Related literature {#sec1}
==================

For background information, see: Deming (1997[@bb2]); Kricheldorf (2006[@bb3]); Lin *et al.* (2008[@bb4]); Peng *et al.* (2008[@bb5]). For related structures: see: Yang *et al.* (1993[@bb7]).

Experimental {#sec2}
============

 {#sec2.1}

### Crystal data {#sec2.1.1}

\[Pd(C~13~H~10~N~3~O)~2~\]*M* *~r~* = 554.88Monoclinic,*a* = 12.9768 (7) Å*b* = 5.6990 (3) Å*c* = 15.6035 (8) Åβ = 109.287 (3)°*V* = 1089.19 (10) Å^3^*Z* = 2Mo *K*α radiationμ = 0.89 mm^−1^*T* = 295 K0.20 × 0.10 × 0.08 mm

### Data collection {#sec2.1.2}

Bruker APEXII CCD diffractometerAbsorption correction: multi-scan (*SADABS*; Bruker, 2008[@bb1]) *T* ~min~ = 0.842, *T* ~max~ = 0.9329857 measured reflections2690 independent reflections1959 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.104

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.031*wR*(*F* ^2^) = 0.066*S* = 1.032690 reflections161 parametersH-atom parameters constrainedΔρ~max~ = 0.42 e Å^−3^Δρ~min~ = −0.82 e Å^−3^

 {#d5e433}

Data collection: *APEX2* (Bruker, 2008[@bb1]); cell refinement: *SAINT* (Bruker, 2008[@bb1]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb6]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb6]); molecular graphics: *SHELXTL* (Sheldrick, 2008[@bb6]); software used to prepare material for publication: *SHELXTL*.

Supplementary Material
======================

Crystal structure: contains datablocks I, global. DOI: [10.1107/S1600536809016390/rk2144sup1.cif](http://dx.doi.org/10.1107/S1600536809016390/rk2144sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536809016390/rk2144Isup2.hkl](http://dx.doi.org/10.1107/S1600536809016390/rk2144Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?rk2144&file=rk2144sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?rk2144sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?rk2144&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [RK2144](http://scripts.iucr.org/cgi-bin/sendsup?rk2144)).

The authors gratefully acknowledge financial support in part from the National Science Council, Taiwan (grant No. NSC97-2113-M-033-005-MY2), and in part from the project of the specific research fields in the Chung Yuan Christian University, Taiwan (grant No. CYCU-97-CR-CH).

Comment
=======

During the last 2 decades, the synthesis and characterization of polypeptides is an interesting research field that received considerable attentions. The chemical synthesis of high molecular weight poly(α-peptides) can be accomplished by the ring-opening polymerization of α-amino acid *N*-carboxyanhydride (α-*NCA*) initiated by suitable initiators/catalysts. Among these initiators/catalysts, the Ni, Co, Fe, Pd, Pt, Ru, Ir, and Al complexes modified by adequate ligands have been shown to be active initiators/catalysts for *NCA* polymerization (Kricheldorf, 2006). In particular, Deming, (1997), reported that Schiff base ligand containing primary amine complexes of Co, Ni, Pd, and Cu metal ion could efficiently catalyze polymerizations of γ-benzyl *L*-glutamate *N*-carboxyanhydride (*Glu*-*NCA*) to achieve poly(γ-benzyl *L*-glutamate). Recently, Peng *et al.*, 2008, has also reported the Pt complex supported by amido-sulfonamidate ligand and this complex has been demonstrated as efficient initiators for living ROP of α-*NCA*. Most recently, we have successfully synthesized and structural characterized a *N,N\',O*-tridentate Schiff base of Cu(II) complex (Lin *et al.*, 2008). We report herein the synthesis and crystal structure of *N,O*-bidentate benzotriazol-phenolate ligands incorporated Pd^II^ complex (I), a potential catalyst for chemical synthesis of poly(peptides) (Scheme 1).

The solid structure of (I) reveals a monomeric Pd^II^ complex (Fig. 1) containing two six-member rings coordinated from these two *N,O*-bidentate benzotriazol-phenolate ligands. It was found that the asymmetric unit has one half of molecule in which the Pd atom lies on a centre of symmetry. The Pd atom is tetra-coordinated with a normal square planar environment in which two N atoms and two O atoms are coplanar. The two N atoms and two O atoms around Pd atom are trans to each other with bond angle of O--Pd--N1 of 91.74 (7)°. The distances between the Pd atom and O and N1 are 1.9676 (15)Å, 1.9986 (18)Å, respectively. These bond distances of Pd--O and Pd--N1 are around 0.1 Å shorter to those found in the other Schiff base Pd^II^ complexes (Yang *et al.*,1993). The bond distance of imine bond, C7--N1 of the benzotriazol group is 1.359 (3)Å and is 0.01Å longer than the other imine bond, C12--N3 (1.348 (3)Å). This is probably due to the existing coordination bond of the former nitrogen, N1.

