).

The species 12 and 13 diﬀer only in the axial substituents on

Cu, being Cl and H₂O in 12 and 2ONO₂in 13; in the latter one

half of the formula unit comprises the asymmetric unit of the

structure as modelled in space group C2/c, the copper atom

lying on a crystallographic inversion centre, entailing modelling

of the nitro group as disordered over the two possible equiv-

alent axial sites at either end of the symmetrical ligand frame-

work. Signiﬁcant diﬀerences are found in the environmental

parameters of the metal relative to those of 9 and 10, as might

be expected contingent upon the change from ﬁve-coordination

found with the open chain quadridentate ligands. In 12

the cations stack up the short axis a, with hydrogen bonds

between the chloro and aqua ligands of successive molecules

(Cl ؒ ؒ ؒ O(0) (x Ϫ 1, y, z) 3.085(4) Å), a not uncommon

occurrence with a recent parallel in a similar array.³²The [PF₆]^Ϫ

anions and lattice water molecules lie in tunnels between the

stacks.

Fig. 9 (a) Projection of the trans-[Co(H₂L⁹)Cl₂]^3ϩcation in 11, down

the Cl–Co–Cl line. (b) Torsion angles (to nearest degree) within the

rings (s.u.’s are typically 0.5Њ).

intramolecular with intermolecular pathways, leading to both

hexamine and octamine species in these reactions. (1R),(2R)-

trans-Cyclohexane-1,2-diamine is somewhat restricted in

its conformational mobility compared to that of ethane-1,2-

diamine and this may be the reason that its reaction with the

tetrakis(benzenesulfonate) of pentaerythritol gives but a single

product, both spectroscopic and analytical measurements

indicating it to be the hexamine L⁹(Fig. 1). Determination

of the crystal structure of the cobalt() complex 11 (Fig. 9;

Table 5) shows that the ligand is indeed the species formed by

displacement of two sulfonate groups by one diamine unit to

give a seven-membered ring and the other two sulfonate groups

by independent diamine units. The trans-CoN₄Cl₂environment

of the metal is as expected from the green colour of the

complex and dimensions of this inner unit are generally rather

similar to those in the previously characterised⁸analogue

derived from ethane-1,2-diamine, though the ﬁxed chirality of

the cyclohexane moieties imposes rather diﬀerent conform-

J. Chem. Soc., Dalton Trans., 2001, 707–722

719

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Fig. 10 Projections of: (a) The [Cu(L¹⁰)Cl(OH₂)]^ϩcation of 12; (b) the centrosymmetric [Cu(L¹⁰)(ONO₂)₂]^ϩcation of 13 (the nitro group is

scrambled with its inversion-related methyl counterpart; one isolated complex unit is shown) and (c) the asymmetric unit of complex 14 in its one-

dimensional polymeric stack. A ﬁgure of the unit cell contents of 12, projected down a, showing the stacking of cations up that axis, is deposited

as ESI.

The precipitation of 14 as a tetrachlorocuprate species is

Conclusion

somewhat puzzling in regard to the origin of the [CuCl₄]^2Ϫ

entity. This may mean that it is incorrect to consider the macro-

cycle formation reaction as occurring stereospeciﬁcally, and

that another isomer is formed which does not strongly bind

to Cu^II, ultimately releasing it to provide the counter anion

in the isolated solid. The phenomenon has been observed

Both the present observations and those already in the liter-

ature indicate that the formation of polyamines by reaction

of polyalkylating agents with diamines reaches a critical point

at the change from 1,2- to 1,3-diamines. All reactions of 1,3-

diamines studied to date result in what might be considered the

simplest outcome in that intermolecular reactions appear to be

completely dominant and thus the products are exclusively

open-chain species. It is interesting that this seems to be true

even when it is possible to form rings of a size which appears

to be favoured when formed in an inverse reaction involving a

1,2-diamine. Thus, the reactions of pentaerythritol derivatives

with both ethane-1,2-diamine^5,8and (1R),(2R)-trans-cyclo-

hexane-1,2-diamine result in signiﬁcant or exclusive (in the

latter case) formation of polyamines containing a seven-

membered ring unit produced by intramolecular reaction, yet

seven-membered ring-containing species have not been detected

in the products of reaction of glycerol tris(benzenesulfonate)

with propane-1,3-diamine. Clearly, purely statistical factors

may have some inﬂuence here, as may diﬀerences in proton

before, however, in crystallisation of

a closely similar

compound^30bafter puriﬁcation and may simply be a reﬂection

of the low solubility of the isolated material and halide

ion assisted removal of Cu^IIfrom the macrocycle. Unlike

this related species derived from a 13-membered ring macro-

cycle, which is dimeric, 14 is in fact polymeric, with the

[CuCl₄]^2Ϫunit bridging [(L¹¹)Cu]^2ϩentities and forming chains

similar to the perchlorate bridged entities found in 1, 3

and many related species.^20,30The geometry of the anion, as

is not uncommon, is greatly distorted from the tetrahedral

norm, subject to serious squashing down one of the tetrahedral

¯

4 axes, and with two of the Cu–Cl distances slightly lengthened,

presumably in consequence of their interactions with the

cations.

