Effect of Clonidine as Adjuvant in Thoracic Paravertebral Block for Patients Undergoing Breast Cancer Surgery: A Prospective, Randomized, Placebo-controlled, Double-blind Study.

BACKGROUND AND AIMS: Postoperative pain after breast cancer surgery is unavoidable. Thoracic paravertebral block (TPVB), a locoregional anesthetic technique, has been proven successful for postoperative pain management in different thoracic surgical procedures, such as thoracotomy, breast cancer surgeries. Clonidine, an adjuvant, in TPVB may enhance the quality and prolong the duration of analgesia. This prospective study was to evaluate the effectiveness of clonidine; administered with TPVB; in addition to conventional local anesthetic solution. MATERIALS AND METHODS: Fifty-two patients (25-55 years) scheduled for breast cancer surgery under general anesthesia were randomly divided into Group A (n = 26) receiving preoperative TPVB at T3 with clonidine added to local anesthesia solution and Group B (n = 26) receiving identical TPVB with local anesthesia but without any adjuvant. This was followed by balanced general anesthesia. A visual analog scale was used to assess pain postoperatively up to 48 h. Meantime to administration of the first dose of rescue analgesic was noted. Total dose of fentanyl consumption, hemodynamic parameters, and side effects were all recorded for each patient. RESULTS: The dosage of fentanyl required in the intraoperative period was significantly lower in Group A. Mean time to administration of rescue analgesic was found to be significantly longer in clonidine group. Hemodynamics and side effects were quite comparable among two groups. CONCLUSION: Clonidine as adjuvant in TPVB provided profound analgesia for up to 48 h postoperatively for patients undergoing breast cancer surgery without any appreciable side effects.

Perineural Nalbuphine in Ambulatory Upper Limb Surgery: A Comparison of Effects of Levobupivacaine with and without Nalbuphine as Adjuvant in Supraclavicular Brachial Plexus Block - A Prospective, Double-blinded, Randomized Controlled Study.

BACKGROUND AND AIMS: Various opioid additives have been trialed to prolong brachial plexus block. We evaluated the effect of adding nalbuphine hydrochloride to levobupivacaine for supraclavicular brachial plexus blockade. The primary end-points were the onset and duration of sensory and motor blocks and duration of analgesia. MATERIALS AND METHODS: Seventy-eight patients (aged 25-45 years) posted for ambulatory forearm and hand surgery under supraclavicular brachial plexus block were divided into two equal groups (Groups LN and LC) in a randomized, double-blind fashion. In Group LN (n = 39), 30 ml 0.5% levobupivacaine + 10 mg (diluted in 2 ml 0.9% saline) nalbuphine hydrochloride, and in Group LC (n = 39), 30 ml 0.5% levobupivacaine + 2 ml normal saline (0.9%) were administered in supraclavicular block. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative visual analog scale (VAS), hemodynamics, and side effects were recorded for each patient. RESULTS: Although with similar demographic profile and block (sensory and motor) onset time, sensory and motor block duration and time to first analgesic use were significantly longer and the total need for rescue analgesics was lower in Group LN (P < 0.05) than Group LC. Postoperative VAS value at 24 h was significantly lower in Group LN (P < 0.05). Intraoperative hemodynamics was comparable between two groups, and no any appreciable side effect was noted throughout the study period. CONCLUSION: It can be concluded that adding nalbuphine hydrochloride to supraclavicular brachial plexus block increases the sensory and motor block duration and time to first analgesic use, and decreases total analgesic use with no side effects.

Postoperative Sore Throat Prevention in Ambulatory Surgery: A Comparison between Preoperative Aspirin and Magnesium Sulfate Gargle - A Prospective, Randomized, Double-blind Study.