Experimental {#experimental}
============

The title complex was synthesized by the following procedures (Fig. 2): 2-(2*H*-benzotriazol-2-yl)-4-methylphenol (0.45 g, 2.0 mmol) and Pd(O*Ac*)~2~ (0.22 g, 1.0 mmol) was stirred at ambient temperature in *THF* (25 ml) for 12 h during which a red-orange precipitate formed (yield: 75%). The resulting solids were crystallized from CH~2~Cl~2~ solution to yield red crystals. Anal. calcd for C~26~H~20~N~6~O~2~Pd: C, 56.28; H, 3.63; N, 15.15%. Found: C, 56.13; H, 3.79; N, 15.46%.

Refinement {#refinement}
==========

The H atoms were placed in idealized positions and constrained to ride on their parent atoms, with C--H = 0.93 and 0.96Å with *U*~iso~(H) = 1.2 and 1.5*U*~eq~(C).

Figures
=======

![A view of the title molecule I with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius. Symmetry code: (i) 2-x, -y, 1-z.](e-65-0m619-fig1){#Fap1}

![Synthesis pass of title compound I.](e-65-0m619-fig2){#Fap2}

Crystal data {#tablewrapcrystaldatalong}
============

  ---------------------------- ---------------------------------------
  \[Pd(C~13~H~10~N~3~O)~2~\]   *F*(000) = 560
  *M~r~* = 554.88              *D*~x~ = 1.692 Mg m^−3^
  Monoclinic, *P*2~1~/*c*      Mo *K*α radiation, λ = 0.71073 Å
  Hall symbol: -P 2ybc         Cell parameters from 3862 reflections
  *a* = 12.9768 (7) Å          θ = 2.7--28.2°
  *b* = 5.6990 (3) Å           µ = 0.89 mm^−1^
  *c* = 15.6035 (8) Å          *T* = 295 K
  β = 109.287 (3)°             Columnar, red
  *V* = 1089.19 (10) Å^3^      0.20 × 0.10 × 0.08 mm
  *Z* = 2                      
  ---------------------------- ---------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  ------------------------------------------------------------ --------------------------------------
  Bruker APEXII CCD diffractometer                             2690 independent reflections
  Radiation source: fine-focus sealed tube                     1959 reflections with *I* \> 2σ(*I*)
  graphite                                                     *R*~int~ = 0.104
  φ and ω scans                                                θ~max~ = 28.3°, θ~min~ = 1.7°
  Absorption correction: multi-scan (*SADABS*; Bruker, 2008)   *h* = −16→17
  *T*~min~ = 0.842, *T*~max~ = 0.932                           *k* = −7→7
  9857 measured reflections                                    *l* = −20→20
  ------------------------------------------------------------ --------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- ------------------------------------------------------------------------------------
  Refinement on *F*^2^                  Primary atom site location: structure-invariant direct methods
  Least-squares matrix: full            Secondary atom site location: difference Fourier map
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.031   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.066                  H-atom parameters constrained
  *S* = 1.03                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.019*P*)^2^\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  2690 reflections                      (Δ/σ)~max~ = 0.002
  161 parameters                        Δρ~max~ = 0.42 e Å^−3^
  0 restraints                          Δρ~min~ = −0.82 e Å^−3^
  ------------------------------------- ------------------------------------------------------------------------------------

Special details {#specialdetails}
===============

  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Geometry. All s.u.\'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.\'s are taken into account individually in the estimation of s.u.\'s in distances, angles and torsion angles; correlations between s.u.\'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.\'s is used for estimating s.u.\'s involving l.s. planes.
  Refinement. Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ \> 2σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.
  -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^2^) {#tablewrapcoords}
==================================================================================================

