The crystal structures of 2, 3 and 4 (Fig. 2–4) reveal several
interesting features. All compounds show various degrees of ruf
(ruffled) distortion induced by the small Ni(II) ion.16 Compound 4
exhibits only a small degree of distortion [average Ni–N bond
˚
length 1.963(3) A]. Secondary amine 3 has both a relatively planar
˚
macrocycle [Ni1–N = 1.952(4) A] and a severely ruffled one [Ni1–
Notes and references
{ Crystal data (all grown from CH2Cl2/MeOH using standard techniques9):
2: C38H25N5Ni, M = 610.34, orthorhombic, a = 6.4778(2), b = 19.0155(6),
3
˚
˚
c = 22.2824(7) A, U = 2744.72(15) A , T = 90 K, space group P212121, Z =
4, m(Mo-Ka) = 0.746 mm21, 31404 reflections measured, 6313 unique
(Rint = 0.0612) which were used in all calculations. The final wR(F2) was
0.08 (all data). 3: C76H47N9Ni2, M = 1203.65, triclinic, a = 12.4790(9), b =
˚
N = 1.905(4) A], while primary amine 2 shows an intermediate
˚
degree of distortion [Ni–N = 1.939(2) A]. All compounds exhibit
˚
14.1516(9), c = 16.1406(11) A, a = 101.5380(10), b = 99.8540(10), c =
3
˚
¯
95.8160(10)u, U = 2724.3(3) A , T = 90 K, space group P1, Z = 2, m(Mo-
Ka) = 0.75 mm21, 27815 reflections measured, 10802 unique (Rint = 0.079)
which were used in all calculations. The final wR(F2) was 0.1354 (all data).
very close intermolecular packing arrangements. Compound 2
forms p-stacked polymers in which the amino nitrogen atom is
˚
located on top of a neighboring Ni(II) center [Ni–N1 = 3.109 A,
4: C38H24N3NiO, M = 611.32, triclinic, a = 9.6815(19), b = 12.028(2), c =
˚
3
˚
12.986(3) A, a = 69.02(3), b = 77.92(3), c = 85.14(3)u, U = 1380.6(6) A , T =
90 K, space group P1, Z = 2, m(Mo-Ka) = 0.744 mm21, 15377 reflections
˚
Ni–H1B = 2.866 A]. The other side of the macrocycle exhibits a
¯
˚
short phenyl hydrogen–nickel contact [Ni–H15B = 2.819 A].
measured, 5050 unique (Rint = 0.0624) which were used in all calculations.
The final wR(F2) was 0.169 (all data). CCDC 610310 (2); 610308 (3);
610309 (4). For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b608365j
Compound 3 forms polymeric zig-zag chains in which a pyrrole
b-hydrogen atom and a phenyl hydrogen atom are located close to
˚
a neighboring Ni(II) center [Ni1–H37 = 3.037 A, Ni1–H103 =
˚
˚
2.945 A, Ni2–H3A = 2.776 A]. The hydroxyporphyrin 4 forms
very closely packed p-stacked dimers,14,17 where an aryl hydrogen
atom is coordinated to a Ni(II) center and a pyrrole nitrogen atom
1 For reviews on Pd catalysed couplings on tetrapyrroles, see:
W. M. Sharman and J. E. van Lier, J. Porphyrins Phthalocyanines,
2000, 4, 441; J. Setsune, J. Porphyrins Phthalocyanines, 2004, 8, 93; for
general porphyrin functionalisation, including nucleophilic substitutions,
see: M. O. Senge and J. Richter, J. Porphyrins Phthalocyanines, 2004, 8,
934; M. O. Senge, Acc. Chem. Res., 2005, 38, 733.
2 T. Takanami, M. Hayashi, F. Hino and K. Suda, Tetrahedron Lett.,
2003, 44, 7353.
3 Y. Chen and X. P. Zhang, J. Org. Chem., 2003, 68, 4432.
4 G. Y. Gao, Y. Chen and X. P. Zhang, Org. Lett., 2004, 6,
1837.
5 G. Y. Gao, A. J. Colvin, Y. Chen and X. P. Zhang, Org. Lett., 2003, 5,
3261.