BACKGROUND: Postoperative sore throat (POST) frequently hampers the positive feedback of ambulatory surgery in spite of so many measures. This study was carried out to compare the efficacy of preoperative magnesium sulfate and aspirin gargle in preventing POST after ambulatory surgery. MATERIALS AND METHODS: It was a prospective, randomized, and double-blinded study. Fifty-six adult patients of either sex, aged 25-50, of American Society of Anesthesiologists physical status I-II, scheduled for day care surgery, were randomly allocated to Group A ([n = 28] receiving aspirin gargle [325 mg tablet]) and Group M ([n = 28] receiving magnesium sulfate [20 mg/kg] gargle). In both groups, the medications were made into 20 mL of (5% dextrose) solution. Patients were asked to gargle with this mixture for 30 s, 15 min before induction of anesthesia. Episodes of POST were measured at 0, 2, 4, 6, 9, 12, and 16 h postoperatively with a four-point scale. RESULTS: Both groups had a similar demographic profile with comparable oxygen saturation, hemodynamics, and consciousness status at immediate postoperative period. Number of patients with sore throat was significantly lower in magnesium group compared to aspirin group at 0 h (P = 0.0376), 2 h (P = 0.0429), 4 h (P = 0.0394) after the operation. POST pain score (visual analog scale) was significantly (P < 0.05) lower in magnesium group compared to aspirin group after the operation at 0, 2, 4 h after operation. CONCLUSION: It is evident that preoperative magnesium sulfate gargle significantly attenuated the incidence and severity of POST, especially in the early postoperative period, with no adverse effects in patients undergoing day care surgery under general anesthesia.

The effect of dexmedetomidine added to preemptive (2% lignocaine with adrenaline) infiltration on intraoperative hemodynamics and postoperative pain after ambulatory maxillofacial surgeries under general anesthesia.

BACKGROUND: Lignocaine + adrenaline; a local anesthetic agent; frequently used for perilesional infiltration, maintains the stable hemodynamics and decreases the postoperative pain after maxillofacial surgery. α2 agonists have peripheral analgesic effects. This prospective study was to evaluate the effectiveness of perilesional dexmedetomidine administered preincisionally in addition to conventional lignocaine adrenaline combinations for reconstructive maxillofacial surgery in an ambulatory care setting. MATERIALS AND METHODS: 76, American Society of Anesthesiologists I-II patients scheduled for unilateral traumatic maxillofacial surgeries were randomly allocated into group DL (n = 38) receiving 15 cc of 2% lignocaine + adrenaline (1:200,000) mixed with 1 µg/kg dexmedetomidine and group PL receiving 15 cc of 2% lignocaine + adrenaline with normal saline (placebo) via local wound infiltration 5 min prior to skin incision. Perioperative hemodynamics, time to first analgesic use, total analgesic need, bleeding, and side effects were recorded for each patient. RESULTS: Dosage of supplemental propofol; total perioperative, postoperative, and postanesthesia care unit (PACU) fentanyl consumption was significantly lower (P = 0.0001, P= 0.0001, P= 0.0001, P= 0.004, respectively) in dexmedetomine treated group than placebo. Rescue analgesic requirement was significantly earlier in group PL than group DL. Group DL patients suffered from significantly less (P = 0.02) bleeding and surgeon's satisfaction score was also high in this group. Discharge from PACU was significantly earlier in group DL. Intraoperative hemodynamic parameters were significantly lower in group DL (P < 0.05) without any appreciable side effects. CONCLUSION: Thus, prior dexmedetomidine local infiltration at the site of maxillofacial trauma has significantly reduced bleeding from wound site; perioperative fentanyl, propofol consumption, and subsequently ensured earlier discharge from PACU, better surgeon's satisfaction score with better hemodynamic control and lesser side effects.

Repeat spinal anesthesia in cesarean section: A comparison between 10 mg and 12 mg doses of intrathecal hyperbaric (0.05%) bupivacaine repeated after failed spinal anesthesia: A prospective, parallel group study.