  ------ -------------- ------------- -------------- -------------------- --
         *x*            *y*           *z*            *U*~iso~\*/*U*~eq~   
  Pd     1.0000         0.0000        0.5000         0.02562 (9)          
  O      0.98900 (13)   0.1401 (3)    0.38204 (11)   0.0359 (4)           
  N1     0.84675 (14)   −0.1144 (3)   0.44409 (13)   0.0284 (4)           
  N2     0.76972 (15)   −0.0006 (3)   0.37741 (13)   0.0270 (4)           
  N3     0.66977 (16)   −0.0858 (3)   0.35839 (14)   0.0328 (5)           
  C1     0.89890 (19)   0.2481 (4)    0.33261 (16)   0.0309 (5)           
  C2     0.79138 (18)   0.1917 (4)    0.32782 (15)   0.0280 (5)           
  C3     0.70175 (19)   0.3162 (4)    0.27150 (16)   0.0324 (5)           
  H3B    0.6319         0.2736        0.2698         0.039\*              
  C4     0.7139 (2)     0.4982 (4)    0.21906 (17)   0.0352 (5)           
  C5     0.8191 (2)     0.5568 (4)    0.22219 (18)   0.0406 (7)           
  H5A    0.8293         0.6805        0.1870         0.049\*              
  C6     0.9083 (2)     0.4351 (4)    0.27641 (18)   0.0392 (6)           
  H6A    0.9773         0.4775        0.2760         0.047\*              
  C7     0.79189 (19)   −0.2925 (4)   0.46805 (16)   0.0301 (5)           
  C8     0.8287 (2)     −0.4786 (4)   0.52925 (18)   0.0375 (6)           
  H8A    0.9021         −0.4980       0.5630         0.045\*              
  C9     0.7499 (2)     −0.6305 (4)   0.53637 (18)   0.0429 (7)           
  H9A    0.7707         −0.7559       0.5766         0.051\*              
  C10    0.6391 (2)     −0.6036 (5)   0.48527 (19)   0.0463 (7)           
  H10A   0.5890         −0.7107       0.4933         0.056\*              
  C11    0.6026 (2)     −0.4273 (4)   0.4248 (2)     0.0408 (6)           
  H11A   0.5291         −0.4116       0.3908         0.049\*              
  C12    0.68220 (19)   −0.2680 (4)   0.41576 (17)   0.0328 (5)           
  C13    0.6164 (2)     0.6324 (5)    0.15814 (19)   0.0511 (7)           
  H13A   0.5514         0.5803        0.1690         0.077\*              
  H13B   0.6094         0.6049        0.0958         0.077\*              
  H13C   0.6266         0.7971        0.1711         0.077\*              
  ------ -------------- ------------- -------------- -------------------- --

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ----- -------------- -------------- -------------- -------------- -------------- --------------
        *U*^11^        *U*^22^        *U*^33^        *U*^12^        *U*^13^        *U*^23^
  Pd    0.01933 (15)   0.02899 (11)   0.02833 (15)   0.00099 (10)   0.00758 (11)   0.00236 (11)
  O     0.0225 (9)     0.0518 (10)    0.0342 (10)    0.0034 (7)     0.0102 (8)     0.0126 (8)
  N1    0.0228 (11)    0.0311 (9)     0.0307 (11)    0.0003 (8)     0.0080 (9)     0.0017 (8)
  N2    0.0196 (10)    0.0309 (8)     0.0289 (11)    −0.0003 (8)    0.0057 (9)     −0.0005 (9)
  N3    0.0215 (12)    0.0359 (9)     0.0387 (12)    −0.0033 (8)    0.0070 (10)    −0.0023 (9)
  C1    0.0281 (14)    0.0388 (11)    0.0259 (13)    −0.0002 (10)   0.0089 (11)    −0.0002 (10)
  C2    0.0285 (14)    0.0302 (10)    0.0255 (13)    −0.0014 (9)    0.0090 (11)    −0.0011 (9)
  C3    0.0254 (14)    0.0373 (11)    0.0332 (14)    0.0034 (9)     0.0079 (12)    −0.0021 (10)
  C4    0.0361 (15)    0.0391 (11)    0.0264 (13)    0.0074 (11)    0.0049 (11)    0.0006 (11)
  C5    0.0445 (18)    0.0419 (14)    0.0335 (15)    −0.0010 (10)   0.0107 (14)    0.0095 (10)
  C6    0.0302 (15)    0.0493 (13)    0.0368 (16)    −0.0050 (10)   0.0093 (13)    0.0086 (11)
  C7    0.0287 (14)    0.0312 (10)    0.0320 (14)    −0.0044 (9)    0.0124 (12)    −0.0045 (9)
  C8    0.0385 (16)    0.0358 (12)    0.0359 (15)    −0.0038 (10)   0.0093 (13)    0.0021 (11)
  C9    0.057 (2)      0.0341 (12)    0.0400 (16)    −0.0080 (11)   0.0194 (15)    0.0011 (11)
  C10   0.053 (2)      0.0425 (13)    0.0505 (19)    −0.0198 (13)   0.0266 (16)    −0.0053 (13)
  C11   0.0329 (16)    0.0444 (12)    0.0467 (18)    −0.0132 (11)   0.0154 (14)    −0.0069 (12)
  C12   0.0284 (14)    0.0349 (11)    0.0365 (14)    −0.0046 (9)    0.0124 (12)    −0.0067 (10)
  C13   0.0457 (18)    0.0549 (16)    0.0448 (18)    0.0142 (13)    0.0041 (15)    0.0105 (13)
  ----- -------------- -------------- -------------- -------------- -------------- --------------

