Some Pb(II) complexes of 2, 6-bis (Hydroxymethyl) Pyridine with different Pb(II) Salts involving the anions chloride, Perchlorate and Nitrate. A Photoelectron spectroscopic study

 

Abhishek Kumar*,  Shishir Malviya, Shekhar Srivastava

Department of Chemistry, University of Allahabad, Allahabad-211002 (U.P.) India

*Corresponding Author E-mail: abhishekrajpoot02@gmail.com

 

 

ABSTRACT:

Some Pb(II) complexes of 2,6-bis(hydroxymethyl)pyridine (dhmp) with different Pb(II) salts [PbCl2.6H2O, Pb(ClO4)2.6H2O, Pb(NO3)2.3H2O] are synthesized and characterized and studied by IR, NMR and mass spectroscopy. The distortion of the coordination polyhedron, dependent on the anion kind influence on the distribution of donor sites and the formation of mononuclear complexes. There is no case the contortions of Pb(II) salt or water of hydration were found in the coordination sphere. Spectroscopy data shows that complexes are mononuclear 2 : 1 (L : M) complexes. The ligand dhmp components is mono-deprotonated and act as anionic ligand. The complex number 4 show same behavior. But in 1,2  and 4 complexes it behave as neutral ligand. The basal planes are occupied by O donors and N atoms are in the axial positions of Octahedral in 3 and 4 the basis are formed by two O and two N donor atoms, and O atoms are in the axes. Complex 3 shows the N atoms in trans position but 4 shows N atoms in cis position.  Complexes (1-4) shows packing and cationic complex unit is strong and weak hydrogen bond interactions involving the contortions and hydroxyl hydrogen atoms or aromatic hydrogen atoms to stabilize the complexes.

 

KEYWORDS: Mononuclear complexes, Heavy metal, Photoelectron spectroscopy, NMR and mass spectroscopy.

 

 

1. INTRODUCTION:

The ability of pyridine to act as a ligand in metal complexes is well know and has been well studied.[1-3] A number of coordination polymers involves as coordinative groups pyridine fragment that bind to metal atoms [4-7]. 2, 6 disubstituted pyridine derivatives open the possibility for a chelates effect. A typical example of 2, 6 bis (hydroxymethyl) pyridine (dhmp, LH2) which is monodentate ligand in Pt-complex[8], a bidentate partial deprotonated ligand in complexes with Tc[9] and monomeric bis alkoxy Sn(IV)derivative or a tridentate ligand for Hg(II) or Cu(II). [10-11] The aim of designing a new types of coordinates complexes that based on (dhmp) as co-ordinate building block, we became interested in synthesis and study of several Pb(II) complexes of (dhmp) in the competitive effect of anions on the coordination of this ligand. with salt of Pb(II) with are different in the contortions including PbCl2.2H2O, Pb(ClO4)2.6H2O and Cu(NO3)2.3H2O. In the present paper we report on synthesis, IR spectroscopy, NMR, Mass spectrum and Photoelectron spectroscopy of complexes with these salts.   

 

2. MATERIAL AND METHODS:  

All chemicals, reagents as well as solvents were analytical grade and purchased commercially and used with further purification. 2,6-bis (hydroxymethyl) pyridine(dhmp) (7mmol) and (3.5mmol) of respective Pb(II) salts were dissolved in 30 to 50 ml ethanol. The mixture was refluxed for 1h then the solvent was removed under reduced pressure and the residue recrsytallized from little water. The compounds were collected and washed with small portions of cold water and cold ethanol in this sequence.

 

Complex (1) 

Bis[2,6-bis(hydroxymethyl-K2O,O']Pyridine-KN] Lead(II) Chloride:

Lead (II) chloride dehydrate was used differing from the general procedure, 10 ml of water was added in order to improve solubility of the salt 46% of green crystals were collected which changes colour from green to yellow at 150Co.  C14H18Cl2PbN2O4 (mw= 542.2) C 40.73 (Calc 40.74), H 4.43 (4.40), N 6.82 (6.79) %

 

IR (KBr) : ν(OH) 3058 Vs.ν(CH2) 2882-2825 J(Pyridine 1613, 1580, 1479 m-s- i d (CH2) 1452 d ip (C-OH) 12965 ν (C-O) 1042-1025 Vs δoop (CH) 2,6 disubstituted. pyridine 805 δoop (OH) 627 cm-1.m MS (ESI 15O0C) M/Z = 339 [Pb(LH)2]+ 76%) 201 [(PbLH)+, 19% 139 (LH2)+ 100%]

 

Complex (2 and 3) 

Bis[2,6-bis(hydroxymethyl]-K2O,O')PyridineKN]Lead(II) Perchlorate:

The preparation and recrystallization is same as for complex number 1 but lead (II) Perchlorate hexahydrate was used. Recrystallization yield 52% of yellow ppt. of complex number 2 beside a trace amount of blue crystals identified at mp. > 2340C (dec) C14 H18Cl2 Pb N2O12 (Mw=670.2) (30.60 (Calc 31.10) H 3.61 (3.35) N 5.5 (5.18)%

 

IR (KBr) : ν(OH) 3098 Vs νaxis (CH2) 2930-2825 M1 ν(Pyridine) 1615, 1585, 1480 m-Si S (CH2) 1455s δ (C-OH)] 295 mi ν (CClO4) 1150-1095 S.VS ν (C-O) 1045-1025 ν-VS δoop (CH) 2, 6 disubstituted Pyridine 800m, δ (ClO4) and δoop (OH) 635-625 cm-1 s-VS. MS (ESI ISS0C) M/z = 445 ([Pb(LH2)2ClO4]+, 7%), 345 ([PbLH2LH]+ 100%), 305 [(PbLH2ClO4)+, 4%] 235[     (PbLH+CH3OH)+, 7% (PbLH)+, 16%].

 

Complex (4) 

Bis [2-6-bis(hydroxymethyl] k2O, O') Pyridine-KN] Lead (II) Nitrate:

The preparation and recrystallization is same as for complex number 1but lead (II) nitrate hexahydrate is used, 48% light blue crystals were collected M.P. > 1900 (dec) C14H18 PbN4O10 (M= 606.2) (38.15 (Cal 36.10) H 3.91 (3.90) N 11.80 (12.03) %

 

IR (KBr) : ν (OH) 3080 Vs ν (CH2) 2840m, ν (Pyridine) 1615, 1590, 1480 m-s : δ (CM2) 1460S Vas (NO3) 1380-1360 Vs.δip (C-OH), 1290S ν (C-O) 1045-1025s : and (NO3) 835; 825 W-m δoop (CH) 2, 6-disubstituted Pyridine 795m δoop (OH) 625 cm-1 MS (ESI : 1502) M/Z = 345 C[PbLH2LH]+, 100%, 20S ([PbLH)+] 19%, 140 ([LH2+H; 52%).

 

 

 

 

 

 

Fig. 1 and 2

 

 

 

Fig. 3 and 4

 

 

4. RESULTS AND DISCUSSION:

On the basis of elemental analysis and IR spectroscopic study the structure of the compounds are elucidated. In order to obtain a first indication of the state of binding comparative IR spectra including the solid complexes and free dhmp(LH2) were recorded. All the above compounds (1-4) showed characteristic shifts of relevant frequencies. In particular, a shift of the pyridine ruing valence vibrations to higher frequencies resulting due to the coordination of the pyridine-N atom to Cu ion is observed [12-16]. However, potential chelates bridges formed by the hydroxyl groups and the metal ion are indicated by the lowering at the ν(OH) frequencies of the inplane deformation vibrations of the C-OH groups and the ν(C-O) which are also affected. The concrete data are summarized in Table 1.

 

Table 1 IR data for metal Complexes 1-4:

Compound

ν(OH)

ν(ring)

δip(C-OH)

ν(C-O)

LH2

3363

2780

1600

1577

1470

1410

1084

1

2068

1615

1680

1475

1295

1042-1030

2/3

3092

1614

1585

1480

1292

1042-1025

4

3075

1615

1585

1480

1296

1040-1024

 

 

The binding energies data for [PbX2.nH2O ] have shown more value in [PbX2.nH2O ] than in [PbX2.L] complexes[17-18]. From these XPS observation one can conclude that ligand (dhmp) is coordinated to Pb(II) metal ion. Furthermore, N 1s photoelectron peak in[ PbX2.L] have shown higher binding energy with on symmetrical peak than [PbX2.nH2O]. This concluded that both nitrogen atoms of ligand (dhmp) is coordinated with Pb(II) metal ion. Moreover, O 1s photoelectron peak in [PbX2.L] is also found at higher binding energy side with one symmetrical peak, suggesting all four oxygen atoms are coordinated with Pb(II) metal ion.

 

The complexes 1-4 we synthesized are of good yield. We also show the effect of anions on coordination with metal. On the basis of elemental analysis, IR and XPS data the structural geometry of above complexes 1-4 are determined as octahedral geometry(Fig. 1,2,3 and 4).

 

5. ACKNOWLEDGEMENT:

The author AK is thankful to University Grants Commission for providing financial assistance.

 

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Received on 02.05.2016         Modified on 28.05.2016

Accepted on 10.06.2016         © AJRC All right reserved

Asian J. Research Chem 9(6): June 2016; Page 277-280.

DOI: 10.5958/0974-4150.2016.00045.6