BACKGROUND: Spinal anesthesia for cesarean section is not a 100% successful technique. At times, despite straightforward insertion and drug administration, intrathecal anesthesia for cesarean section fails to obtain any sensory or motor block. Very few studies and literature are available regarding repeat administration of spinal anesthesia and its drug dosage, especially after first spinal failure in cesarean section lower segment cesarean section (LSCS) due to fear of the excessive spread of drug. The aim of our study is to compare the outcome between two different doses of 0.5% hyperbaric bupivacaine repeated intrathecally after failed spinal. MATERIALS AND METHODS: After taking informed consent and Ethical Committee approval this prospective, randomized single-blinded study was conducted in 100 parturients of American Society of Anesthesiologists I-II who were posted for elective LSCS and had Bromage score 0 and no sensory block even at L4 dermatome after 10 min of first spinal anesthesia; were included in the study. Group A (n = 50) patients received 2.4 ml and Group B (n = 50) patients received 2 ml of 0.5% hyperbaric bupivacaine respectively for administering repeat spinal anesthesia. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), oxygen saturation, respiratory rate and electrocardiogram were monitored both intra- and post-operatively and complications were recorded. RESULTS: Incidence of high spinal, bradycardia, hypotension, respiratory complications, and nausea vomiting are significantly higher in Group A compared to Group B (P < 0.05). SBP, DBP, and HR were significantly low in Group A patients compared to Group B in the first 10 min (P < 0.05). CONCLUSION: Spinal anesthesia can be safely repeated in the cesarean section with 10 mg of 0.5% hyperbaric bupivacaine provided after first spinal anesthesia, the level of sensory block is below L4 and motor power in Bromage scale is 0.

Does the preoperative administration of tranexamic acid reduce perioperative blood loss and transfusion requirements after head neck cancer surgery? A randomized, controlled trial.

BACKGROUND: Head and neck cancer (HNC) surgery is associated with high intraoperative blood loss which may require urgent blood transfusion. Many strategies have been recommended to decrease the need for allogenic transfusion. Use of perioperative tranexamic acid (TA) has a promising role. AIMS: This study was to evaluate the effectiveness of single preoperative bolus dose of TA on blood loss prevention and red blood cell transfusion in patients undergoing HNC surgery. STUDY DESIGN: A prospective, double-blind, and randomized controlled study. MATERIALS AND METHODS: From 2007 July to 2010 January; 80 patients, aged (35-55), of American Society of Anesthesiologists II-III scheduled for unilateral HNC surgeries were randomly received either TA (Group T) in a dose of 20 mg/kg diluted to 25 cc with normal saline or an equivalent volume of normal saline (Group C) in a tertiary care hospital. Hemoglobin (Hb) concentration, platelet count, packed cell volume, fibrinogen level, D-dimer level were measured pre- and post-operatively. RESULTS: Saline (C) Group required more blood, colloid, crystalloid for blood loss. In Group T, 32 patients did not require transfusion of any blood products compared to five patients in Group C (P < 0.0001) and only eight units of blood was transfused in Group T, whereas a total of 42 units of blood was transfused in Group C. Even after numerous transfusions, Hb% after 6 h and 24 h in Group C were significantly low in comparison with Group T (P < 0.05). CONCLUSION: Thus, TA significantly reduces blood loss and chances of colloid, blood, and crystalloid transfusion caused by HNC surgery.

Effect of Two Different Doses of Dexmedetomidine as Adjuvant in Bupivacaine Induced Subarachnoid Block for Elective Abdominal Hysterectomy Operations: A Prospective, Double-blind, Randomized Controlled Study.