Geometric parameters (Å, °) {#tablewrapgeomlong}
===========================

  ------------------- ------------- ------------------- -------------
  Pd---O^i^           1.9676 (15)   C5---C6             1.375 (4)
  Pd---O              1.9677 (15)   C5---H5A            0.9300
  Pd---N1             1.9986 (18)   C6---H6A            0.9300
  Pd---N1^i^          1.9986 (18)   C7---C12            1.394 (3)
  O---C1              1.321 (3)     C7---C8             1.401 (3)
  N1---N2             1.347 (3)     C8---C9             1.372 (3)
  N1---C7             1.361 (3)     C8---H8A            0.9300
  N2---N3             1.324 (3)     C9---C10            1.403 (4)
  N2---C2             1.422 (3)     C9---H9A            0.9300
  N3---C12            1.346 (3)     C10---C11           1.353 (4)
  C1---C2             1.410 (3)     C10---H10A          0.9300
  C1---C6             1.410 (3)     C11---C12           1.417 (3)
  C2---C3             1.398 (3)     C11---H11A          0.9300
  C3---C4             1.362 (3)     C13---H13A          0.9600
  C3---H3B            0.9300        C13---H13B          0.9600
  C4---C5             1.391 (4)     C13---H13C          0.9600
  C4---C13            1.515 (3)                         
                                                        
  O^i^---Pd---O       180.0         C4---C5---H5A       119.4
  O^i^---Pd---N1      91.74 (7)     C5---C6---C1        122.4 (2)
  O---Pd---N1         88.26 (7)     C5---C6---H6A       118.8
  O^i^---Pd---N1^i^   88.27 (7)     C1---C6---H6A       118.8
  O---Pd---N1^i^      91.73 (7)     N1---C7---C12       106.86 (19)
  N1---Pd---N1^i^     180.0         N1---C7---C8        131.3 (2)
  C1---O---Pd         120.80 (13)   C12---C7---C8       121.8 (2)
  N2---N1---C7        104.42 (18)   C9---C8---C7        115.9 (3)
  N2---N1---Pd        123.90 (14)   C9---C8---H8A       122.0
  C7---N1---Pd        131.19 (16)   C7---C8---H8A       122.0
  N3---N2---N1        114.76 (18)   C8---C9---C10       122.4 (2)
  N3---N2---C2        121.06 (19)   C8---C9---H9A       118.8
  N1---N2---C2        124.15 (18)   C10---C9---H9A      118.8
  N2---N3---C12       103.9 (2)     C11---C10---C9      122.3 (2)
  O---C1---C2         126.5 (2)     C11---C10---H10A    118.8
  O---C1---C6         118.3 (2)     C9---C10---H10A     118.8
  C2---C1---C6        115.3 (2)     C10---C11---C12     116.5 (3)
  C3---C2---C1        121.4 (2)     C10---C11---H11A    121.7
  C3---C2---N2        117.4 (2)     C12---C11---H11A    121.7
  C1---C2---N2        121.1 (2)     N3---C12---C7       110.0 (2)
  C4---C3---C2        121.8 (2)     N3---C12---C11      129.0 (2)
  C4---C3---H3B       119.1         C7---C12---C11      121.0 (2)
  C2---C3---H3B       119.1         C4---C13---H13A     109.5
  C3---C4---C5        117.9 (2)     C4---C13---H13B     109.5
  C3---C4---C13       121.6 (2)     H13A---C13---H13B   109.5
  C5---C4---C13       120.5 (2)     C4---C13---H13C     109.5
  C6---C5---C4        121.2 (2)     H13A---C13---H13C   109.5
  C6---C5---H5A       119.4         H13B---C13---H13C   109.5
  ------------------- ------------- ------------------- -------------

Symmetry codes: (i) −*x*+2, −*y*, −*z*+1.

###### Selected geometric parameters (Å, °)

  ----------- -------------
  Pd---O^i^   1.9676 (15)
  Pd---N1     1.9986 (18)
  ----------- -------------

  ----------------- -----------
  O^i^---Pd---O     180.0
  O^i^---Pd---N1    91.74 (7)
  O---Pd---N1       88.26 (7)
  N1---Pd---N1^i^   180.0
  ----------------- -----------

Symmetry code: (i) .