6 G. Y. Gao, A. J. Colvin, Y. Chen and X. P. Zhang, J. Org. Chem.,
2004, 69, 8886.
7 F. Atefi, J. C. McMurtrie, P. Turner, M. Duriska and D. P. Arnold,
Inorg. Chem., 2006, 45, 6479.
8 L. J. Esdaile, J. C. McMurtrie, P. Turner and D. P. Arnold, Tetrahedron
Lett., 2005, 46, 6931.
9 H. Hope, Prog. Inorg. Chem., 1994, 41, 1; M. O. Senge and K. M. Smith,
Acta Crystallogr., Sect. C, 2005, 61, o537.
˚
˚
[Ni–H156 = 3.037 A, N21–H156 = 2.488 A]. In the absences of
any real acceptor groups, the donor –OH or –NH2 hydrogen
atoms are not involved in any other binding in either structure.
In summary, the novel reactions we have uncovered suggest
several new avenues of study, in both porphyrin chemistry and
more generally in palladium catalysis of unsuspected processes.
While there are many cases of reductive cleavage of hydrazine(s)
by transition metal species,18 the use of hydrazine as an ammonia
surrogate in Pd catalysed aminations of aryl bromides is
unprecedented and invites further investigation. Primary amine
synthesis by Pd catalysed amination is normally achieved in two
steps using (di)allylamines, tert-butyl carbamate, imines, or
sulfoximines as intermediates.12 Likewise, the formation of the
hydroxyporphyrin from a carbonate base suggests that the direct
substitution of haloarenes to form phenol analogues may be
viable. Our own interests lie in the new porphyrin chemistry and
especially in the further study of the secondary amines such as 3.
We are currently pursuing the coupling reactions and redox
chemistry of 3, as bis(diarylamines) linked by conjugated bridges
are currently of significant interest due to the delocalised electronic
structures of their mixed-valence radical cations. Porphyrin
analogues of such species may offer favourable electronic
delocalisation and stability of relevance to molecular electronics
applications.19
10 D. P. Arnold, R. C. Bott, H. Eldridge, F. Elms, G. Smith and M. Zojaji,
Aust. J. Chem., 1997, 50, 495.
11 M. O. Senge, M. G. H. Vicente, K. R. Gerzevske, T. P. Forsyth and
K. M. Smith, Inorg. Chem., 1994, 33, 5625.
12 D. Prim, J.-M. Campagne, D. Joseph and B. Andrioletti, Tetrahedron,
2002, 58, 2041.
13 A. L. Balch, Coord. Chem. Rev., 2000, 200–202, 349 and refs.
therein.
´
´ ´
14 J. Wojaczynski, M. Ste˛pien and L. Latos-Graz˙ynski, Eur. J. Inorg.
Chem., 2002, 1806.
15 A. L. Balch, M. Mazzanti and M. M. Olmstead, Inorg. Chem., 1993, 32,
4737.
16 M. O. Senge, Chem. Commun., 2006, 243.
DPA thanks the Australian Research Council for financial
support through Discovery Grant DP0663774, MOS gratefully
acknowledges support by Science Foundation Ireland (SFI
Research Professorship 04/RP1/B482), and LJE thanks the
Faculty of Science and the Synthesis and Molecular Recognition
Program, Queensland University of Technology for a postgrad-
uate scholarship.
17 M. O. Senge and K. M. Smith, J. Chem. Soc., Chem. Commun., 1992,
1108; M. O. Senge, C. W. Eigenbrot, T. D. Brennan, W. R. Scheidt and
K. M. Smith, Inorg. Chem., 1993, 32, 313.
18 For example: I. Takei, K. Dohki, K. Kobayashi, T. Suzuki and
M. Hidai, Inorg. Chem., 2005, 44, 3768; M. P. Shaver and M. D. Fryzuk,
J. Am. Chem. Soc., 2005, 127, 500.
19 For a porphyrin example, see: J.-C. Chang, C.-J. Ma, G.-H. Lee,
S.-M. Peng and C.-Y. Yeh, Dalton Trans., 2005, 1504.
4194 | Chem. Commun., 2006, 4192–4194
This journal is ß The Royal Society of Chemistry 2006