OBJECTIVES: Improvements in perioperative pain management for lower abdominal operations has been shown to reduce morbidity, induce early ambulation, and improve patients' long-term outcomes. Dexmedetomidine, a selective alpha-2 agonist, has recently been used intrathecally as adjuvant to spinal anesthesia to prolong its efficacy. We compared two different doses of dexmedetomidine added to hyperbaric bupivacaine for spinal anesthesia. The primary endpoints were the onset and duration of sensory and motor block, and duration of analgesia. . METHODS: A total of 100 patients, aged 35-60 years old, assigned to have elective abdominal hysterectomy under spinal anesthesia were divided into two equally sized groups (D5 and D10) in a randomized, double-blind fashion. The D5 group was intrathecally administered 3ml 0.5% hyperbaric bupivacaine with 5µg dexmedetomidine in 0.5ml of normal saline and the D10 group 3ml 0.5% bupivacaine with 10µg dexmedetomidine in 0.5ml of normal saline. For each patient, sensory and motor block onset times, block durations, time to first analgesic use, total analgesic need, postoperative visual analogue scale (VAS) scores, hemodynamics, and side effects were recorded. . RESULTS: Although both groups had a similar demographic profile, sensory and motor block in the D10 group (p<0.050) was earlier than the D5 group. Sensory and motor block duration and time to first analgesic use were significantly longer and the need for rescue analgesics was lower in the D10 group than the D5 group. The 24-hour VAS score was significantly lower in the D10 group (p<0.050). Intergroup hemodynamics were comparable (p>0.050) without any appreciable side effects. . CONCLUSION: Spinal dexmedetomidine increases the sensory and motor block duration and time to first analgesic use, and decreases analgesic consumption in a dose-dependent manner.

Clinicopathological study and management of liver abscess in a tertiary care center.

BACKGROUND: Liver abscess is a burning problem in tropical nations, with often lethal consequences and diagnostic/therapeutic challenges. We have determined etiopathology, clinical, radiological, and bacteriological characteristics of this condition and review its management strategies. MATERIALS AND METHODS: During the period of the month from May 2007 to September 2009, a prospective study was performed involving 125 patients admitted to the in-patient ward of the Department of General Surgery of N.R.S Medical College their diagnosis was made on the basis of clinical features (such as right upper abdomen pain, and fever), laboratory investigations and radiological evidence of liver abscess. RESULTS: Amoebic liver abscess was the most common (88%) type of liver abscess among the study groups. There was a strong correlation with the occurrence of liver abscesses and addiction to alcohol, history of diabetes mellitus and low socioeconomic status. The most common etiology of pyogenic liver abscess was Escherichia coli. Ultrasonography (USG) of the abdomen was accurate and cost-effective in diagnosis of liver abscesses. Percutaneous catheter drainage was the most effective method of treatment (with a 100% success rate). CONCLUSION: Most patients in our study had liver abscess of amoebic origin and had temporal relationship with diabetes, alcoholism, and staggering socioeconomic status. We suggest early recognition of clinical features and prompt abdominal USG as cost-effective means for treatment initiation and reducing complications.

Does a single loading dose of tranexamic acid reduce perioperative blood loss and transfusion requirements after total knee replacement surgery? A randomized, controlled trial.

BACKGROUND: Total knee replacement (TKR) is associated with high-perioperative blood loss, which often requires allogenic blood transfusion. Among the many strategies to decrease the need for allogenic transfusion, tranexamic acid (TA) is used systemically in perioperative setting with promising outcome. Here we evaluated the efficacy of single preoperative bolus dose of TA on reduction in blood loss and red blood cell transfusion in patients undergoing unilateral TKR. MATERIALS AND METHODS: 70, American Society of Anesthesiologists I-II patients scheduled for unilateral TKR were included. Patients were randomly allocated into two groups to receive either TA (Group-TA; 20 mg/kg diluted to 25 cc with normal saline) or an equivalent volume of normal saline (Group P). Hemoglobin concentration, packed cell volume, platelet count, fibrinogen level, D-dimer level was measured preoperatively and at 6(th) and 24(th) h postoperative period. RESULTS: In Group P more blood, colloid and crystalloid solutions were used to replace the blood loss. 27 patients in Group TA did not require transfusion of any blood products compared to 6 patients in Group P (P < 0.0001) and only 3 units of blood was transfused in Group TA where as a total of 32 units of blood was transfused in Group P. Despite the more numerous transfusions, Hb% after 6 h and 24 h in Group P were considerably low in comparison with Group TA (P < 0.0001). CONCLUSION: Tranexamic acid while significantly reducing blood loss caused by TKR surgery collaterally reduced the need for postoperative blood transfusion.