720

J. Chem. Soc., Dalton Trans., 2001, 707–722

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Table 6 Selected geometries of structures 12, 13 and 14

(a) The metal environment (distances/Å; angles/Њ); in 12, X, XЈ are Cl, O(H₂), in 13, ONO₂(× 2, symmetry related),^ain 14 Cl(3), Cl(4), (x, 2 Ϫ y,

1

–

₂Ϫ z)

Atom

N(3)

r

N(6)

N(3Ј)

93.1(1)

93.46(6)

93.5(4)

177.5(1)

(180(Ϫ))

178.6(5)

N(6Ј)

X

XЈ

84.5(1)

89.02(6)

89.0(3)

89.2(1)

89.18(6)

89.7(3)

88.4(1)

(90.98(6))

88.8(3)

91.8(1)

(90.82(6)

91.8(2)

2.021(3)

2.020(2)

2.02(1)

2.019(3)

2.008(2)

2.02(1)

2.021(3)

(2.008(2))

2.000(9)

2.011(3)

(2.020(2))

1.996(9)

2.693(1)

2.532(1)

2.920(4)

2.622(4)

(2.532(1))

2.874(4)

86.1(1)

86.54(6)

86.5(4)

176.2(1)

180(Ϫ)

179.2(5)

94.5(1)

(93.46(6))

93.6(4)

86.1(1)

94.27(9)

90.98(6)

90.9(3)

90.2(1)

90.82(6)

91.8(3)

92.1(1)

(89.02(6))

89.6(3)

89.5(1)

(89.18(6))

88.3(2)

N(6)

N(3Ј)

N(6Ј)

X

(86.54(6))

86.5(3)

178.70(9)

180(Ϫ)

178.4(2)

XЈ

(b) Torsion angles; where there are two values in each entry, they are for the unprimed and primed segments

Atoms

Parameter

Atoms

Parameter

C(2Ј)–C(1)–C(2)–N(3)

Ϫ57.8(5), 63.1(5)

Ϫ64.3(2)

C(7Ј)–C(8)–C(7)–N(6)

Ϫ67.9(4), 66.9(5)

Ϫ63.4(2)

Ϫ59(1), 65(1)

174.1(3), 177.2(3)

179.1(2)

178.1(1), Ϫ174(1)

Ϫ172.9(3), 168.2(3)

Ϫ170.7(2)

Ϫ166(1), 172(1)

55.9(4), Ϫ55.8(4)

55.7(2)

50(1), Ϫ59(1)

51.1(4), Ϫ60.6(4)

56.2(2)

54(1), Ϫ53(1)

Ϫ43.3(4), 40.7(4)

Ϫ41.4(2)

Ϫ65(1), 65(1)

Ϫ178.9(3), Ϫ178.6(3)

179.3(2)

Ϫ178(1), Ϫ173(1)

Ϫ170.4(3), 173.1(3)

Ϫ171.7(2)

C(1)–C(2)–N(3)–C(4)

C(2)–N(3)–C(4)–C(5)

N(3)–C(4)–C(5)–N(6)

Cu–N(3)–C(2)–C(1)

Cu–N(3)–C(4)–C(5)

C(5)–N(6)–C(7)–C(8)

C(4)–C(5)–N(6)–C(7)

Ϫ170(1), 174(1)

Cu–N(6)–C(5)–C(4)

Cu–N(6)–C(7)–C(8)

Ϫ39.4(4), 42.0(4)

Ϫ40.7(2)

Ϫ36(1), 44(1)

55.9(4), Ϫ53.5(4)

54.7(2)

Ϫ36(1), 44(1)

53(1), Ϫ57(1)

^aFor N(3Ј,6Ј), XЈ read inversion related N(6,3), X. In 14, for the [CuCl₄]^2Ϫanion: Cu(2)–Cl (1,2,3,4), 2.233(3), 2.250(3), 2.274(5), 2.267(5) Å;

Cl(1)–Cu(2)–Cl(2,3,4) 140.7(1), 96.0(2), 96.4(1); Cl(2)–Cu(2)–Cl(3,4) 97.3(1), 98.2(2); Cl(3)–Cu(2)–Cl(4), 137.7(1)Њ. Cu(1)–Cl(3)–Cu(2) is 126.3(1);

1

–

Cu(2)–Cl(4)–Cu(1) (x, 2 Ϫ y, z Ϫ ₂) is 125.6(1)Њ.

distributions over the nitrogen centres of reaction inter-

mediates, which may themselves diﬀer (aziridines vs. azetidines,

for example), and very small energy diﬀerences between reac-

tion pathways can, of course, give rise to seemingly dramatic-

References

1 (a) D. A. House, in Comprehensive Coordination Chemistry, eds. J. A.

McCleverty, R. D. Gillard and G. Wilkinson, Pergamon, Oxford,

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ally diﬀerent product distributions. Observations based solely

on preparative procedures cannot, however, be attributed the

weight that might be given to a full investigation of rates and

rate laws for these reactions and have value only for a very

restricted range of conditions.

The ligand syntheses investigated herein were intended to

provide polyamines suitable for extended syntheses of new and

functionalised macro(poly)cycles, as well as, in the case of

species derived from (1R),(2R)-trans-cyclohexane-1,2-diamine,

for use as chiral ligands in complexes potentially of value as

asymmetric catalysts.³³We will report our investigations of

these and other prospects in later publications.

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Acknowledgements

We gratefully acknowledge partial support of this work by the

Australian Research Council and by grants (to Y. K.) from

Kosin University. We thank Annegret Hall for magnetic

measurements.

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722

J. Chem. Soc., Dalton Trans., 2001, 707–722

Article Doi

Inter- and intra-molecular pathways in polyamine synthesis from diamines

DOI: 10.1039/b008452m

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