A Prospective, double-blinded randomized controlled study comparing two different Trendelenburg tilts in laparoscopically assisted vaginal hysterectomy positioning.

BACKGROUND: Bispectral index (BIS) used for intra-operative depth assessment under general anesthesia (GA) can be altered by different factors. This study was designed to detect the alteration in BIS reading with two different Trendelenburg (TBG) tilt in laparoscopically assisted vaginal hysterectomy (LAVH) procedure. MATERIALS AND METHODS: A prospective, double-blinded, randomized controlled study was designed involving 40 American Society of Anesthesiologists Grade I and II female patients, aged 35-60 years, scheduled to undergo LAVH under GA. Patients were divided into two groups with TBG >30° and TBG <30°. BIS readings; systolic and diastolic blood pressure, heart rate were recorded in supine position. Patients were then shifted to desired TBG position either (>30°) or (<30°) as per group allotment. Data were recorded at 30 min intervals and all the patients were followed upto 24 h postoperatively for any recall. RESULTS: A rise in BIS value was noticed, when position was changed from supine to head down in both groups. During comparison between two groups with different angulations, TBG >30° showed a higher BIS value than TBG <30°. This statistically significant (P < 0.05) trend was observed at all the 30, 60, 90, and 120(th) min interval. Interestingly, BIS values returned to preoperative levels following adopting final supine position. No incidence of awareness was reported in both the series throughout the study. CONCLUSION: Though awareness remains unaltered BIS value gets increased with higher angle of inclination in TBG position during LAVH operation.

Emergence agitation prevention in paediatric ambulatory surgery: A comparison between intranasal Dexmedetomidine and Clonidine.

OBJECTIVE: Emergence agitation (EA), a short-lived, self-limiting phenomenon, arises frequently after the use of inhalational agents and hampers the implementation of pediatric ambulatory surgery in spite of using so many drugs with variable efficacy. METHODS: In this prospective, double-blinded, parallel group study (2008-2009), 80 children of both sex aged 3-7 years, with American Society of Anesthesiologists (ASA) physical status grade I-II, undergoing sevoflurane-based general anesthesia for elective day care surgery were randomly assigned into groups C or D. Group C received 4 µg/kg intranasal clonidine, whereas group D received 1 µg/kg intranasal dexmedetomidine, 45 min before induction of anesthesia. In postanesthesia care unit (PACU), the incidence of EA was assessed with Aonos four-point scale and the severity of EA was assessed with pediatric anesthesia emergence delirium scale upon admission (T0), after 5 min (T5), 15 min (T15), and 25 min (T25). Extubation time, emergence time, duration of PACU stay, dose and incidence of fentanyl use for pain control were noted. FINDINGS: Based on comparable demographic profiles, the incidence and severity of EA were significantly lower in group D as compared to group C at T0, T5, T15, and T25. But time of regular breathing, awakening, extubation, and emergence were significantly delayed in group D than C. The number and dose of fentanyl used in group C were significantly higher than group D. PACU and hospital stay were quite comparable between groups. CONCLUSION: Intranasal dexmedetomidine 1 µg/kg was more effective than clonidine 4 µg/kg in decreasing the incidence and severity of EA, when administered 45 min before the induction of anesthesia with sevoflurane for pediatric day care surgery. Dexmedetomidine also significantly reduced fentanyl consumption in PACU.

Effect of dexmedetomidine as adjuvant in ropivacaine-induced supraclavicular brachial plexus block: A prospective, double-blinded and randomized controlled study.

BACKGROUND AND AIMS: Different additives have been used to prolong brachial plexus block. We evaluated the effect of adding dexmedetomidine to ropivacaine for supraclavicular brachial plexus blockade. The primary endpoints were the onset and duration of sensory and motor block and duration of analgesia. MATERIALS AND METHODS: A total of 84 patients (20-50 years) posted for elective forearm and hand surgery under supraclavicular brachial plexus block were divided into two equal groups (Group R and RD) in a randomized, double-blind fashion. In group RD (n = 42) 30 ml 0.5% ropivacaine +1 ml (100 µg) of dexmedetomidine and group R (n = 42) 30 ml 0.5% ropivacaine +1 ml normal saline were administered in supraclavicular block. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative visual analog scale (VAS), hemodynamics and side-effects were recorded for each patient. RESULTS: Though with similar demographic profile in both groups, sensory and motor block in group RD (P < 0.05) was earlier than group R. Sensory and motor block duration and time to first analgesic use were significantly longer and the total need for rescue analgesics was lower in group RD (P < 0.05) than group R. Post-operative VAS value at 12 h were significantly lower in group RD (P < 0.05). Intra-operative hemodynamics were significantly lower in group RD (P < 0.05) without any appreciable side-effects. CONCLUSION: It can be concluded that adding dexmedetomidine to supraclavicular brachial plexus block increases the sensory and motor block duration and time to first analgesic use, and decreases total analgesic use with no side-effects.

A comparative study of the efficacy of intravenous Paracetamol and Dexmedetomidine on peri-operative hemodynamics and post-operative analgesia for patients undergoing laparoscopic cholecystectomy.

BACKGROUND: Unrelieved post-operative pain may result in the physical suffering as well as multiple physiological and the psychological consequences, which may adversely affect the peri-operative outcome and contribute to increase the length of stay in hospital. OBJECTIVES: We designed this study to evaluate the effect of IV Paracetamol and Dexmedetomidine as multimodal analgesic technique on post-operative analgesia and to reduce the consumption of the systemic opioid and its adverse effects in cases of laparoscopic cholecystectomy. MATERIALS AND METHODS: Eighty consenting, American society of Anesthesiologist-physical status-I (ASA-PS-I), female patients, aged 19-60 year was randomly assigned to one of the following two groups: Group P (n = 40) received IV 1 g Paracetamol infusion over 10 min pre-operatively and 6 hourly thereafter and Group D (n = 40) received IV Dexmedetomidine 1 µg/kg bolus over 10 min pre-operatively and 0.2-0.4 µg/kg/h thereafter for 24 h. Peri-operative hemodynamic variables, post-operative pain scores, and the need for rescue analgesics were recorded and compared. RESULTS: Profiles of intra-operative hemodynamic changes were similar in both groups in respect to heart rate (HR), diastolic blood pressure, mean arterial pressure except in the systolic blood pressure where Dexmedetomidine significantly reduced it in compare to Paracetamol (P = 0.014). Post-operatively 4(th) h and 24(th) h changes in mean HR between two groups was a statistically significant (P < 0.05). Visual analog scale scores were significantly lower in the Group P compared with Group D at 8(th), 16(th), and 24(th) h (P < 0.001). Sedation score were statistically higher in the Group D compared with the Group P at post-operative 4(th), 8(th), 16(th), and 24(th) h (P < 0.006). CONCLUSION: Adjunctive use of both Paracetamol and Dexmedetomidine infusion reduced opioid use. However, Paracetamol peri-operatively provides adequate analgesia with the less sedation whereas Dexmedetomidine provides analgesia and co-operative sedation.

Synthesis, structure and reactivity of azosalophen complexes of vanadium(IV): studies on cytotoxic properties.

The free ligands, 2-{(o-hydroxyaryl)azo}-1-N-salicylidene phenylamine, H(2)L [where H(2)L = RC(6)H(4)N=NC(6)H(4)N=CH-C(6)H(4)OHR = p-H for H(2)L(1), p-Me for H(2)L(2) and p-Cl for H(2)L(3)], were prepared by the condensation of salicylaldehyde with 2-{(o-hydroxy aryl)azo} aniline. Reaction of H(2)L with VOSO(4) afforded the oxovanadium complex, (L)V(O)(H(2)O). The (L(1))V(O)(H(2)O) complex displays two reversible responses at 0.7 V and -0.65 V vs. SCE in cyclic voltammetry. Catalytic activity of (L(1))V(O)(H(2)O) toward H(2)O(2) induced oxidation of organic thioethers to sulfoxide and sulfones have been examined. The cytotoxicity of (L(1))V(O)(H(2)O) has also been examined on human lung cancer cells.

Reactions of 2-(arylazo) aniline with RhCl3: synthesis and structure of new cyclometalated complexes of Rh(III) and recognition of RhCl3 assisted azo (-N=N-) cleavage.

The reactions of 2-(arylazo) anilines, HL (1) [where HL is 2-(ArN=N)C6H4NH2; Ar is C6H5 (for HL1, 1a) and p-MeC6H4 (for HL2, 1b); H of HL represents the proton of Ar which gets dissociated upon orthometalation] with RhCl3 in methanol afforded new orthometalated complexes of composition (L)(HL)Rh(III)Cl2 (2) and (L)(ArNH2)Rh(III)Cl2 (3). The anionic L- binds the metal in tridentate (C, N, N) manner in both the complexes, while HL and ArNH2 bind the metal of 2 and 3 in monodentate fashion through the amino nitrogen. The ArNH2 of 3 was formed in situ due to cleavage of azo (-N=N-) function of monodentate HL of 2. The scission of N=N has been authenticated.

A Bis(azo-imine)palladium(II) System with 10 Ligand pi Electrons. Synthesis, Structure, Serial Redox, and Relationship to Bis(azooximates) and Other Species.

The first azo-imine chelate system, Pd(N(H)C(R)NNPh)(2) (Pd(RA)(2)), has been isolated in the form of diamagnetic solids by the 6e(-)-6H(+) reduction of bis(phenylazooximato)palladium(II), Pd(N(O)C(R)NNPh)(2) (abbreviated Pd(RB)(2)), with ascorbic acid in a mixed solvent (R = Ph, alpha-naphthyl). Selected spectral features are described. The X-ray structures of Pd(PhA)(2) and Pd(PhB)(2) have revealed trans-planar geometry consistent with metal oxidation state of +2. Bond length trends within the chelate rings are rationalized in terms of steric and electronic factors. In Pd(PhA)(2) a total of 10 ligand pi electrons are present, each formally monoanionic ligand contributing five. Model EHMO studies have revealed that the filled HOMO (a(u)) in Pd(RA)(2) is a bonding combination of two ligand pi orbitals with large azo contributions. The LUMO (b(g)) is roughly the corresponding antibonding combination. The outer pi-electron configuration of Pd(RA)(2) is (a(u))(2)(b(g))(0). Four successive voltammetric responses, two oxidative and two reductive, are observed. The E(1/2) range is -1.3 to +0.8 V vs SCE for Pd(PhA)(2) in a 1:9 MeCN-CH(2)Cl(2) mixture (Pt electrode). EPR and electronic spectra of the electrogenerated one-electron-oxidized complex Pd(PhA)(2)(+) are described. The azo-imine system is compared with imine-imine and azo-azo systems. Crystal data for the complexes are as follows. Pd(PhA)(2): crystal system monoclinic; space group C2/c; a = 18.167(5) Å, b = 7.420(3) Å, c = 16.527(6) Å; beta = 92.70(3) degrees; V = 2225(1) Å(3); Z = 4; R = 2.61%, R(w) = 3.58%. Pd(PhB)(2): crystal system monoclinic; space group P2(1)/n; a = 5.735(5) Å, b = 10.797(6) Å, c = 18.022(11) Å; beta = 97.73(6) Å; V = 1105(1) Å(3); Z = 2; R = 3.37%; R(w) = 3.40%.